Abnormally rapid heartbeat, usually with a HEART RATE above 100 beats per minute for adults. Tachycardia accompanied by disturbance in the cardiac depolarization (cardiac arrhythmia) is called tachyarrhythmia.
An abnormally rapid ventricular rhythm usually in excess of 150 beats per minute. It is generated within the ventricle below the BUNDLE OF HIS, either as autonomic impulse formation or reentrant impulse conduction. Depending on the etiology, onset of ventricular tachycardia can be paroxysmal (sudden) or nonparoxysmal, its wide QRS complexes can be uniform or polymorphic, and the ventricular beating may be independent of the atrial beating (AV dissociation).
A generic expression for any tachycardia that originates above the BUNDLE OF HIS.
Abnormally rapid heartbeats caused by reentry of atrial impulse into the dual (fast and slow) pathways of ATRIOVENTRICULAR NODE. The common type involves a blocked atrial impulse in the slow pathway which reenters the fast pathway in a retrograde direction and simultaneously conducts to the atria and the ventricles leading to rapid HEART RATE of 150-250 beats per minute.
Abnormally rapid heartbeats with sudden onset and cessation.
Abnormally rapid heartbeats originating from one or more automatic foci (nonsinus pacemakers) in the HEART ATRIUM but away from the SINOATRIAL NODE. Unlike the reentry mechanism, automatic tachycardia speeds up and slows down gradually. The episode is characterized by a HEART RATE between 135 to less than 200 beats per minute and lasting 30 seconds or longer.
Simple rapid heartbeats caused by rapid discharge of impulses from the SINOATRIAL NODE, usually between 100 and 180 beats/min in adults. It is characterized by a gradual onset and termination. Sinus tachycardia is common in infants, young children, and adults during strenuous physical activities.
Removal of tissue with electrical current delivered via electrodes positioned at the distal end of a catheter. Energy sources are commonly direct current (DC-shock) or alternating current at radiofrequencies (usually 750 kHz). The technique is used most often to ablate the AV junction and/or accessory pathways in order to interrupt AV conduction and produce AV block in the treatment of various tachyarrhythmias.
Recording of the moment-to-moment electromotive forces of the HEART as projected onto various sites on the body's surface, delineated as a scalar function of time. The recording is monitored by a tracing on slow moving chart paper or by observing it on a cardioscope, which is a CATHODE RAY TUBE DISPLAY.
A rare form of supraventricular tachycardia caused by automatic, not reentrant, conduction initiated from sites at the atrioventricular junction, but not the ATRIOVENTRICULAR NODE. It usually occurs during myocardial infarction, after heart surgery, or in digitalis intoxication with a HEART RATE ranging from 140 to 250 beats per minute.
A syndrome of ORTHOSTATIC INTOLERANCE combined with excessive upright TACHYCARDIA, and usually without associated ORTHOSTATIC HYPOTENSION. All variants have in common an excessively reduced venous return to the heart (central HYPOVOLEMIA) while upright.
Abnormally rapid heartbeats caused by reentrant conduction over the accessory pathways between the HEART ATRIA and the HEART VENTRICLES. The impulse can also travel in the reverse direction, as in some cases, atrial impulses travel to the ventricles over the accessory pathways and back to the atria over the BUNDLE OF HIS and the ATRIOVENTRICULAR NODE.
Abnormally rapid heartbeats caused by reentry circuit in or around the SINOATRIAL NODE. It is characterized by sudden onset and offset episodes of tachycardia with a HEART RATE of 100-150 beats per minute. The P wave is identical to the sinus P wave but with a longer PR interval.
An impulse-conducting system composed of modified cardiac muscle, having the power of spontaneous rhythmicity and conduction more highly developed than the rest of the heart.
Methods to induce and measure electrical activities at specific sites in the heart to diagnose and treat problems with the heart's electrical system.
Regulation of the rate of contraction of the heart muscles by an artificial pacemaker.
Agents used for the treatment or prevention of cardiac arrhythmias. They may affect the polarization-repolarization phase of the action potential, its excitability or refractoriness, or impulse conduction or membrane responsiveness within cardiac fibers. Anti-arrhythmia agents are often classed into four main groups according to their mechanism of action: sodium channel blockade, beta-adrenergic blockade, repolarization prolongation, or calcium channel blockade.
A small nodular mass of specialized muscle fibers located in the interatrial septum near the opening of the coronary sinus. It gives rise to the atrioventricular bundle of the conduction system of the heart.
Small band of specialized CARDIAC MUSCLE fibers that originates in the ATRIOVENTRICULAR NODE and extends into the membranous part of the interventricular septum. The bundle of His, consisting of the left and the right bundle branches, conducts the electrical impulses to the HEART VENTRICLES in generation of MYOCARDIAL CONTRACTION.
Recording of regional electrophysiological information by analysis of surface potentials to give a complete picture of the effects of the currents from the heart on the body surface. It has been applied to the diagnosis of old inferior myocardial infarction, localization of the bypass pathway in Wolff-Parkinson-White syndrome, recognition of ventricular hypertrophy, estimation of the size of a myocardial infarct, and the effects of different interventions designed to reduce infarct size. The limiting factor at present is the complexity of the recording and analysis, which requires 100 or more electrodes, sophisticated instrumentation, and dedicated personnel. (Braunwald, Heart Disease, 4th ed)
Any disturbances of the normal rhythmic beating of the heart or MYOCARDIAL CONTRACTION. Cardiac arrhythmias can be classified by the abnormalities in HEART RATE, disorders of electrical impulse generation, or impulse conduction.
A form of ventricular pre-excitation characterized by a short PR interval and a long QRS interval with a delta wave. In this syndrome, atrial impulses are abnormally conducted to the HEART VENTRICLES via an ACCESSORY CONDUCTING PATHWAY that is located between the wall of the right or left atria and the ventricles, also known as a BUNDLE OF KENT. The inherited form can be caused by mutation of PRKAG2 gene encoding a gamma-2 regulatory subunit of AMP-activated protein kinase.
A potentially lethal cardiac arrhythmia that is characterized by uncoordinated extremely rapid firing of electrical impulses (400-600/min) in HEART VENTRICLES. Such asynchronous ventricular quivering or fibrillation prevents any effective cardiac output and results in unconsciousness (SYNCOPE). It is one of the major electrocardiographic patterns seen with CARDIAC ARREST.
The number of times the HEART VENTRICLES contract per unit of time, usually per minute.
Implantable devices which continuously monitor the electrical activity of the heart and automatically detect and terminate ventricular tachycardia (TACHYCARDIA, VENTRICULAR) and VENTRICULAR FIBRILLATION. They consist of an impulse generator, batteries, and electrodes.
An antianginal and class III antiarrhythmic drug. It increases the duration of ventricular and atrial muscle action by inhibiting POTASSIUM CHANNELS and VOLTAGE-GATED SODIUM CHANNELS. There is a resulting decrease in heart rate and in vascular resistance.
Method in which prolonged electrocardiographic recordings are made on a portable tape recorder (Holter-type system) or solid-state device ("real-time" system), while the patient undergoes normal daily activities. It is useful in the diagnosis and management of intermittent cardiac arrhythmias and transient myocardial ischemia.
A potent anti-arrhythmia agent, effective in a wide range of ventricular and atrial ARRHYTHMIAS and TACHYCARDIAS.
A type of cardiac arrhythmia with premature contractions of the HEART VENTRICLES. It is characterized by the premature QRS complex on ECG that is of abnormal shape and great duration (generally >129 msec). It is the most common form of all cardiac arrhythmias. Premature ventricular complexes have no clinical significance except in concurrence with heart diseases.
The use of freezing as a special surgical technique to destroy or excise tissue.
The chambers of the heart, to which the BLOOD returns from the circulation.
A class Ia antiarrhythmic drug that is structurally-related to PROCAINE.
The innermost layer of the heart, comprised of endothelial cells.
Rapid, irregular atrial contractions caused by a block of electrical impulse conduction in the right atrium and a reentrant wave front traveling up the inter-atrial septum and down the right atrial free wall or vice versa. Unlike ATRIAL FIBRILLATION which is caused by abnormal impulse generation, typical atrial flutter is caused by abnormal impulse conduction. As in atrial fibrillation, patients with atrial flutter cannot effectively pump blood into the lower chambers of the heart (HEART VENTRICLES).
Impaired conduction of cardiac impulse that can occur anywhere along the conduction pathway, such as between the SINOATRIAL NODE and the right atrium (SA block) or between atria and ventricles (AV block). Heart blocks can be classified by the duration, frequency, or completeness of conduction block. Reversibility depends on the degree of structural or functional defects.
A form of heart block in which the electrical stimulation of HEART VENTRICLES is interrupted at either one of the branches of BUNDLE OF HIS thus preventing the simultaneous depolarization of the two ventricles.
A group of conditions in which HEART VENTRICLE activation by the atrial impulse is faster than the normal impulse conduction from the SINOATRIAL NODE. In these pre-excitation syndromes, atrial impulses often bypass the ATRIOVENTRICULAR NODE delay and travel via ACCESSORY CONDUCTING PATHWAYS connecting the atrium directly to the BUNDLE OF HIS.
Extra impulse-conducting tissue in the heart that creates abnormal impulse-conducting connections between HEART ATRIA and HEART VENTRICLES.
The lower right and left chambers of the heart. The right ventricle pumps venous BLOOD into the LUNGS and the left ventricle pumps oxygenated blood into the systemic arterial circulation.
A group of cardiac arrhythmias in which the cardiac contractions are not initiated at the SINOATRIAL NODE. They include both atrial and ventricular premature beats, and are also known as extra or ectopic heartbeats. Their frequency is increased in heart diseases.
The study of the generation and behavior of electrical charges in living organisms particularly the nervous system and the effects of electricity on living organisms.
Unexpected rapid natural death due to cardiovascular collapse within one hour of initial symptoms. It is usually caused by the worsening of existing heart diseases. The sudden onset of symptoms, such as CHEST PAIN and CARDIAC ARRHYTHMIAS, particularly VENTRICULAR TACHYCARDIA, can lead to the loss of consciousness and cardiac arrest followed by biological death. (from Braunwald's Heart Disease: A Textbook of Cardiovascular Medicine, 7th ed., 2005)
An electrical current applied to the HEART to terminate a disturbance of its rhythm, ARRHYTHMIAS, CARDIAC. (Stedman, 25th ed)
A transient loss of consciousness and postural tone caused by diminished blood flow to the brain (i.e., BRAIN ISCHEMIA). Presyncope refers to the sensation of lightheadedness and loss of strength that precedes a syncopal event or accompanies an incomplete syncope. (From Adams et al., Principles of Neurology, 6th ed, pp367-9)
Recording the locations and measurements of electrical activity in the EPICARDIUM by placing electrodes on the surface of the heart to analyze the patterns of activation and to locate arrhythmogenic sites.
Studies in which individuals or populations are followed to assess the outcome of exposures, procedures, or effects of a characteristic, e.g., occurrence of disease.
Evaluation undertaken to assess the results or consequences of management and procedures used in combating disease in order to determine the efficacy, effectiveness, safety, and practicability of these interventions in individual cases or series.
An adrenergic beta-antagonist that is used in the treatment of life-threatening arrhythmias.
Abnormal cardiac rhythm that is characterized by rapid, uncoordinated firing of electrical impulses in the upper chambers of the heart (HEART ATRIA). In such case, blood cannot be effectively pumped into the lower chambers of the heart (HEART VENTRICLES). It is caused by abnormal impulse generation.
Abnormal accumulation of serous fluid in two or more fetal compartments, such as SKIN; PLEURA; PERICARDIUM; PLACENTA; PERITONEUM; AMNIOTIC FLUID. General fetal EDEMA may be of non-immunologic origin, or of immunologic origin as in the case of ERYTHROBLASTOSIS FETALIS.
A congenital cardiomyopathy that is characterized by infiltration of adipose and fibrous tissue into the RIGHT VENTRICLE wall and loss of myocardial cells. Primary injuries usually are at the free wall of right ventricular and right atria resulting in ventricular and supraventricular arrhythmias.
The return of a sign, symptom, or disease after a remission.
A group of diseases in which the dominant feature is the involvement of the CARDIAC MUSCLE itself. Cardiomyopathies are classified according to their predominant pathophysiological features (DILATED CARDIOMYOPATHY; HYPERTROPHIC CARDIOMYOPATHY; RESTRICTIVE CARDIOMYOPATHY) or their etiological/pathological factors (CARDIOMYOPATHY, ALCOHOLIC; ENDOCARDIAL FIBROELASTOSIS).
The domestic dog, Canis familiaris, comprising about 400 breeds, of the carnivore family CANIDAE. They are worldwide in distribution and live in association with people. (Walker's Mammals of the World, 5th ed, p1065)
A device designed to stimulate, by electric impulses, contraction of the heart muscles. It may be temporary (external) or permanent (internal or internal-external).
A conical fibro-serous sac surrounding the HEART and the roots of the great vessels (AORTA; VENAE CAVAE; PULMONARY ARTERY). Pericardium consists of two sacs: the outer fibrous pericardium and the inner serous pericardium. The latter consists of an outer parietal layer facing the fibrous pericardium, and an inner visceral layer (epicardium) resting next to the heart, and a pericardial cavity between these two layers.
Drugs that bind to but do not activate beta-adrenergic receptors thereby blocking the actions of beta-adrenergic agonists. Adrenergic beta-antagonists are used for treatment of hypertension, cardiac arrhythmias, angina pectoris, glaucoma, migraine headaches, and anxiety.
The study of the electrical activity and characteristics of the HEART; MYOCARDIUM; and CARDIOMYOCYTES.
Elements of limited time intervals, contributing to particular results or situations.
An antiarrhythmia agent that is particularly effective in ventricular arrhythmias. It also has weak beta-blocking activity.
Cardiac arrhythmias that are characterized by excessively slow HEART RATE, usually below 50 beats per minute in human adults. They can be classified broadly into SINOATRIAL NODE dysfunction and ATRIOVENTRICULAR BLOCK.
PRESSURE of the BLOOD on the ARTERIES and other BLOOD VESSELS.
A form of ventricular pre-excitation characterized by a normal PR interval and a long QRS interval with an initial slow deflection (delta wave). In this syndrome, the atrial impulse travel to the ventricle via the MAHAIM FIBERS which connect ATRIOVENTRICULAR NODE directly to the right ventricle wall (NODOVENTRICULAR ACCESSORY PATHWAY) or to the RIGHT BUNDLE BRANCH OF HIS (nodofascicular accessory pathway).
A calcium channel blocker that is a class IV anti-arrhythmia agent.
The hollow, muscular organ that maintains the circulation of the blood.
Impaired impulse conduction from HEART ATRIA to HEART VENTRICLES. AV block can mean delayed or completely blocked impulse conduction.
A widely used non-cardioselective beta-adrenergic antagonist. Propranolol has been used for MYOCARDIAL INFARCTION; ARRHYTHMIA; ANGINA PECTORIS; HYPERTENSION; HYPERTHYROIDISM; MIGRAINE; PHEOCHROMOCYTOMA; and ANXIETY but adverse effects instigate replacement by newer drugs.
The movement and the forces involved in the movement of the blood through the CARDIOVASCULAR SYSTEM.
NECROSIS of the MYOCARDIUM caused by an obstruction of the blood supply to the heart (CORONARY CIRCULATION).
A cardiotonic glycoside obtained mainly from Digitalis lanata; it consists of three sugars and the aglycone DIGOXIGENIN. Digoxin has positive inotropic and negative chronotropic activity. It is used to control ventricular rate in ATRIAL FIBRILLATION and in the management of congestive heart failure with atrial fibrillation. Its use in congestive heart failure and sinus rhythm is less certain. The margin between toxic and therapeutic doses is small. (From Martindale, The Extra Pharmacopoeia, 30th ed, p666)
The small mass of modified cardiac muscle fibers located at the junction of the superior vena cava (VENA CAVA, SUPERIOR) and right atrium. Contraction impulses probably start in this node, spread over the atrium (HEART ATRIUM) and are then transmitted by the atrioventricular bundle (BUNDLE OF HIS) to the ventricle (HEART VENTRICLE).
Antiarrhythmic agent pharmacologically similar to LIDOCAINE. It may have some anticonvulsant properties.
A standard and widely accepted diagnostic test used to identify patients who have a vasodepressive and/or cardioinhibitory response as a cause of syncope. (From Braunwald, Heart Disease, 7th ed)
Studies used to test etiologic hypotheses in which inferences about an exposure to putative causal factors are derived from data relating to characteristics of persons under study or to events or experiences in their past. The essential feature is that some of the persons under study have the disease or outcome of interest and their characteristics are compared with those of unaffected persons.
A condition in which HEART VENTRICLES exhibit impaired function.
Procedures using an electrically heated wire or scalpel to treat hemorrhage (e.g., bleeding ulcers) and to ablate tumors, mucosal lesions, and refractory arrhythmias. It is different from ELECTROSURGERY which is used more for cutting tissue than destroying and in which the patient is part of the electric circuit.
Acidic protein found in SARCOPLASMIC RETICULUM that binds calcium to the extent of 700-900 nmoles/mg. It plays the role of sequestering calcium transported to the interior of the intracellular vesicle.
Ultrasonic recording of the size, motion, and composition of the heart and surrounding tissues. The standard approach is transthoracic.
Procedures in which placement of CARDIAC CATHETERS is performed for therapeutic or diagnostic procedures.
The abrupt cessation of all vital bodily functions, manifested by the permanent loss of total cerebral, respiratory, and cardiovascular functions.
Isopropyl analog of EPINEPHRINE; beta-sympathomimetic that acts on the heart, bronchi, skeletal muscle, alimentary tract, etc. It is used mainly as bronchodilator and heart stimulant.
The hemodynamic and electrophysiological action of the RIGHT ATRIUM.
Pathophysiological conditions of the FETUS in the UTERUS. Some fetal diseases may be treated with FETAL THERAPIES.
A form of CARDIAC MUSCLE disease that is characterized by ventricular dilation, VENTRICULAR DYSFUNCTION, and HEART FAILURE. Risk factors include SMOKING; ALCOHOL DRINKING; HYPERTENSION; INFECTION; PREGNANCY; and mutations in the LMNA gene encoding LAMIN TYPE A, a NUCLEAR LAMINA protein.
The period of time following the triggering of an ACTION POTENTIAL when the CELL MEMBRANE has changed to an unexcitable state and is gradually restored to the resting (excitable) state. During the absolute refractory period no other stimulus can trigger a response. This is followed by the relative refractory period during which the cell gradually becomes more excitable and the stronger impulse that is required to illicit a response gradually lessens to that required during the resting state.
Observation of a population for a sufficient number of persons over a sufficient number of years to generate incidence or mortality rates subsequent to the selection of the study group.
The fibrous tissue that replaces normal tissue during the process of WOUND HEALING.
Cessation of heart beat or MYOCARDIAL CONTRACTION. If it is treated within a few minutes, heart arrest can be reversed in most cases to normal cardiac rhythm and effective circulation.
A condition that is characterized by episodes of fainting (SYNCOPE) and varying degree of ventricular arrhythmia as indicated by the prolonged QT interval. The inherited forms are caused by mutation of genes encoding cardiac ion channel proteins. The two major forms are ROMANO-WARD SYNDROME and JERVELL-LANGE NIELSEN SYNDROME.
A type of cardiac arrhythmia with premature atrial contractions or beats caused by signals originating from ectopic atrial sites. The ectopic signals may or may not conduct to the HEART VENTRICLES. Atrial premature complexes are characterized by premature P waves on ECG which are different in configuration from the P waves generated by the normal pacemaker complex in the SINOATRIAL NODE.
The veins that return the oxygenated blood from the lungs to the left atrium of the heart.
A malignant form of polymorphic ventricular tachycardia that is characterized by HEART RATE between 200 and 250 beats per minute, and QRS complexes with changing amplitude and twisting of the points. The term also describes the syndrome of tachycardia with prolonged ventricular repolarization, long QT intervals exceeding 500 milliseconds or BRADYCARDIA. Torsades de pointes may be self-limited or may progress to VENTRICULAR FIBRILLATION.
An autosomal dominant defect of cardiac conduction that is characterized by an abnormal ST-segment in leads V1-V3 on the ELECTROCARDIOGRAM resembling a right BUNDLE-BRANCH BLOCK; high risk of VENTRICULAR TACHYCARDIA; or VENTRICULAR FIBRILLATION; SYNCOPAL EPISODE; and possible sudden death. This syndrome is linked to mutations of gene encoding the cardiac SODIUM CHANNEL alpha subunit.
The thoracolumbar division of the autonomic nervous system. Sympathetic preganglionic fibers originate in neurons of the intermediolateral column of the spinal cord and project to the paravertebral and prevertebral ganglia, which in turn project to target organs. The sympathetic nervous system mediates the body's response to stressful situations, i.e., the fight or flight reactions. It often acts reciprocally to the parasympathetic system.
A short vein that collects about two thirds of the venous blood from the MYOCARDIUM and drains into the RIGHT ATRIUM. Coronary sinus, normally located between the LEFT ATRIUM and LEFT VENTRICLE on the posterior surface of the heart, can serve as an anatomical reference for cardiac procedures.
Modified cardiac muscle fibers composing the terminal portion of the heart conduction system.
AMINO ALCOHOLS containing the propanolamine (NH2CH2CHOHCH2) group and its derivatives.
A class I anti-arrhythmic agent (one that interferes directly with the depolarization of the cardiac membrane and thus serves as a membrane-stabilizing agent) with a depressant action on the heart similar to that of guanidine. It also possesses some anticholinergic and local anesthetic properties.
A general class of ortho-dihydroxyphenylalkylamines derived from tyrosine.
A tetrameric calcium release channel in the SARCOPLASMIC RETICULUM membrane of SMOOTH MUSCLE CELLS, acting oppositely to SARCOPLASMIC RETICULUM CALCIUM-TRANSPORTING ATPASES. It is important in skeletal and cardiac excitation-contraction coupling and studied by using RYANODINE. Abnormalities are implicated in CARDIAC ARRHYTHMIAS and MUSCULAR DISEASES.
The amount of BLOOD pumped out of the HEART per beat, not to be confused with cardiac output (volume/time). It is calculated as the difference between the end-diastolic volume and the end-systolic volume.
Symptoms of cerebral hypoperfusion or autonomic overaction which develop while the subject is standing, but are relieved on recumbency. Types of this include NEUROCARDIOGENIC SYNCOPE; POSTURAL ORTHOSTATIC TACHYCARDIA SYNDROME; and neurogenic ORTHOSTATIC HYPOTENSION. (From Noseworthy, JH., Neurological Therapeutics Principles and Practice, 2007, p2575-2576)
The dilatation of the aortic wall behind each of the cusps of the aortic valve.
In screening and diagnostic tests, the probability that a person with a positive test is a true positive (i.e., has the disease), is referred to as the predictive value of a positive test; whereas, the predictive value of a negative test is the probability that the person with a negative test does not have the disease. Predictive value is related to the sensitivity and specificity of the test.
A type of automatic, not reentrant, ectopic ventricular rhythm with episodes lasting from a few seconds to a minute which usually occurs in patients with acute myocardial infarction or with DIGITALIS toxicity. The ventricular rate is faster than normal but slower than tachycardia, with an upper limit of 100 -120 beats per minute. Suppressive therapy is rarely necessary.
Computer-assisted processing of electric, ultrasonic, or electronic signals to interpret function and activity.
Developmental abnormalities involving structures of the heart. These defects are present at birth but may be discovered later in life.
Production of an image when x-rays strike a fluorescent screen.
A nucleoside that is composed of ADENINE and D-RIBOSE. Adenosine or adenosine derivatives play many important biological roles in addition to being components of DNA and RNA. Adenosine itself is a neurotransmitter.
The ENTERIC NERVOUS SYSTEM; PARASYMPATHETIC NERVOUS SYSTEM; and SYMPATHETIC NERVOUS SYSTEM taken together. Generally speaking, the autonomic nervous system regulates the internal environment during both peaceful activity and physical or emotional stress. Autonomic activity is controlled and integrated by the CENTRAL NERVOUS SYSTEM, especially the HYPOTHALAMUS and the SOLITARY NUCLEUS, which receive information relayed from VISCERAL AFFERENTS.
The position or attitude of the body.
The muscular structure separating the right and the left lower chambers (HEART VENTRICLES) of the heart. The ventricular septum consists of a very small membranous portion just beneath the AORTIC VALVE, and a large thick muscular portion consisting of three sections including the inlet septum, the trabecular septum, and the outlet septum.
A condition in which the LEFT VENTRICLE of the heart was functionally impaired. This condition usually leads to HEART FAILURE; MYOCARDIAL INFARCTION; and other cardiovascular complications. Diagnosis is made by measuring the diminished ejection fraction and a depressed level of motility of the left ventricular wall.
The muscle tissue of the HEART. It is composed of striated, involuntary muscle cells (MYOCYTES, CARDIAC) connected to form the contractile pump to generate blood flow.
An alkaloid, originally from Atropa belladonna, but found in other plants, mainly SOLANACEAE. Hyoscyamine is the 3(S)-endo isomer of atropine.
A significant drop in BLOOD PRESSURE after assuming a standing position. Orthostatic hypotension is a finding, and defined as a 20-mm Hg decrease in systolic pressure or a 10-mm Hg decrease in diastolic pressure 3 minutes after the person has risen from supine to standing. Symptoms generally include DIZZINESS, blurred vision, and SYNCOPE.
Abrupt changes in the membrane potential that sweep along the CELL MEMBRANE of excitable cells in response to excitation stimuli.
Glycosides from plants of the genus DIGITALIS. Some of these are useful as cardiotonic and anti-arrhythmia agents. Included also are semi-synthetic derivatives of the naturally occurring glycosides. The term has sometimes been used more broadly to include all CARDIAC GLYCOSIDES, but here is restricted to those related to Digitalis.
A form of CARDIAC MUSCLE disease, characterized by left and/or right ventricular hypertrophy (HYPERTROPHY, LEFT VENTRICULAR; HYPERTROPHY, RIGHT VENTRICULAR), frequent asymmetrical involvement of the HEART SEPTUM, and normal or reduced left ventricular volume. Risk factors include HYPERTENSION; AORTIC STENOSIS; and gene MUTATION; (FAMILIAL HYPERTROPHIC CARDIOMYOPATHY).
Pathologic processes that affect patients after a surgical procedure. They may or may not be related to the disease for which the surgery was done, and they may or may not be direct results of the surgery.
A combination of congenital heart defects consisting of four key features including VENTRICULAR SEPTAL DEFECTS; PULMONARY STENOSIS; RIGHT VENTRICULAR HYPERTROPHY; and a dextro-positioned AORTA. In this condition, blood from both ventricles (oxygen-rich and oxygen-poor) is pumped into the body often causing CYANOSIS.
The hemodynamic and electrophysiological action of the HEART ATRIA.
A beta-1 adrenergic antagonist that has been used in the emergency treatment of CARDIAC ARRYTHMIAS.
A voltage-gated sodium channel subtype that mediates the sodium ion PERMEABILITY of CARDIOMYOCYTES. Defects in the SCN5A gene, which codes for the alpha subunit of this sodium channel, are associated with a variety of CARDIAC DISEASES that result from loss of sodium channel function.
This structure includes the thin muscular atrial septum between the two HEART ATRIA, and the thick muscular ventricular septum between the two HEART VENTRICLES.
A beta-2 adrenergic agonist used in the treatment of ASTHMA and BRONCHIAL SPASM.
A characteristic symptom complex.
Injections made into a vein for therapeutic or experimental purposes.
Transmission of the readings of instruments to a remote location by means of wires, radio waves, or other means. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)
Irregular HEART RATE caused by abnormal function of the SINOATRIAL NODE. It is characterized by a greater than 10% change between the maximum and the minimum sinus cycle length or 120 milliseconds.
A disorder of cardiac function caused by insufficient blood flow to the muscle tissue of the heart. The decreased blood flow may be due to narrowing of the coronary arteries (CORONARY ARTERY DISEASE), to obstruction by a thrombus (CORONARY THROMBOSIS), or less commonly, to diffuse narrowing of arterioles and other small vessels within the heart. Severe interruption of the blood supply to the myocardial tissue may result in necrosis of cardiac muscle (MYOCARDIAL INFARCTION).
A cardioselective beta-1 adrenergic blocker possessing properties and potency similar to PROPRANOLOL, but without a negative inotropic effect.
An ethanolamine derivative that is an adrenergic alpha-1 agonist. It is used as a vasoconstrictor agent in the treatment of HYPOTENSION.
A form of inherited long QT syndrome (or LQT7) that is characterized by a triad of potassium-sensitive periodic paralysis, VENTRICULAR ECTOPIC BEATS, and abnormal features such as short stature, low-set ears, and SCOLIOSIS. It results from mutations of KCNJ2 gene which encodes a channel protein (INWARD RECTIFIER POTASSIUM CHANNELS) that regulates resting membrane potential.
A non-selective beta-adrenergic antagonist with a long half-life, used in cardiovascular disease to treat arrhythmias, angina pectoris, and hypertension. Nadolol is also used for MIGRAINE DISORDERS and for tremor.
Controlled physical activity which is performed in order to allow assessment of physiological functions, particularly cardiovascular and pulmonary, but also aerobic capacity. Maximal (most intense) exercise is usually required but submaximal exercise is also used.
The active sympathomimetic hormone from the ADRENAL MEDULLA. It stimulates both the alpha- and beta- adrenergic systems, causes systemic VASOCONSTRICTION and gastrointestinal relaxation, stimulates the HEART, and dilates BRONCHI and cerebral vessels. It is used in ASTHMA and CARDIAC FAILURE and to delay absorption of local ANESTHETICS.
Electric conductors through which electric currents enter or leave a medium, whether it be an electrolytic solution, solid, molten mass, gas, or vacuum.
Visualization of the heart structure and cardiac blood flow for diagnostic evaluation or to guide cardiac procedures via techniques including ENDOSCOPY (cardiac endoscopy, sometimes refered to as cardioscopy), RADIONUCLIDE IMAGING; MAGNETIC RESONANCE IMAGING; TOMOGRAPHY; or ULTRASONOGRAPHY.
The continuous measurement of physiological processes, blood pressure, heart rate, renal output, reflexes, respiration, etc., in a patient or experimental animal; includes pharmacologic monitoring, the measurement of administered drugs or their metabolites in the blood, tissues, or urine.
Failure of equipment to perform to standard. The failure may be due to defects or improper use.
The 10th cranial nerve. The vagus is a mixed nerve which contains somatic afferents (from skin in back of the ear and the external auditory meatus), visceral afferents (from the pharynx, larynx, thorax, and abdomen), parasympathetic efferents (to the thorax and abdomen), and efferents to striated muscle (of the larynx and pharynx).
Forced expiratory effort against a closed GLOTTIS.
Use of electric potential or currents to elicit biological responses.
Surgery performed on the heart.
Disorders of the AUTONOMIC NERVOUS SYSTEM occurring as a primary condition. Manifestations can involve any or all body systems but commonly affect the BLOOD PRESSURE and HEART RATE.
Patient care procedures performed during the operation that are ancillary to the actual surgery. It includes monitoring, fluid therapy, medication, transfusion, anesthesia, radiography, and laboratory tests.
A localized bulging or dilatation in the muscle wall of a heart (MYOCARDIUM), usually in the LEFT VENTRICLE. Blood-filled aneurysms are dangerous because they may burst. Fibrous aneurysms interfere with the heart function through the loss of contractility. True aneurysm is bound by the vessel wall or cardiac wall. False aneurysms are HEMATOMA caused by myocardial rupture.
A response by the BARORECEPTORS to increased BLOOD PRESSURE. Increased pressure stretches BLOOD VESSELS which activates the baroreceptors in the vessel walls. The net response of the CENTRAL NERVOUS SYSTEM is a reduction of central sympathetic outflow. This reduces blood pressure both by decreasing peripheral VASCULAR RESISTANCE and by lowering CARDIAC OUTPUT. Because the baroreceptors are tonically active, the baroreflex can compensate rapidly for both increases and decreases in blood pressure.
A condition caused by dysfunctions related to the SINOATRIAL NODE including impulse generation (CARDIAC SINUS ARREST) and impulse conduction (SINOATRIAL EXIT BLOCK). It is characterized by persistent BRADYCARDIA, chronic ATRIAL FIBRILLATION, and failure to resume sinus rhythm following CARDIOVERSION. This syndrome can be congenital or acquired, particularly after surgical correction for heart defects.
Naturally occurring or experimentally induced animal diseases with pathological processes sufficiently similar to those of human diseases. They are used as study models for human diseases.
Expenditure of energy during PHYSICAL ACTIVITY. Intensity of exertion may be measured by rate of OXYGEN CONSUMPTION; HEAT produced, or HEART RATE. Perceived exertion, a psychological measure of exertion, is included.
Abnormally low BLOOD PRESSURE that can result in inadequate blood flow to the brain and other vital organs. Common symptom is DIZZINESS but greater negative impacts on the body occur when there is prolonged depravation of oxygen and nutrients.
The HEART and the BLOOD VESSELS by which BLOOD is pumped and circulated through the body.
A prediction of the probable outcome of a disease based on a individual's condition and the usual course of the disease as seen in similar situations.
Pathological conditions involving the HEART including its structural and functional abnormalities.
The hemodynamic and electrophysiological action of the left HEART VENTRICLE. Its measurement is an important aspect of the clinical evaluation of patients with heart disease to determine the effects of the disease on cardiac performance.
A local anesthetic and cardiac depressant used as an antiarrhythmia agent. Its actions are more intense and its effects more prolonged than those of PROCAINE but its duration of action is shorter than that of BUPIVACAINE or PRILOCAINE.
An infant during the first month after birth.
Binary classification measures to assess test results. Sensitivity or recall rate is the proportion of true positives. Specificity is the probability of correctly determining the absence of a condition. (From Last, Dictionary of Epidemiology, 2d ed)
Theoretical representations that simulate the behavior or activity of the cardiovascular system, processes, or phenomena; includes the use of mathematical equations, computers and other electronic equipment.
A condition in which the RIGHT VENTRICLE of the heart was functionally impaired. This condition usually leads to HEART FAILURE or MYOCARDIAL INFARCTION, and other cardiovascular complications. Diagnosis is made by measuring the diminished ejection fraction and a depressed level of motility of the right ventricular wall.
An imbalance between myocardial functional requirements and the capacity of the CORONARY VESSELS to supply sufficient blood flow. It is a form of MYOCARDIAL ISCHEMIA (insufficient blood supply to the heart muscle) caused by a decreased capacity of the coronary vessels.
The heart rate of the FETUS. The normal range at term is between 120 and 160 beats per minute.
Contractile activity of the MYOCARDIUM.
A paravertebral sympathetic ganglion formed by the fusion of the inferior cervical and first thoracic ganglia.
Drugs that selectively bind to and activate beta-adrenergic receptors.
The hemodynamic and electrophysiological action of the HEART VENTRICLES.
Striated muscle cells found in the heart. They are derived from cardiac myoblasts (MYOBLASTS, CARDIAC).
The relationship between the dose of an administered drug and the response of the organism to the drug.
A heterogeneous condition in which the heart is unable to pump out sufficient blood to meet the metabolic need of the body. Heart failure can be caused by structural defects, functional abnormalities (VENTRICULAR DYSFUNCTION), or a sudden overload beyond its capacity. Chronic heart failure is more common than acute heart failure which results from sudden insult to cardiac function, such as MYOCARDIAL INFARCTION.
An imprecise term which may refer to a sense of spatial disorientation, motion of the environment, or lightheadedness.
Electromagnetic waves with frequencies between about 3 kilohertz (very low frequency - VLF) and 300,000 megahertz (extremely high frequency - EHF). They are used in television and radio broadcasting, land and satellite communications systems, radionavigation, radiolocation, and DIATHERMY. The highest frequency radio waves are MICROWAVES.
Precursor of epinephrine that is secreted by the adrenal medulla and is a widespread central and autonomic neurotransmitter. Norepinephrine is the principal transmitter of most postganglionic sympathetic fibers and of the diffuse projection system in the brain arising from the locus ceruleus. It is also found in plants and is used pharmacologically as a sympathomimetic.
An aspect of personal behavior or lifestyle, environmental exposure, or inborn or inherited characteristic, which, on the basis of epidemiologic evidence, is known to be associated with a health-related condition considered important to prevent.
Serotonin derivative proposed as potentiator for hypnotics and sedatives.
Agents that have a strengthening effect on the heart or that can increase cardiac output. They may be CARDIAC GLYCOSIDES; SYMPATHOMIMETICS; or other drugs. They are used after MYOCARDIAL INFARCT; CARDIAC SURGICAL PROCEDURES; in SHOCK; or in congestive heart failure (HEART FAILURE).
The artificial substitution of heart and lung action as indicated for HEART ARREST resulting from electric shock, DROWNING, respiratory arrest, or other causes. The two major components of cardiopulmonary resuscitation are artificial ventilation (RESPIRATION, ARTIFICIAL) and closed-chest CARDIAC MASSAGE.
A nicotinic antagonist most commonly used as an experimental tool. It has been used as a ganglionic blocker in the treatment of hypertension but has largely been supplanted for that purpose by more specific drugs.
The qualitative or quantitative estimation of the likelihood of adverse effects that may result from exposure to specified health hazards or from the absence of beneficial influences. (Last, Dictionary of Epidemiology, 1988)
A selective adrenergic beta-1 blocking agent that is commonly used to treat ANGINA PECTORIS; HYPERTENSION; and CARDIAC ARRHYTHMIAS.
The long-term (minutes to hours) administration of a fluid into the vein through venipuncture, either by letting the fluid flow by gravity or by pumping it.
Diseases of the parasympathetic or sympathetic divisions of the AUTONOMIC NERVOUS SYSTEM; which has components located in the CENTRAL NERVOUS SYSTEM and PERIPHERAL NERVOUS SYSTEM. Autonomic dysfunction may be associated with HYPOTHALAMIC DISEASES; BRAIN STEM disorders; SPINAL CORD DISEASES; and PERIPHERAL NERVOUS SYSTEM DISEASES. Manifestations include impairments of vegetative functions including the maintenance of BLOOD PRESSURE; HEART RATE; pupil function; SWEATING; REPRODUCTIVE AND URINARY PHYSIOLOGY; and DIGESTION.
The process of generating three-dimensional images by electronic, photographic, or other methods. For example, three-dimensional images can be generated by assembling multiple tomographic images with the aid of a computer, while photographic 3-D images (HOLOGRAPHY) can be made by exposing film to the interference pattern created when two laser light sources shine on an object.
An abnormally low volume of blood circulating through the body. It may result in hypovolemic shock (see SHOCK).
A beta-adrenergic antagonist used in the treatment of hypertension, angina pectoris, arrhythmias, and anxiety.
Any operation on the spinal cord. (Stedman, 26th ed)
A state characterized by loss of feeling or sensation. This depression of nerve function is usually the result of pharmacologic action and is induced to allow performance of surgery or other painful procedures.
Nerves and plexuses of the autonomic nervous system. The central nervous system structures which regulate the autonomic nervous system are not included.
Drugs that bind to and block the activation of ADRENERGIC BETA-1 RECEPTORS.
Post-systolic relaxation of the HEART, especially the HEART VENTRICLES.
Studies to determine the advantages or disadvantages, practicability, or capability of accomplishing a projected plan, study, or project.
A guanidinium antihypertensive agent that acts by blocking adrenergic transmission. The precise mode of action is not clear.
Optical imaging techniques used for recording patterns of electrical activity in tissues by monitoring transmembrane potentials via FLUORESCENCE imaging with voltage-sensitive fluorescent dyes.
Drugs that mimic the effects of stimulating postganglionic adrenergic sympathetic nerves. Included here are drugs that directly stimulate adrenergic receptors and drugs that act indirectly by provoking the release of adrenergic transmitters.
The measurement of magnetic fields generated by electric currents from the heart. The measurement of these fields provides information which is complementary to that provided by ELECTROCARDIOGRAPHY.
A statistical technique that isolates and assesses the contributions of categorical independent variables to variation in the mean of a continuous dependent variable.
A congenital heart defect characterized by downward or apical displacement of the TRICUSPID VALVE, usually with the septal and posterior leaflets being attached to the wall of the RIGHT VENTRICLE. It is characterized by a huge RIGHT ATRIUM and a small and less effective right ventricle.

AV reentrant and idiopathic ventricular double tachycardias: complicated interactions between two tachycardias. (1/1980)

An electrophysiological study was performed in a 61 year old man with Wolff- Parkinson-White (WPW) syndrome. At baseline, neither ventricular nor supraventricular tachycardias could be induced. During isoprenaline infusion, ventricular tachycardia originating from the right ventricular outflow tract (RVOT) with a cycle length of 280 ms was induced and subsequently atrioventricular reentrant tachycardia (AVRT) with a cycle length of 300 ms using an accessory pathway in the left free wall appeared. During these tachycardias, AVRT was entrained by ventricular tachycardia. The earliest ventricular activation site during the ventricular tachycardia was determined to be the RVOT site and a radiofrequency current at 30 W successfully ablated the ventricular tachycardia at this site. The left free wall accessory pathway was also successfully ablated during right ventricular pacing. The coexistence of WPW syndrome and cathecolamine sensitive ventricular tachycardia originating from the RVOT has rarely been reported. Furthermore, the tachycardias were triggered by previous tachycardias.  (+info)

Tachycardia induced tachycardia: case report of right ventricular outflow tract tachycardia and AV nodal reentrant tachycardia. (2/1980)

Tachycardia induced tachycardia, or so called double tachycardia, is rare. A 34 year old woman is described who had a history of syncope, frequent extrasystoles, and episodes of non-sustained ventricular tachycardia, perceived as palpitation, without syncope. At electrophysiological study, during infusion of isoprenaline, an episode of non-sustained ventricular tachycardia arising from the right ventricular outflow tract initiated sustained atrioventricular nodal reentrant tachycardia, thought to be the cause of the patient's syncope. Ablation of the right ventricular outflow tract focus abolished the ventricular ectopy; the slow AV nodal pathway was also ablated. The patient no longer has either syncope or palpitation.  (+info)

ECG diagnosis of native heart ventricular tachycardia in a heterotopic heart transplant recipient. (3/1980)

A case is reported of haemodynamic collapse in a 51 year old male heterotopic heart transplant recipient caused by native heart ventricular tachycardia. An accurate diagnosis was made by selective right and left sided electrocardiography. Synchronised electrical cardioversion of the native heart (200 J) resulted in restoration of sinus rhythm with prompt relief of symptoms and amelioration of the clinical situation.  (+info)

New-onset sustained ventricular tachycardia after cardiac surgery. (4/1980)

BACKGROUND: The de novo occurrence of sustained ventricular tachycardia (VT) after CABG has been described, but the incidence, mortality rate, long-term follow-up, and mechanism are not well defined. METHODS AND RESULTS: This prospective study enrolled consecutive patients undergoing CABG at a single institution. Patients were followed up for the development of sustained VT, and a detailed analysis of clinical, angiographic, and surgical variables associated with the occurrence of VT was performed. A total of 382 patients participated, and 12 patients (3.1%) experienced >/=1 episode of sustained VT 4.1+/-4.8 days after CABG. In 11 of 12 patients, no postoperative complication explained the VT; 1 patient had a perioperative myocardial infarction. The in-hospital mortality rate was 25%. Patients with VT were more likely to have prior myocardial infarction (92% versus 50%, P<0.01), severe congestive heart failure (56% versus 21%, P<0.01), and ejection fraction <0.40 (70% versus 29%, P<0.01). When all 3 factors were present, the risk of VT was 30%, a 14-fold increase. Patients with VT had more noncollateralized totally occluded vessels on angiogram (1.4+/-0.97 versus 0.54+/-0.7, P<0.01), a bypass graft across a noncollateralized occluded vessel (1.50+/-1.0 versus 0.42+/-0.62, P<0.01), and a bypass graft across a noncollateralized occluded vessel to an infarct zone (1.50+/-1.0 versus 0.17+/-0.38, P<0.01). By multivariate analysis, the number of bypass grafts across a noncollateralized occluded vessel to an infarct zone was the only independent factor predicting VT. CONCLUSIONS: The first presentation of sustained monomorphic VT in the recovery period after CABG is uncommon, but the incidence is high in specific clinical subsets. Placement of a bypass graft across a noncollateralized total occlusion in a vessel supplying an infarct zone was strongly and independently associated with the development of VT.  (+info)

Differential effects of a segment of slow conduction on reentrant ventricular tachycardia in the rabbit heart. (5/1980)

BACKGROUND: The purpose of this study was to compare differential effects of a segment of slow conduction during ventricular tachycardia (VT) due to depression of the action potential and electrical uncoupling. METHODS AND RESULTS: In 33 Langendorff-perfused rabbit hearts, a ring of anisotropic left ventricular subepicardium was created by a cryoprocedure. Reentrant VT was produced by incremental pacing. Slow conduction in a segment of the ring was created by selective perfusion of the LAD with 10 mmol/L potassium or 0.75 mmol/L heptanol. As a result, VT cycle length increased from 193+/-34 to 235+/-37 ms (potassium) and 227+/-42 ms (heptanol). Reset curves were made by applying premature stimuli proximal to the area of depressed conduction. In a ring of uniform anisotropic tissue, the reset curve was almost completely flat. Electrical uncoupling of part of the ring (nonuniform anisotropy) resulted in a mixed reset curve. In both substrates, early premature beats failed to terminate VT. Depression of part of the ring by increasing K+ resulted in a completely sloped reset curve, indicating a gap of partial excitability. Under these conditions, in 19 of 24 hearts, premature beats terminated VT by conduction block in the high K+ area. CONCLUSIONS: The nature of the area of slow conduction determines the type of reset response and the ability to terminate VT.  (+info)

Clinical application of an integrated 3-phase mapping technique for localization of the site of origin of idiopathic ventricular tachycardia. (6/1980)

BACKGROUND: Radiofrequency (RF) catheter ablation provides curative treatment for idiopathic ventricular tachycardia (VT). METHODS AND RESULTS: Nineteen consecutive patients with an idiopathic VT underwent RF catheter ablation. An integrated 3-phase mapping approach was used, consisting of the successive application of online 62-lead body surface QRS integral mapping, directed regional paced body surface QRS integral mapping, and local activation sequence mapping. Mapping phase 1 was localization of the segment of VT origin by comparing the VT QRS integral map with a database of mean paced QRS integral maps. Mapping phase 2 was body surface pace mapping during sinus rhythm in the segment localized in phase 1 until the site at which the paced QRS integral map matched the VT QRS integral map was identified (ie, VT exit site). Mapping phase 3 was local activation sequence mapping at the circumscribed area identified in phase 2 to identify the site with the earliest local endocardial activation (ie, site of VT origin). This site became the ablation target. Ten VTs were ablated in the right ventricular outflow tract, 2 at the basal LV septum, and 7 at the midapical posterior left ventricle. A high long-term ablation success (mean follow-up duration, 14+/-9 months) was achieved in 17 of the 19 patients (89%) with a low number of RF pulses (mean, 3.3+/-2.2 pulses per patient). CONCLUSIONS: This prospective study shows that integrated 3-phase mapping for localization of the site of origin of idiopathic VT offers efficient and accurate localization of the target site for RF catheter ablation.  (+info)

Cardiac involvement in proximal myotonic myopathy. (7/1980)

Proximal myotonic myopathy (PROMM) is a recently described autosomal dominantly inherited disorder resulting in proximal muscles weakness, myotonia, and cataracts. A few patients with cardiac involvement (sinus bradycardia, supraventricular bigeminy, conduction abnormalities) have been reported. The cases of three relatives with PROMM (weakness of neck flexors and proximal extremity muscles, calf hypertrophy, myotonia, cataracts) are reported: a 54 year old man, his 73 year old mother, and 66 year old aunt. All three presented with conduction abnormalities and one had repeated, life threatening, sustained monomorphic ventricular tachycardia. This illustrates that severe cardiac involvement may occur in PROMM.  (+info)

Mechanisms of altered excitation-contraction coupling in canine tachycardia-induced heart failure, I: experimental studies. (8/1980)

Pacing-induced heart failure in the dog recapitulates many of the electrophysiological and hemodynamic abnormalities of the human disease; however, the mechanisms underlying altered Ca2+ handling have not been investigated in this model. We now show that left ventricular midmyocardial myocytes isolated from dogs subjected to 3 to 4 weeks of rapid pacing have prolonged action potentials and Ca2+ transients with reduced peaks, but durations approximately 3-fold longer than controls. To discriminate between action potential effects on Ca2+ kinetics and direct changes in Ca2+ regulatory processes, voltage-clamp steps were used to examine the time constant for cytosolic Ca2+ removal (tauCa). tauCa was prolonged by just 35% in myocytes from failing hearts after fixed voltage steps in physiological solutions (tauCa control, 216+/-25 ms, n=17; tauCa failing, 292+/-23 ms, n=22; P<0.05), but this difference was markedly accentuated when Na+/Ca2+ exchange was eliminated (tauCa control, 282+/-30 ms, n=13; tauCa failing, 576+/-83 ms, n=11; P<0. 005). Impaired sarcoplasmic reticular (SR) Ca2+ uptake and a greater dependence on Na+/Ca2+ exchange for cytosolic Ca2+ removal was confirmed by inhibiting SR Ca2+ ATPase with cyclopiazonic acid, which slowed Ca2+ removal more in control than in failing myocytes. beta-Adrenergic stimulation of SR Ca2+ uptake in cells from failing hearts sufficed only to accelerate tauCa to the range of unstimulated controls. Protein levels of SERCA2a, phospholamban, and Na+/Ca2+ exchanger revealed a pattern of changes qualitatively similar to the functional measurements; SERCA2a and phospholamban were both reduced in failing hearts by 28%, and Na+/Ca2+ exchange protein was increased 104% relative to controls. Thus, SR Ca2+ uptake is markedly downregulated in failing hearts, but this defect is partially compensated by enhanced Na+/Ca2+ exchange. The alterations are similar to those reported in human heart failure, which reinforces the utility of the pacing-induced dog model as a surrogate for the human disease.  (+info)

Tachycardia is a medical term that refers to an abnormally rapid heart rate, often defined as a heart rate greater than 100 beats per minute in adults. It can occur in either the atria (upper chambers) or ventricles (lower chambers) of the heart. Different types of tachycardia include supraventricular tachycardia (SVT), atrial fibrillation, atrial flutter, and ventricular tachycardia.

Tachycardia can cause various symptoms such as palpitations, shortness of breath, dizziness, lightheadedness, chest discomfort, or syncope (fainting). In some cases, tachycardia may not cause any symptoms and may only be detected during a routine physical examination or medical test.

The underlying causes of tachycardia can vary widely, including heart disease, electrolyte imbalances, medications, illicit drug use, alcohol abuse, smoking, stress, anxiety, and other medical conditions. In some cases, the cause may be unknown. Treatment for tachycardia depends on the underlying cause, type, severity, and duration of the arrhythmia.

Ventricular Tachycardia (VT) is a rapid heart rhythm that originates from the ventricles, the lower chambers of the heart. It is defined as three or more consecutive ventricular beats at a rate of 120 beats per minute or greater in a resting adult. This abnormal heart rhythm can cause the heart to pump less effectively, leading to inadequate blood flow to the body and potentially life-threatening conditions such as hypotension, shock, or cardiac arrest.

VT can be classified into three types based on its duration, hemodynamic stability, and response to treatment:

1. Non-sustained VT (NSVT): It lasts for less than 30 seconds and is usually well tolerated without causing significant symptoms or hemodynamic instability.
2. Sustained VT (SVT): It lasts for more than 30 seconds, causes symptoms such as palpitations, dizziness, shortness of breath, or chest pain, and may lead to hemodynamic instability.
3. Pulseless VT: It is a type of sustained VT that does not produce a pulse, blood pressure, or adequate cardiac output, requiring immediate electrical cardioversion or defibrillation to restore a normal heart rhythm.

VT can occur in people with various underlying heart conditions such as coronary artery disease, cardiomyopathy, valvular heart disease, congenital heart defects, and electrolyte imbalances. It can also be triggered by certain medications, substance abuse, or electrical abnormalities in the heart. Prompt diagnosis and treatment of VT are crucial to prevent complications and improve outcomes.

Supraventricular tachycardia (SVT) is a rapid heart rhythm that originates above the ventricles (the lower chambers of the heart). This type of tachycardia includes atrial tachycardia, atrioventricular nodal reentrant tachycardia (AVNRT), and atrioventricular reentrant tachycardia (AVRT). SVT usually causes a rapid heartbeat that starts and stops suddenly, and may not cause any other symptoms. However, some people may experience palpitations, shortness of breath, chest discomfort, dizziness, or fainting. SVT is typically diagnosed through an electrocardiogram (ECG) or Holter monitor, and can be treated with medications, cardioversion, or catheter ablation.

Atrioventricular (AV) nodal reentrant tachycardia (AVNRT) is a type of supraventricular tachycardia (SVT), which is a rapid heart rhythm originating at or above the atrioventricular node. In AVNRT, an abnormal electrical circuit in or near the AV node creates a reentry pathway that allows for rapid heart rates, typically greater than 150-250 beats per minute.

In normal conduction, the electrical impulse travels from the atria to the ventricles through the AV node and then continues down the bundle branches to the Purkinje fibers, resulting in a coordinated contraction of the heart. In AVNRT, an extra electrical pathway exists that allows for the reentry of the electrical impulse back into the atria, creating a rapid and abnormal circuit.

AVNRT is classified based on the direction of the reentry circuit:

1. Typical or common AVNRT: The most common form, accounting for 90% of cases. In this type, the reentry circuit involves an "anterior" and a "posterior" loop in or near the AV node. The anterior loop has slower conduction velocity than the posterior loop, creating a "short" reentry circuit that is responsible for the rapid heart rate.
2. Atypical AVNRT: Less common, accounting for 10% of cases. In this type, the reentry circuit involves an "outer" and an "inner" loop around the AV node. The outer loop has slower conduction velocity than the inner loop, creating a "long" reentry circuit that is responsible for the rapid heart rate.

AVNRT can present with symptoms such as palpitations, dizziness, lightheadedness, shortness of breath, chest discomfort, or syncope (fainting). Treatment options include observation, vagal maneuvers, medications, and catheter ablation. Catheter ablation is a curative treatment that involves the destruction of the abnormal electrical pathway using radiofrequency energy or cryotherapy.

Paroxysmal Tachycardia is a type of arrhythmia (abnormal heart rhythm) characterized by rapid and abrupt onset and offset of episodes of tachycardia, which are faster than normal heart rates. The term "paroxysmal" refers to the sudden and recurring nature of these episodes.

Paroxysmal Tachycardia can occur in various parts of the heart, including the atria (small upper chambers) or ventricles (larger lower chambers). The two most common types are Atrial Paroxysmal Tachycardia (APT) and Ventricular Paroxysmal Tachycardia (VPT).

APT is more common and typically results in a rapid heart rate of 100-250 beats per minute. It usually begins and ends suddenly, lasting for seconds to hours. APT can cause symptoms such as palpitations, lightheadedness, shortness of breath, chest discomfort, or anxiety.

VPT is less common but more serious because it involves the ventricles, which are responsible for pumping blood to the rest of the body. VPT can lead to decreased cardiac output and potentially life-threatening conditions such as syncope (fainting) or even cardiac arrest.

Treatment options for Paroxysmal Tachycardia depend on the underlying cause, severity, and frequency of symptoms. These may include lifestyle modifications, medications, cardioversion (electrical shock to restore normal rhythm), catheter ablation (destroying problematic heart tissue), or implantable devices such as pacemakers or defibrillators.

Tachycardia is a heart rate that is faster than normal when resting. In adults, a normal resting heart rate is typically between 60 and 100 beats per minute (bpm). Tachycardia is generally considered to be a heart rate of more than 100 bpm.

Ectopic atrial tachycardia (EAT) is a type of supraventricular tachycardia (SVT), which means that the abnormal rapid heartbeats originate in the atria, the upper chambers of the heart. EAT is caused by an ectopic focus, or an abnormal electrical focus outside of the sinoatrial node (the heart's natural pacemaker). This ectopic focus can be located in one of the pulmonary veins or in other atrial tissue.

EAT may present with symptoms such as palpitations, lightheadedness, shortness of breath, chest discomfort, or syncope (fainting). In some cases, EAT may not cause any symptoms and can be an incidental finding on an electrocardiogram (ECG) or Holter monitor.

The diagnosis of EAT is typically made based on the ECG findings, which show a regular narrow QRS complex tachycardia with P waves that are inverted in the inferior leads and often dissociated from the QRS complexes. Treatment options for EAT include observation, pharmacologic therapy, cardioversion, or catheter ablation.

Sinus tachycardia is a type of rapid heart rate, characterized by an abnormally fast sinus rhythm, with a rate greater than 100 beats per minute in adults. The sinoatrial node (SA node), which is the natural pacemaker of the heart, generates these impulses regularly and at an increased rate.

Sinus tachycardia is usually a physiological response to various stimuli or conditions, such as physical exertion, strong emotions, fever, anxiety, pain, or certain medications. It can also be caused by hormonal imbalances, anemia, hyperthyroidism, or other medical disorders.

In most cases, sinus tachycardia is not harmful and resolves once the underlying cause is addressed. However, if it occurs persistently or is associated with symptoms like palpitations, shortness of breath, dizziness, or chest discomfort, further evaluation by a healthcare professional is recommended to rule out any underlying heart conditions or other medical issues.

Catheter ablation is a medical procedure in which specific areas of heart tissue that are causing arrhythmias (irregular heartbeats) are destroyed or ablated using heat energy (radiofrequency ablation), cold energy (cryoablation), or other methods. The procedure involves threading one or more catheters through the blood vessels to the heart, where the tip of the catheter can be used to selectively destroy the problematic tissue. Catheter ablation is often used to treat atrial fibrillation, atrial flutter, and other types of arrhythmias that originate in the heart's upper chambers (atria). It may also be used to treat certain types of arrhythmias that originate in the heart's lower chambers (ventricles), such as ventricular tachycardia.

The goal of catheter ablation is to eliminate or reduce the frequency and severity of arrhythmias, thereby improving symptoms and quality of life. In some cases, it may also help to reduce the risk of stroke and other complications associated with arrhythmias. Catheter ablation is typically performed by a specialist in heart rhythm disorders (electrophysiologist) in a hospital or outpatient setting under local anesthesia and sedation. The procedure can take several hours to complete, depending on the complexity of the arrhythmia being treated.

It's important to note that while catheter ablation is generally safe and effective, it does carry some risks, such as bleeding, infection, damage to nearby structures, and the possibility of recurrent arrhythmias. Patients should discuss the potential benefits and risks of the procedure with their healthcare provider before making a decision about treatment.

Electrocardiography (ECG or EKG) is a medical procedure that records the electrical activity of the heart. It provides a graphic representation of the electrical changes that occur during each heartbeat. The resulting tracing, called an electrocardiogram, can reveal information about the heart's rate and rhythm, as well as any damage to its cells or abnormalities in its conduction system.

During an ECG, small electrodes are placed on the skin of the chest, arms, and legs. These electrodes detect the electrical signals produced by the heart and transmit them to a machine that amplifies and records them. The procedure is non-invasive, painless, and quick, usually taking only a few minutes.

ECGs are commonly used to diagnose and monitor various heart conditions, including arrhythmias, coronary artery disease, heart attacks, and electrolyte imbalances. They can also be used to evaluate the effectiveness of certain medications or treatments.

Tachycardia refers to a rapid heart rate, typically defined as over 100 beats per minute in adults. Ectopic junctional tachycardia (EJT) is a specific type of abnormal heart rhythm that originates from the junction between the atria (the upper chambers of the heart) and ventricles (the lower chambers).

In EJT, the electrical impulse arises from an ectopic focus (an area outside of the normal conduction system) located in or near the atrioventricular (AV) node. This results in a rapid heart rate that can range from 100 to 250 beats per minute.

EJT is often seen in patients after cardiac surgery, and it can also occur in other conditions such as myocarditis, digoxin toxicity, or following congenital heart disease repair. It may cause symptoms such as palpitations, shortness of breath, chest discomfort, or dizziness. Treatment options for EJT include medications, cardioversion, or ablation therapy, depending on the underlying cause and severity of symptoms.

Postural Orthostatic Tachycardia Syndrome (POTS) is a condition characterized by an abnormally rapid heart rate (tachycardia) that occurs upon standing, leading to symptoms such as dizziness, lightheadedness, and fainting. The diagnostic criteria for POTS include:

1. A heart rate increase of 30 beats per minute or more within the first 10 minutes of standing or a heart rate of 120 beats per minute or more within the first 10 minutes of standing, measured by a heart rate monitor.
2. The presence of symptoms such as lightheadedness, dizziness, blurred vision, weakness, fatigue, headache, shortness of breath, or chest pain upon standing that are relieved by lying down.
3. Symptoms must be present for at least three months and occur in the absence of other medical conditions that could explain them.

POTS is thought to be caused by a dysfunction of the autonomic nervous system, which controls involuntary functions such as heart rate and blood pressure. Treatment may include lifestyle modifications, such as increasing fluid and salt intake, wearing compression stockings, and avoiding prolonged standing or sitting. Medications that help regulate blood pressure and heart rate may also be prescribed.

Reciprocating tachycardia is a type of supraventricular tachycardia (SVT), which is a rapid heart rhythm originating in the atria or atrioventricular node. In reciprocating tachycardia, there are abnormal electrical connections between the atria and ventricles called "accessory pathways" that allow electrical impulses to bypass the normal conduction system.

In this type of tachycardia, an electrical impulse originates in one of the atria and travels down the normal conduction system to the ventricles, but then instead of following the normal route back up to the atria, it takes a shortcut through an accessory pathway. This creates a reentry circuit, where the electrical impulse continuously circulates between the atria and ventricles, causing a rapid heart rate.

Reciprocating tachycardia can be classified as either orthodromic or antidromic, depending on the direction of the electrical impulse through the accessory pathway. In orthodromic reciprocating tachycardia, the electrical impulse travels down the normal conduction system to the ventricles and then returns up the accessory pathway to the atria. This type of reciprocating tachycardia is more common than antidromic reciprocating tachycardia, which occurs when the electrical impulse travels down the accessory pathway to the ventricles and then returns up the normal conduction system to the atria.

Symptoms of reciprocating tachycardia may include palpitations, lightheadedness, shortness of breath, chest discomfort, or syncope (fainting). Treatment options for reciprocating tachycardia include medications, cardioversion, catheter ablation, and surgery.

Tachycardia is a heart rate that is faster than normal. In sinoatrial nodal reentry tachycardia (SANRT), the abnormally fast heart rhythm originates in the sinoatrial node, which is the natural pacemaker of the heart. This type of tachycardia occurs due to a reentry circuit within the sinoatrial node, where an electrical impulse travels in a circular pattern and repeatedly stimulates the node to fire off abnormal rapid heartbeats. SANRT is typically characterized by a heart rate of over 100 beats per minute, palpitations, lightheadedness, or occasionally chest discomfort. It is usually a benign condition but can cause symptoms that affect quality of life. In some cases, treatment may be required to prevent recurrences and manage symptoms.

The heart conduction system is a group of specialized cardiac muscle cells that generate and conduct electrical impulses to coordinate the contraction of the heart chambers. The main components of the heart conduction system include:

1. Sinoatrial (SA) node: Also known as the sinus node, it is located in the right atrium near the entrance of the superior vena cava and functions as the primary pacemaker of the heart. It sets the heart rate by generating electrical impulses at regular intervals.
2. Atrioventricular (AV) node: Located in the interatrial septum, near the opening of the coronary sinus, it serves as a relay station for electrical signals between the atria and ventricles. The AV node delays the transmission of impulses to allow the atria to contract before the ventricles.
3. Bundle of His: A bundle of specialized cardiac muscle fibers that conducts electrical impulses from the AV node to the ventricles. It divides into two main branches, the right and left bundle branches, which further divide into smaller Purkinje fibers.
4. Right and left bundle branches: These are extensions of the Bundle of His that transmit electrical impulses to the respective right and left ventricular myocardium. They consist of specialized conducting tissue with large diameters and minimal resistance, allowing for rapid conduction of electrical signals.
5. Purkinje fibers: Fine, branching fibers that arise from the bundle branches and spread throughout the ventricular myocardium. They are responsible for transmitting electrical impulses to the working cardiac muscle cells, triggering coordinated ventricular contraction.

In summary, the heart conduction system is a complex network of specialized muscle cells responsible for generating and conducting electrical signals that coordinate the contraction of the atria and ventricles, ensuring efficient blood flow throughout the body.

Electrophysiologic techniques, cardiac, refer to medical procedures used to study the electrical activities and conduction systems of the heart. These techniques involve the insertion of electrode catheters into the heart through blood vessels under fluoroscopic guidance to record and stimulate electrical signals. The information obtained from these studies can help diagnose and evaluate various cardiac arrhythmias, determine the optimal treatment strategy, and assess the effectiveness of therapies such as ablation or implantable devices.

The electrophysiologic study (EPS) is a type of cardiac electrophysiologic technique that involves the measurement of electrical signals from different regions of the heart to evaluate its conduction system's function. The procedure can help identify the location of abnormal electrical pathways responsible for arrhythmias and determine the optimal treatment strategy, such as catheter ablation or medication therapy.

Cardiac electrophysiologic techniques are also used in device implantation procedures, such as pacemaker or defibrillator implantation, to ensure proper placement and function of the devices. These techniques can help program and test the devices to optimize their settings for each patient's needs.

In summary, cardiac electrophysiologic techniques are medical procedures used to study and manipulate the electrical activities of the heart, helping diagnose and treat various arrhythmias and other cardiac conditions.

Artificial cardiac pacing is a medical procedure that involves the use of an artificial device to regulate and stimulate the contraction of the heart muscle. This is often necessary when the heart's natural pacemaker, the sinoatrial node, is not functioning properly and the heart is beating too slowly or irregularly.

The artificial pacemaker consists of a small generator that produces electrical impulses and leads that are positioned in the heart to transmit the impulses. The generator is typically implanted just under the skin in the chest, while the leads are inserted into the heart through a vein.

There are different types of artificial cardiac pacing systems, including single-chamber pacemakers, which stimulate either the right atrium or right ventricle, and dual-chamber pacemakers, which stimulate both chambers of the heart. Some pacemakers also have additional features that allow them to respond to changes in the body's needs, such as during exercise or sleep.

Artificial cardiac pacing is a safe and effective treatment for many people with abnormal heart rhythms, and it can significantly improve their quality of life and longevity.

Anti-arrhythmia agents are a class of medications used to treat abnormal heart rhythms or arrhythmias. These drugs work by modifying the electrical activity of the heart to restore and maintain a normal heart rhythm. There are several types of anti-arrhythmia agents, including:

1. Sodium channel blockers: These drugs slow down the conduction of electrical signals in the heart, which helps to reduce rapid or irregular heartbeats. Examples include flecainide, propafenone, and quinidine.
2. Beta-blockers: These medications work by blocking the effects of adrenaline on the heart, which helps to slow down the heart rate and reduce the force of heart contractions. Examples include metoprolol, atenolol, and esmolol.
3. Calcium channel blockers: These drugs block the entry of calcium into heart muscle cells, which helps to slow down the heart rate and reduce the force of heart contractions. Examples include verapamil and diltiazem.
4. Potassium channel blockers: These medications work by prolonging the duration of the heart's electrical cycle, which helps to prevent abnormal rhythms. Examples include amiodarone and sotalol.
5. Digoxin: This drug increases the force of heart contractions and slows down the heart rate, which can help to restore a normal rhythm in certain types of arrhythmias.

It's important to note that anti-arrhythmia agents can have significant side effects and should only be prescribed by a healthcare professional who has experience in managing arrhythmias. Close monitoring is necessary to ensure the medication is working effectively and not causing any adverse effects.

The atrioventricular (AV) node is a critical part of the electrical conduction system of the heart. It is a small cluster of specialized cardiac muscle cells located in the lower interatrial septum, near the opening of the coronary sinus. The AV node receives electrical impulses from the sinoatrial node (the heart's natural pacemaker) via the internodal pathways and delays their transmission for a brief period before transmitting them to the bundle of His and then to the ventricles. This delay allows the atria to contract and empty their contents into the ventricles before the ventricles themselves contract, ensuring efficient pumping of blood throughout the body.

The AV node plays an essential role in maintaining a normal heart rhythm, as it can also function as a backup pacemaker if the sinoatrial node fails to generate impulses. However, certain heart conditions or medications can affect the AV node's function and lead to abnormal heart rhythms, such as atrioventricular block or atrial tachycardia.

The Bundle of His is a bundle of specialized cardiac muscle fibers that conduct electrical impulses to the Purkinje fibers, which then stimulate contraction of the ventricles in the heart. It is named after Wilhelm His, Jr., who first described it in 1893.

The Bundle of His is a part of the electrical conduction system of the heart that helps coordinate the contraction of the atria and ventricles to ensure efficient pumping of blood. The bundle originates from the atrioventricular node, which receives electrical impulses from the sinoatrial node (the heart's natural pacemaker) and transmits them through the Bundle of His to the Purkinje fibers.

The Bundle of His is divided into two main branches, known as the right and left bundle branches, which further divide into smaller fascicles that spread throughout the ventricular myocardium. This ensures a coordinated contraction of the ventricles, allowing for efficient pumping of blood to the rest of the body.

Body Surface Potential Mapping (BSPM) is a non-invasive medical technique used to record and analyze the electrical activity of the heart from the surface of the body. It involves placing multiple electrodes on the skin of the chest, back, and limbs to measure the potential differences between these points during each heartbeat. This information is then used to create a detailed, visual representation of the electrical activation pattern of the heart, which can help in the diagnosis and evaluation of various cardiac disorders such as arrhythmias, myocardial infarction, and ventricular hypertrophy.

The BSPM technique provides high-resolution spatial and temporal information about the cardiac electrical activity, making it a valuable tool for both clinical and research purposes. It can help identify the origin and spread of abnormal electrical signals in the heart, which is crucial for determining appropriate treatment strategies. Overall, Body Surface Potential Mapping is an important diagnostic modality that offers unique insights into the electrical functioning of the heart.

Cardiac arrhythmias are abnormal heart rhythms that result from disturbances in the electrical conduction system of the heart. The heart's normal rhythm is controlled by an electrical signal that originates in the sinoatrial (SA) node, located in the right atrium. This signal travels through the atrioventricular (AV) node and into the ventricles, causing them to contract and pump blood throughout the body.

An arrhythmia occurs when there is a disruption in this electrical pathway or when the heart's natural pacemaker produces an abnormal rhythm. This can cause the heart to beat too fast (tachycardia), too slow (bradycardia), or irregularly.

There are several types of cardiac arrhythmias, including:

1. Atrial fibrillation: A rapid and irregular heartbeat that starts in the atria (the upper chambers of the heart).
2. Atrial flutter: A rapid but regular heartbeat that starts in the atria.
3. Supraventricular tachycardia (SVT): A rapid heartbeat that starts above the ventricles, usually in the atria or AV node.
4. Ventricular tachycardia: A rapid and potentially life-threatening heart rhythm that originates in the ventricles.
5. Ventricular fibrillation: A chaotic and disorganized electrical activity in the ventricles, which can be fatal if not treated immediately.
6. Heart block: A delay or interruption in the conduction of electrical signals from the atria to the ventricles.

Cardiac arrhythmias can cause various symptoms, such as palpitations, dizziness, shortness of breath, chest pain, and fatigue. In some cases, they may not cause any symptoms and go unnoticed. However, if left untreated, certain types of arrhythmias can lead to serious complications, including stroke, heart failure, or even sudden cardiac death.

Treatment for cardiac arrhythmias depends on the type, severity, and underlying causes. Options may include lifestyle changes, medications, cardioversion (electrical shock therapy), catheter ablation, implantable devices such as pacemakers or defibrillators, and surgery. It is essential to consult a healthcare professional for proper evaluation and management of cardiac arrhythmias.

Wolff-Parkinson-White (WPW) Syndrome is a heart condition characterized by the presence of an accessory pathway or abnormal electrical connection between the atria (the upper chambers of the heart) and ventricles (the lower chambers of the heart). This accessory pathway allows electrical impulses to bypass the normal conduction system, leading to a shorter PR interval and a "delta wave" on the electrocardiogram (ECG), which is the hallmark of WPW Syndrome.

Individuals with WPW Syndrome may experience no symptoms or may have palpitations, rapid heartbeat (tachycardia), or episodes of atrial fibrillation. In some cases, WPW Syndrome can lead to more serious heart rhythm disturbances and may require treatment, such as medication, catheter ablation, or in rare cases, surgery.

It is important to note that not all individuals with WPW Syndrome will experience symptoms or complications, and many people with this condition can lead normal, active lives with appropriate monitoring and management.

Ventricular Fibrillation (VF) is a type of cardiac arrhythmia, which is an abnormal heart rhythm. In VF, the ventricles, which are the lower chambers of the heart, beat in a rapid and unorganized manner. This results in the heart being unable to pump blood effectively to the rest of the body, leading to immediate circulatory collapse and cardiac arrest if not treated promptly. It is often caused by underlying heart conditions such as coronary artery disease, structural heart problems, or electrolyte imbalances. VF is a medical emergency that requires immediate defibrillation to restore a normal heart rhythm.

Heart rate is the number of heartbeats per unit of time, often expressed as beats per minute (bpm). It can vary significantly depending on factors such as age, physical fitness, emotions, and overall health status. A resting heart rate between 60-100 bpm is generally considered normal for adults, but athletes and individuals with high levels of physical fitness may have a resting heart rate below 60 bpm due to their enhanced cardiovascular efficiency. Monitoring heart rate can provide valuable insights into an individual's health status, exercise intensity, and response to various treatments or interventions.

An implantable defibrillator is a medical device that is surgically placed inside the chest to continuously monitor the heart's rhythm and deliver electrical shocks to restore a normal heartbeat when it detects a life-threatening arrhythmia, such as ventricular fibrillation or ventricular tachycardia.

The device consists of a small generator that is implanted in the upper chest, along with one or more electrode leads that are threaded through veins and positioned in the heart's chambers. The generator contains a battery and a microcomputer that constantly monitors the heart's electrical activity and detects any abnormal rhythms.

When an arrhythmia is detected, the defibrillator delivers an electrical shock to the heart to restore a normal rhythm. This can be done automatically by the device or manually by a healthcare provider using an external programmer.

Implantable defibrillators are typically recommended for people who have a high risk of sudden cardiac death due to a history of heart attacks, heart failure, or inherited heart conditions that affect the heart's electrical system. They can significantly reduce the risk of sudden cardiac death and improve quality of life for those at risk.

Amiodarone is a Class III antiarrhythmic medication used to treat and prevent various types of irregular heart rhythms (arrhythmias). It works by stabilizing the electrical activity of the heart and slowing down the nerve impulses in the heart tissue. Amiodarone is available in oral tablet and injection forms.

The medical definition of 'Amiodarone' is:

A benzofuran derivative with Class III antiarrhythmic properties, used for the treatment of ventricular arrhythmias. It has a relatively slow onset of action and is therefore not useful in acute situations. Additionally, it has negative inotropic effects and may exacerbate heart failure. The most serious adverse effect is pulmonary fibrosis, which occurs in approximately 1-2% of patients. Other important side effects include corneal microdeposits, hepatotoxicity, thyroid dysfunction, and photosensitivity. Amiodarone has a very long half-life (approximately 50 days) due to its extensive tissue distribution. It is metabolized by the liver and excreted in bile and urine.

Sources:

1. UpToDate - Amiodarone use in adults: Indications, dosing, and adverse effects.
2. Micromedex - Amiodarone.
3. Drugs.com - Amiodarone.

Ambulatory electrocardiography, also known as ambulatory ECG or Holter monitoring, is a non-invasive method of recording the electrical activity of the heart over an extended period of time (typically 24 hours or more) while the patient goes about their daily activities. The device used to record the ECG is called a Holter monitor, which consists of a small, portable recorder that is attached to the patient's chest with electrodes.

The recorded data provides information on any abnormalities in the heart's rhythm or electrical activity during different stages of activity and rest, allowing healthcare providers to diagnose and evaluate various cardiac conditions such as arrhythmias, ischemia, and infarction. The ability to monitor the heart's activity over an extended period while the patient performs their normal activities provides valuable information that may not be captured during a standard ECG, which only records the heart's electrical activity for a few seconds.

In summary, ambulatory electrocardiography is a diagnostic tool used to evaluate the electrical activity of the heart over an extended period, allowing healthcare providers to diagnose and manage various cardiac conditions.

Flecainide is an antiarrhythmic medication used to regularize abnormal heart rhythms, specifically certain types of irregular heartbeats called ventricular arrhythmias and paroxysmal atrial tachycardia/atrial fibrillation. It works by blocking sodium channels in the heart, which helps to slow down the conduction of electrical signals and reduces the likelihood of erratic heart rhythms.

Flecainide is available in oral forms such as tablets or capsules and is typically prescribed under the supervision of a healthcare professional experienced in managing heart rhythm disorders. It's important to note that flecainide can have serious side effects, including increasing the risk of dangerous arrhythmias in some patients, so it should only be used under close medical monitoring.

This definition is for informational purposes only and should not be considered a substitute for professional medical advice, diagnosis, or treatment. If you have any questions about your medications or health conditions, please consult with your healthcare provider.

Ventricular Premature Complexes (VPCs), also known as Ventricular Extrasystoles or Premature Ventricular Contractions (PVCs), are extra heartbeats that originate in the ventricles, the lower chambers of the heart. These premature beats disrupt the normal sequence of electrical impulses in the heart and cause the ventricles to contract earlier than they should.

VPCs can result in a noticeable "skipped" or "extra" beat sensation, often followed by a stronger beat as the heart returns to its regular rhythm. They may occur occasionally in healthy individuals with no underlying heart condition, but frequent VPCs could indicate an underlying issue such as heart disease, electrolyte imbalance, or digitalis toxicity. In some cases, VPCs can be harmless and require no treatment; however, if they are frequent or associated with structural heart problems, further evaluation and management may be necessary to prevent potential complications like reduced cardiac output or heart failure.

Cryosurgery is a medical procedure that uses extreme cold, such as liquid nitrogen or argon gas, to destroy abnormal or unwanted tissue. The intense cold causes the water inside the cells to freeze and form ice crystals, which can rupture the cell membrane and cause the cells to die. Cryosurgery is often used to treat a variety of conditions including skin growths such as warts and tumors, precancerous lesions, and some types of cancer. The procedure is typically performed in a doctor's office or outpatient setting and may require local anesthesia.

The heart atria are the upper chambers of the heart that receive blood from the veins and deliver it to the lower chambers, or ventricles. There are two atria in the heart: the right atrium receives oxygen-poor blood from the body and pumps it into the right ventricle, which then sends it to the lungs to be oxygenated; and the left atrium receives oxygen-rich blood from the lungs and pumps it into the left ventricle, which then sends it out to the rest of the body. The atria contract before the ventricles during each heartbeat, helping to fill the ventricles with blood and prepare them for contraction.

Procainamide is an antiarrhythmic medication used to treat various types of irregular heart rhythms (arrhythmias), such as atrial fibrillation, atrial flutter, and ventricular tachycardia. It works by prolonging the duration of the cardiac action potential and decreasing the slope of the phase 0 depolarization, which helps to stabilize the heart's electrical activity and restore a normal rhythm.

Procainamide is classified as a Class Ia antiarrhythmic drug, according to the Vaughan Williams classification system. It primarily affects the fast sodium channels in the heart muscle cells, reducing their availability during depolarization. This results in a decreased rate of impulse generation and conduction velocity, which can help to suppress abnormal rhythms.

The medication is available as an oral formulation (procainamide hydrochloride) and as an injectable solution for intravenous use. Common side effects of procainamide include nausea, vomiting, diarrhea, headache, and dizziness. Procainamide can also cause a lupus-like syndrome, characterized by joint pain, skin rashes, and other autoimmune symptoms, in some patients who take the medication for an extended period.

It is essential to monitor procainamide levels in the blood during treatment to ensure that the drug is within the therapeutic range and to minimize the risk of adverse effects. Healthcare providers should also regularly assess patients' renal function, as procainamide and its active metabolite, N-acetylprocainamide (NAPA), are primarily excreted by the kidneys.

The endocardium is the innermost layer of tissue that lines the chambers of the heart and the valves between them. It is a thin, smooth membrane that is in contact with the blood within the heart. This layer helps to maintain the heart's internal environment, facilitates the smooth movement of blood through the heart, and provides a protective barrier against infection and other harmful substances. The endocardium is composed of simple squamous epithelial cells called endothelial cells, which are supported by a thin layer of connective tissue.

Atrial flutter is a type of abnormal heart rhythm or arrhythmia that originates in the atria - the upper chambers of the heart. In atrial flutter, the atria beat too quickly, usually between 250 and 350 beats per minute, which is much faster than the normal resting rate of 60 to 100 beats per minute.

This rapid beating causes the atria to quiver or "flutter" instead of contracting effectively. As a result, blood may not be pumped efficiently into the ventricles - the lower chambers of the heart - which can lead to reduced cardiac output and symptoms such as palpitations, shortness of breath, fatigue, dizziness, or chest discomfort.

Atrial flutter is often caused by underlying heart conditions, such as coronary artery disease, hypertension, valvular heart disease, or congenital heart defects. It can also be a complication of cardiac surgery or other medical procedures. In some cases, atrial flutter may occur without any apparent underlying cause, which is known as lone atrial flutter.

Treatment for atrial flutter typically involves medications to control the heart rate and rhythm, electrical cardioversion to restore a normal heart rhythm, or catheter ablation to destroy the abnormal electrical pathways in the heart that are causing the arrhythmia. In some cases, surgical intervention may be necessary to treat atrial flutter.

Heart block is a cardiac condition characterized by the interruption of electrical impulse transmission from the atria (the upper chambers of the heart) to the ventricles (the lower chambers of the heart). This disruption can lead to abnormal heart rhythms, including bradycardia (a slower-than-normal heart rate), and in severe cases, can cause the heart to stop beating altogether. Heart block is typically caused by damage to the heart's electrical conduction system due to various factors such as aging, heart disease, or certain medications.

There are three types of heart block: first-degree, second-degree, and third-degree (also known as complete heart block). Each type has distinct electrocardiogram (ECG) findings and symptoms. Treatment for heart block depends on the severity of the condition and may include monitoring, medication, or implantation of a pacemaker to regulate the heart's electrical activity.

Bundle-branch block (BBB) is a type of conduction delay or block in the heart's electrical system that affects the way electrical impulses travel through the ventricles (the lower chambers of the heart). In BBB, one of the two main bundle branches that conduct electrical impulses to the ventricles is partially or completely blocked, causing a delay in the contraction of one of the ventricles.

There are two types of bundle-branch block: right bundle-branch block (RBBB) and left bundle-branch block (LBBB). In RBBB, the right bundle branch is affected, while in LBBB, the left bundle branch is affected. The symptoms and severity of BBB can vary depending on the underlying cause and the presence of other heart conditions.

In some cases, BBB may not cause any noticeable symptoms and may only be detected during a routine electrocardiogram (ECG). However, if BBB occurs along with other heart conditions such as coronary artery disease, heart failure, or cardiomyopathy, it can increase the risk of serious complications such as arrhythmias, syncope, and even sudden cardiac death.

Treatment for bundle-branch block depends on the underlying cause and the severity of the condition. In some cases, no treatment may be necessary, while in others, medications, pacemakers, or other treatments may be recommended to manage symptoms and prevent complications.

Pre-excitation syndromes are a group of cardiac conditions characterized by the presence of an accessory electrical pathway between the atria and ventricles of the heart. This pathway allows electrical impulses to bypass the normal conduction system, leading to early activation (pre-excitation) of a portion of the ventricular muscle. The most common pre-excitation syndrome is Wolff-Parkinson-White (WPW) syndrome, but other types include Lown-Ganong-Levine syndrome and Mahaim syndrome. These conditions can potentially lead to tachyarrhythmias or abnormally fast heart rhythms, which in some cases can be life-threatening if not properly managed.

The accessory atrioventricular (AV) bundle, also known as the bundle of Kent, is an abnormal electrical connection between the atria and ventricles of the heart. It is a type of accessory pathway that bypasses the normal AV node conduction system, allowing electrical impulses to travel directly from the atria to the ventricles.

This abnormal connection can lead to a type of arrhythmia called Wolff-Parkinson-White (WPW) syndrome, which is characterized by a short PR interval and a wide QRS complex on an electrocardiogram (ECG). WPW syndrome can cause palpitations, rapid heartbeat, and in some cases, may lead to more serious arrhythmias such as atrial fibrillation or atrial flutter.

Accessory AV bundles are typically congenital, meaning they are present from birth, but may not cause any symptoms until later in life. Treatment for WPW syndrome may include medication, catheter ablation to destroy the accessory pathway, or in some cases, surgery.

The heart ventricles are the two lower chambers of the heart that receive blood from the atria and pump it to the lungs or the rest of the body. The right ventricle pumps deoxygenated blood to the lungs, while the left ventricle pumps oxygenated blood to the rest of the body. Both ventricles have thick, muscular walls to generate the pressure necessary to pump blood through the circulatory system.

Premature cardiac complexes, also known as premature heartbeats or premature ventricular contractions (PVCs), refer to extra or early heartbeats that originate in the lower chambers of the heart (the ventricles). These extra beats disrupt the normal rhythm and sequence of heartbeats, causing the heart to beat earlier than expected.

Premature cardiac complexes can occur in healthy individuals as well as those with heart disease. They are usually harmless and do not cause any symptoms, but in some cases, they may cause palpitations, skipped beats, or a fluttering sensation in the chest. In rare cases, frequent premature cardiac complexes can lead to more serious heart rhythm disorders or decreased heart function.

The diagnosis of premature cardiac complexes is usually made through an electrocardiogram (ECG) or Holter monitoring, which records the electrical activity of the heart over a period of time. Treatment is typically not necessary unless the premature complexes are frequent, symptomatic, or associated with underlying heart disease. In such cases, medications, cardioversion, or catheter ablation may be recommended.

Electrophysiology is a branch of medicine that deals with the electrical activities of the body, particularly the heart. In a medical context, electrophysiology studies (EPS) are performed to assess abnormal heart rhythms (arrhythmias) and to evaluate the effectiveness of certain treatments, such as medication or pacemakers.

During an EPS, electrode catheters are inserted into the heart through blood vessels in the groin or neck. These catheters can record the electrical activity of the heart and stimulate it to help identify the source of the arrhythmia. The information gathered during the study can help doctors determine the best course of treatment for each patient.

In addition to cardiac electrophysiology, there are also other subspecialties within electrophysiology, such as neuromuscular electrophysiology, which deals with the electrical activity of the nervous system and muscles.

Sudden cardiac death (SCD) is a sudden, unexpected natural death caused by the cessation of cardiac activity. It is often caused by cardiac arrhythmias, particularly ventricular fibrillation, and is often associated with underlying heart disease, although it can occur in people with no known heart condition. SCD is typically defined as a natural death due to cardiac causes that occurs within one hour of the onset of symptoms, or if the individual was last seen alive in a normal state of health, it can be defined as occurring within 24 hours.

It's important to note that sudden cardiac arrest (SCA) is different from SCD, although they are related. SCA refers to the sudden cessation of cardiac activity, which if not treated immediately can lead to SCD.

Electric countershock, also known as defibrillation, is a medical procedure that uses an electric current to restore normal heart rhythm in certain types of cardiac arrhythmias, such as ventricular fibrillation or pulseless ventricular tachycardia. The procedure involves delivering a therapeutic dose of electrical energy to the heart through electrodes placed on the chest wall or directly on the heart. This electric current helps to depolarize a large number of cardiac cells simultaneously, which can help to interrupt the abnormal electrical activity in the heart and allow the normal conduction system to regain control and restore a normal rhythm. Electric countershock is typically delivered using an automated external defibrillator (AED) or a manual defibrillator, and it is a critical component of advanced cardiac life support (ACLS).

Syncope is a medical term defined as a transient, temporary loss of consciousness and postural tone due to reduced blood flow to the brain. It's often caused by a drop in blood pressure, which can be brought on by various factors such as dehydration, emotional stress, prolonged standing, or certain medical conditions like heart diseases, arrhythmias, or neurological disorders.

During a syncope episode, an individual may experience warning signs such as lightheadedness, dizziness, blurred vision, or nausea before losing consciousness. These episodes usually last only a few minutes and are followed by a rapid, full recovery. However, if left untreated or undiagnosed, recurrent syncope can lead to severe injuries from falls or even life-threatening conditions related to the underlying cause.

Epicardial mapping is a medical procedure used to create a detailed map of the electrical activity on the surface of the heart (epicardium). This technique is often used during electrophysiology studies to help diagnose and locate the source of abnormal heart rhythms, such as ventricular tachycardia or atrial fibrillation.

During epicardial mapping, a specialist (usually an electrophysiologist) will introduce a catheter through a vein or artery, which is then guided to the heart. Once in position, electrodes on the tip of the catheter record electrical signals from the heart's surface. These signals are used to create a detailed map of the heart's electrical activity, allowing the specialist to identify areas with abnormal electrical patterns.

This information can be crucial for determining the best course of treatment, such as targeted ablation therapy to eliminate the source of the arrhythmia. Epicardial mapping is typically performed in an electrophysiology lab or cardiac catheterization laboratory under fluoroscopy guidance, and it requires expertise in both cardiovascular medicine and interventional techniques.

Follow-up studies are a type of longitudinal research that involve repeated observations or measurements of the same variables over a period of time, in order to understand their long-term effects or outcomes. In medical context, follow-up studies are often used to evaluate the safety and efficacy of medical treatments, interventions, or procedures.

In a typical follow-up study, a group of individuals (called a cohort) who have received a particular treatment or intervention are identified and then followed over time through periodic assessments or data collection. The data collected may include information on clinical outcomes, adverse events, changes in symptoms or functional status, and other relevant measures.

The results of follow-up studies can provide important insights into the long-term benefits and risks of medical interventions, as well as help to identify factors that may influence treatment effectiveness or patient outcomes. However, it is important to note that follow-up studies can be subject to various biases and limitations, such as loss to follow-up, recall bias, and changes in clinical practice over time, which must be carefully considered when interpreting the results.

Treatment outcome is a term used to describe the result or effect of medical treatment on a patient's health status. It can be measured in various ways, such as through symptoms improvement, disease remission, reduced disability, improved quality of life, or survival rates. The treatment outcome helps healthcare providers evaluate the effectiveness of a particular treatment plan and make informed decisions about future care. It is also used in clinical research to compare the efficacy of different treatments and improve patient care.

Sotalol is a non-selective beta blocker and class III antiarrhythmic drug. It works by blocking the action of certain natural substances in your body, such as adrenaline, on the heart. This helps to decrease the heart's workload, slow the heart rate, and regulate certain types of irregular heartbeats (such as atrial fibrillation).

Sotalol is used to treat various types of irregular heartbeats (atrial fibrillation/flutter, ventricular tachycardia) and may also be used to help maintain a normal heart rhythm after a heart attack. It is important to note that Sotalol should only be prescribed by a healthcare professional who has experience in treating heart rhythm disorders.

This medical definition is based on the information provided by the National Library of Medicine (NLM).

Atrial fibrillation (A-tre-al fi-bru-la'shun) is a type of abnormal heart rhythm characterized by rapid and irregular beating of the atria, the upper chambers of the heart. In this condition, the electrical signals that coordinate heartbeats don't function properly, causing the atria to quiver instead of contracting effectively. As a result, blood may not be pumped efficiently into the ventricles, which can lead to blood clots, stroke, and other complications. Atrial fibrillation is a common type of arrhythmia and can cause symptoms such as palpitations, shortness of breath, fatigue, and dizziness. It can be caused by various factors, including heart disease, high blood pressure, age, and genetics. Treatment options include medications, electrical cardioversion, and surgical procedures to restore normal heart rhythm.

Hydrops Fetalis is a serious condition characterized by the accumulation of excessive fluid in two or more fetal compartments, including the abdomen (ascites), around the heart (pericardial effusion), and/or within the lungs (pleural effusion). This accumulation can also affect the skin, causing it to become edematous. Hydrops Fetalis is often associated with various underlying causes, such as chromosomal abnormalities, congenital infections, genetic disorders, and structural defects that impair the fetus's ability to maintain fluid balance. In some cases, the cause may remain unknown. The prognosis for Hydrops Fetalis is generally poor, with a high mortality rate, although early detection and appropriate management can improve outcomes in certain situations.

Arrhythmogenic Right Ventricular Dysplasia (ARVD) is a rare cardiac condition characterized by the replacement of the normal heart muscle tissue in the right ventricle with fatty and fibrous tissues. This can lead to abnormal heart rhythms (arrhythmias), particularly during exercise or emotional stress.

The condition can be inherited and is often associated with genetic mutations that affect the desmosomes, which are protein structures that help connect heart muscle cells together. These mutations can weaken the heart muscle and make it more prone to arrhythmias and heart failure over time.

Symptoms of ARVD may include palpitations, chest pain, shortness of breath, dizziness, or fainting, especially during exercise. In some cases, the condition may not cause any symptoms and may only be discovered during a routine medical exam or evaluation for another condition.

Diagnosis of ARVD typically involves a combination of clinical evaluation, imaging tests such as echocardiography or magnetic resonance imaging (MRI), and electrophysiological testing to assess heart rhythm abnormalities. Treatment may include medications to control arrhythmias, implantable devices such as pacemakers or defibrillators, and lifestyle modifications such as avoiding strenuous exercise. In severe cases, a heart transplant may be necessary.

Recurrence, in a medical context, refers to the return of symptoms or signs of a disease after a period of improvement or remission. It indicates that the condition has not been fully eradicated and may require further treatment. Recurrence is often used to describe situations where a disease such as cancer comes back after initial treatment, but it can also apply to other medical conditions. The likelihood of recurrence varies depending on the type of disease and individual patient factors.

Cardiomyopathies are a group of diseases that affect the heart muscle, leading to mechanical and/or electrical dysfunction. The American Heart Association (AHA) defines cardiomyopathies as "a heterogeneous group of diseases of the myocardium associated with mechanical and/or electrical dysfunction that usually (but not always) exhibit inappropriate ventricular hypertrophy or dilatation and frequently lead to heart failure."

There are several types of cardiomyopathies, including:

1. Dilated cardiomyopathy (DCM): This is the most common type of cardiomyopathy, characterized by an enlarged left ventricle and impaired systolic function, leading to heart failure.
2. Hypertrophic cardiomyopathy (HCM): In this type, there is abnormal thickening of the heart muscle, particularly in the septum between the two ventricles, which can obstruct blood flow and increase the risk of arrhythmias.
3. Restrictive cardiomyopathy (RCM): This is a rare form of cardiomyopathy characterized by stiffness of the heart muscle, impaired relaxation, and diastolic dysfunction, leading to reduced filling of the ventricles and heart failure.
4. Arrhythmogenic right ventricular cardiomyopathy (ARVC): In this type, there is replacement of the normal heart muscle with fatty or fibrous tissue, primarily affecting the right ventricle, which can lead to arrhythmias and sudden cardiac death.
5. Unclassified cardiomyopathies: These are conditions that do not fit into any of the above categories but still significantly affect the heart muscle and function.

Cardiomyopathies can be caused by genetic factors, acquired conditions (e.g., infections, toxins, or autoimmune disorders), or a combination of both. The diagnosis typically involves a comprehensive evaluation, including medical history, physical examination, electrocardiogram (ECG), echocardiography, cardiac magnetic resonance imaging (MRI), and sometimes genetic testing. Treatment depends on the type and severity of the condition but may include medications, lifestyle modifications, implantable devices, or even heart transplantation in severe cases.

I believe there might be a misunderstanding in your question. "Dogs" is not a medical term or condition. It is the common name for a domesticated carnivore of the family Canidae, specifically the genus Canis, which includes wolves, foxes, and other extant and extinct species of mammals. Dogs are often kept as pets and companions, and they have been bred in a wide variety of forms and sizes for different purposes, such as hunting, herding, guarding, assisting police and military forces, and providing companionship and emotional support.

If you meant to ask about a specific medical condition or term related to dogs, please provide more context so I can give you an accurate answer.

An artificial pacemaker is a medical device that uses electrical impulses to regulate the beating of the heart. It is typically used when the heart's natural pacemaker, the sinoatrial node, is not functioning properly and the heart rate is too slow or irregular. The pacemaker consists of a small generator that contains a battery and electronic circuits, which are connected to one or more electrodes that are placed in the heart.

The generator sends electrical signals through the electrodes to stimulate the heart muscle and cause it to contract, thereby maintaining a regular heart rhythm. Artificial pacemakers can be programmed to deliver electrical impulses at a specific rate or in response to the body's needs. They are typically implanted in the chest during a surgical procedure and can last for many years before needing to be replaced.

Artificial pacemakers are an effective treatment for various types of bradycardia, which is a heart rhythm disorder characterized by a slow heart rate. Pacemakers can significantly improve symptoms associated with bradycardia, such as fatigue, dizziness, shortness of breath, and fainting spells.

The pericardium is the double-walled sac that surrounds the heart. It has an outer fibrous layer and an inner serous layer, which further divides into two parts: the parietal layer lining the fibrous pericardium and the visceral layer (epicardium) closely adhering to the heart surface.

The space between these two layers is filled with a small amount of lubricating serous fluid, allowing for smooth movement of the heart within the pericardial cavity. The pericardium provides protection, support, and helps maintain the heart's normal position within the chest while reducing friction during heart contractions.

Adrenergic beta-antagonists, also known as beta blockers, are a class of medications that block the effects of adrenaline and noradrenaline (also known as epinephrine and norepinephrine) on beta-adrenergic receptors. These receptors are found in various tissues throughout the body, including the heart, lungs, and blood vessels.

Beta blockers work by binding to these receptors and preventing the activation of certain signaling pathways that lead to increased heart rate, force of heart contractions, and relaxation of blood vessels. As a result, beta blockers can lower blood pressure, reduce heart rate, and decrease the workload on the heart.

Beta blockers are used to treat a variety of medical conditions, including hypertension (high blood pressure), angina (chest pain), heart failure, irregular heart rhythms, migraines, and certain anxiety disorders. Some common examples of beta blockers include metoprolol, atenolol, propranolol, and bisoprolol.

It is important to note that while beta blockers can have many benefits, they can also cause side effects such as fatigue, dizziness, and shortness of breath. Additionally, sudden discontinuation of beta blocker therapy can lead to rebound hypertension or worsening chest pain. Therefore, it is important to follow the dosing instructions provided by a healthcare provider carefully when taking these medications.

Cardiac electrophysiology is a branch of medicine that deals with the study and understanding of the electrical activities of the heart. It involves the diagnosis and treatment of various heart rhythm disorders (arrhythmias) such as bradycardia (slow heart rate), tachycardia (fast heart rate), atrial fibrillation, atrial flutter, ventricular fibrillation, and other rhythm abnormalities.

Cardiac electrophysiologists use various diagnostic tests, including electrocardiograms (ECGs), Holter monitors, event monitors, and invasive procedures such as electrophysiology studies (EPS) and catheter ablation to evaluate and treat heart rhythm disorders. The goal of treatment is to restore a normal heart rhythm and prevent complications associated with arrhythmias, such as stroke or heart failure.

In the field of medicine, "time factors" refer to the duration of symptoms or time elapsed since the onset of a medical condition, which can have significant implications for diagnosis and treatment. Understanding time factors is crucial in determining the progression of a disease, evaluating the effectiveness of treatments, and making critical decisions regarding patient care.

For example, in stroke management, "time is brain," meaning that rapid intervention within a specific time frame (usually within 4.5 hours) is essential to administering tissue plasminogen activator (tPA), a clot-busting drug that can minimize brain damage and improve patient outcomes. Similarly, in trauma care, the "golden hour" concept emphasizes the importance of providing definitive care within the first 60 minutes after injury to increase survival rates and reduce morbidity.

Time factors also play a role in monitoring the progression of chronic conditions like diabetes or heart disease, where regular follow-ups and assessments help determine appropriate treatment adjustments and prevent complications. In infectious diseases, time factors are crucial for initiating antibiotic therapy and identifying potential outbreaks to control their spread.

Overall, "time factors" encompass the significance of recognizing and acting promptly in various medical scenarios to optimize patient outcomes and provide effective care.

Propafenone is an antiarrhythmic medication used to treat certain types of irregular heartbeats (such as atrial fibrillation, paroxysmal supraventricular tachycardia). It works by blocking certain electrical signals in the heart to help it beat regularly. Propafenone belongs to a class of drugs known as Class IC antiarrhythmics.

It is important to note that this definition provides an overview of what propafenone is and how it is used, but it does not cover all possible uses, precautions, side effects, and interactions related to the drug. For more detailed information about propafenone, including its specific indications, contraindications, and potential adverse effects, consult a reliable medical reference or speak with a healthcare professional.

Bradycardia is a medical term that refers to an abnormally slow heart rate, typically defined as a resting heart rate of less than 60 beats per minute in adults. While some people, particularly well-trained athletes, may have a naturally low resting heart rate, bradycardia can also be a sign of an underlying health problem.

There are several potential causes of bradycardia, including:

* Damage to the heart's electrical conduction system, such as from heart disease or aging
* Certain medications, including beta blockers, calcium channel blockers, and digoxin
* Hypothyroidism (underactive thyroid gland)
* Sleep apnea
* Infection of the heart (endocarditis or myocarditis)
* Infiltrative diseases such as amyloidosis or sarcoidosis

Symptoms of bradycardia can vary depending on the severity and underlying cause. Some people with bradycardia may not experience any symptoms, while others may feel weak, fatigued, dizzy, or short of breath. In severe cases, bradycardia can lead to fainting, confusion, or even cardiac arrest.

Treatment for bradycardia depends on the underlying cause. If a medication is causing the slow heart rate, adjusting the dosage or switching to a different medication may help. In other cases, a pacemaker may be necessary to regulate the heart's rhythm. It is important to seek medical attention if you experience symptoms of bradycardia, as it can be a sign of a serious underlying condition.

Blood pressure is the force exerted by circulating blood on the walls of the blood vessels. It is measured in millimeters of mercury (mmHg) and is given as two figures:

1. Systolic pressure: This is the pressure when the heart pushes blood out into the arteries.
2. Diastolic pressure: This is the pressure when the heart rests between beats, allowing it to fill with blood.

Normal blood pressure for adults is typically around 120/80 mmHg, although this can vary slightly depending on age, sex, and other factors. High blood pressure (hypertension) is generally considered to be a reading of 130/80 mmHg or higher, while low blood pressure (hypotension) is usually defined as a reading below 90/60 mmHg. It's important to note that blood pressure can fluctuate throughout the day and may be affected by factors such as stress, physical activity, and medication use.

"Pre-excitation, Mahaim-type" is a medical term used to describe a specific electrical conduction pattern in the heart that can lead to an abnormal heart rhythm (arrhythmia). This condition involves an accessory pathway, also known as a "Mahaim fiber," which connects the atria (the upper chambers of the heart) to the ventricles (the lower chambers) in a way that bypasses the normal conduction system.

In this type of pre-excitation, the electrical impulses travel through the accessory pathway and reach the ventricles earlier than they would via the normal conduction system, resulting in a characteristic pattern on an electrocardiogram (ECG) known as a "delta wave." This pre-excitation can lead to tachyarrhythmias such as atrioventricular reentrant tachycardia (AVRT), which can cause symptoms like palpitations, dizziness, or even syncope (fainting).

It's important to note that not all individuals with Mahaim-type pre-excitation will develop arrhythmias, but some may require treatment if they experience symptoms or have a high risk of complications. Treatment options include medications, catheter ablation, or surgical intervention.

Verapamil is a calcium channel blocker medication that is primarily used to treat hypertension (high blood pressure), angina (chest pain), and certain types of cardiac arrhythmias (irregular heart rhyats). It works by relaxing the smooth muscle cells in the walls of blood vessels, which causes them to dilate or widen, reducing the resistance to blood flow and thereby lowering blood pressure. Verapamil also slows down the conduction of electrical signals within the heart, which can help to regulate the heart rate and rhythm.

In addition to its cardiovascular effects, verapamil is sometimes used off-label for the treatment of other conditions such as migraine headaches, Raynaud's phenomenon, and certain types of tremors. It is available in various forms, including immediate-release tablets, extended-release capsules, and intravenous (IV) injection.

It is important to note that verapamil can interact with other medications, so it is essential to inform your healthcare provider about all the drugs you are taking before starting this medication. Additionally, verapamil should be used with caution in people with certain medical conditions, such as heart failure, liver disease, and low blood pressure.

In medical terms, the heart is a muscular organ located in the thoracic cavity that functions as a pump to circulate blood throughout the body. It's responsible for delivering oxygen and nutrients to the tissues and removing carbon dioxide and other wastes. The human heart is divided into four chambers: two atria on the top and two ventricles on the bottom. The right side of the heart receives deoxygenated blood from the body and pumps it to the lungs, while the left side receives oxygenated blood from the lungs and pumps it out to the rest of the body. The heart's rhythmic contractions and relaxations are regulated by a complex electrical conduction system.

Atrioventricular (AV) block is a disorder of the electrical conduction system of the heart that causes a delay or interruption in the transmission of electrical signals from the atria (the upper chambers of the heart) to the ventricles (the lower chambers of the heart). This results in an abnormal heart rhythm, also known as an arrhythmia.

There are three degrees of AV block:

1. First-degree AV block: In this type of AV block, there is a delay in the conduction of electrical signals from the atria to the ventricles, but all signals are eventually conducted. This condition may not cause any symptoms and is often discovered during a routine electrocardiogram (ECG).
2. Second-degree AV block: In this type of AV block, some electrical signals from the atria are not conducted to the ventricles. There are two types of second-degree AV block: Mobitz type I and Mobitz type II. Mobitz type I is characterized by a progressive prolongation of the PR interval (the time between the electrical activation of the atria and ventricles) until a QRS complex (which represents the electrical activation of the ventricles) is dropped. Mobitz type II is characterized by a constant PR interval with occasional non-conducted P waves.
3. Third-degree AV block: In this type of AV block, no electrical signals are conducted from the atria to the ventricles. The atria and ventricles beat independently of each other, resulting in a slow heart rate (bradycardia) and an irregular rhythm. This condition can be life-threatening if not treated promptly.

The causes of AV block include aging, heart disease, medications, and certain medical conditions such as hypothyroidism and Lyme disease. Treatment depends on the severity of the condition and may include medication, a pacemaker, or surgery.

Propranolol is a medication that belongs to a class of drugs called beta blockers. Medically, it is defined as a non-selective beta blocker, which means it blocks the effects of both epinephrine (adrenaline) and norepinephrine (noradrenaline) on the heart and other organs. These effects include reducing heart rate, contractility, and conduction velocity, leading to decreased oxygen demand by the myocardium. Propranolol is used in the management of various conditions such as hypertension, angina pectoris, arrhythmias, essential tremor, anxiety disorders, and infants with congenital heart defects. It may also be used to prevent migraines and reduce the risk of future heart attacks. As with any medication, it should be taken under the supervision of a healthcare provider due to potential side effects and contraindications.

Hemodynamics is the study of how blood flows through the cardiovascular system, including the heart and the vascular network. It examines various factors that affect blood flow, such as blood volume, viscosity, vessel length and diameter, and pressure differences between different parts of the circulatory system. Hemodynamics also considers the impact of various physiological and pathological conditions on these variables, and how they in turn influence the function of vital organs and systems in the body. It is a critical area of study in fields such as cardiology, anesthesiology, and critical care medicine.

Myocardial infarction (MI), also known as a heart attack, is a medical condition characterized by the death of a segment of heart muscle (myocardium) due to the interruption of its blood supply. This interruption is most commonly caused by the blockage of a coronary artery by a blood clot formed on the top of an atherosclerotic plaque, which is a buildup of cholesterol and other substances in the inner lining of the artery.

The lack of oxygen and nutrients supply to the heart muscle tissue results in damage or death of the cardiac cells, causing the affected area to become necrotic. The extent and severity of the MI depend on the size of the affected area, the duration of the occlusion, and the presence of collateral circulation.

Symptoms of a myocardial infarction may include chest pain or discomfort, shortness of breath, nausea, lightheadedness, and sweating. Immediate medical attention is necessary to restore blood flow to the affected area and prevent further damage to the heart muscle. Treatment options for MI include medications, such as thrombolytics, antiplatelet agents, and pain relievers, as well as procedures such as percutaneous coronary intervention (PCI) or coronary artery bypass grafting (CABG).

Digoxin is a medication that belongs to a class of drugs called cardiac glycosides. It is used to treat various heart conditions, such as heart failure and atrial fibrillation, by helping the heart beat stronger and more regularly. Digoxin works by inhibiting the sodium-potassium pump in heart muscle cells, which leads to an increase in intracellular calcium and a strengthening of heart contractions. It is important to monitor digoxin levels closely, as too much can lead to toxicity and serious side effects.

The sinoatrial (SA) node, also known as the sinus node, is the primary pacemaker of the heart. It is a small bundle of specialized cardiac conduction tissue located in the upper part of the right atrium, near the entrance of the superior vena cava. The SA node generates electrical impulses that initiate each heartbeat, causing the atria to contract and pump blood into the ventricles. This process is called sinus rhythm.

The SA node's electrical activity is regulated by the autonomic nervous system, which can adjust the heart rate in response to changes in the body's needs, such as during exercise or rest. The SA node's rate of firing determines the heart rate, with a normal resting heart rate ranging from 60 to 100 beats per minute.

If the SA node fails to function properly or its electrical impulses are blocked, other secondary pacemakers in the heart may take over, resulting in abnormal heart rhythms called arrhythmias.

Mexiletine is defined as an antiarrhythmic agent, classified as a Class IB medication. It works by blocking sodium channels in the heart, which helps to stabilize cardiac membranes and reduces the rate of firing of cardiac cells. This makes it useful for treating certain types of irregular heart rhythms (ventricular arrhythmias).

Mexiletine is also known to have analgesic properties and is sometimes used off-label for the treatment of neuropathic pain. It is available in oral form, and its use should be under the close supervision of a healthcare provider due to its potential side effects, which can include gastrointestinal symptoms, dizziness, tremors, and cardiac arrhythmias.

A tilt-table test is a diagnostic procedure used to evaluate symptoms of syncope (fainting) or near-syncope. It measures your body's cardiovascular response to changes in position. During the test, you lie on a table that can be tilted to change the angle of your body from horizontal to upright. This simulates what happens when you stand up from a lying down position.

The test monitors heart rate, blood pressure, and oxygen levels while you're in different positions. If you experience symptoms like dizziness or fainting during the test, these can provide clues about the cause of your symptoms. The test is used to diagnose conditions like orthostatic hypotension (a sudden drop in blood pressure when standing), vasovagal syncope (fainting due to an overactive vagus nerve), and other heart rhythm disorders.

Retrospective studies, also known as retrospective research or looking back studies, are a type of observational study that examines data from the past to draw conclusions about possible causal relationships between risk factors and outcomes. In these studies, researchers analyze existing records, medical charts, or previously collected data to test a hypothesis or answer a specific research question.

Retrospective studies can be useful for generating hypotheses and identifying trends, but they have limitations compared to prospective studies, which follow participants forward in time from exposure to outcome. Retrospective studies are subject to biases such as recall bias, selection bias, and information bias, which can affect the validity of the results. Therefore, retrospective studies should be interpreted with caution and used primarily to generate hypotheses for further testing in prospective studies.

Ventricular dysfunction is a term that refers to the impaired ability of the ventricles, which are the lower chambers of the heart, to fill with blood or pump it efficiently to the rest of the body. This condition can lead to reduced cardiac output and may cause symptoms such as shortness of breath, fatigue, and fluid retention.

There are two types of ventricular dysfunction:

1. Systolic dysfunction: This occurs when the ventricles cannot contract forcefully enough to eject an adequate amount of blood out of the heart during each beat. This is often due to damage to the heart muscle, such as that caused by a heart attack or cardiomyopathy.
2. Diastolic dysfunction: This happens when the ventricles are unable to relax and fill properly with blood between beats. This can be caused by stiffening of the heart muscle, often due to aging, high blood pressure, or diabetes.

Both types of ventricular dysfunction can lead to heart failure, a serious condition in which the heart is unable to pump blood effectively to meet the body's needs. Treatment for ventricular dysfunction may include medications, lifestyle changes, and in some cases, medical procedures or surgery.

Electrocoagulation is a medical procedure that uses heat generated from an electrical current to cause coagulation (clotting) of tissue. This procedure is often used to treat a variety of medical conditions, such as:

* Gastrointestinal bleeding: Electrocoagulation can be used to control bleeding in the stomach or intestines by applying an electrical current to the affected blood vessels, causing them to shrink and clot.
* Skin lesions: Electrocoagulation can be used to remove benign or malignant skin lesions, such as warts, moles, or skin tags, by applying an electrical current to the growth, which causes it to dehydrate and eventually fall off.
* Vascular malformations: Electrocoagulation can be used to treat vascular malformations (abnormal blood vessels) by applying an electrical current to the affected area, causing the abnormal vessels to shrink and clot.

The procedure is typically performed using a specialized device that delivers an electrical current through a needle or probe. The intensity and duration of the electrical current can be adjusted to achieve the desired effect. Electrocoagulation may be used alone or in combination with other treatments, such as surgery or medication.

It's important to note that electrocoagulation is not without risks, including burns, infection, and scarring. It should only be performed by a qualified medical professional who has experience with the procedure.

Calsequestrin is a protein found primarily in the sarcoplasmic reticulum of muscle cells, including both cardiac and skeletal muscles. It plays a crucial role in muscle function by binding calcium ions (Ca²+) and regulating calcium release during muscle contraction and relaxation cycles.

There are two main types of calsequestrin:

1. Calsequestrin 1 (CSQ1): This form is predominantly found in the sarcoplasmic reticulum of fast-twitch skeletal muscle fibers, which have a higher contraction speed and fatigability. CSQ1 has a high capacity for calcium binding but a lower affinity compared to calsequestrin 2.
2. Calsequestrin 2 (CSQ2): This form is primarily found in the sarcoplasmic reticulum of cardiac and slow-twitch skeletal muscle fibers, which have a lower contraction speed and fatigability. CSQ2 has a lower capacity for calcium binding but a higher affinity compared to calsequestrin 1.

Calsequestrin's ability to bind large amounts of calcium ions helps maintain low cytoplasmic calcium concentrations during muscle relaxation, while also serving as a reservoir for rapid calcium release during muscle contraction. Dysregulation of calsequestrin function has been implicated in several muscle disorders, including certain forms of cardiomyopathy and neuromuscular diseases.

Echocardiography is a medical procedure that uses sound waves to produce detailed images of the heart's structure, function, and motion. It is a non-invasive test that can help diagnose various heart conditions, such as valve problems, heart muscle damage, blood clots, and congenital heart defects.

During an echocardiogram, a transducer (a device that sends and receives sound waves) is placed on the chest or passed through the esophagus to obtain images of the heart. The sound waves produced by the transducer bounce off the heart structures and return to the transducer, which then converts them into electrical signals that are processed to create images of the heart.

There are several types of echocardiograms, including:

* Transthoracic echocardiography (TTE): This is the most common type of echocardiogram and involves placing the transducer on the chest.
* Transesophageal echocardiography (TEE): This type of echocardiogram involves passing a specialized transducer through the esophagus to obtain images of the heart from a closer proximity.
* Stress echocardiography: This type of echocardiogram is performed during exercise or medication-induced stress to assess how the heart functions under stress.
* Doppler echocardiography: This type of echocardiogram uses sound waves to measure blood flow and velocity in the heart and blood vessels.

Echocardiography is a valuable tool for diagnosing and managing various heart conditions, as it provides detailed information about the structure and function of the heart. It is generally safe, non-invasive, and painless, making it a popular choice for doctors and patients alike.

Cardiac catheterization is a medical procedure used to diagnose and treat cardiovascular conditions. In this procedure, a thin, flexible tube called a catheter is inserted into a blood vessel in the arm or leg and threaded up to the heart. The catheter can be used to perform various diagnostic tests, such as measuring the pressure inside the heart chambers and assessing the function of the heart valves.

Cardiac catheterization can also be used to treat certain cardiovascular conditions, such as narrowed or blocked arteries. In these cases, a balloon or stent may be inserted through the catheter to open up the blood vessel and improve blood flow. This procedure is known as angioplasty or percutaneous coronary intervention (PCI).

Cardiac catheterization is typically performed in a hospital cardiac catheterization laboratory by a team of healthcare professionals, including cardiologists, radiologists, and nurses. The procedure may be done under local anesthesia with sedation or general anesthesia, depending on the individual patient's needs and preferences.

Overall, cardiac catheterization is a valuable tool in the diagnosis and treatment of various heart conditions, and it can help improve symptoms, reduce complications, and prolong life for many patients.

Sudden death is a term used to describe a situation where a person dies abruptly and unexpectedly, often within minutes to hours of the onset of symptoms. It is typically caused by cardiac or respiratory arrest, which can be brought on by various medical conditions such as heart disease, stroke, severe infections, drug overdose, or trauma. In some cases, the exact cause of sudden death may remain unknown even after a thorough post-mortem examination.

It is important to note that sudden death should not be confused with "sudden cardiac death," which specifically refers to deaths caused by the abrupt loss of heart function (cardiac arrest). Sudden cardiac death is often related to underlying heart conditions such as coronary artery disease, cardiomyopathy, or electrical abnormalities in the heart.

Isoproterenol is a medication that belongs to a class of drugs called beta-adrenergic agonists. Medically, it is defined as a synthetic catecholamine with both alpha and beta adrenergic receptor stimulating properties. It is primarily used as a bronchodilator to treat conditions such as asthma and chronic obstructive pulmonary disease (COPD) by relaxing the smooth muscles in the airways, thereby improving breathing.

Isoproterenol can also be used in the treatment of bradycardia (abnormally slow heart rate), cardiac arrest, and heart blocks by increasing the heart rate and contractility. However, due to its non-selective beta-agonist activity, it may cause various side effects such as tremors, palpitations, and increased blood pressure. Its use is now limited due to the availability of more selective and safer medications.

Right atrial function refers to the role and performance of the right atrium in the heart. The right atrium is one of the four chambers of the heart and is responsible for receiving deoxygenated blood from the body via the superior and inferior vena cava. It then contracts to help pump the blood into the right ventricle, which subsequently sends it to the lungs for oxygenation.

Right atrial function can be assessed through various methods, including echocardiography, cardiac magnetic resonance imaging (MRI), and electrocardiogram (ECG). Abnormalities in right atrial function may indicate underlying heart conditions such as right-sided heart failure, atrial fibrillation, or other cardiovascular diseases. Proper evaluation and monitoring of right atrial function are essential for effective diagnosis, treatment, and management of these conditions.

Fetal diseases are medical conditions or abnormalities that affect a fetus during pregnancy. These diseases can be caused by genetic factors, environmental influences, or a combination of both. They can range from mild to severe and may impact various organ systems in the developing fetus. Examples of fetal diseases include congenital heart defects, neural tube defects, chromosomal abnormalities such as Down syndrome, and infectious diseases such as toxoplasmosis or rubella. Fetal diseases can be diagnosed through prenatal testing, including ultrasound, amniocentesis, and chorionic villus sampling. Treatment options may include medication, surgery, or delivery of the fetus, depending on the nature and severity of the disease.

Dilated cardiomyopathy (DCM) is a type of cardiomyopathy characterized by the enlargement and weakened contraction of the heart's main pumping chamber (the left ventricle). This enlargement and weakness can lead to symptoms such as shortness of breath, fatigue, and fluid retention. DCM can be caused by various factors including genetics, viral infections, alcohol and drug abuse, and other medical conditions like high blood pressure and diabetes. It is important to note that this condition can lead to heart failure if left untreated.

The refractory period, electrophysiological, refers to the time interval during which a cardiac or neural cell is unable to respond to a new stimulus immediately after an action potential has been generated. This period is divided into two phases: the absolute refractory period and the relative refractory period.

During the absolute refractory period, the cell cannot be re-stimulated, regardless of the strength of the stimulus, due to the rapid inactivation of voltage-gated sodium channels that are responsible for the rapid depolarization during an action potential. This phase is crucial for maintaining the unidirectional conduction of electrical impulses and preventing the occurrence of re-entry circuits, which can lead to life-threatening arrhythmias in the heart or hyperexcitability in neural tissue.

The relative refractory period follows the absolute refractory period and is characterized by a reduced excitability of the cell. During this phase, a stronger than normal stimulus is required to elicit an action potential due to the slower recovery of voltage-gated sodium channels and the partial activation of potassium channels, which promote repolarization. The duration of both the absolute and relative refractory periods varies depending on the cell type, its physiological state, and other factors such as temperature and pH.

In summary, the electrophysiological refractory period is a fundamental property of excitable cells that ensures proper electrical signaling and prevents uncontrolled excitation or re-entry circuits.

Prospective studies, also known as longitudinal studies, are a type of cohort study in which data is collected forward in time, following a group of individuals who share a common characteristic or exposure over a period of time. The researchers clearly define the study population and exposure of interest at the beginning of the study and follow up with the participants to determine the outcomes that develop over time. This type of study design allows for the investigation of causal relationships between exposures and outcomes, as well as the identification of risk factors and the estimation of disease incidence rates. Prospective studies are particularly useful in epidemiology and medical research when studying diseases with long latency periods or rare outcomes.

A cicatrix is a medical term that refers to a scar or the process of scar formation. It is the result of the healing process following damage to body tissues, such as from an injury, wound, or surgery. During the healing process, specialized cells called fibroblasts produce collagen, which helps to reconnect and strengthen the damaged tissue. The resulting scar tissue may have a different texture, color, or appearance compared to the surrounding healthy tissue.

Cicatrix formation is a natural part of the body's healing response, but excessive scarring can sometimes cause functional impairment, pain, or cosmetic concerns. In such cases, various treatments may be used to minimize or improve the appearance of scars, including topical creams, steroid injections, laser therapy, and surgical revision.

Cardiac arrest, also known as heart arrest, is a medical condition where the heart suddenly stops beating or functioning properly. This results in the cessation of blood flow to the rest of the body, including the brain, leading to loss of consciousness and pulse. Cardiac arrest is often caused by electrical disturbances in the heart that disrupt its normal rhythm, known as arrhythmias. If not treated immediately with cardiopulmonary resuscitation (CPR) and defibrillation, it can lead to death or permanent brain damage due to lack of oxygen supply. It's important to note that a heart attack is different from cardiac arrest; a heart attack occurs when blood flow to a part of the heart is blocked, often by a clot, causing damage to the heart muscle, but the heart continues to beat. However, a heart attack can sometimes trigger a cardiac arrest.

Long QT syndrome (LQTS) is a cardiac electrical disorder characterized by a prolonged QT interval on the electrocardiogram (ECG), which can potentially trigger rapid, chaotic heartbeats known as ventricular tachyarrhythmias, such as torsades de pointes. These arrhythmias can be life-threatening and lead to syncope (fainting) or sudden cardiac death. LQTS is often congenital but may also be acquired due to certain medications, medical conditions, or electrolyte imbalances. It's essential to identify and manage LQTS promptly to reduce the risk of severe complications.

Atrial premature complexes (APCs or APCTs) are extra heartbeats that originate in the atria, which are the upper chambers of the heart. These early beats disrupt the normal rhythm and cause a premature contraction before the next scheduled beat. APCs can sometimes be felt as a "skipped" beat or palpitation. They are usually benign and do not require treatment unless they occur frequently or are associated with underlying heart disease.

Pulmonary veins are blood vessels that carry oxygenated blood from the lungs to the left atrium of the heart. There are four pulmonary veins in total, two from each lung, and they are the only veins in the body that carry oxygen-rich blood. The oxygenated blood from the pulmonary veins is then pumped by the left ventricle to the rest of the body through the aorta. Any blockage or damage to the pulmonary veins can lead to various cardiopulmonary conditions, such as pulmonary hypertension and congestive heart failure.

Torsades de Pointes is a type of polymorphic ventricular tachycardia, characterized by a distinct pattern on the electrocardiogram (ECG) where the QRS complexes appear to twist around the isoelectric line. This condition is often associated with a prolonged QT interval, which can be congenital or acquired due to various factors such as medications, electrolyte imbalances, or heart diseases. Torsades de Pointes can degenerate into ventricular fibrillation, leading to sudden cardiac death if not promptly treated.

Brugada Syndrome is a genetic disorder characterized by abnormal electrocardiogram (ECG) findings and an increased risk of sudden cardiac death. It is typically caused by a mutation in the SCN5A gene, which encodes for a sodium channel protein in the heart. This mutation can lead to abnormal ion transport in the heart cells, causing changes in the electrical activity of the heart that can trigger dangerous arrhythmias.

The ECG findings associated with Brugada Syndrome include a distinct pattern of ST-segment elevation in the right precordial leads (V1-V3), which can appear spontaneously or be induced by certain medications. The syndrome is often classified into two types based on the presence or absence of symptoms:

* Type 1 Brugada Syndrome: This type is characterized by a coved-type ST-segment elevation of at least 2 mm in height in at least one right precordial lead, with a negative T wave. This pattern must be present to make the diagnosis, and it should not be transient or induced by any medication or condition. Type 1 Brugada Syndrome is associated with a higher risk of sudden cardiac death.
* Type 2 Brugada Syndrome: This type is characterized by a saddleback-type ST-segment elevation of at least 2 mm in height in at least one right precordial lead, with a positive or biphasic T wave. The ST segment should return to the baseline level or below within 0.08 seconds after the J point (the junction between the QRS complex and the ST segment). Type 2 Brugada Syndrome is associated with a lower risk of sudden cardiac death compared to Type 1, but it can still pose a significant risk in some individuals.

Brugada Syndrome can affect people of any age, gender, or ethnicity, although it is more commonly diagnosed in middle-aged men of Asian descent. The syndrome can be inherited in an autosomal dominant manner, meaning that a child has a 50% chance of inheriting the mutation from a parent who carries the gene. However, not all individuals with the genetic mutation will develop symptoms or have abnormal ECG findings.

Treatment for Brugada Syndrome typically involves implanting a cardioverter-defibrillator (ICD) to prevent sudden cardiac death. Medications such as quinidine or isoproterenol may also be used to reduce the risk of arrhythmias. Lifestyle modifications, such as avoiding alcohol and certain medications that can trigger arrhythmias, may also be recommended.

The sympathetic nervous system (SNS) is a part of the autonomic nervous system that operates largely below the level of consciousness, and it functions to produce appropriate physiological responses to perceived danger. It's often associated with the "fight or flight" response. The SNS uses nerve impulses to stimulate target organs, causing them to speed up (e.g., increased heart rate), prepare for action, or otherwise respond to stressful situations.

The sympathetic nervous system is activated due to stressful emotional or physical situations and it prepares the body for immediate actions. It dilates the pupils, increases heart rate and blood pressure, accelerates breathing, and slows down digestion. The primary neurotransmitter involved in this system is norepinephrine (also known as noradrenaline).

The coronary sinus is a large vein that receives blood from the heart's muscle tissue. It is located on the posterior side of the heart and is a part of the cardiovascular system. The coronary sinus collects oxygen-depleted blood from the myocardium (the heart muscle) and drains it into the right atrium, where it will then be pumped to the lungs for oxygenation.

The coronary sinus is an essential structure in medical procedures such as cardiac catheterization and electrophysiological studies. It is also a common site for the implantation of pacemakers and other cardiac devices.

Purkinje fibers are specialized cardiac muscle fibers that are located in the subendocardial region of the inner ventricular walls of the heart. They play a crucial role in the electrical conduction system of the heart, transmitting electrical impulses from the bundle branches to the ventricular myocardium, which enables the coordinated contraction of the ventricles during each heartbeat.

These fibers have a unique structure that allows for rapid and efficient conduction of electrical signals. They are larger in diameter than regular cardiac muscle fibers, have fewer branching points, and possess more numerous mitochondria and a richer blood supply. These features enable Purkinje fibers to conduct electrical impulses at faster speeds, ensuring that the ventricles contract simultaneously and forcefully, promoting efficient pumping of blood throughout the body.

Propanolamines are a class of pharmaceutical compounds that contain a propan-2-olamine functional group, which is a secondary amine formed by the replacement of one hydrogen atom in an ammonia molecule with a propan-2-ol group. They are commonly used as decongestants and bronchodilators in medical treatments.

Examples of propanolamines include:

* Phenylephrine: a decongestant used to relieve nasal congestion.
* Pseudoephedrine: a decongestant and stimulant used to treat nasal congestion and sinus pressure.
* Ephedrine: a bronchodilator, decongestant, and stimulant used to treat asthma, nasal congestion, and low blood pressure.

It is important to note that propanolamines can have side effects such as increased heart rate, elevated blood pressure, and insomnia, so they should be used with caution and under the supervision of a healthcare professional.

Disopyramide is an antiarrhythmic medication that is primarily used to treat certain types of irregular heart rhythms (arrhythmias), such as ventricular tachycardia and atrial fibrillation. It works by blocking the activity of sodium channels in the heart, which helps to slow down and regulate the heart rate.

Disopyramide is available in immediate-release and extended-release forms, and it may be taken orally as a tablet or capsule. Common side effects of this medication include dry mouth, blurred vision, constipation, and difficulty urinating. More serious side effects can include dizziness, fainting, irregular heartbeat, and allergic reactions.

It is important to take disopyramide exactly as directed by a healthcare provider, as improper use or dosing can lead to serious complications. Additionally, individuals with certain medical conditions, such as heart failure, kidney disease, or myasthenia gravis, may not be able to safely take this medication.

Catecholamines are a group of hormones and neurotransmitters that are derived from the amino acid tyrosine. The most well-known catecholamines are dopamine, norepinephrine (also known as noradrenaline), and epinephrine (also known as adrenaline). These hormones are produced by the adrenal glands and are released into the bloodstream in response to stress. They play important roles in the "fight or flight" response, increasing heart rate, blood pressure, and alertness. In addition to their role as hormones, catecholamines also function as neurotransmitters, transmitting signals in the nervous system. Disorders of catecholamine regulation can lead to a variety of medical conditions, including hypertension, mood disorders, and neurological disorders.

The Ryanodine Receptor (RyR) is a calcium release channel located on the sarcoplasmic reticulum (SR), a type of endoplasmic reticulum found in muscle cells. It plays a crucial role in excitation-contraction coupling, which is the process by which electrical signals are converted into mechanical responses in muscle fibers.

In more detail, when an action potential reaches the muscle fiber's surface membrane, it triggers the opening of voltage-gated L-type calcium channels (Dihydropyridine Receptors or DHPRs) in the sarcolemma (the cell membrane of muscle fibers). This influx of calcium ions into the cytoplasm causes a conformational change in the RyR, leading to its own opening and the release of stored calcium from the SR into the cytoplasm. The increased cytoplasmic calcium concentration then initiates muscle contraction through interaction with contractile proteins like actin and myosin.

There are three isoforms of RyR: RyR1, RyR2, and RyR3. RyR1 is primarily found in skeletal muscle, while RyR2 is predominantly expressed in cardiac muscle. Both RyR1 and RyR2 are large homotetrameric proteins with a molecular weight of approximately 2.2 million Daltons. They contain multiple domains including an ion channel pore, regulatory domains, and a foot structure that interacts with DHPRs. RyR3 is more widely distributed, being found in various tissues such as the brain, smooth muscle, and some types of neurons.

Dysfunction of these channels has been implicated in several diseases including malignant hyperthermia, central core disease, catecholaminergic polymorphic ventricular tachycardia (CPVT), and certain forms of heart failure.

Stroke volume is a term used in cardiovascular physiology and medicine. It refers to the amount of blood that is pumped out of the left ventricle of the heart during each contraction (systole). Specifically, it is the difference between the volume of blood in the left ventricle at the end of diastole (when the ventricle is filled with blood) and the volume at the end of systole (when the ventricle has contracted and ejected its contents into the aorta).

Stroke volume is an important measure of heart function, as it reflects the ability of the heart to pump blood effectively to the rest of the body. A low stroke volume may indicate that the heart is not pumping efficiently, while a high stroke volume may suggest that the heart is working too hard. Stroke volume can be affected by various factors, including heart disease, high blood pressure, and physical fitness level.

The formula for calculating stroke volume is:

Stroke Volume = End-Diastolic Volume - End-Systolic Volume

Where end-diastolic volume (EDV) is the volume of blood in the left ventricle at the end of diastole, and end-systolic volume (ESV) is the volume of blood in the left ventricle at the end of systole.

Orthostatic intolerance is a condition in which an individual experiences lightheadedness, dizziness, or fainting when standing or maintaining an upright position for extended periods. It is caused by an abnormal physiological response to gravity and results in inadequate blood flow to the brain upon standing.

The medical definition of orthostatic intolerance includes symptoms that are exacerbated by upright posture and relieved by recumbent (lying down) position. The underlying mechanisms involve dysfunction in the autonomic nervous system, which controls involuntary bodily functions such as heart rate, blood pressure, and vasoconstriction.

Orthostatic intolerance can be a symptom of various medical conditions, including postural orthostatic tachycardia syndrome (POTS), neurogenic orthostatic hypotension, and other autonomic disorders. Proper diagnosis and management require a thorough evaluation by a healthcare professional to identify the underlying cause and develop an appropriate treatment plan.

The Sinus of Valsalva are three pouch-like dilations or outpouchings located at the upper part (root) of the aorta, just above the aortic valve. They are named after Antonio Maria Valsalva, an Italian anatomist and physician. These sinuses are divided into three parts:

1. Right Sinus of Valsalva: It is located to the right of the ascending aorta and usually gives rise to the right coronary artery.
2. Left Sinus of Valsalva: It is situated to the left of the ascending aorta and typically gives rise to the left coronary artery.
3. Non-coronary Sinus of Valsalva: This sinus is located in between the right and left coronary sinuses, and it does not give rise to any coronary arteries.

These sinuses play a crucial role during the cardiac cycle, particularly during ventricular contraction (systole). The pressure difference between the aorta and the ventricles causes the aortic valve cusps to be pushed into these sinuses, preventing the backflow of blood from the aorta into the ventricles.

Anatomical variations in the size and shape of the Sinuses of Valsalva can occur, and certain conditions like congenital heart diseases (e.g., aortic valve stenosis or bicuspid aortic valve) may affect their structure and function. Additionally, aneurysms or ruptures of the sinuses can lead to severe complications, such as cardiac tamponade, endocarditis, or stroke.

The Predictive Value of Tests, specifically the Positive Predictive Value (PPV) and Negative Predictive Value (NPV), are measures used in diagnostic tests to determine the probability that a positive or negative test result is correct.

Positive Predictive Value (PPV) is the proportion of patients with a positive test result who actually have the disease. It is calculated as the number of true positives divided by the total number of positive results (true positives + false positives). A higher PPV indicates that a positive test result is more likely to be a true positive, and therefore the disease is more likely to be present.

Negative Predictive Value (NPV) is the proportion of patients with a negative test result who do not have the disease. It is calculated as the number of true negatives divided by the total number of negative results (true negatives + false negatives). A higher NPV indicates that a negative test result is more likely to be a true negative, and therefore the disease is less likely to be present.

The predictive value of tests depends on the prevalence of the disease in the population being tested, as well as the sensitivity and specificity of the test. A test with high sensitivity and specificity will generally have higher predictive values than a test with low sensitivity and specificity. However, even a highly sensitive and specific test can have low predictive values if the prevalence of the disease is low in the population being tested.

Accelerated idioventricular rhythm (AIVR) is a type of cardiac arrhythmia, which refers to an abnormal heart rhythm. In AIVR, the ventricles of the heart beat at a rate that is faster than normal but still slower than the rate seen in ventricular tachycardia. Specifically, the ventricular rate in AIVR is typically between 60 and 100 beats per minute.

AIVR originates from the ventricles of the heart, rather than from the normal pacemaker of the heart, which is located in the sinoatrial node in the right atrium. This means that the ventricles are activating themselves independently of the atria, resulting in a dissociation between the two chambers of the heart.

AIVR is often seen in patients who have underlying heart disease, such as myocardial infarction (heart attack), cardiomyopathy, or heart failure. It can also occur after cardiac surgery or other invasive procedures. In many cases, AIVR is benign and requires no treatment. However, if it is associated with hemodynamic instability or other symptoms, such as palpitations, shortness of breath, or chest pain, then further evaluation and treatment may be necessary.

Computer-assisted signal processing is a medical term that refers to the use of computer algorithms and software to analyze, interpret, and extract meaningful information from biological signals. These signals can include physiological data such as electrocardiogram (ECG) waves, electromyography (EMG) signals, electroencephalography (EEG) readings, or medical images.

The goal of computer-assisted signal processing is to automate the analysis of these complex signals and extract relevant features that can be used for diagnostic, monitoring, or therapeutic purposes. This process typically involves several steps, including:

1. Signal acquisition: Collecting raw data from sensors or medical devices.
2. Preprocessing: Cleaning and filtering the data to remove noise and artifacts.
3. Feature extraction: Identifying and quantifying relevant features in the signal, such as peaks, troughs, or patterns.
4. Analysis: Applying statistical or machine learning algorithms to interpret the extracted features and make predictions about the underlying physiological state.
5. Visualization: Presenting the results in a clear and intuitive way for clinicians to review and use.

Computer-assisted signal processing has numerous applications in healthcare, including:

* Diagnosing and monitoring cardiac arrhythmias or other heart conditions using ECG signals.
* Assessing muscle activity and function using EMG signals.
* Monitoring brain activity and diagnosing neurological disorders using EEG readings.
* Analyzing medical images to detect abnormalities, such as tumors or fractures.

Overall, computer-assisted signal processing is a powerful tool for improving the accuracy and efficiency of medical diagnosis and monitoring, enabling clinicians to make more informed decisions about patient care.

Congenital heart defects (CHDs) are structural abnormalities in the heart that are present at birth. They can affect any part of the heart's structure, including the walls of the heart, the valves inside the heart, and the major blood vessels that lead to and from the heart.

Congenital heart defects can range from mild to severe and can cause various symptoms depending on the type and severity of the defect. Some common symptoms of CHDs include cyanosis (a bluish tint to the skin, lips, and fingernails), shortness of breath, fatigue, poor feeding, and slow growth in infants and children.

There are many different types of congenital heart defects, including:

1. Septal defects: These are holes in the walls that separate the four chambers of the heart. The two most common septal defects are atrial septal defect (ASD) and ventricular septal defect (VSD).
2. Valve abnormalities: These include narrowed or leaky valves, which can affect blood flow through the heart.
3. Obstruction defects: These occur when blood flow is blocked or restricted due to narrowing or absence of a part of the heart's structure. Examples include pulmonary stenosis and coarctation of the aorta.
4. Cyanotic heart defects: These cause a lack of oxygen in the blood, leading to cyanosis. Examples include tetralogy of Fallot and transposition of the great arteries.

The causes of congenital heart defects are not fully understood, but genetic factors and environmental influences during pregnancy may play a role. Some CHDs can be detected before birth through prenatal testing, while others may not be diagnosed until after birth or later in childhood. Treatment for CHDs may include medication, surgery, or other interventions to improve blood flow and oxygenation of the body's tissues.

Fluoroscopy is a type of medical imaging that uses X-rays to obtain real-time moving images of the internal structures of the body. A continuous X-ray beam is passed through the body part being examined, and the resulting fluoroscopic images are transmitted to a monitor, allowing the medical professional to view the structure and movement of the internal organs and bones in real time.

Fluoroscopy is often used to guide minimally invasive procedures such as catheterization, stent placement, or joint injections. It can also be used to diagnose and monitor a variety of medical conditions, including gastrointestinal disorders, musculoskeletal injuries, and cardiovascular diseases.

It is important to note that fluoroscopy involves exposure to ionizing radiation, and the risks associated with this exposure should be carefully weighed against the benefits of the procedure. Medical professionals are trained to use the lowest possible dose of radiation necessary to obtain the desired diagnostic information.

Adenosine is a purine nucleoside that is composed of a sugar (ribose) and the base adenine. It plays several important roles in the body, including serving as a precursor for the synthesis of other molecules such as ATP, NAD+, and RNA.

In the medical context, adenosine is perhaps best known for its use as a pharmaceutical agent to treat certain cardiac arrhythmias. When administered intravenously, it can help restore normal sinus rhythm in patients with paroxysmal supraventricular tachycardia (PSVT) by slowing conduction through the atrioventricular node and interrupting the reentry circuit responsible for the arrhythmia.

Adenosine can also be used as a diagnostic tool to help differentiate between narrow-complex tachycardias of supraventricular origin and those that originate from below the ventricles (such as ventricular tachycardia). This is because adenosine will typically terminate PSVT but not affect the rhythm of VT.

It's worth noting that adenosine has a very short half-life, lasting only a few seconds in the bloodstream. This means that its effects are rapidly reversible and generally well-tolerated, although some patients may experience transient symptoms such as flushing, chest pain, or shortness of breath.

The Autonomic Nervous System (ANS) is a part of the peripheral nervous system that operates largely below the level of consciousness and controls visceral functions. It is divided into two main subdivisions: the sympathetic and parasympathetic nervous systems, which generally have opposing effects and maintain homeostasis in the body.

The Sympathetic Nervous System (SNS) prepares the body for stressful or emergency situations, often referred to as the "fight or flight" response. It increases heart rate, blood pressure, respiratory rate, and metabolic rate, while also decreasing digestive activity. This response helps the body respond quickly to perceived threats.

The Parasympathetic Nervous System (PNS), on the other hand, promotes the "rest and digest" state, allowing the body to conserve energy and restore itself after the stress response has subsided. It decreases heart rate, blood pressure, and respiratory rate, while increasing digestive activity and promoting relaxation.

These two systems work together to maintain balance in the body by adjusting various functions based on internal and external demands. Disorders of the Autonomic Nervous System can lead to a variety of symptoms, such as orthostatic hypotension, gastroparesis, and cardiac arrhythmias, among others.

Posture is the position or alignment of body parts supported by the muscles, especially the spine and head in relation to the vertebral column. It can be described as static (related to a stationary position) or dynamic (related to movement). Good posture involves training your body to stand, walk, sit, and lie in positions where the least strain is placed on supporting muscles and ligaments during movement or weight-bearing activities. Poor posture can lead to various health issues such as back pain, neck pain, headaches, and respiratory problems.

The ventricular septum is the thick, muscular wall that separates the left and right ventricles, which are the lower chambers of the heart. Its main function is to prevent the oxygen-rich blood in the left ventricle from mixing with the oxygen-poor blood in the right ventricle.

A congenital heart defect called a ventricular septal defect (VSD) can occur when there is an abnormal opening or hole in the ventricular septum, allowing blood to flow between the two ventricles. This can result in various symptoms and complications, depending on the size of the defect and the amount of blood that passes through it. VSDs are typically diagnosed and treated by pediatric cardiologists or cardiac surgeons.

Left ventricular dysfunction (LVD) is a condition characterized by the impaired ability of the left ventricle of the heart to pump blood efficiently during contraction. The left ventricle is one of the four chambers of the heart and is responsible for pumping oxygenated blood to the rest of the body.

LVD can be caused by various underlying conditions, such as coronary artery disease, cardiomyopathy, valvular heart disease, or hypertension. These conditions can lead to structural changes in the left ventricle, including remodeling, hypertrophy, and dilation, which ultimately impair its contractile function.

The severity of LVD is often assessed by measuring the ejection fraction (EF), which is the percentage of blood that is pumped out of the left ventricle during each contraction. A normal EF ranges from 55% to 70%, while an EF below 40% is indicative of LVD.

LVD can lead to various symptoms, such as shortness of breath, fatigue, fluid retention, and decreased exercise tolerance. It can also increase the risk of complications, such as heart failure, arrhythmias, and cardiac arrest. Treatment for LVD typically involves managing the underlying cause, along with medications to improve contractility, reduce fluid buildup, and control heart rate. In severe cases, devices such as implantable cardioverter-defibrillators (ICDs) or left ventricular assist devices (LVADs) may be required.

The myocardium is the middle layer of the heart wall, composed of specialized cardiac muscle cells that are responsible for pumping blood throughout the body. It forms the thickest part of the heart wall and is divided into two sections: the left ventricle, which pumps oxygenated blood to the rest of the body, and the right ventricle, which pumps deoxygenated blood to the lungs.

The myocardium contains several types of cells, including cardiac muscle fibers, connective tissue, nerves, and blood vessels. The muscle fibers are arranged in a highly organized pattern that allows them to contract in a coordinated manner, generating the force necessary to pump blood through the heart and circulatory system.

Damage to the myocardium can occur due to various factors such as ischemia (reduced blood flow), infection, inflammation, or genetic disorders. This damage can lead to several cardiac conditions, including heart failure, arrhythmias, and cardiomyopathy.

Atropine is an anticholinergic drug that blocks the action of the neurotransmitter acetylcholine in the central and peripheral nervous system. It is derived from the belladonna alkaloids, which are found in plants such as deadly nightshade (Atropa belladonna), Jimson weed (Datura stramonium), and Duboisia spp.

In clinical medicine, atropine is used to reduce secretions, increase heart rate, and dilate the pupils. It is often used before surgery to dry up secretions in the mouth, throat, and lungs, and to reduce salivation during the procedure. Atropine is also used to treat certain types of nerve agent and pesticide poisoning, as well as to manage bradycardia (slow heart rate) and hypotension (low blood pressure) caused by beta-blockers or calcium channel blockers.

Atropine can have several side effects, including dry mouth, blurred vision, dizziness, confusion, and difficulty urinating. In high doses, it can cause delirium, hallucinations, and seizures. Atropine should be used with caution in patients with glaucoma, prostatic hypertrophy, or other conditions that may be exacerbated by its anticholinergic effects.

Orthostatic hypotension is a type of low blood pressure that occurs when you stand up from a sitting or lying position. The drop in blood pressure causes a brief period of lightheadedness or dizziness, and can even cause fainting in some cases. This condition is also known as postural hypotension.

Orthostatic hypotension is caused by a rapid decrease in blood pressure when you stand up, which reduces the amount of blood that reaches your brain. Normally, when you stand up, your body compensates for this by increasing your heart rate and constricting blood vessels to maintain blood pressure. However, if these mechanisms fail or are impaired, orthostatic hypotension can occur.

Orthostatic hypotension is more common in older adults, but it can also affect younger people who have certain medical conditions or take certain medications. Some of the risk factors for orthostatic hypotension include dehydration, prolonged bed rest, pregnancy, diabetes, heart disease, Parkinson's disease, and certain neurological disorders.

If you experience symptoms of orthostatic hypotension, it is important to seek medical attention. Your healthcare provider can perform tests to determine the underlying cause of your symptoms and recommend appropriate treatment options. Treatment may include lifestyle changes, such as increasing fluid intake, avoiding alcohol and caffeine, and gradually changing positions from lying down or sitting to standing up. In some cases, medication may be necessary to manage orthostatic hypotension.

An action potential is a brief electrical signal that travels along the membrane of a nerve cell (neuron) or muscle cell. It is initiated by a rapid, localized change in the permeability of the cell membrane to specific ions, such as sodium and potassium, resulting in a rapid influx of sodium ions and a subsequent efflux of potassium ions. This ion movement causes a brief reversal of the electrical potential across the membrane, which is known as depolarization. The action potential then propagates along the cell membrane as a wave, allowing the electrical signal to be transmitted over long distances within the body. Action potentials play a crucial role in the communication and functioning of the nervous system and muscle tissue.

Digitalis glycosides are a type of cardiac glycoside that are derived from the foxglove plant (Digitalis purpurea) and related species. These compounds have a steroidal structure with a lactone ring attached to the molecule, which is responsible for their positive inotropic effects on the heart.

The two main digitalis glycosides used clinically are digoxin and digitoxin. They work by inhibiting the sodium-potassium pump in cardiac muscle cells, leading to an increase in intracellular calcium levels and a subsequent enhancement of myocardial contractility. This makes them useful in the treatment of heart failure and atrial arrhythmias such as atrial fibrillation.

However, digitalis glycosides have a narrow therapeutic index, meaning that there is only a small difference between their therapeutic and toxic doses. Therefore, they must be administered with caution and patients should be closely monitored for signs of toxicity such as nausea, vomiting, visual disturbances, and cardiac arrhythmias.

Hypertrophic cardiomyopathy (HCM) is a genetic disorder characterized by the thickening of the heart muscle, specifically the ventricles (the lower chambers of the heart that pump blood out to the body). This thickening can make it harder for the heart to pump blood effectively, which can lead to symptoms such as shortness of breath, chest pain, and fatigue. In some cases, HCM can also cause abnormal heart rhythms (arrhythmias) and may increase the risk of sudden cardiac death.

The thickening of the heart muscle in HCM is caused by an overgrowth of the cells that make up the heart muscle, known as cardiomyocytes. This overgrowth can be caused by mutations in any one of several genes that encode proteins involved in the structure and function of the heart muscle. These genetic mutations are usually inherited from a parent, but they can also occur spontaneously in an individual with no family history of the disorder.

HCM is typically diagnosed using echocardiography (a type of ultrasound that uses sound waves to create images of the heart) and other diagnostic tests such as electrocardiogram (ECG) and cardiac magnetic resonance imaging (MRI). Treatment for HCM may include medications to help manage symptoms, lifestyle modifications, and in some cases, surgical procedures or implantable devices to help prevent or treat arrhythmias.

Postoperative complications refer to any unfavorable condition or event that occurs during the recovery period after a surgical procedure. These complications can vary in severity and may include, but are not limited to:

1. Infection: This can occur at the site of the incision or inside the body, such as pneumonia or urinary tract infection.
2. Bleeding: Excessive bleeding (hemorrhage) can lead to a drop in blood pressure and may require further surgical intervention.
3. Blood clots: These can form in the deep veins of the legs (deep vein thrombosis) and can potentially travel to the lungs (pulmonary embolism).
4. Wound dehiscence: This is when the surgical wound opens up, which can lead to infection and further complications.
5. Pulmonary issues: These include atelectasis (collapsed lung), pneumonia, or respiratory failure.
6. Cardiovascular problems: These include abnormal heart rhythms (arrhythmias), heart attack, or stroke.
7. Renal failure: This can occur due to various reasons such as dehydration, blood loss, or the use of certain medications.
8. Pain management issues: Inadequate pain control can lead to increased stress, anxiety, and decreased mobility.
9. Nausea and vomiting: These can be caused by anesthesia, opioid pain medication, or other factors.
10. Delirium: This is a state of confusion and disorientation that can occur in the elderly or those with certain medical conditions.

Prompt identification and management of these complications are crucial to ensure the best possible outcome for the patient.

Tetralogy of Fallot is a congenital heart defect that consists of four components: ventricular septal defect (a hole between the lower chambers of the heart), pulmonary stenosis (narrowing of the pulmonary valve and outflow tract), overriding aorta (the aorta lies directly over the ventricular septal defect), and right ventricular hypertrophy (thickening of the right ventricular muscle). This condition results in insufficient oxygenation of the blood, leading to cyanosis (bluish discoloration of the skin and mucous membranes) and other symptoms such as shortness of breath, fatigue, and poor growth. Treatment typically involves surgical repair, which is usually performed during infancy or early childhood.

Atrial function in a medical context refers to the role and performance of the two upper chambers of the heart, known as the atria. The main functions of the atria are to receive blood from the veins and help pump it into the ventricles, which are the lower pumping chambers of the heart.

The atria contract in response to electrical signals generated by the sinoatrial node, which is the heart's natural pacemaker. This contraction helps to fill the ventricles with blood before they contract and pump blood out to the rest of the body. Atrial function can be assessed through various diagnostic tests, such as echocardiograms or electrocardiograms (ECGs), which can help identify any abnormalities in atrial structure or electrical activity that may affect heart function.

Pracitolol is not a medical condition, it's a medication. Practolol is a beta blocker drug that is primarily used to treat various cardiovascular conditions such as hypertension (high blood pressure), angina (chest pain due to reduced blood flow to the heart), and certain types of arrhythmias (irregular heart rhythms).

Beta blockers like practolol work by blocking the effects of certain hormones, such as adrenaline, on the heart and blood vessels. This helps to reduce the heart rate, lower blood pressure, and decrease the force of heart contractions, which can improve overall cardiovascular function and reduce the risk of heart-related complications.

It's important to note that practolol is not commonly used in clinical practice due to its association with a rare but serious side effect known as the "practolol syndrome." This condition can cause various symptoms such as dry eyes, skin rashes, and abnormalities of the thyroid gland. As a result, other beta blockers are generally preferred over practolol for the treatment of cardiovascular conditions.

NAV1.5, also known as SCN5A, is a specific type of voltage-gated sodium channel found in the heart muscle cells (cardiomyocytes). These channels play a crucial role in the generation and transmission of electrical signals that coordinate the contraction of the heart.

More specifically, NAV1.5 channels are responsible for the rapid influx of sodium ions into cardiomyocytes during the initial phase of the action potential, which is the electrical excitation of the cell. This rapid influx of sodium ions helps to initiate and propagate the action potential throughout the heart muscle, allowing for coordinated contraction and proper heart function.

Mutations in the SCN5A gene, which encodes the NAV1.5 channel, have been associated with various cardiac arrhythmias, including long QT syndrome, Brugada syndrome, and familial atrial fibrillation, among others. These genetic disorders can lead to abnormal heart rhythms, syncope, and in some cases, sudden cardiac death.

The heart septum is the thick, muscular wall that divides the right and left sides of the heart. It consists of two main parts: the atrial septum, which separates the right and left atria (the upper chambers of the heart), and the ventricular septum, which separates the right and left ventricles (the lower chambers of the heart). A normal heart septum ensures that oxygen-rich blood from the lungs does not mix with oxygen-poor blood from the body. Any defect or abnormality in the heart septum is called a septal defect, which can lead to various congenital heart diseases.

Metaproterenol is a short-acting, selective beta-2 adrenergic receptor agonist. It is primarily used as a bronchodilator to treat and prevent bronchospasms associated with reversible obstructive airway diseases such as asthma, chronic bronchitis, and emphysema. Metaproterenol works by relaxing the smooth muscles in the airways, thereby opening up the air passages and making it easier to breathe. It is available in oral (tablet or liquid) and inhalation (aerosol or solution for nebulization) forms. Common side effects include tremors, nervousness, headache, tachycardia, and palpitations.

A syndrome, in medical terms, is a set of symptoms that collectively indicate or characterize a disease, disorder, or underlying pathological process. It's essentially a collection of signs and/or symptoms that frequently occur together and can suggest a particular cause or condition, even though the exact physiological mechanisms might not be fully understood.

For example, Down syndrome is characterized by specific physical features, cognitive delays, and other developmental issues resulting from an extra copy of chromosome 21. Similarly, metabolic syndromes like diabetes mellitus type 2 involve a group of risk factors such as obesity, high blood pressure, high blood sugar, and abnormal cholesterol or triglyceride levels that collectively increase the risk of heart disease, stroke, and diabetes.

It's important to note that a syndrome is not a specific diagnosis; rather, it's a pattern of symptoms that can help guide further diagnostic evaluation and management.

Intravenous injections are a type of medical procedure where medication or fluids are administered directly into a vein using a needle and syringe. This route of administration is also known as an IV injection. The solution injected enters the patient's bloodstream immediately, allowing for rapid absorption and onset of action. Intravenous injections are commonly used to provide quick relief from symptoms, deliver medications that are not easily absorbed by other routes, or administer fluids and electrolytes in cases of dehydration or severe illness. It is important that intravenous injections are performed using aseptic technique to minimize the risk of infection.

Telemetry is the automated measurement and wireless transmission of data from remote or inaccessible sources to receiving stations for monitoring and analysis. In a medical context, telemetry is often used to monitor patients' vital signs such as heart rate, blood pressure, oxygen levels, and other important physiological parameters continuously and remotely. This technology allows healthcare providers to track patients' conditions over time, detect any abnormalities or trends, and make informed decisions about their care, even when they are not physically present with the patient. Telemetry is commonly used in hospitals, clinics, and research settings to monitor patients during procedures, after surgery, or during extended stays in intensive care units.

Sinus arrhythmia is a type of heart rhythm disorder (arrhythmia) where the normal rhythm generated by the sinus node in the heart varies in rate or pattern. The sinus node is the natural pacemaker of the heart and usually sets a steady pace for heartbeats. However, in sinus arrhythmia, the heart rate may speed up or slow down abnormally during breathing in (inspiration) or breathing out (expiration).

When the heart rate increases during inspiration, it is called "inspiratory sinus arrhythmia," and when the heart rate decreases during expiration, it is called "expiratory sinus arrhythmia." Most people experience a mild form of inspiratory sinus arrhythmia, which is considered normal, especially in children and young adults.

However, if the variation in heart rate is significant or accompanied by symptoms such as palpitations, dizziness, shortness of breath, or chest discomfort, it may require medical evaluation and treatment. Sinus arrhythmia can be caused by various factors, including lung disease, heart disease, electrolyte imbalances, or the use of certain medications.

Myocardial ischemia is a condition in which the blood supply to the heart muscle (myocardium) is reduced or blocked, leading to insufficient oxygen delivery and potential damage to the heart tissue. This reduction in blood flow typically results from the buildup of fatty deposits, called plaques, in the coronary arteries that supply the heart with oxygen-rich blood. The plaques can rupture or become unstable, causing the formation of blood clots that obstruct the artery and limit blood flow.

Myocardial ischemia may manifest as chest pain (angina pectoris), shortness of breath, fatigue, or irregular heartbeats (arrhythmias). In severe cases, it can lead to myocardial infarction (heart attack) if the oxygen supply is significantly reduced or cut off completely, causing permanent damage or death of the heart muscle. Early diagnosis and treatment of myocardial ischemia are crucial for preventing further complications and improving patient outcomes.

Atenolol is a beta-blocker medication that is primarily used to treat hypertension (high blood pressure), angina (chest pain), and certain types of heart rhythm disorders. It works by blocking the action of certain hormones in the body, such as adrenaline, on the heart and blood vessels. This helps to reduce the heart's workload, lower its rate and force of contractions, and improve blood flow.

Beta-blockers like atenolol are also sometimes used to prevent migraines or to treat symptoms of anxiety, such as rapid heartbeat or tremors. Atenolol is available in immediate-release and extended-release forms, and it is typically taken orally once or twice a day. As with any medication, atenolol can have side effects, including dizziness, fatigue, and gastrointestinal symptoms, and it may interact with other medications or medical conditions. It is important to use atenolol only under the supervision of a healthcare provider.

Midodrine is a medication that belongs to a class of drugs called vasoconstrictors. It works by narrowing the blood vessels and increasing blood pressure. The medical definition of Midodrine is:

A synthetic derivative of the imidazole compound, adrenergic agonist, which is used in the treatment of orthostatic hypotension. Midodrine is a prodrug that is rapidly metabolized to its active form, desglymidodrine, after oral administration. It selectively binds to and activates alpha-1 adrenergic receptors, causing vasoconstriction and an increase in blood pressure. The drug's effects are most pronounced on the venous side of the circulation, leading to increased venous return and cardiac output. Midodrine is typically administered orally in divided doses throughout the day, and its use is usually reserved for patients who have not responded to other treatments for orthostatic hypotension.

Andersen Syndrome is a rare genetic disorder characterized by the presence of three major features:

1. Periodic episodes of muscle weakness (periodic paralysis)
2. Potassium-sensitive ventricular arrhythmias
3. Physical deformities of the face and skeleton

The periodic paralysis in Andersen Syndrome is typically less severe than other forms of periodic paralysis, and it can be triggered by factors such as cold, emotional stress, or infection. The potassium-sensitive ventricular arrhythmias can be life-threatening and may require treatment with medications or an implantable cardioverter-defibrillator (ICD).

The physical deformities associated with Andersen Syndrome can include a short stature, low-set ears, a broad nose, widely spaced eyes, a cleft palate, and skeletal abnormalities such as scoliosis or clubfoot. These features may vary in severity among individuals with the disorder.

Andersen Syndrome is caused by mutations in the gene for the protein called the inward rectifier potassium channel (Kir2.1), which is involved in regulating the flow of potassium ions across cell membranes. This gene is located on chromosome 17 and is designated KCNJ2. The disorder is inherited in an autosomal dominant manner, meaning that a person has a 50% chance of inheriting the mutated gene from an affected parent. However, some cases of Andersen Syndrome are due to new (de novo) mutations and occur in people with no family history of the disorder.

Nadolol is a non-selective beta blocker medication that works by blocking the action of certain natural substances such as adrenaline (epinephrine) on the heart and blood vessels. This results in a decrease in heart rate, heart contractions strength, and lowering of blood pressure. Nadolol is used to treat high blood pressure, angina (chest pain), irregular heartbeats, and to prevent migraines. It may also be used for other conditions as determined by your doctor.

Nadolol is available in oral tablet form and is typically taken once a day. The dosage will depend on the individual's medical condition, response to treatment, and any other medications they may be taking. Common side effects of Nadolol include dizziness, lightheadedness, tiredness, and weakness. Serious side effects are rare but can occur, such as slow or irregular heartbeat, shortness of breath, swelling of the hands or feet, mental/mood changes, and unusual weight gain.

It is important to follow your doctor's instructions carefully when taking Nadolol, and to inform them of any other medications you are taking, as well as any medical conditions you may have, such as diabetes, asthma, or liver disease. Additionally, it is recommended to avoid sudden discontinuation of the medication without consulting with your healthcare provider, as this can lead to withdrawal symptoms such as increased heart rate and blood pressure.

An exercise test, also known as a stress test or an exercise stress test, is a medical procedure used to evaluate the heart's function and response to physical exertion. It typically involves walking on a treadmill or pedaling a stationary bike while being monitored for changes in heart rate, blood pressure, electrocardiogram (ECG), and sometimes other variables such as oxygen consumption or gas exchange.

During the test, the patient's symptoms, such as chest pain or shortness of breath, are also closely monitored. The exercise test can help diagnose coronary artery disease, assess the severity of heart-related symptoms, and evaluate the effectiveness of treatments for heart conditions. It may also be used to determine a person's safe level of physical activity and fitness.

There are different types of exercise tests, including treadmill stress testing, stationary bike stress testing, nuclear stress testing, and stress echocardiography. The specific type of test used depends on the patient's medical history, symptoms, and overall health status.

Epinephrine, also known as adrenaline, is a hormone and a neurotransmitter that is produced in the body. It is released by the adrenal glands in response to stress or excitement, and it prepares the body for the "fight or flight" response. Epinephrine works by binding to specific receptors in the body, which causes a variety of physiological effects, including increased heart rate and blood pressure, improved muscle strength and alertness, and narrowing of the blood vessels in the skin and intestines. It is also used as a medication to treat various medical conditions, such as anaphylaxis (a severe allergic reaction), cardiac arrest, and low blood pressure.

An electrode is a medical device that can conduct electrical currents and is used to transmit or receive electrical signals, often in the context of medical procedures or treatments. In a medical setting, electrodes may be used for a variety of purposes, such as:

1. Recording electrical activity in the body: Electrodes can be attached to the skin or inserted into body tissues to measure electrical signals produced by the heart, brain, muscles, or nerves. This information can be used to diagnose medical conditions, monitor the effectiveness of treatments, or guide medical procedures.
2. Stimulating nerve or muscle activity: Electrodes can be used to deliver electrical impulses to nerves or muscles, which can help to restore function or alleviate symptoms in people with certain medical conditions. For example, electrodes may be used to stimulate the nerves that control bladder function in people with spinal cord injuries, or to stimulate muscles in people with muscle weakness or paralysis.
3. Administering treatments: Electrodes can also be used to deliver therapeutic treatments, such as transcranial magnetic stimulation (TMS) for depression or deep brain stimulation (DBS) for movement disorders like Parkinson's disease. In these procedures, electrodes are implanted in specific areas of the brain and connected to a device that generates electrical impulses, which can help to regulate abnormal brain activity and improve symptoms.

Overall, electrodes play an important role in many medical procedures and treatments, allowing healthcare professionals to diagnose and treat a wide range of conditions that affect the body's electrical systems.

Cardiac imaging techniques are diagnostic methods used to visualize and assess the structure and function of the heart. These techniques can be non-invasive or invasive, and they use various forms of energy such as sound waves, radiation, and magnetic fields to produce detailed images of the heart. Some common cardiac imaging techniques include:

1. Echocardiography: This technique uses ultrasound waves to create images of the heart's structure and function. It can provide information about the size and shape of the heart chambers, the thickness and movement of the heart walls, and the valves' function.
2. Cardiac Magnetic Resonance Imaging (MRI): This technique uses a strong magnetic field and radio waves to create detailed images of the heart's structure and function. It can provide information about the size and shape of the heart chambers, the thickness and movement of the heart walls, the valves' function, and the blood flow in the heart.
3. Computed Tomography (CT) Angiography: This technique uses X-rays to create detailed images of the heart's blood vessels. It can provide information about the presence and extent of blockages or narrowing in the coronary arteries.
4. Nuclear Cardiac Imaging: This technique uses small amounts of radioactive substances to produce images of the heart's blood flow. It can provide information about the size and function of the heart chambers, the presence of damaged heart muscle, and the extent of coronary artery disease.
5. Invasive Coronary Angiography: This technique involves inserting a catheter into a blood vessel in the arm or leg and guiding it to the heart's coronary arteries. A contrast dye is then injected through the catheter, and X-ray images are taken to visualize the blood flow in the coronary arteries. This technique can provide detailed information about the presence and extent of blockages or narrowing in the coronary arteries.

Physiological monitoring is the continuous or intermittent observation and measurement of various body functions or parameters in a patient, with the aim of evaluating their health status, identifying any abnormalities or changes, and guiding clinical decision-making and treatment. This may involve the use of specialized medical equipment, such as cardiac monitors, pulse oximeters, blood pressure monitors, and capnographs, among others. The data collected through physiological monitoring can help healthcare professionals assess the effectiveness of treatments, detect complications early, and make timely adjustments to patient care plans.

Equipment failure is a term used in the medical field to describe the malfunction or breakdown of medical equipment, devices, or systems that are essential for patient care. This can include simple devices like syringes and thermometers, as well as complex machines such as ventilators, infusion pumps, and imaging equipment.

Equipment failure can have serious consequences for patients, including delayed or inappropriate treatment, injury, or even death. It is therefore essential that medical equipment is properly maintained, tested, and repaired to ensure its safe and effective operation.

There are many potential causes of equipment failure, including:

* Wear and tear from frequent use
* Inadequate cleaning or disinfection
* Improper handling or storage
* Power supply issues
* Software glitches or bugs
* Mechanical failures or defects
* Human error or misuse

To prevent equipment failure, healthcare facilities should have established policies and procedures for the acquisition, maintenance, and disposal of medical equipment. Staff should be trained in the proper use and handling of equipment, and regular inspections and testing should be performed to identify and address any potential issues before they lead to failure.

The vagus nerve, also known as the 10th cranial nerve (CN X), is the longest of the cranial nerves and extends from the brainstem to the abdomen. It has both sensory and motor functions and plays a crucial role in regulating various bodily functions such as heart rate, digestion, respiratory rate, speech, and sweating, among others.

The vagus nerve is responsible for carrying sensory information from the internal organs to the brain, and it also sends motor signals from the brain to the muscles of the throat and voice box, as well as to the heart, lungs, and digestive tract. The vagus nerve helps regulate the body's involuntary responses, such as controlling heart rate and blood pressure, promoting relaxation, and reducing inflammation.

Dysfunction in the vagus nerve can lead to various medical conditions, including gastroparesis, chronic pain, and autonomic nervous system disorders. Vagus nerve stimulation (VNS) is a therapeutic intervention that involves delivering electrical impulses to the vagus nerve to treat conditions such as epilepsy, depression, and migraine headaches.

The Valsalva maneuver is a medical procedure that involves forced exhalation against a closed airway, typically by closing one's mouth, pinching the nose shut, and then blowing. This maneuver increases the pressure in the chest and affects the heart's filling and pumping capabilities, as well as the pressures within the ears and eyes.

It is often used during medical examinations to test for conditions such as heart murmurs or to help clear the ears during changes in air pressure (like when scuba diving or flying). It can also be used to help diagnose or monitor conditions related to the autonomic nervous system, such as orthostatic hypotension or dysautonomia.

However, it's important to perform the Valsalva maneuver correctly and under medical supervision, as improper technique or overdoing it can lead to adverse effects like increased heart rate, changes in blood pressure, or even damage to the eardrum.

Electric stimulation, also known as electrical nerve stimulation or neuromuscular electrical stimulation, is a therapeutic treatment that uses low-voltage electrical currents to stimulate nerves and muscles. It is often used to help manage pain, promote healing, and improve muscle strength and mobility. The electrical impulses can be delivered through electrodes placed on the skin or directly implanted into the body.

In a medical context, electric stimulation may be used for various purposes such as:

1. Pain management: Electric stimulation can help to block pain signals from reaching the brain and promote the release of endorphins, which are natural painkillers produced by the body.
2. Muscle rehabilitation: Electric stimulation can help to strengthen muscles that have become weak due to injury, illness, or surgery. It can also help to prevent muscle atrophy and improve range of motion.
3. Wound healing: Electric stimulation can promote tissue growth and help to speed up the healing process in wounds, ulcers, and other types of injuries.
4. Urinary incontinence: Electric stimulation can be used to strengthen the muscles that control urination and reduce symptoms of urinary incontinence.
5. Migraine prevention: Electric stimulation can be used as a preventive treatment for migraines by applying electrical impulses to specific nerves in the head and neck.

It is important to note that electric stimulation should only be administered under the guidance of a qualified healthcare professional, as improper use can cause harm or discomfort.

Cardiac surgical procedures are operations that are performed on the heart or great vessels (the aorta and vena cava) by cardiothoracic surgeons. These surgeries are often complex and require a high level of skill and expertise. Some common reasons for cardiac surgical procedures include:

1. Coronary artery bypass grafting (CABG): This is a surgery to improve blood flow to the heart in patients with coronary artery disease. During the procedure, a healthy blood vessel from another part of the body is used to create a detour around the blocked or narrowed portion of the coronary artery.
2. Valve repair or replacement: The heart has four valves that control blood flow through and out of the heart. If one or more of these valves become damaged or diseased, they may need to be repaired or replaced. This can be done using artificial valves or valves from animal or human donors.
3. Aneurysm repair: An aneurysm is a weakened area in the wall of an artery that can bulge out and potentially rupture. If an aneurysm occurs in the aorta, it may require surgical repair to prevent rupture.
4. Heart transplantation: In some cases, heart failure may be so severe that a heart transplant is necessary. This involves removing the diseased heart and replacing it with a healthy donor heart.
5. Arrhythmia surgery: Certain types of abnormal heart rhythms (arrhythmias) may require surgical treatment. One such procedure is called the Maze procedure, which involves creating a pattern of scar tissue in the heart to disrupt the abnormal electrical signals that cause the arrhythmia.
6. Congenital heart defect repair: Some people are born with structural problems in their hearts that require surgical correction. These may include holes between the chambers of the heart or abnormal blood vessels.

Cardiac surgical procedures carry risks, including bleeding, infection, stroke, and death. However, for many patients, these surgeries can significantly improve their quality of life and longevity.

Primary dysautonomias, also known as primary autonomic disorders or idiopathic dysautonomia, refer to a group of conditions that affect the autonomic nervous system (ANS) without an identifiable underlying cause. The ANS is responsible for regulating many automatic bodily functions such as heart rate, blood pressure, digestion, and body temperature.

In primary dysautonomias, the ANS fails to function properly, leading to a variety of symptoms that can affect different organ systems. These symptoms may include orthostatic intolerance (lightheadedness or fainting upon standing), irregular heart rate, excessive sweating, heat or cold intolerance, difficulty with digestion, and pupillary abnormalities.

Examples of primary dysautonomias include pure autonomic failure, multiple system atrophy, and familial dysautonomia. These conditions are typically progressive, meaning that symptoms tend to worsen over time. Treatment for primary dysautonomias is focused on managing symptoms and improving quality of life.

Intraoperative care refers to the medical care and interventions provided to a patient during a surgical procedure. This care is typically administered by a team of healthcare professionals, including anesthesiologists, surgeons, nurses, and other specialists as needed. The goal of intraoperative care is to maintain the patient's physiological stability throughout the surgery, minimize complications, and ensure the best possible outcome.

Intraoperative care may include:

1. Anesthesia management: Administering and monitoring anesthetic drugs to keep the patient unconscious and free from pain during the surgery.
2. Monitoring vital signs: Continuously tracking the patient's heart rate, blood pressure, oxygen saturation, body temperature, and other key physiological parameters to ensure they remain within normal ranges.
3. Fluid and blood product administration: Maintaining adequate intravascular volume and oxygen-carrying capacity through the infusion of fluids and blood products as needed.
4. Intraoperative imaging: Utilizing real-time imaging techniques, such as X-ray, ultrasound, or CT scans, to guide the surgical procedure and ensure accurate placement of implants or other devices.
5. Neuromonitoring: Using electrophysiological methods to monitor the functional integrity of nerves and neural structures during surgery, particularly in procedures involving the brain, spine, or peripheral nerves.
6. Intraoperative medication management: Administering various medications as needed for pain control, infection prophylaxis, or the treatment of medical conditions that may arise during the surgery.
7. Temperature management: Regulating the patient's body temperature to prevent hypothermia or hyperthermia, which can have adverse effects on surgical outcomes and overall patient health.
8. Communication and coordination: Ensuring effective communication among the members of the surgical team to optimize patient care and safety.

A heart aneurysm, also known as a ventricular aneurysm, is a localized bulging or ballooning of the heart muscle in the left ventricle, which is the main pumping chamber of the heart. This condition typically occurs following a myocardial infarction (heart attack), where blood flow to a portion of the heart muscle is blocked, leading to tissue death and weakness in the heart wall. As a result, the weakened area may stretch and form a sac-like bulge or aneurysm.

Heart aneurysms can vary in size and may cause complications such as blood clots, arrhythmias (irregular heartbeats), or heart failure. In some cases, they may be asymptomatic and discovered during routine imaging tests. The diagnosis of a heart aneurysm is typically made through echocardiography, cardiac MRI, or cardiac CT scans. Treatment options depend on the size, location, and symptoms of the aneurysm and may include medications, surgical repair, or implantation of a device to support heart function.

The baroreflex is a physiological mechanism that helps regulate blood pressure and heart rate in response to changes in stretch of the arterial walls. It is mediated by baroreceptors, which are specialized sensory nerve endings located in the carotid sinus and aortic arch. These receptors detect changes in blood pressure and send signals to the brainstem via the glossopharyngeal (cranial nerve IX) and vagus nerves (cranial nerve X), respectively.

In response to an increase in arterial pressure, the baroreceptors are stimulated, leading to increased firing of afferent neurons that signal the brainstem. This results in a reflexive decrease in heart rate and cardiac output, as well as vasodilation of peripheral blood vessels, which collectively work to reduce blood pressure back towards its normal level. Conversely, if arterial pressure decreases, the baroreceptors are less stimulated, leading to an increase in heart rate and cardiac output, as well as vasoconstriction of peripheral blood vessels, which helps restore blood pressure.

Overall, the baroreflex is a crucial homeostatic mechanism that helps maintain stable blood pressure and ensure adequate perfusion of vital organs.

Sick Sinus Syndrome (SSS) is a term used to describe a group of abnormal heart rhythm disturbances that originates in the sinoatrial node (the natural pacemaker of the heart). This syndrome is characterized by impaired functioning of the sinoatrial node, resulting in various abnormalities such as sinus bradycardia (abnormally slow heart rate), sinus arrest (complete cessation of sinus node activity), and/or sinoatrial exit block (failure of the electrical impulse to leave the sinus node and spread to the atria).

People with SSS may experience symptoms such as palpitations, dizziness, fatigue, shortness of breath, or syncope (fainting) due to inadequate blood supply to the brain caused by slow heart rate. The diagnosis of SSS is typically made based on the patient's symptoms and the results of an electrocardiogram (ECG), Holter monitoring, or event recorder that shows evidence of abnormal sinus node function. Treatment options for SSS may include lifestyle modifications, medications, or implantation of a pacemaker to regulate the heart rate.

Animal disease models are specialized animals, typically rodents such as mice or rats, that have been genetically engineered or exposed to certain conditions to develop symptoms and physiological changes similar to those seen in human diseases. These models are used in medical research to study the pathophysiology of diseases, identify potential therapeutic targets, test drug efficacy and safety, and understand disease mechanisms.

The genetic modifications can include knockout or knock-in mutations, transgenic expression of specific genes, or RNA interference techniques. The animals may also be exposed to environmental factors such as chemicals, radiation, or infectious agents to induce the disease state.

Examples of animal disease models include:

1. Mouse models of cancer: Genetically engineered mice that develop various types of tumors, allowing researchers to study cancer initiation, progression, and metastasis.
2. Alzheimer's disease models: Transgenic mice expressing mutant human genes associated with Alzheimer's disease, which exhibit amyloid plaque formation and cognitive decline.
3. Diabetes models: Obese and diabetic mouse strains like the NOD (non-obese diabetic) or db/db mice, used to study the development of type 1 and type 2 diabetes, respectively.
4. Cardiovascular disease models: Atherosclerosis-prone mice, such as ApoE-deficient or LDLR-deficient mice, that develop plaque buildup in their arteries when fed a high-fat diet.
5. Inflammatory bowel disease models: Mice with genetic mutations affecting intestinal barrier function and immune response, such as IL-10 knockout or SAMP1/YitFc mice, which develop colitis.

Animal disease models are essential tools in preclinical research, but it is important to recognize their limitations. Differences between species can affect the translatability of results from animal studies to human patients. Therefore, researchers must carefully consider the choice of model and interpret findings cautiously when applying them to human diseases.

Physical exertion is defined as the act of applying energy to physically demandable activities or tasks, which results in various body systems working together to produce movement and maintain homeostasis. It often leads to an increase in heart rate, respiratory rate, and body temperature, among other physiological responses. The level of physical exertion can vary based on the intensity, duration, and frequency of the activity.

It's important to note that engaging in regular physical exertion has numerous health benefits, such as improving cardiovascular fitness, strengthening muscles and bones, reducing stress, and preventing chronic diseases like obesity, diabetes, and heart disease. However, it is also crucial to balance physical exertion with adequate rest and recovery time to avoid overtraining or injury.

Hypotension is a medical term that refers to abnormally low blood pressure, usually defined as a systolic blood pressure less than 90 millimeters of mercury (mm Hg) or a diastolic blood pressure less than 60 mm Hg. Blood pressure is the force exerted by the blood against the walls of the blood vessels as the heart pumps blood.

Hypotension can cause symptoms such as dizziness, lightheadedness, weakness, and fainting, especially when standing up suddenly. In severe cases, hypotension can lead to shock, which is a life-threatening condition characterized by multiple organ failure due to inadequate blood flow.

Hypotension can be caused by various factors, including certain medications, medical conditions such as heart disease, endocrine disorders, and dehydration. It is important to seek medical attention if you experience symptoms of hypotension, as it can indicate an underlying health issue that requires treatment.

The cardiovascular system, also known as the circulatory system, is a biological system responsible for pumping and transporting blood throughout the body in animals and humans. It consists of the heart, blood vessels (comprising arteries, veins, and capillaries), and blood. The main function of this system is to transport oxygen, nutrients, hormones, and cellular waste products throughout the body to maintain homeostasis and support organ function.

The heart acts as a muscular pump that contracts and relaxes to circulate blood. It has four chambers: two atria on the top and two ventricles on the bottom. The right side of the heart receives deoxygenated blood from the body, pumps it through the lungs for oxygenation, and then sends it back to the left side of the heart. The left side of the heart then pumps the oxygenated blood through the aorta and into the systemic circulation, reaching all parts of the body via a network of arteries and capillaries. Deoxygenated blood is collected by veins and returned to the right atrium, completing the cycle.

The cardiovascular system plays a crucial role in regulating temperature, pH balance, and fluid balance throughout the body. It also contributes to the immune response and wound healing processes. Dysfunctions or diseases of the cardiovascular system can lead to severe health complications, such as hypertension, coronary artery disease, heart failure, stroke, and peripheral artery disease.

Prognosis is a medical term that refers to the prediction of the likely outcome or course of a disease, including the chances of recovery or recurrence, based on the patient's symptoms, medical history, physical examination, and diagnostic tests. It is an important aspect of clinical decision-making and patient communication, as it helps doctors and patients make informed decisions about treatment options, set realistic expectations, and plan for future care.

Prognosis can be expressed in various ways, such as percentages, categories (e.g., good, fair, poor), or survival rates, depending on the nature of the disease and the available evidence. However, it is important to note that prognosis is not an exact science and may vary depending on individual factors, such as age, overall health status, and response to treatment. Therefore, it should be used as a guide rather than a definitive forecast.

Heart disease is a broad term for a class of diseases that involve the heart or blood vessels. It's often used to refer to conditions that include:

1. Coronary artery disease (CAD): This is the most common type of heart disease. It occurs when the arteries that supply blood to the heart become hardened and narrowed due to the buildup of cholesterol and other substances, which can lead to chest pain (angina), shortness of breath, or a heart attack.

2. Heart failure: This condition occurs when the heart is unable to pump blood efficiently to meet the body's needs. It can be caused by various conditions, including coronary artery disease, high blood pressure, and cardiomyopathy.

3. Arrhythmias: These are abnormal heart rhythms, which can be too fast, too slow, or irregular. They can lead to symptoms such as palpitations, dizziness, and fainting.

4. Valvular heart disease: This involves damage to one or more of the heart's four valves, which control blood flow through the heart. Damage can be caused by various conditions, including infection, rheumatic fever, and aging.

5. Cardiomyopathy: This is a disease of the heart muscle that makes it harder for the heart to pump blood efficiently. It can be caused by various factors, including genetics, viral infections, and drug abuse.

6. Pericardial disease: This involves inflammation or other problems with the sac surrounding the heart (pericardium). It can cause chest pain and other symptoms.

7. Congenital heart defects: These are heart conditions that are present at birth, such as a hole in the heart or abnormal blood vessels. They can range from mild to severe and may require medical intervention.

8. Heart infections: The heart can become infected by bacteria, viruses, or parasites, leading to various symptoms and complications.

It's important to note that many factors can contribute to the development of heart disease, including genetics, lifestyle choices, and certain medical conditions. Regular check-ups and a healthy lifestyle can help reduce the risk of developing heart disease.

Left ventricular function refers to the ability of the left ventricle (the heart's lower-left chamber) to contract and relax, thereby filling with and ejecting blood. The left ventricle is responsible for pumping oxygenated blood to the rest of the body. Its function is evaluated by measuring several parameters, including:

1. Ejection fraction (EF): This is the percentage of blood that is pumped out of the left ventricle with each heartbeat. A normal ejection fraction ranges from 55% to 70%.
2. Stroke volume (SV): The amount of blood pumped by the left ventricle in one contraction. A typical SV is about 70 mL/beat.
3. Cardiac output (CO): The total volume of blood that the left ventricle pumps per minute, calculated as the product of stroke volume and heart rate. Normal CO ranges from 4 to 8 L/minute.

Assessment of left ventricular function is crucial in diagnosing and monitoring various cardiovascular conditions such as heart failure, coronary artery disease, valvular heart diseases, and cardiomyopathies.

Lidocaine is a type of local anesthetic that numbs painful areas and is used to prevent pain during certain medical procedures. It works by blocking the nerves that transmit pain signals to the brain. In addition to its use as an anesthetic, lidocaine can also be used to treat irregular heart rates and relieve itching caused by allergic reactions or skin conditions such as eczema.

Lidocaine is available in various forms, including creams, gels, ointments, sprays, solutions, and injectable preparations. It can be applied directly to the skin or mucous membranes, or it can be administered by injection into a muscle or vein. The specific dosage and method of administration will depend on the reason for its use and the individual patient's medical history and current health status.

Like all medications, lidocaine can have side effects, including allergic reactions, numbness that lasts too long, and in rare cases, heart problems or seizures. It is important to follow the instructions of a healthcare provider carefully when using lidocaine to minimize the risk of adverse effects.

A newborn infant is a baby who is within the first 28 days of life. This period is also referred to as the neonatal period. Newborns require specialized care and attention due to their immature bodily systems and increased vulnerability to various health issues. They are closely monitored for signs of well-being, growth, and development during this critical time.

Sensitivity and specificity are statistical measures used to describe the performance of a diagnostic test or screening tool in identifying true positive and true negative results.

* Sensitivity refers to the proportion of people who have a particular condition (true positives) who are correctly identified by the test. It is also known as the "true positive rate" or "recall." A highly sensitive test will identify most or all of the people with the condition, but may also produce more false positives.
* Specificity refers to the proportion of people who do not have a particular condition (true negatives) who are correctly identified by the test. It is also known as the "true negative rate." A highly specific test will identify most or all of the people without the condition, but may also produce more false negatives.

In medical testing, both sensitivity and specificity are important considerations when evaluating a diagnostic test. High sensitivity is desirable for screening tests that aim to identify as many cases of a condition as possible, while high specificity is desirable for confirmatory tests that aim to rule out the condition in people who do not have it.

It's worth noting that sensitivity and specificity are often influenced by factors such as the prevalence of the condition in the population being tested, the threshold used to define a positive result, and the reliability and validity of the test itself. Therefore, it's important to consider these factors when interpreting the results of a diagnostic test.

Cardiovascular models are simplified representations or simulations of the human cardiovascular system used in medical research, education, and training. These models can be physical, computational, or mathematical and are designed to replicate various aspects of the heart, blood vessels, and blood flow. They can help researchers study the structure and function of the cardiovascular system, test new treatments and interventions, and train healthcare professionals in diagnostic and therapeutic techniques.

Physical cardiovascular models may include artificial hearts, blood vessels, or circulation systems made from materials such as plastic, rubber, or silicone. These models can be used to study the mechanics of heart valves, the effects of different surgical procedures, or the impact of various medical devices on blood flow.

Computational and mathematical cardiovascular models use algorithms and equations to simulate the behavior of the cardiovascular system. These models may range from simple representations of a single heart chamber to complex simulations of the entire circulatory system. They can be used to study the electrical activity of the heart, the biomechanics of blood flow, or the distribution of drugs in the body.

Overall, cardiovascular models play an essential role in advancing our understanding of the human body and improving patient care.

Right ventricular dysfunction is a condition characterized by the impaired ability of the right ventricle (one of the two pumping chambers in the heart) to fill with blood during the diastolic phase or eject blood during the systolic phase. This results in reduced cardiac output from the right ventricle, which can lead to various complications such as fluid accumulation in the body, particularly in the abdomen and lower extremities, and ultimately congestive heart failure if left untreated.

Right ventricular dysfunction can be caused by various factors, including damage to the heart muscle due to a heart attack, high blood pressure in the lungs (pulmonary hypertension), chronic lung diseases, congenital heart defects, viral infections, and certain medications. Symptoms of right ventricular dysfunction may include shortness of breath, fatigue, swelling in the legs, ankles, or abdomen, and a decreased tolerance for physical activity.

Diagnosis of right ventricular dysfunction typically involves a combination of medical history, physical examination, imaging tests such as echocardiography, cardiac MRI, or CT scan, and other diagnostic procedures such as electrocardiogram (ECG) or cardiac catheterization. Treatment options depend on the underlying cause but may include medications to reduce fluid buildup, improve heart function, and manage symptoms, as well as lifestyle modifications such as reducing salt intake and increasing physical activity levels. In severe cases, more invasive treatments such as surgery or implantable devices like pacemakers or ventricular assist devices may be necessary.

Coronary artery disease, often simply referred to as coronary disease, is a condition in which the blood vessels that supply oxygen-rich blood to the heart become narrowed or blocked due to the buildup of fatty deposits called plaques. This can lead to chest pain (angina), shortness of breath, or in severe cases, a heart attack.

The medical definition of coronary artery disease is:

A condition characterized by the accumulation of atheromatous plaques in the walls of the coronary arteries, leading to decreased blood flow and oxygen supply to the myocardium (heart muscle). This can result in symptoms such as angina pectoris, shortness of breath, or arrhythmias, and may ultimately lead to myocardial infarction (heart attack) or heart failure.

Risk factors for coronary artery disease include age, smoking, high blood pressure, high cholesterol, diabetes, obesity, physical inactivity, and a family history of the condition. Lifestyle changes such as quitting smoking, exercising regularly, eating a healthy diet, and managing stress can help reduce the risk of developing coronary artery disease. Medical treatments may include medications to control blood pressure, cholesterol levels, or irregular heart rhythms, as well as procedures such as angioplasty or bypass surgery to improve blood flow to the heart.

Fetal heart rate (FHR) is the number of times a fetus's heart beats in one minute. It is measured through the use of a fetoscope, Doppler ultrasound device, or cardiotocograph (CTG). A normal FHR ranges from 120 to 160 beats per minute (bpm), although it can vary throughout pregnancy and is usually faster than an adult's heart rate. Changes in the FHR pattern may indicate fetal distress, hypoxia, or other conditions that require medical attention. Regular monitoring of FHR during pregnancy, labor, and delivery helps healthcare providers assess fetal well-being and ensure a safe outcome for both the mother and the baby.

Myocardial contraction refers to the rhythmic and forceful shortening of heart muscle cells (myocytes) in the myocardium, which is the muscular wall of the heart. This process is initiated by electrical signals generated by the sinoatrial node, causing a wave of depolarization that spreads throughout the heart.

During myocardial contraction, calcium ions flow into the myocytes, triggering the interaction between actin and myosin filaments, which are the contractile proteins in the muscle cells. This interaction causes the myofilaments to slide past each other, resulting in the shortening of the sarcomeres (the functional units of muscle contraction) and ultimately leading to the contraction of the heart muscle.

Myocardial contraction is essential for pumping blood throughout the body and maintaining adequate circulation to vital organs. Any impairment in myocardial contractility can lead to various cardiac disorders, such as heart failure, cardiomyopathy, and arrhythmias.

The Stellate Ganglion is a part of the sympathetic nervous system. It's a collection of nerve cells (a ganglion) located in the neck, more specifically at the level of the sixth and seventh cervical vertebrae. The stellate ganglion is formed by the fusion of the inferior cervical ganglion and the first thoracic ganglion.

This ganglion plays a crucial role in the body's "fight or flight" response, providing sympathetic innervation to the head, neck, upper extremities, and heart. It's responsible for various functions including regulation of blood flow, sweat gland activity, and contributing to the sensory innervation of the head and neck.

Stellate ganglion block is a medical procedure used to diagnose or treat certain conditions like pain disorders, by injecting local anesthetic near the stellate ganglion to numb the area and interrupt nerve signals.

Adrenergic beta-agonists are a class of medications that bind to and activate beta-adrenergic receptors, which are found in various tissues throughout the body. These receptors are part of the sympathetic nervous system and mediate the effects of the neurotransmitter norepinephrine (also called noradrenaline) and the hormone epinephrine (also called adrenaline).

When beta-agonists bind to these receptors, they stimulate a range of physiological responses, including relaxation of smooth muscle in the airways, increased heart rate and contractility, and increased metabolic rate. As a result, adrenergic beta-agonists are often used to treat conditions such as asthma, chronic obstructive pulmonary disease (COPD), and bronchitis, as they can help to dilate the airways and improve breathing.

There are several different types of beta-agonists, including short-acting and long-acting formulations. Short-acting beta-agonists (SABAs) are typically used for quick relief of symptoms, while long-acting beta-agonists (LABAs) are used for more sustained symptom control. Examples of adrenergic beta-agonists include albuterol (also known as salbutamol), terbutaline, formoterol, and salmeterol.

It's worth noting that while adrenergic beta-agonists can be very effective in treating respiratory conditions, they can also have side effects, particularly if used in high doses or for prolonged periods of time. These may include tremors, anxiety, palpitations, and increased blood pressure. As with any medication, it's important to use adrenergic beta-agonists only as directed by a healthcare professional.

Ventricular function, in the context of cardiac medicine, refers to the ability of the heart's ventricles (the lower chambers) to fill with blood during the diastole phase and eject blood during the systole phase. The ventricles are primarily responsible for pumping oxygenated blood out to the body (left ventricle) and deoxygenated blood to the lungs (right ventricle).

There are several ways to assess ventricular function, including:

1. Ejection Fraction (EF): This is the most commonly used measure of ventricular function. It represents the percentage of blood that is ejected from the ventricle during each heartbeat. A normal left ventricular ejection fraction is typically between 55% and 70%.
2. Fractional Shortening (FS): This is another measure of ventricular function, which calculates the change in size of the ventricle during contraction as a percentage of the original size. A normal FS for the left ventricle is typically between 25% and 45%.
3. Stroke Volume (SV): This refers to the amount of blood that is pumped out of the ventricle with each heartbeat. SV is calculated by multiplying the ejection fraction by the end-diastolic volume (the amount of blood in the ventricle at the end of diastole).
4. Cardiac Output (CO): This is the total amount of blood that the heart pumps in one minute. It is calculated by multiplying the stroke volume by the heart rate.

Impaired ventricular function can lead to various cardiovascular conditions, such as heart failure, cardiomyopathy, and valvular heart disease. Assessing ventricular function is crucial for diagnosing these conditions, monitoring treatment response, and guiding clinical decision-making.

Cardiac myocytes are the muscle cells that make up the heart muscle, also known as the myocardium. These specialized cells are responsible for contracting and relaxing in a coordinated manner to pump blood throughout the body. They differ from skeletal muscle cells in several ways, including their ability to generate their own electrical impulses, which allows the heart to function as an independent rhythmical pump. Cardiac myocytes contain sarcomeres, the contractile units of the muscle, and are connected to each other by intercalated discs that help coordinate contraction and ensure the synchronous beating of the heart.

A dose-response relationship in the context of drugs refers to the changes in the effects or symptoms that occur as the dose of a drug is increased or decreased. Generally, as the dose of a drug is increased, the severity or intensity of its effects also increases. Conversely, as the dose is decreased, the effects of the drug become less severe or may disappear altogether.

The dose-response relationship is an important concept in pharmacology and toxicology because it helps to establish the safe and effective dosage range for a drug. By understanding how changes in the dose of a drug affect its therapeutic and adverse effects, healthcare providers can optimize treatment plans for their patients while minimizing the risk of harm.

The dose-response relationship is typically depicted as a curve that shows the relationship between the dose of a drug and its effect. The shape of the curve may vary depending on the drug and the specific effect being measured. Some drugs may have a steep dose-response curve, meaning that small changes in the dose can result in large differences in the effect. Other drugs may have a more gradual dose-response curve, where larger changes in the dose are needed to produce significant effects.

In addition to helping establish safe and effective dosages, the dose-response relationship is also used to evaluate the potential therapeutic benefits and risks of new drugs during clinical trials. By systematically testing different doses of a drug in controlled studies, researchers can identify the optimal dosage range for the drug and assess its safety and efficacy.

Heart failure is a pathophysiological state in which the heart is unable to pump sufficient blood to meet the metabolic demands of the body or do so only at the expense of elevated filling pressures. It can be caused by various cardiac disorders, including coronary artery disease, hypertension, valvular heart disease, cardiomyopathy, and arrhythmias. Symptoms may include shortness of breath, fatigue, and fluid retention. Heart failure is often classified based on the ejection fraction (EF), which is the percentage of blood that is pumped out of the left ventricle during each contraction. A reduced EF (less than 40%) is indicative of heart failure with reduced ejection fraction (HFrEF), while a preserved EF (greater than or equal to 50%) is indicative of heart failure with preserved ejection fraction (HFpEF). There is also a category of heart failure with mid-range ejection fraction (HFmrEF) for those with an EF between 40-49%.

Dizziness is a term used to describe a range of sensations, such as feeling lightheaded, faint, unsteady, or a false sense of spinning or moving. Medically, dizziness is often described as a non-specific symptom that can be caused by various underlying conditions or factors. These may include:

1. Inner ear disorders (such as benign paroxysmal positional vertigo, labyrinthitis, vestibular neuronitis, or Meniere's disease)
2. Cardiovascular problems (like low blood pressure, arrhythmias, or orthostatic hypotension)
3. Neurological issues (such as migraines, multiple sclerosis, or stroke)
4. Anxiety disorders and panic attacks
5. Side effects of medications
6. Dehydration or overheating
7. Infections (like viral infections or bacterial meningitis)
8. Head or neck injuries
9. Low blood sugar levels (hypoglycemia)

It is essential to consult a healthcare professional if you experience persistent dizziness, as it can be a sign of a more severe underlying condition. The appropriate treatment will depend on the specific cause of the dizziness.

Radio waves are not a medical term, but rather a type of electromagnetic radiation with frequencies ranging from about 30 kilohertz (kHz) to 300 gigahertz (GHz). They have longer wavelengths and lower frequencies than other types of electromagnetic radiation such as microwaves, infrared light, visible light, ultraviolet light, X-rays, and gamma rays.

In the medical field, radio waves are used in various diagnostic and therapeutic applications, including:

* Diagnostic imaging: Magnetic resonance imaging (MRI) uses radio waves in combination with a strong magnetic field to generate detailed images of internal organs and tissues.
* Radiation therapy: High-energy radio waves are used to destroy cancer cells or shrink tumors in radiation therapy.
* Cardiac ablation: Radiofrequency ablation is a medical procedure that uses radio waves to destroy small areas of heart tissue that cause abnormal heart rhythms.

It's important to note that while radio waves have many medical applications, they are not themselves a medical term or condition.

Norepinephrine, also known as noradrenaline, is a neurotransmitter and a hormone that is primarily produced in the adrenal glands and is released into the bloodstream in response to stress or physical activity. It plays a crucial role in the "fight-or-flight" response by preparing the body for action through increasing heart rate, blood pressure, respiratory rate, and glucose availability.

As a neurotransmitter, norepinephrine is involved in regulating various functions of the nervous system, including attention, perception, motivation, and arousal. It also plays a role in modulating pain perception and responding to stressful or emotional situations.

In medical settings, norepinephrine is used as a vasopressor medication to treat hypotension (low blood pressure) that can occur during septic shock, anesthesia, or other critical illnesses. It works by constricting blood vessels and increasing heart rate, which helps to improve blood pressure and perfusion of vital organs.

Medical Definition:

"Risk factors" are any attribute, characteristic or exposure of an individual that increases the likelihood of developing a disease or injury. They can be divided into modifiable and non-modifiable risk factors. Modifiable risk factors are those that can be changed through lifestyle choices or medical treatment, while non-modifiable risk factors are inherent traits such as age, gender, or genetic predisposition. Examples of modifiable risk factors include smoking, alcohol consumption, physical inactivity, and unhealthy diet, while non-modifiable risk factors include age, sex, and family history. It is important to note that having a risk factor does not guarantee that a person will develop the disease, but rather indicates an increased susceptibility.

5-Methoxytryptamine is a psychedelic tryptamine that is found in some plants and animals, as well as being produced synthetically. It is structurally similar to the neurotransmitter serotonin and is known for its ability to alter perception, thought, and mood. 5-Methoxytryptamine is also referred to as "mexamine" or "O-methylated tryptamine." It is a Schedule I controlled substance in the United States, making it illegal to possess or distribute without a license from the Drug Enforcement Administration (DEA).

In the medical field, 5-Methoxytryptamine does not have a specific use as a medication. However, it has been used in some research settings to study its effects on the brain and behavior. It is important to note that the use of 5-Methoxytryptamine or any other psychedelic substance should only be done under the supervision of trained medical professionals in a controlled setting due to the potential risks associated with their use.

Cardiotonic agents are a type of medication that have a positive inotropic effect on the heart, meaning they help to improve the contractility and strength of heart muscle contractions. These medications are often used to treat heart failure, as they can help to improve the efficiency of the heart's pumping ability and increase cardiac output.

Cardiotonic agents work by increasing the levels of calcium ions inside heart muscle cells during each heartbeat, which in turn enhances the force of contraction. Some common examples of cardiotonic agents include digitalis glycosides (such as digoxin), which are derived from the foxglove plant, and synthetic medications such as dobutamine and milrinone.

While cardiotonic agents can be effective in improving heart function, they can also have potentially serious side effects, including arrhythmias, electrolyte imbalances, and digestive symptoms. As a result, they are typically used under close medical supervision and their dosages may need to be carefully monitored to minimize the risk of adverse effects.

Cardiopulmonary resuscitation (CPR) is a lifesaving procedure that is performed when someone's breathing or heartbeat has stopped. It involves a series of steps that are designed to manually pump blood through the body and maintain the flow of oxygen to the brain until advanced medical treatment can be provided.

CPR typically involves a combination of chest compressions and rescue breaths, which are delivered in a specific rhythm and frequency. The goal is to maintain circulation and oxygenation of vital organs, particularly the brain, until advanced life support measures such as defibrillation or medication can be administered.

Chest compressions are used to manually pump blood through the heart and into the rest of the body. This is typically done by placing both hands on the lower half of the chest and pressing down with enough force to compress the chest by about 2 inches. The compressions should be delivered at a rate of at least 100-120 compressions per minute.

Rescue breaths are used to provide oxygen to the lungs and maintain oxygenation of the body's tissues. This is typically done by pinching the nose shut, creating a seal around the person's mouth with your own, and blowing in enough air to make the chest rise. The breath should be delivered over about one second, and this process should be repeated until the person begins to breathe on their own or advanced medical help arrives.

CPR can be performed by trained laypeople as well as healthcare professionals. It is an important skill that can help save lives in emergency situations where a person's breathing or heartbeat has stopped.

I'm sorry for any confusion, but "Pempidine" does not appear to be a recognized term in medical terminology or pharmacology. It is possible that there may be a spelling error or typo in the term you are looking for. Please double-check the spelling and try again. If you meant "Pimobendan," I would be happy to provide information on that instead.

If you indeed meant "Pempidine," please let me know, and I will do my best to find more information about it.

Risk assessment in the medical context refers to the process of identifying, evaluating, and prioritizing risks to patients, healthcare workers, or the community related to healthcare delivery. It involves determining the likelihood and potential impact of adverse events or hazards, such as infectious diseases, medication errors, or medical devices failures, and implementing measures to mitigate or manage those risks. The goal of risk assessment is to promote safe and high-quality care by identifying areas for improvement and taking action to minimize harm.

Metoprolol is a type of medication known as a beta blocker. According to the US National Library of Medicine's MedlinePlus, metoprolol is used to treat high blood pressure, angina (chest pain), and heart conditions that may occur after a heart attack. It works by blocking the action of certain natural chemicals in your body, such as epinephrine, on the heart and blood vessels. This helps to reduce the heart's workload, lower its blood pressure, and regulate its rhythm.

Metoprolol is available under various brand names, including Lopressor and Toprol-XL. It can be taken orally as a tablet or an extended-release capsule. As with any medication, metoprolol should be used under the supervision of a healthcare provider, who can monitor its effectiveness and potential side effects.

It is important to note that this definition is intended to provide a general overview of the medical use of metoprolol and should not be considered a substitute for professional medical advice.

Intravenous (IV) infusion is a medical procedure in which liquids, such as medications, nutrients, or fluids, are delivered directly into a patient's vein through a needle or a catheter. This route of administration allows for rapid absorption and distribution of the infused substance throughout the body. IV infusions can be used for various purposes, including resuscitation, hydration, nutrition support, medication delivery, and blood product transfusion. The rate and volume of the infusion are carefully controlled to ensure patient safety and efficacy of treatment.

The Autonomic Nervous System (ANS) is a part of the nervous system that controls involuntary actions, such as heart rate, digestion, respiratory rate, pupillary response, urination, and sexual arousal. It consists of two subdivisions: the sympathetic and parasympathetic nervous systems, which generally have opposing effects and maintain homeostasis in the body.

Autonomic Nervous System Diseases (also known as Autonomic Disorders or Autonomic Neuropathies) refer to a group of conditions that affect the functioning of the autonomic nervous system. These diseases can cause damage to the nerves that control automatic functions, leading to various symptoms and complications.

Autonomic Nervous System Diseases can be classified into two main categories:

1. Primary Autonomic Nervous System Disorders: These are conditions that primarily affect the autonomic nervous system without any underlying cause. Examples include:
* Pure Autonomic Failure (PAF): A rare disorder characterized by progressive loss of autonomic nerve function, leading to symptoms such as orthostatic hypotension, urinary retention, and constipation.
* Multiple System Atrophy (MSA): A degenerative neurological disorder that affects both the autonomic nervous system and movement coordination. Symptoms may include orthostatic hypotension, urinary incontinence, sexual dysfunction, and Parkinsonian features like stiffness and slowness of movements.
* Autonomic Neuropathy associated with Parkinson's Disease: Some individuals with Parkinson's disease develop autonomic symptoms such as orthostatic hypotension, constipation, and urinary dysfunction due to the degeneration of autonomic nerves.
2. Secondary Autonomic Nervous System Disorders: These are conditions that affect the autonomic nervous system as a result of an underlying cause or disease. Examples include:
* Diabetic Autonomic Neuropathy: A complication of diabetes mellitus that affects the autonomic nerves, leading to symptoms such as orthostatic hypotension, gastroparesis (delayed gastric emptying), and sexual dysfunction.
* Autoimmune-mediated Autonomic Neuropathies: Conditions like Guillain-Barré syndrome or autoimmune autonomic ganglionopathy can cause autonomic symptoms due to the immune system attacking the autonomic nerves.
* Infectious Autonomic Neuropathies: Certain infections, such as HIV or Lyme disease, can lead to autonomic dysfunction as a result of nerve damage.
* Toxin-induced Autonomic Neuropathy: Exposure to certain toxins, like heavy metals or organophosphate pesticides, can cause autonomic neuropathy.

Autonomic nervous system disorders can significantly impact a person's quality of life and daily functioning. Proper diagnosis and management are crucial for improving symptoms and preventing complications. Treatment options may include lifestyle modifications, medications, and in some cases, devices or surgical interventions.

Three-dimensional (3D) imaging in medicine refers to the use of technologies and techniques that generate a 3D representation of internal body structures, organs, or tissues. This is achieved by acquiring and processing data from various imaging modalities such as X-ray computed tomography (CT), magnetic resonance imaging (MRI), ultrasound, or confocal microscopy. The resulting 3D images offer a more detailed visualization of the anatomy and pathology compared to traditional 2D imaging techniques, allowing for improved diagnostic accuracy, surgical planning, and minimally invasive interventions.

In 3D imaging, specialized software is used to reconstruct the acquired data into a volumetric model, which can be manipulated and viewed from different angles and perspectives. This enables healthcare professionals to better understand complex anatomical relationships, detect abnormalities, assess disease progression, and monitor treatment response. Common applications of 3D imaging include neuroimaging, orthopedic surgery planning, cancer staging, dental and maxillofacial reconstruction, and interventional radiology procedures.

Hypovolemia is a medical condition characterized by a decreased volume of circulating blood in the body, leading to inadequate tissue perfusion and oxygenation. This can occur due to various reasons such as bleeding, dehydration, vomiting, diarrhea, or excessive sweating, which result in a reduced amount of fluid in the intravascular space.

The severity of hypovolemia depends on the extent of fluid loss and can range from mild to severe. Symptoms may include thirst, dry mouth, weakness, dizziness, lightheadedness, confusion, rapid heartbeat, low blood pressure, and decreased urine output. Severe hypovolemia can lead to shock, organ failure, and even death if not treated promptly and effectively.

Oxprenolol is a non-selective beta blocker and partial agonist of beta-adrenergic receptors. It works by blocking the effects of certain chemicals on the heart and blood vessels, which can help to reduce heart rate, blood pressure, and strain on the heart. Oxprenolol is used to treat angina (chest pain), high blood pressure, irregular heartbeats, and tremors. It may also be used for other purposes not listed here.

It's important to note that oxprenolol should only be taken under the supervision of a medical professional, as it can have significant interactions with other medications and medical conditions. Additionally, sudden discontinuation of oxprenolol should be avoided, as it can lead to rebound effects such as increased heart rate and blood pressure.

Cordotomy is a surgical procedure that involves selectively cutting the spinothalamic tract, which carries pain and temperature signals from the body to the brain. This procedure is typically performed in the cervical (neck) region of the spinal cord and is used to treat chronic, severe pain that has not responded to other forms of treatment.

During a cordotomy, a neurosurgeon uses a specialized needle or electrode to locate and destroy the specific nerve fibers responsible for transmitting painful sensations from a particular part of the body. The procedure can be performed under local anesthesia with sedation or general anesthesia, depending on the patient's preferences and medical condition.

While cordotomy can provide significant pain relief in the short term, it is not a permanent solution, as the nerve fibers may eventually regenerate over time. Additionally, there are risks associated with the procedure, including weakness or numbness in the affected limbs, difficulty swallowing, and in rare cases, respiratory failure. Therefore, cordotomy is typically reserved for patients with severe pain who have exhausted other treatment options and have a limited life expectancy due to their underlying medical condition.

Anesthesia is a medical term that refers to the loss of sensation or awareness, usually induced by the administration of various drugs. It is commonly used during surgical procedures to prevent pain and discomfort. There are several types of anesthesia, including:

1. General anesthesia: This type of anesthesia causes a complete loss of consciousness and is typically used for major surgeries.
2. Regional anesthesia: This type of anesthesia numbs a specific area of the body, such as an arm or leg, while the patient remains conscious.
3. Local anesthesia: This type of anesthesia numbs a small area of the body, such as a cut or wound, and is typically used for minor procedures.

Anesthesia can be administered through various routes, including injection, inhalation, or topical application. The choice of anesthesia depends on several factors, including the type and duration of the procedure, the patient's medical history, and their overall health. Anesthesiologists are medical professionals who specialize in administering anesthesia and monitoring patients during surgical procedures to ensure their safety and comfort.

The autonomic nervous system (ANS) is a component of the peripheral nervous system that regulates involuntary physiological functions, such as heart rate, digestion, respiratory rate, pupillary response, urination, and sexual arousal. The autonomic pathways refer to the neural connections and signaling processes that allow the ANS to carry out these functions.

The autonomic pathways consist of two main subdivisions: the sympathetic nervous system (SNS) and the parasympathetic nervous system (PNS). These systems have opposing effects on many organs, with the SNS generally stimulating activity and the PNS inhibiting it. The enteric nervous system, which controls gut function, is sometimes considered a third subdivision of the ANS.

The sympathetic pathway originates in the thoracic and lumbar regions of the spinal cord, with preganglionic neurons synapsing on postganglionic neurons in paravertebral ganglia or prevertebral ganglia. The parasympathetic pathway originates in the brainstem (cranial nerves III, VII, IX, and X) and the sacral region of the spinal cord (S2-S4), with preganglionic neurons synapsing on postganglionic neurons near or within the target organ.

Acetylcholine is the primary neurotransmitter used in both the sympathetic and parasympathetic pathways, although norepinephrine (noradrenaline) is also released by some postganglionic sympathetic neurons. The specific pattern of neural activation and inhibition within the autonomic pathways helps maintain homeostasis and allows for adaptive responses to changes in the internal and external environment.

Adrenergic beta-1 receptor antagonists, also known as beta blockers, are a class of medications that block the effects of adrenaline and noradrenaline (also known as epinephrine and norepinephrine) on beta-1 receptors. These receptors are found primarily in the heart and kidneys, where they mediate various physiological responses such as increased heart rate, contractility, and conduction velocity, as well as renin release from the kidneys.

By blocking the action of adrenaline and noradrenaline on these receptors, beta blockers can help to reduce heart rate, lower blood pressure, decrease the force of heart contractions, and improve symptoms of angina (chest pain). They are commonly used to treat a variety of conditions, including hypertension, heart failure, arrhythmias, and certain types of tremors. Examples of beta blockers include metoprolol, atenolol, and propranolol.

Diastole is the phase of the cardiac cycle during which the heart muscle relaxes and the chambers of the heart fill with blood. It follows systole, the phase in which the heart muscle contracts and pumps blood out to the body. In a normal resting adult, diastole lasts for approximately 0.4-0.5 seconds during each heartbeat. The period of diastole is divided into two phases: early diastole and late diastole. During early diastole, the ventricles fill with blood due to the pressure difference between the atria and ventricles. During late diastole, the atrioventricular valves close, and the ventricles continue to fill with blood due to the relaxation of the ventricular muscle and the compliance of the ventricular walls. The duration and pressure changes during diastole are important for maintaining adequate cardiac output and blood flow to the body.

A feasibility study is a preliminary investigation or analysis conducted to determine the viability of a proposed project, program, or product. In the medical field, feasibility studies are often conducted before implementing new treatments, procedures, equipment, or facilities. These studies help to assess the practicality and effectiveness of the proposed intervention, as well as its potential benefits and risks.

Feasibility studies in healthcare typically involve several steps:

1. Problem identification: Clearly define the problem that the proposed project, program, or product aims to address.
2. Objectives setting: Establish specific, measurable, achievable, relevant, and time-bound (SMART) objectives for the study.
3. Literature review: Conduct a thorough review of existing research and best practices related to the proposed intervention.
4. Methodology development: Design a methodology for data collection and analysis that will help answer the research questions and achieve the study's objectives.
5. Resource assessment: Evaluate the availability and adequacy of resources, including personnel, time, and finances, required to carry out the proposed intervention.
6. Risk assessment: Identify potential risks and challenges associated with the implementation of the proposed intervention and develop strategies to mitigate them.
7. Cost-benefit analysis: Estimate the costs and benefits of the proposed intervention, including direct and indirect costs, as well as short-term and long-term benefits.
8. Stakeholder engagement: Engage relevant stakeholders, such as patients, healthcare providers, administrators, and policymakers, to gather their input and support for the proposed intervention.
9. Decision-making: Based on the findings of the feasibility study, make an informed decision about whether or not to proceed with the proposed project, program, or product.

Feasibility studies are essential in healthcare as they help ensure that resources are allocated efficiently and effectively, and that interventions are evidence-based, safe, and beneficial for patients.

Bethanidine is a non-cardioselective, moderately potent, short-acting antihypertensive drug. It belongs to the class of medications known as ganglionic blockers, which work by blocking the action of certain nerves in the body, leading to a decrease in blood pressure.

Bethanidine is used to treat high blood pressure and has been used in the management of symptoms associated with congestive heart failure. However, its use has declined over the years due to the availability of safer and more effective antihypertensive medications.

Like other ganglionic blockers, bethanidine can cause side effects such as dry mouth, blurred vision, constipation, difficulty urinating, dizziness, and weakness. It should be used with caution in patients with certain medical conditions, including kidney or liver disease, narrow-angle glaucoma, and bladder neck obstruction.

It is important to note that bethanidine is not commonly used in clinical practice today due to its potential for serious side effects and the availability of safer alternatives.

Voltage-sensitive dye imaging (VSDI) is not a medical definition itself, but it is a technique used in the field of physiology and neuroscience to measure the electrical activity of cells, particularly excitable cells such as neurons and cardiac myocytes. Here's a brief explanation:

Voltage-sensitive dyes are fluorescent or luminescent molecules that change their optical properties in response to changes in membrane potential. When these dyes bind to the cell membrane, they can report on the electrical activity of the cell by changing their emission intensity, polarization, or lifetime depending on the voltage across the membrane.

VSDI is a technique that uses these voltage-sensitive dyes to measure changes in membrane potential in a population of cells or even in an entire organ. By illuminating the sample with light and measuring the emitted fluorescence or luminescence, researchers can visualize and quantify the electrical activity of cells in real-time.

VSDI has many applications in basic research, including studying the electrical properties of neurons, mapping neural circuits, investigating the mechanisms of excitation-contraction coupling in cardiac myocytes, and developing new drugs that target ion channels. However, it is not a commonly used clinical technique due to its limitations, such as the need for specialized equipment, the potential for phototoxicity, and the difficulty of interpreting signals from complex tissues.

Sympathomimetic drugs are substances that mimic or stimulate the actions of the sympathetic nervous system. The sympathetic nervous system is one of the two divisions of the autonomic nervous system, which regulates various automatic physiological functions in the body. The sympathetic nervous system's primary function is to prepare the body for the "fight-or-flight" response, which includes increasing heart rate, blood pressure, respiratory rate, and metabolism while decreasing digestive activity.

Sympathomimetic drugs can exert their effects through various mechanisms, including directly stimulating adrenergic receptors (alpha and beta receptors) or indirectly causing the release of norepinephrine and epinephrine from nerve endings. These drugs are used in various clinical settings to treat conditions such as asthma, nasal congestion, low blood pressure, and attention deficit hyperactivity disorder (ADHD). Examples of sympathomimetic drugs include epinephrine, norepinephrine, dopamine, dobutamine, albuterol, pseudoephedrine, and methylphenidate.

It is important to note that sympathomimetic drugs can also have adverse effects, particularly when used in high doses or in individuals with certain medical conditions. These adverse effects may include anxiety, tremors, palpitations, hypertension, arrhythmias, and seizures. Therefore, these medications should be used under the close supervision of a healthcare provider.

Magnetocardiography (MCG) is a non-invasive diagnostic technique that measures the magnetic fields produced by the electrical activity of the heart. It uses highly sensitive devices called magnetometers to detect and record these magnetic signals, which are then processed and analyzed to provide information about the heart's electrical function and structure.

MCG can be used to detect and monitor various cardiac conditions, including arrhythmias, ischemia (reduced blood flow to the heart), and myocardial infarction (heart attack). It can also help in identifying abnormalities in the heart's conduction system and assessing the effectiveness of treatments such as pacemakers.

One advantage of MCG over other diagnostic techniques like electrocardiography (ECG) is that it is not affected by the conductive properties of body tissues, which can distort ECG signals. This makes MCG a more accurate tool for measuring the heart's magnetic fields and can provide additional information about the underlying electrical activity. However, MCG requires specialized equipment and shielding to reduce interference from external magnetic sources, making it less widely available than ECG.

Analysis of Variance (ANOVA) is a statistical technique used to compare the means of two or more groups and determine whether there are any significant differences between them. It is a way to analyze the variance in a dataset to determine whether the variability between groups is greater than the variability within groups, which can indicate that the groups are significantly different from one another.

ANOVA is based on the concept of partitioning the total variance in a dataset into two components: variance due to differences between group means (also known as "between-group variance") and variance due to differences within each group (also known as "within-group variance"). By comparing these two sources of variance, ANOVA can help researchers determine whether any observed differences between groups are statistically significant, or whether they could have occurred by chance.

ANOVA is a widely used technique in many areas of research, including biology, psychology, engineering, and business. It is often used to compare the means of two or more experimental groups, such as a treatment group and a control group, to determine whether the treatment had a significant effect. ANOVA can also be used to compare the means of different populations or subgroups within a population, to identify any differences that may exist between them.

Ebstein anomaly is a congenital heart defect that affects the tricuspid valve, which is the valve between the right atrium and right ventricle of the heart. In Ebstein anomaly, the tricuspid valve is abnormally formed and positioned, causing it to leak blood back into the right atrium. This can lead to various symptoms such as shortness of breath, fatigue, and cyanosis (bluish discoloration of the skin). Treatment for Ebstein anomaly may include medication, surgery, or a combination of both. It is important to note that the severity of the condition can vary widely among individuals, and some people with Ebstein anomaly may require more intensive treatment than others.

... may turn into ventricular fibrillation and can result in cardiac arrest. Ventricular tachycardia can ... B Garner, J; M Miller, J (April 2013). "Wide Complex Tachycardia - Ventricular Tachycardia or Not Ventricular Tachycardia, That ... Right ventricular outflow tract (RVOT) tachycardia is a type of monomorphic ventricular tachycardia originating in the right ... Ventricular tachycardia can be classified based on its morphology:[citation needed] Monomorphic ventricular tachycardia means ...
The ventricular tachycardia may take a characteristic form known as bidirectional ventricular tachycardia. This form of ... and classically take the form of bidirectional ventricular tachycardia or ventricular fibrillation. Those affected may be ... abnormal heart rhythms such as bidirectional ventricular tachycardia or frequent polymorphic ventricular ectopic beats may be ... The bidirectional ventricular tachycardia associated with this condition was described in 1975. The term "Catecholaminergic ...
Gregory Crouch (2012). "Chapter 17: Ventricular tachycardia". China's Wings: War, Intrigue, Romance and Adventure in the Middle ...
Gregory Crouch (2012). "Chapter 17: Ventricular Tachycardia". China's Wings: War, Intrigue, Romance and Adventure in the Middle ...
Ventricular tachycardia". China's Wings: War, Intrigue, Romance and Adventure in the Middle Kingdom during the Golden Age of ...
Gregory Crouch (2012). "Chapter 17: Ventricular Tachycardia". China's Wings: War, Intrigue, Romance and Adventure in the Middle ...
Lieve KV, van der Werf C, Wilde AA (May 2016). "Catecholaminergic Polymorphic Ventricular Tachycardia". Circulation Journal. 80 ... calsequestrin are responsible for an autosomal recessive form of catecholaminergic polymorphic ventricular tachycardia, an ...
... ventricular fibrillation, or ventricular tachycardia), this does not necessarily improve the person's chances of survival to ... or unstable ventricular tachycardia that is not producing a pulse, which can potentially be treated with defibrillation) ... "Ventricular Tachycardias". Critical Care Nursing Clinics of North America. 28 (3): 317-329. doi:10.1016/j.cnc.2016.04.004. PMID ... Asystole is different from very fine occurrences of ventricular fibrillation, though both have a poor prognosis, and untreated ...
Wide complex Ventricular tachycardia, any tachycardia that originates in the ventricles Any narrow complex tachycardia combined ... Tachycardia >169 bpm 1-2 years: Tachycardia >151 bpm 3-4 years: Tachycardia >137 bpm 5-7 years: Tachycardia >133 bpm 8-11 years ... Tachycardia >159 beats per minute (bpm) 3-6 days: Tachycardia >166 bpm 1-3 weeks: Tachycardia >182 bpm 1-2 months: Tachycardia ... Samie FH, Jalife J (May 2001). "Mechanisms underlying ventricular tachycardia and its transition to ventricular fibrillation in ...
Both ventricular fibrillation and ventricular tachycardia can result in the heart ineffectively pumping blood to the body. ... "Ventricular tachycardia - Symptoms and causes". Mayo Clinic. Retrieved 2021-11-29. "Ventricular fibrillation - Symptoms and ... The two shockable rhythms are ventricular fibrillation and pulseless ventricular tachycardia. In children, 2 to 4 J/Kg is ... The two "shockable" rhythms are ventricular fibrillation and pulseless ventricular tachycardia, while the two "non-shockable" ...
Marchant B, Wray R, Leach A, Nama M (September 1989). "Flumazenil causing convulsions and ventricular tachycardia". BMJ. 299 ( ... or in patients who have tachycardia, widened QRS complex on ECG, anticholinergic signs, or a history of seizures. Due to these ...
Indications for Class Ia agents are supraventricular tachycardia, ventricular tachycardia, symptomatic ventricular premature ... Class Ib agents are indicated for the treatment of ventricular tachycardia and symptomatic premature ventricular beats, and ... and as a last line treatment for refractory life-threatening ventricular tachycardia or ventricular fibrillation. These agents ... "Ventricular Tachycardia Medication: Antiarrhythmics, Class IC". Retrieved 4 October 2017. Wood JN, Boorman J (2005). "Voltage- ...
... can be used to distinguish between ventricular tachycardia and supraventricular tachycardia by slowing the rate of conduction ... Hess, D. S.; Hanlon, T.; Scheinman, M.; Budge, R.; Desai, J. (March 1982). "Termination of ventricular tachycardia by carotid ... Wei, J. Y.; Greene, H. L.; Weisfeldt, M. L. (January 1980). "Cough-facilitated conversion of ventricular tachycardia". The ... Vagal maneuvers may be used to terminate hemodynamically stable ventricular tachycardia. Various vagal maneuvers are suggested ...
... some forms of ventricular tachycardia), others by an irritable focus (e.g. focal atrial tachycardia), while others are caused ... AV nodal re-entrant tachycardia) whilst others arise from the ventricles (e.g. ventricular tachycardia). Some tachyarrhythmias ... Torsades de pointes type ventricular tachycardia, ventricular fibrillation and risk of sudden cardiac death. Short QT syndrome ... Catecholaminergic polymorphic ventricular tachycardia (CPVT). Progressive cardiac conduction defect (PCCD). Early ...
If 3 or more consecutive PVCs occur in a row it may be called ventricular tachycardia. The precise shape of the QRS can give an ... Specifically, if this shows exercise-induced ventricular tachycardia this would require specific treatment. If PVCs are ... ed.). "Premature Ventricular Contractions (PVCs, PVC): What happens during a premature ventricular contraction?". MedicineNet. ... ed.). "Premature Ventricular Contractions (PVCs, PVC): What causes premature ventricular contractions?". MedicineNet. Retrieved ...
In addition, an isolated incident of a non-sustained 14-beat ventricular tachycardia (Figure 1), with a maximum heart rate of ... However, one crewmember experienced a 5-beat run of ventricular tachycardia during a lower-body negative pressure protocol, and ... The published report of non-sustained ventricular tachycardia during prolonged space flight supports this hypothesis, in that ... Lerman, BB; Stein, KM; Markowitz, SM (June 1996). "Adenosine-sensitive ventricular tachycardia: a conceptual approach". Journal ...
The classical feature is Bidirectional ventricular tachycardia. Also seen in catecholaminergic polymorphic ventricular ... underlie catecholaminergic polymorphic ventricular tachycardia". Circulation. 103 (2): 196-200. doi:10.1161/01.cir.103.2.196. ... Early afterdepolarizations can result in torsades de pointes, tachycardia, and other arrhythmias. EADs can be triggered by ... tachycardia (CPVT). Delayed afterdepolarization is also seen in myocardial infarction. Purkinje fibers which survive myocardial ...
... such as during ventricular tachycardia or shock. The character of the apex beat may provide vital diagnostic clues: A forceful ... such as premature ventricular contraction or atrial fibrillation. Sustained apex beat, namely prolonged upward cardiac force ... apex beat involving a larger area than normal indicates ventricular dysfunction; such as an aneurysm following myocardial ...
Walts LF (1963). "Ventricular tachycardia with gallamine and cyclopropane anesthesia". Anesthesiology. 24: 119. doi:10.1097/ ... Morgenstern C, Splith G (October 1965). "[Studies on the causes of gallamine tachycardia and its antagonistic modification by ... Gallamine triethiodide has a parasympatholytic effect on the cardiac vagus nerve, which causes tachycardia and occasionally ...
... who produced an electrocardiogram showing ventricular tachycardia evolving into ventricular fibrillation. The re-entry ... Ventricular fibrillation is initially found in about 10% of people with cardiac arrest. Ventricular fibrillation can occur due ... Ventricular excitability may generate re-entry ventricular arrhythmia.[citation needed] Most myocardial cells with an ... It follows then that, on the basis of the fact that ventricular fibrillation itself is common, idiopathic ventricular ...
... or to the disorganised electrical activity of either ventricular fibrillation or ventricular tachycardia. Cardiac resuscitation ... Baldzizhar, A; Manuylova, E; Marchenko, R; Kryvalap, Y; Carey, MG (September 2016). "Ventricular Tachycardias: Characteristics ... Tachycardia Trauma (e.g., hypovolemia from blood loss) The possible mechanisms by which the above conditions can cause ...
Catecholaminergic polymorphic ventricular tachycardia Katz, Arnold M. (2005). Physiology of the Heart (4th ed.). Lippincott ... A lack of or mutation in CSQ2 has been directly associated with catecholaminergic polymorphic ventricular tachycardia (CPVT). A ... GeneReviews/NCBI/NIH/UW entry on Catecholaminergic Polymorphic Ventricular Tachycardia Calsequestrin at the U.S. National ...
Accelerated idioventricular rhythm Monomorphic ventricular tachycardia Polymorphic ventricular tachycardia Ventricular ... Right ventricular outflow tract tachycardia is the most common type of ventricular tachycardia in otherwise healthy individuals ... Ventricular arrhythmias include ventricular fibrillation and ventricular tachycardia. Bradyarrhythmias are due to sinus node ... It is needed for the chaotic rhythm of ventricular fibrillation and is also used for pulseless ventricular tachycardia. Often, ...
It is also used to treat ventricular tachycardia. When used for local anaesthesia or in nerve blocks, lidocaine typically ... Lidocaine is also the most important class-1b antiarrhythmic drug; it is used intravenously for the treatment of ventricular ...
Gouaux, JL; Ashman, R (Sep 1947). "Auricular fibrillation with aberration simulating ventricular paroxysmal tachycardia". ... Oreto, G; Luzza, F; Satullo, G; Donato, A; Carbone, V; Calabrò, MP (Sep 2009). "[Wide QRS complex tachycardia: an old and new ... It is more often misinterpreted as a premature ventricular complex. It is named for Richard Ashman (of New Orleans) (1890 -1969 ... Chenevert, M; Lewis, RJ (Mar-Apr 1992). "Ashman's phenomenon--a source of nonsustained wide-complex tachycardia: case report ...
Hank Gathers, 23, American basketball player, ventricular tachycardia. Konstantin Konstantinovich Kokkinaki, 79, Soviet fighter ...
December 2017). "Noninvasive Cardiac Radiation for Ablation of Ventricular Tachycardia". The New England Journal of Medicine. ... If not controlled, such arrhythmias increase the risk of ventricular fibrillation and sudden cardiac arrest. The ablation ... A 2018 study showed efficacy of cardiac ablation for treatment of Premature Ventricular Contraction as 94.1%. Catheter ablation ... September 2009). "Meta-analysis of ablation of atrial flutter and supraventricular tachycardia". The American Journal of ...
Taihō Kōki, 72, Japanese sumo wrestler, ventricular tachycardia. Michel Las Vergnas, 72, French mathematician. Li Minhua, 95, ...
This includes ventricular and supraventricular tachycardias. Its use is only recommended in those with dangerous arrhythmias or ... It has use in the treatment of right ventricular outflow tract (RVOT) tachycardia and in the suppression of arrhythmias in ... January 2001). "Torsades de pointes ventricular tachycardia induced by mosapride and flecainide in the presence of hypokalemia ... Flecainide is used in the treatment of many types of supraventricular tachycardias, including AV nodal re-entrant tachycardia ( ...
"An Episode of Ventricular Tachycardia During Long-Duration Spaceflight". The American Journal of Cardiology. 81 (11): 1391-1392 ...
ventricular) is fundamental since they are treated differently. In addition, ventricular tachycardia can quickly degenerate ... Multifocal atrial tachycardia (MAT) Atrial fibrillation with rapid ventricular response Atrial flutter with rapid ventricular ... tachycardia that is seen. Junctional ectopic tachycardia (JET) is a rare tachycardia caused by increased automaticity of the AV ... AV nodal reentrant tachycardia (AVNRT) or junctional reciprocating tachycardia (JRT) AV reciprocating tachycardia (AVRT) - ...
Ventricular tachycardia may turn into ventricular fibrillation and can result in cardiac arrest. Ventricular tachycardia can ... B Garner, J; M Miller, J (April 2013). "Wide Complex Tachycardia - Ventricular Tachycardia or Not Ventricular Tachycardia, That ... Right ventricular outflow tract (RVOT) tachycardia is a type of monomorphic ventricular tachycardia originating in the right ... Ventricular tachycardia can be classified based on its morphology:[citation needed] Monomorphic ventricular tachycardia means ...
Ventricular tachycardia (VT) is a rapid heartbeat that starts in the lower chambers of the heart (ventricles). ... Ventricular tachycardia (VT) is a rapid heartbeat that starts in the lower chambers of the heart (ventricles). ... Ventricular tachycardia may not cause symptoms in some people. However, it can be deadly. It is a major cause of sudden cardiac ... Ventricular tachycardia (VT) is a rapid heartbeat that starts in the lower chambers of the heart (ventricles). ...
The rhythm may arise from ventricular myocardium, the distal conduction system, or both. ... Ventricular tachycardia (VT) refers to any rhythm faster than 100 (or 120) beats/min arising distal to the bundle of His. ... encoded search term (Ventricular Tachycardia) and Ventricular Tachycardia What to Read Next on Medscape ... Using the 12-lead ECG to localize the origin of atrial and ventricular tachycardias: part 2--ventricular tachycardia. J ...
Wide-complex tachycardia; V tach; Tachycardia - ventricular. Definition. Ventricular tachycardia is a rapid heart beat ... The ICD may also be programmed to send a rapid burst of paced beats to interrupt the ventricular tachycardia. The ventricular ... "Torsade de pointes" is a form of ventricular tachycardia with a specific variation in the conduction of the ventricular ... Ventricular tachycardia can occur in the absence of apparent Heart disease. It can also develop as an early or a late ...
... , Torsades de Pointes, Torsades, Ventricular Tachycardia Management in Pregnancy ... Ventricular Tachycardia Management in the Adult. Ventricular Tachycardia Management in the Adult Aka: Ventricular Tachycardia ... of Ventricular Tachycardia converts with Adenosine. *Response to Adenosine does NOT rule out Ventricular Tachycardia ... Approach: Regular Wide Complex Tachycardia (stable) *INITIAL: Adenosine (or go to below under Ventricular Tachycardia). *AVOID ...
Ventricular tachycardia, Torsade de pointes Overview. Polymorphic ventricular tachcardia is a form of ventricular tachycardia ... Review articles on Polymorphic ventricular tachycardia Articles on Polymorphic ventricular tachycardia in N Eng J Med, Lancet, ... Ongoing Trials on Polymorphic ventricular tachycardia at Clinical Trials.gov Trial results on Polymorphic ventricular ... US National Guidelines Clearinghouse on Polymorphic ventricular tachycardia NICE Guidance on Polymorphic ventricular ...
Ventricular Tachycardia - Learn about the causes, symptoms, diagnosis & treatment from the Merck Manuals - Medical Consumer ... Ventricular tachycardia sometimes turns into ventricular fibrillation Ventricular Fibrillation Ventricular fibrillation is a ... de Pointes Ventricular Tachycardia Torsades de pointes ventricular tachycardia is a specific type of ventricular tachycardia ... What is ventricular tachycardia? Ventricular tachycardia is a type of abnormal heart rhythm Overview of Abnormal Heart Rhythms ...
Ventricular tachycardia. Ventricular tachycardias were recorded during a 30-day period with a textile ECG Holter (Nuubo ECG ... Nonsustained ventricular tachycardia is independently associated with sustained ventricular arrhythmias in nonischemic dilated ... right ventricular cardiomyopathy/dysplasia and no prior ventricular fibrillation or sustained ventricular tachycardia. ... Rapid-rate non-sustained ventricular tachycardias (RR-NSVTs) are a surrogate of sudden cardiac death in this population. ...
Ventricular Tachycardia Market. Ventricular Tachycardia Market - Global Industry Analysis, Size, Share, Growth, Trends, and ...
Identification of patients prone to ventricular tachycardia using wavelet analysis. Title. Identification of patients prone to ...
... a case of catheter and surgical therapy of sustained monomorphic ventricular tachycardia. ... a case of catheter and surgical therapy of sustained monomorphic ventricular tachycardia. ...
Ventricular tachycardia is a fast, abnormal heart rate and may lead to sudden cardiac arrest if not treated successfully. ... Ventricular Tachycardia Ablation versus Escalation of Antiarrhythmic Drugs. N Engl J Med [Internet]. 2016/05/06. 2016;375(2): ... Acute failure of catheter ablation for ventricular tachycardia due to structural heart disease: causes and significance. J Am ... Irrigated radiofrequency catheter ablation guided by electroanatomic mapping for recurrent ventricular tachycardia after ...
Ventricular tachycardia may not cause symptoms in some people. However, it can be deadly. It is a major cause of sudden cardiac ... Ventricular tachycardia (VT) is a rapid heartbeat that starts in the lower chambers of the heart (ventricles). ... Garan H. Ventricular arrhythmias. In: Goldman L, Schafer AI, eds. Goldman-Cecil Medicine. 26th ed. Philadelphia, PA: Elsevier; ... Stevenson WG, Keppenfeld K. Ventricular Arrhythmias. In: Libby P, Bonow RO, Mann DL, Tomaselli GF, Bhatt DL, Solomon SD, eds. ...
Return to Article Details Outcome after out-of-hospital ventricular fibrillation or pulseless ventricular tachycardia: ...
Multifocal ventricular tachycardia. Definition: An electrocardiographic finding of a ventricular tachycardia in which the ... Synonyms (terms occurring on more labels are shown first): polymorphic ventricular tachycardia More information: PubMed search ... ventricular activation sequence is variable. The morphology of the electrocardiographic waveform is variable and is referred to ...
... ventricular tachycardia, ventricular tachycardias, tachycardia ventricular More information: PubMed search and possibly ... Ventricular tachycardia. Definition: An abnormally rapid ventricular rhythm usually in excess of 150 beats per minute. It is ... Depending on the etiology, onset of ventricular tachycardia can be paroxysmal (sudden) or nonparoxysmal, its wide QRS complexes ... can be uniform or polymorphic, and the ventricular beating may be independent of the atrial beating (AV dissociation). ...
Another example of ventricular tachycardia, featuring a fusion beat (arrowhead). (ECG contributor: Marc Mickiewicz, MD.) ... "Ventricular Tachycardia." The Atlas of Emergency Medicine, 5e Knoop KJ, Stack LB, Storrow AB, Thurman R. Knoop K.J., & Stack L. ... Ventricular Tachycardia. In: Knoop KJ, Stack LB, Storrow AB, Thurman R. Knoop K.J., & Stack L.B., & Storrow A.B., & Thurman R( ... Ventricular tachycardia. Knoop KJ, Stack LB, Storrow AB, Thurman R. Knoop K.J., & Stack L.B., & Storrow A.B., & Thurman R(Eds ...
... time magnetic resonance imaging-guided electrophysiology system for structural and electrophysiological ventricular tachycardia ... time magnetic resonance imaging-guided electrophysiology system for structural and electrophysiological ventricular tachycardia ... time magnetic resonance imaging-guided electrophysiology system for structural and electrophysiological ventricular tachycardia ... time magnetic resonance imaging-guided electrophysiology system for structural and electrophysiological ventricular tachycardia ...
Conventional programmed ventricular stimulation was performed for sustained ventricular tachycardia induction. Endocardial ... system in patients with sustained ventricular tachycardia.Design-20 consecutive patients with sustained ventricular tachycardia ... Angiographic and electrophysiological substrates for ventricular tachycardia mapping through the coronary veins. dc.contributor ... Angiographic and electrophysiological substrates for ventricular tachycardia mapping through the coronary veins. en. ...
Ventricular Tachycardia (VT) - Etiology, pathophysiology, symptoms, signs, diagnosis & prognosis from the MSD Manuals - Medical ... Diagnosis of ventricular tachycardia is by ECG (see figure Broad QRS ventricular tachycardia Broad QRS ventricular tachycardia ... Ventricular Tachycardia Torsades de pointes ventricular tachycardia is a specific form of polymorphic ventricular tachycardia ... Symptoms and Signs of Ventricular Tachycardia Ventricular tachycardia of short duration or slow rate may be asymptomatic. ...
Interpreting Incidentally Identified Variants in Genes Associated With Catecholaminergic Polymorphic Ventricular Tachycardia in ... "Interpreting Incidentally Identified Variants in Genes Associated With Catecholaminergic Polymorphic Ventricular Tachycardia in ... Interpreting Incidentally Identified Variants in Genes Associated With Catecholaminergic Polymorphic Ventricular Tachycardia in ... "Interpreting Incidentally Identified Variants in Genes Associated With Catecholaminergic Polymorphic Ventricular Tachycardia in ...
Clinical Outcomes in Patients With Dilated Cardiomyopathy and Ventricular Tachycardia. Journal of the American College of ... Clinical Outcomes in Patients With Dilated Cardiomyopathy and Ventricular Tachycardia. J Am Coll Cardiol 2022 Sep 13;80(11)1045 ...
Wide-complex tachycardia. Assume any wide-complex tachycardia is ventricular tachycardia until proven otherwise (it is safer to ... Paroxysmal supraventricular tachycardia (PSVT) *AV node re-entry tachycardia (AVNRT). *AV re-entry tachycardia (AVRT) *Lown- ... See also rhythm diagnosis in regular wide complex tachycardia. Management. Wide Regular Tachycardia[1]. Pulseless: see Adult ... 3 wide complexes in a row is considered ventricular tachycardia *Non-sustained if lasts , 30 seconds ...
... is an abnormally fast heartbeat that originates in the bottom chambers of your ... Ventricular tachycardia may only last for a few seconds or it may last for extended periods of time, which is extremely ... If your ventricular tachycardia is sustained (lasts a long time), your doctor will first restore your heart to a normal rhythm ... If the cause of your ventricular tachycardia is a problem with your hearts electrical signalling, your doctor may perform a ...
In this lecture we will discuss Ventricular Tachycardia, also known as V-Tach.. V-Tach is defined as rapid and repetitive ...
... is a rare type of ventricular tachycardia. Learn how to recognize them and ... Left fascicular ventricular tachycardia is the most common of the idiopathic ventricular tachycardias originating in the left ... Posterior Fascicular Ventricular Tachycardia. It is the most frequent form of left fascicular ventricular tachycardia (90%), in ... Catheter Ablation of Fascicular Ventricular Tachycardia 2.. Posterior fascicular ventricular tachycardia:. Wide QRS complex ...
Key words: coronary artery disease, implantable cardioverter-defibrillator, sudden cardiac death, ventricular tachycardia, ...
... familial polymorphic ventricular tachycardia, FPVT, polymorphic ventricular tachycardia, polymorphic VT induced by ... catecholamine-induced polymorphic ventricular tachycardia, catecholamine induced polymorphic ventricular tachycardia, ... Differentiating Catecholaminergic polymorphic ventricular tachycardia from other Diseases. Epidemiology and Demographics. Risk ... American Roentgen Ray Society Images of Catecholaminergic polymorphic ventricular tachycardia All Images. X-rays. Echo & ...
Ventricular tachycardia: Ventricular tachycardia can increase the risk of heart attacks.. *Atrial flutter and atrial ... Ventricular tachycardia. This is when the heartbeat starts in the lower chambers of the heart rather than the top chambers, ... Ventricular tachycardia is rare but serious. It can increase the risk of heart attacks. ... Supraventricular tachycardia. Supraventricular tachycardia is the most common heart rhythm abnormality in children. About 50% ...
AICD placed in 2006 for history of ventricular tachycardia and ventricular fibrillation, diabetes, and hypertension […] ... A Case of AICD Shock in Ventricular Tachycardia Following Opioid Use. HPI: 55-year-old female with a history of opioid abuse, ...
  • Garan H. Ventricular arrhythmias. (medlineplus.gov)
  • Ventricular Arrhythmias and Sudden Cardiac Death. (varian.com)
  • Stevenson WG, Keppenfeld K. Ventricular Arrhythmias. (adam.com)
  • These arrhythmias usually respond to treatment with verapamil, which is why they are also called verapamil-sensitive ventricular tachycardias . (my-ekg.com)
  • Ventricular Arrhythmias in the Absence of Structural Heart Disease. (my-ekg.com)
  • Arrhythmias are generally categorized as ventricular or supraventricular.1 Ventricular arrhythmias are a condition in which extra heartbeats originate from the lower chambers of the heart and can be classified as ventricular tachycardia, ventricular fibrillation, or premature ventricular contractions. (bartleby.com)
  • Supraventricular arrhythmias originate in the upper chambers of the heart and can be less serious than ventricular arrhythmias. (bartleby.com)
  • The disease is characterized by heart failure (both diastolic and systolic), systemic emboli and ventricular arrhythmias. (uitm.edu.my)
  • Arrhythmogenic Right Ventricle in Left Ventricular Noncompaction - In Response to the Letter to the Editor "Diagnostic Dilemmas for Underlying Pathophysiology of Arrhythmias Originating from the Right Ventricle" by: Shohreh Honarbakhsh, MBBS, BSc, MRCP, et al. (uitm.edu.my)
  • Implantable cardioverter defibrillator is recommended for symptomatic patients if optimal medical treatment does not control ventricular arrhythmias. (scitechnol.com)
  • The mainstay of treatment includes supportive intensive care and initiation of thionamides, beta blockers, corticosteroids, and if necessary anti-arrhythmics in the presence of refractory ventricular arrhythmias. (journalmc.org)
  • Reentrant, automatic, or triggered mechanisms may cause VA, just as these mechanisms cause supraventricular tachycardia (SVT) and other arrhythmias. (medscape.com)
  • On ingestion chlorpyrifos mainly affects the nervous system by inhibiting the breakdown of acetyl choline (Ach), a neurotransmitter and thus produces endogenous Ach poisoning resulting in complex ventricular arrhythmias. (manipal.edu)
  • Long QT syndrome (LQTS) is a heritable channelopathy characterized by a prolonged cardiac repolarization that may trigger ventricular arrhythmias (torsade de pointes), recurrent syncopes, seizure, or sudden cardiac death (SCD) (Cerrone et al. (preventiongenetics.com)
  • In particular, ICMs may have an emerging role in the management of patients with atrial fibrillation and in those at risk of ventricular arrhythmias. (medscape.com)
  • Solidarity Entities arrhythmias of Homes and Day Centres of ventricular fibrillation the Solidarity Network and ventricular tachycardia in a patient, and is able to treat them through defibrillation, the application of electrical therapy which stops the arrhythmia, allowing the heart to reestablish an effective rhythm. (who.int)
  • Ventricular tachycardia may result in ventricular fibrillation (VF) and turn into cardiac arrest. (wikipedia.org)
  • The term ventricular arrhythmia refers to the group of abnormal cardiac rhythms originating from the ventricle, which includes ventricular tachycardia, ventricular fibrillation, and torsades de pointes. (wikipedia.org)
  • Ventricular Fibrillation Ventricular fibrillation is a potentially fatal, uncoordinated series of very rapid, ineffective contractions of the ventricles (lower chambers of the heart) caused by many chaotic electrical. (merckmanuals.com)
  • Ventricular Fibrillation (VF) Ventricular fibrillation causes uncoordinated quivering of the ventricle with no useful contractions. (msdmanuals.com)
  • may be life-threatening if degenerated to ventricular fibrillation (VF), and can lead to sudden cardiac arrest [2]. (medihelp.life)
  • Chaotic rhythms (eg, ventricular fibrillation) are also examples of reentry mechanisms. (medscape.com)
  • By implementing dedicated algorithms and sensing parameters similar to those of implanted cardioverter defibrillators (ICDs) and pacemakers, the new-generation ICMs are also able to automatically detect (i.e. without any active intervention by the patient) any kind of arrhythmic event (Fig. 1): from bradycardia to asystole, and from atrial fibrillation (AF) to ventricular tachycardia. (medscape.com)
  • The FF regained a sinus rhythm but his heart rhythm reverted to ventricular fibrillation again as care was being transferred to ED staff. (cdc.gov)
  • citation needed] In monomorphic ventricular tachycardia, the shape of each heart beat on the ECG looks the same because the impulse is either being generated from increased automaticity of a single point in either the left or the right ventricle, or due to a reentry circuit within the ventricle. (wikipedia.org)
  • The most common cause of monomorphic ventricular tachycardia is scarring of the heart muscle from a previous myocardial infarction (heart attack). (wikipedia.org)
  • Other rarer congenital causes of monomorphic VT include right ventricular dysplasia, and right and left ventricular outflow tract VT. (wikipedia.org)
  • This electrocardiogram (ECG) shows rapid monomorphic ventricular tachycardia (VT), 280 beats/min, associated with hemodynamic collapse. (medscape.com)
  • Hypertrophic cardiomyopathy with apical aneurysm: a case of catheter and surgical therapy of sustained monomorphic ventricular tachycardia. (bmj.com)
  • Ventricular tachycardia may be monomorphic or polymorphic and nonsustained or sustained. (msdmanuals.com)
  • This ECG depicts a clear example of monomorphic ventricular tachycardia (VT) characterized by a consistent QRS morphology and a rapid heart rate. (heartmatters.com)
  • Amiodarone-induced thyroid storm can lead to monomorphic ventricular tachycardia. (journalmc.org)
  • Congenital problems include long QT syndrome and catecholaminergic polymorphic ventricular tachycardia. (wikipedia.org)
  • Scholars@Duke publication: Interpreting Incidentally Identified Variants in Genes Associated With Catecholaminergic Polymorphic Ventricular Tachycardia in a Large Cohort of Clinical Whole-Exome Genetic Test Referrals. (duke.edu)
  • Clinicians and genetic researchers are being faced with assessing risk of disease vulnerability from incidentally identified genetic variants which is typified by variants found in genes associated with sudden death-predisposing catecholaminergic polymorphic ventricular tachycardia (CPVT). (duke.edu)
  • Marai I, Boulos M, Khoury A (2014) Pharmacological and Non-Pharmacological Therapies of Catecholaminergic Polymorphic Ventricular Tachycardia. (scitechnol.com)
  • All patients with symptoms suggestive of Long QT and Catecholaminergic Polymorphic Ventricular Tachycardia syndrome are candidates for this test. (preventiongenetics.com)
  • Catecholaminergic Polymorphic Ventricular Tachycardia (CPVT) is an inherited arrhythmogenic heart disorder characterized by life-threatening electrical instability induced by physical or emotional stress without any structural cardiac abnormalities (Napolitano et al. (preventiongenetics.com)
  • Pathogenic variants in CALM1 can cause multiple disorders, such as Long QT syndrome type 14 (LQT14) and Catecholaminergic Polymorphic Ventricular Tachycardia (CPVT). (preventiongenetics.com)
  • Ventricular tachycardia is a potentially lethal disruption of normal heartbeat ( Arrhythmia ) that may cause the heart to become unable to pump adequate blood through the body. (health.am)
  • Ventricular tachycardia is a potentially lethal arrhythmia and may result in an absent pulse. (health.am)
  • No adverse responses were attributed to these burst pacemakers, but concern for possible acceleration of tachycardia and appropriate identification of the arrhythmia were among factors limiting more widespread use of antitachycardia pacing. (elsevierpure.com)
  • Amiodarone and Ocular Toxicity An arrhythmia is a problem associated with the electrical activity of the heart resulting in a heartrate that can be too fast (tachycardia) or too slow (bradycardia). (bartleby.com)
  • Introduction: Ventricular tachycardia (VT) is a potentially life-threatening cardiac arrhythmia characterized by rapid and abnormal electrical impulses originating in the ventricles. (madeformedical.com)
  • Ventricular tachycardia, a potentially life-threatening arrhythmia, is one such condition that can now be effectively treated through a procedure called ablation. (usinsuranceagents.com)
  • We present a case of feminizing adrenal carcinoma with severe elevation in serum estradiol and otherwise unexplained congestive heart failure with ventricular arrhythmia and review the literature on feminizing adrenal tumors and the potential relationship between estrogen and cardiac problems. (ecu.edu)
  • A 54-year-old man presented with congestive heart failure and ventricular arrhythmia. (ecu.edu)
  • Upon 15-month followup, the patient continued to have a normal serum estradiol level, his cardiac function was significantly improved, and he had no further episodes of ventricular arrhythmia. (ecu.edu)
  • The clinical presentation of VT, the rate of VT compared to the underlying sinus rate and the morphology of the tachycardia, are features helping the distinction between benign forms of VT and lethal ventricular arrhythmia. (medihelp.life)
  • Ventricular arrhythmia (VA) may be an isolated and completely benign finding in children, a marker of serious systemic disease or myopathy, or a mechanism for syncope and sudden cardiac death (SCD). (medscape.com)
  • citation needed] Polymorphic ventricular tachycardia, on the other hand, is most commonly caused by abnormalities of ventricular muscle repolarization. (wikipedia.org)
  • Torsades de Pointes Ventricular Tachycardia Torsades de pointes ventricular tachycardia is a specific form of polymorphic ventricular tachycardia in patients with a long QT interval. (msdmanuals.com)
  • Polymorphic Ventricular Tachycardia (CPVT) is an inherited cardiac channelopathy characterized by exercise related ventricular tachycardia (VT) manifested as syncope and sudden death among young patients with structurally normal hearts. (scitechnol.com)
  • Long-term treatment of ventricular tachycardia may require the use of oral anti-arrhythmic medications (such as procainamide, amiodarone, or sotalol). (health.am)
  • To assess the role of permanent pacing in the treatment of ventricular tachycardia, a consecutive series of 160 patients undergoing electrophyslologic testing for recurrent ventricular tachycardia were analyzed. (elsevierpure.com)
  • Magnesium salts in the treatment of ventricular tachycardia]. (unicz.it)
  • This is similar to the re-entrant circuits that are the cause of atrial flutter and the re-entrant forms of supraventricular tachycardia. (wikipedia.org)
  • It may be very difficult to differentiate between ventricular tachycardia and a wide-complex supraventricular tachycardia in some cases. (wikipedia.org)
  • Supraventricular tachycardia is the most common heart rhythm abnormality in children. (healthline.com)
  • However, children who receive a diagnosis of supraventricular tachycardia when they are older are less likely to outgrow it. (healthline.com)
  • A narrow complex tachycardia with an accessory conduction pathway, often termed "supraventricular tachycardia with pre-excitation" (e.g. (wikipedia.org)
  • Tachycardias may be classified as either narrow complex tachycardias (supraventricular tachycardias) or wide complex tachycardias. (wikipedia.org)
  • The ECG showed wide QRS complex tachycardia at 200 beats per minute that could be corresponding to VT or supraventricular tachycardia with aberrant conduction (Fig. 1). (medihelp.life)
  • Some ventricular tachycardias may show in the electrophysiologic study to be suitable for an ablation procedure. (health.am)
  • Radiofrequency catheter ablation is a curative treatment for selected tachycardias. (health.am)
  • Ventricular Tachycardia Ablation versus Escalation of Antiarrhythmic Drugs. (varian.com)
  • Acute failure of catheter ablation for ventricular tachycardia due to structural heart disease: causes and significance. (varian.com)
  • Irrigated radiofrequency catheter ablation guided by electroanatomic mapping for recurrent ventricular tachycardia after myocardial infarction: the multicenter thermocool ventricular tachycardia ablation trial. (varian.com)
  • Objective-To study the value of epicardial mapping through the coronary venous system in patients with sustained ventricular tachycardia.Design-20 consecutive patients with sustained ventricular tachycardia who were candidates for radiofrequency ablation.Setting-Electrophysiological laboratory.Interventions-Coronary venous angiography was performed with a catheter, which provided coronary sinus occlusion during injection of contrast media. (unifesp.br)
  • After simultaneous epicardial and endocardial mapping, successful endocardial radiofrequency ablation was achieved in nine of 14 patients with stable ventricular tachycardia (64%).Conclusions-Epicardial mapping through the coronary veins in patients with ventricular tachycardia is feasible, safe, and can be a useful landmark for endocardial catheter mapping and ablation. (unifesp.br)
  • If the cause of your ventricular tachycardia is a problem with your heart's electrical signalling, your doctor may perform a catheter ablation, during which he will use radiofrequency or cryo energy to modify the tissues in your heart that generate electrical abnormalities. (cmhvi406.com)
  • Catheter Ablation of Fascicular Ventricular Tachycardia 2 . (my-ekg.com)
  • In patients with severe symptoms, frequent episodes or poor response to treatment with verapamil the first line treatmen is catheter ablation of the tachycardia 4 5 . (my-ekg.com)
  • Will health insurance cover Ventricular tachycardia ablation? (usinsuranceagents.com)
  • Home » Understanding Health Insurance » Health Insurance Coverage for Medical Procedures » Will health insurance cover Ventricular tachycardia ablation? (usinsuranceagents.com)
  • Are you wondering if your health insurance will cover the cost of Ventricular tachycardia ablation? (usinsuranceagents.com)
  • Ventricular tachycardia ablation is a procedure that aims to restore the heart's normal rhythm by eliminating the source of the abnormal electrical signals. (usinsuranceagents.com)
  • Arrhythmogenic Right Ventricle in Left Ventricular Non-compaction - In response to 'Right Ventricular Ablation as a Therapeutic Option for Left Ventricular Hypertrabeculation / noncompaction' by: Shohreh Honarbakhsh, MBBS, BSc, MRCP, et al. (uitm.edu.my)
  • Successful Right Ventricular Tachycardia Ablation in a Patient with Left Ventricular Non-compaction Cardiomyopathy by: Shohreh Honarbakhsh, MBBS, BSc, MRCP, et al. (uitm.edu.my)
  • Patients with arrhythmogenic right ventricular cardiomyopathy/dysplasia presenting with right ventricular tachycardia are usually suitable to endocardial successful ablation, which may sometimes include the use of irrigated-tip catheters. (uab.cat)
  • Isolated left ventricular non-compaction cardiomyopathy associated with polymorphous ventricular tachycardia mimicking torsades de pointes by: Oana Dickinson, et al. (uitm.edu.my)
  • In recent years, a preferred treatment for many chronic (long-term) ventricular tachycardias consists of implanting a device called implantable cardioverter defibrillator (ICD). (health.am)
  • Thirty-nine patients received implantable pacemakers, of which 13 were intended for bursts of rapid ventricular pacing. (elsevierpure.com)
  • Comparison of novel intrinsic versus conventional antitachycardia pacing for ventricular tachycardia among implantable cardioverter-defibrillator recipients. (bvsalud.org)
  • This can lead to ventricular tachycardia. (medlineplus.gov)
  • Healed heart attacks form scar tissue which can lead to ventricular tachycardia. (health.am)
  • An abnormally rapid ventricular rhythm usually in excess of 150 beats per minute. (embl.de)
  • Ventricular tachycardia may not cause symptoms in some people, but may be lethal in others - it is a major cause of sudden cardiac death. (health.am)
  • Ventricular tachycardia is a fast, abnormal heart rate and may lead to sudden cardiac arrest if not treated successfully. (varian.com)
  • Depending on the etiology, onset of ventricular tachycardia can be paroxysmal (sudden) or nonparoxysmal, its wide QRS complexes can be uniform or polymorphic, and the ventricular beating may be independent of the atrial beating (AV dissociation). (embl.de)
  • Patients are predisposed to atrial and/or ventricular tachyarrhythmias and sudden cardiac death, particularly during increased adrenergic activity. (msdmanuals.com)
  • Implanted pacemakers can provide a viable alternative to pharmacologic therapy or surgical management of patients with recurrent ventricular tachycardia. (elsevierpure.com)
  • 2. Recurrent sustained ventricular tachycardia requiring therapy due to symptoms, ICD shocks, or requiring hospitalization. (who.int)
  • An electrocardiogram (ECG) is used to classify the type of tachycardia. (wikipedia.org)
  • The electrocardiogram (ECG) showed wide QRS complex tachycardia, and the echocardiogram showed a dilated and hypokinetic cardiomyopathy. (medihelp.life)
  • Ventricular tachycardia may not cause symptoms in some people. (medlineplus.gov)
  • Ventricular tachycardia can occur in episodes during which the person will have a rapid pulse or the symptoms described above. (health.am)
  • Oral verapamil is a therapeutic option in patients with mild symptoms and rare episodes of fascicular tachycardia. (my-ekg.com)
  • The symptoms of ventricular tachycardia can vary depending on the severity and duration of the episodes. (heartmatters.com)
  • VT at 240-300 beats/min is often termed ventricular flutter. (medscape.com)
  • Ventricular tachycardia is a rapid heart beat initiated within the ventricles, characterized by 3 or more consecutive premature ventricular beats. (health.am)
  • The ICD may also be programmed to send a rapid burst of paced beats to interrupt the ventricular tachycardia. (health.am)
  • Ventricular tachycardia is ≥ 3 consecutive ventricular beats at a rate ≥ 120 beats/minute. (msdmanuals.com)
  • Some experts use a cutoff rate of ≥ 100 beats/minute for ventricular tachycardia (VT). (msdmanuals.com)
  • [1] In general, a resting heart rate over 100 beats per minute is accepted as tachycardia in adults. (wikipedia.org)
  • The pediatrician notes at physical exam a hepatomegaly and tachycardia at 200 beats per minute. (medihelp.life)
  • ECG after conversion showed normal sinus rhythm at 120/min, with frequent ventricular premature beats (VPBs) having the same morphology of the QRS during tachycardia (Fig. 2). (medihelp.life)
  • In clinical practice, reentrant rhythms are triggered by premature beats, and the tachycardia is often terminated with direct-current (DC) cardioversion. (medscape.com)
  • citation needed] The diagnosis of ventricular tachycardia is made based on the rhythm seen on either a 12-lead ECG or a telemetry rhythm strip. (wikipedia.org)
  • We describe a case of amiodarone-induced thyrotoxicosis and thyroid storm leading to refractory ventricular tachycardias treated with plasmapheresis when anti-arrhythmic therapy became contraindicated. (journalmc.org)
  • Go to the emergency room or call the local emergency number (such as 911) if you feel a rapid, irregular pulse, fainting, or chest pain - all of which may be indicative of ventricular tachycardia. (health.am)
  • Mexitil is a prescription antiarrhythmic drug used to treat irregular heartbeat conditions, including ventricular tachycardia . (canadadrugsdirect.com)
  • Tachycardias can be further classified as either regular or irregular. (wikipedia.org)
  • PALO ALTO, Calif., May 26, 2021 /PRNewswire/ -- Varian, a Siemens Healthineers company, announced today that the U.S. Food and Drug Administration (FDA) has granted the company Breakthrough Device Designation for its cardiac radioablation (CRA) system, currently in development as a noninvasive therapy for select patients with refractory ventricular tachycardia (VT). (varian.com)
  • 2021). Ventricular tachycardia. (mhmedical.com)
  • Fascicular left ventricular tachycardias usually do not respond to beta-blockers, adenosine, or vagal maneuvers 5 . (my-ekg.com)
  • Upon admission, the patient was given a bolus of adenosine without any change in her tachycardia. (medihelp.life)
  • The rhythm may arise from the working ventricular myocardium, the distal conduction system, or both. (medscape.com)
  • Left fascicular ventricular tachycardia is produced by a mechanism of reentry into the inferoposterior region of the interventricular septum, involving one of the fascicles of the left ventricular conduction system . (my-ekg.com)
  • Diagnostic electrophysiologic study (EPS) requires placement of electrode catheters in the ventricle, followed by programmed ventricular stimulation using progressive pacing protocols. (medscape.com)
  • Conventional programmed ventricular stimulation was performed for sustained ventricular tachycardia induction. (unifesp.br)
  • fascicular left ventricular tachycardia are also called verapamil-sensitive tachycardias . (my-ekg.com)
  • Different Manifestations in Familial Isolated Left Ventricular Non-compaction: Two Case Reports and Literature Review by: Hamida Al Hussein, et al. (uitm.edu.my)
  • The ECG criteria to identify an epicardial origin for right and left ventricular tachycardia are site and substrate dependent. (uab.cat)
  • Ventricular tachycardia is an abnormally fast heartbeat that originates in the bottom chambers of your heart (ventricles). (cmhvi406.com)
  • Sustained ventricular tachycardia is when the abnormal rhythm lasts more than 30 seconds. (merckmanuals.com)
  • If your ventricular tachycardia is sustained (lasts a long time), your doctor will first restore your heart to a normal rhythm, which is most often done through defibrillation. (cmhvi406.com)
  • Ventricular tachycardia is a rapid heart rhythm originating from the ventricles, the lower chambers of the heart responsible for pumping oxygenated blood to the rest of the body. (heartmatters.com)
  • The tachycardia reverts to sinus rhythm few hours later. (medihelp.life)
  • A regular, wide-complex rhythm with a rate above 150 certainly sounds like ventricular tachycardia (VT) on the surface … but is it really VT? (ems1.com)
  • Cardiac monitoring in the bay revealed ventricular tachycardia (a heart rhythm incompatible with life), and cardiopulmonary resuscitation (CPR) and advanced life support (ALS) were begun. (cdc.gov)
  • Torsade de pointes" is a form of ventricular tachycardia with a specific variation in the conduction of the ventricular stimulus. (health.am)
  • The morphology of the tachycardia depends on its cause and the origin of the re-entry electrical circuit in the heart. (wikipedia.org)
  • In those in cardiac arrest due to ventricular tachycardia, cardiopulmonary resuscitation (CPR) and defibrillation is recommended. (wikipedia.org)
  • Ventricular tachycardia can occur due to coronary heart disease, aortic stenosis, cardiomyopathy, electrolyte imbalance, or a heart attack. (wikipedia.org)
  • Objective To investigate the association of accelerometer-measured lifestyle physical activity with rapid-rate non-sustained ventricular tachycardias (RR-NSVTs) in patients with arrhythmogenic cardiomyopathy (AC). (bmj.com)
  • At this stage two diagnostic hypotheses can be posed: dysrhythmic cardiomyopathy or a cardiac pathology complicated by tachycardia. (medihelp.life)
  • Ventricular tachycardia may become an emergency situation and may be require CPR, electrical defibrillation or cardioversion (electric shock), or intravenous anti-arrhythmic medications (such as lidocaine, procainamide, bretylium, or sotalol). (health.am)
  • It is approximately 10% of all idiopathic VTs (the most common idiopathic VT are right ventricle outflow tract tachycardia) 1 . (my-ekg.com)
  • It may also be observed as narrow QRS complex tachycardias, even similar to sinus QRS, or with incomplete bundle branch block pattern ( right or left), with normal heart axis or with right-axis deviation . (my-ekg.com)
  • Narrow complex tachycardias tend to originate in the atria, while wide complex tachycardias tend to originate in the ventricles. (wikipedia.org)
  • In stable patients, first line treatment for left fascicular tachycardias is verapamil IV (bolus 10 mg given for over 1-2 minutes) 4 5 . (my-ekg.com)
  • Pediatric patients with surgical ventricular scars, such as those with postoperative ventricular tachycardia (VT) after repair of tetralogy of Fallot, are commonly cited examples of this mechanism. (medscape.com)
  • Lidocaine can be considered in for ventricular dysrhythmias in TCA toxicity if bicarbonate is ineffective, as it inhibits the sodium channel blockade effects of TCAs. (wikem.org)
  • 1. Definition of ventricular tachycardia. (drbeen.com)
  • One of these is ventricular tachycardia (VT), a condition with potentially significant implications for cardiovascular well-being. (heartmatters.com)
  • A common mechanism for ventricular tachycardia is reentry (re-stimulation of the electrical conductive pathway from a single initial stimulus). (health.am)
  • Ventricular tachycardia (V-tach or VT) is a fast heart rate arising from the lower chambers of the heart. (wikipedia.org)
  • While waiting for a defibrillator, a precordial thump may be attempted (However reserved to those who have the prior experience of doing so) in those on a heart monitor who are seen going into an unstable ventricular tachycardia. (wikipedia.org)
  • Ventricular tachycardia (VT) is a rapid heartbeat that starts in the lower chambers of the heart (ventricles). (medlineplus.gov)
  • In ventricular tachycardia, a very fast heartbeat starts in the ventricles of your heart. (merckmanuals.com)
  • After your heart has stabilized, you may require a long term intervention to address the cause of your tachycardia and prevent it from occurring again. (cmhvi406.com)
  • Ventricular tachycardia can increase the risk of heart attacks. (healthline.com)
  • Tachycardia: Tachycardia typically refers to a heart rate that exceeds the normal range for a resting heart rate. (bartleby.com)
  • Harnoor, Anjana and West, R. Lee and Cook, Fiona J., "Feminizing Adrenal Carcinoma Presenting with Heart Failure and Ventricular Tachycardia," Case Reports in Endocrinology 2012, no. (ecu.edu)
  • Tachycardia , also called tachyarrhythmia , is a heart rate that exceeds the normal resting rate . (wikipedia.org)
  • Sound of a student's heart during tachycardia. (wikipedia.org)
  • In 2012, while digging the garden at the top of his steep Whitianga section, he suddenly suffered tachycardia - a rapidly beating heart. (heartfoundation.org.nz)
  • 1. Cardiogenic shock not due to VT with no possibility of heart transplant or ventricular assist device. (who.int)
  • Ventricular tachycardia (VT) is a rapid heartbeat over 100 bpm that originates in the ventricles. (ekg.academy)
  • Utilizing a 12-lead ECG can help you interpret the difference between true VT and another tachycardia with some sort of aberrancy, like a bundle branch block. (ems1.com)