Arrhythmias, Cardiac: 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.Cranial Sinuses: Large endothelium-lined venous channels situated between the two layers of DURA MATER, the endosteal and the meningeal layers. They are devoid of valves and are parts of the venous system of dura mater. Major cranial sinuses include a postero-superior group (such as superior sagittal, inferior sagittal, straight, transverse, and occipital) and an antero-inferior group (such as cavernous, petrosal, and basilar plexus).Maxillary Sinus: The air space located in the body of the MAXILLARY BONE near each cheek. Each maxillary sinus communicates with the middle passage (meatus) of the NASAL CAVITY on the same side.Arrhythmia, Sinus: 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.Paranasal Sinuses: Air-filled spaces located within the bones around the NASAL CAVITY. They are extensions of the nasal cavity and lined by the ciliated NASAL MUCOSA. Each sinus is named for the cranial bone in which it is located, such as the ETHMOID SINUS; the FRONTAL SINUS; the MAXILLARY SINUS; and the SPHENOID SINUS.Sinus of Valsalva: The dilatation of the aortic wall behind each of the cusps of the aortic valve.Cavernous Sinus: An irregularly shaped venous space in the dura mater at either side of the sphenoid bone.Carotid Sinus: The dilated portion of the common carotid artery at its bifurcation into external and internal carotids. It contains baroreceptors which, when stimulated, cause slowing of the heart, vasodilatation, and a fall in blood pressure.Frontal Sinus: One of the paired, but seldom symmetrical, air spaces located between the inner and outer compact layers of the FRONTAL BONE in the forehead.Paranasal Sinus Diseases: Diseases affecting or involving the PARANASAL SINUSES and generally manifesting as inflammation, abscesses, cysts, or tumors.Electrocardiography: 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.Sphenoid Sinus: One of the paired air spaces located in the body of the SPHENOID BONE behind the ETHMOID BONE in the middle of the skull. Sphenoid sinus communicates with the posterosuperior part of NASAL CAVITY on the same side.Coronary Sinus: 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.Tachycardia, Ventricular: 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).Anti-Arrhythmia Agents: 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.Sick Sinus Syndrome: 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.Sinus Thrombosis, Intracranial: Formation or presence of a blood clot (THROMBUS) in the CRANIAL SINUSES, large endothelium-lined venous channels situated within the SKULL. Intracranial sinuses, also called cranial venous sinuses, include the superior sagittal, cavernous, lateral, petrous sinuses, and many others. Cranial sinus thrombosis can lead to severe HEADACHE; SEIZURE; and other neurological defects.Ethmoid Sinus: The numerous (6-12) small thin-walled spaces or air cells in the ETHMOID BONE located between the eyes. These air cells form an ethmoidal labyrinth.Tachycardia, Sinus: 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.Ventricular Fibrillation: 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.Heart Conduction System: 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.Atrial Fibrillation: 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.Ventricular Premature Complexes: 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.Paranasal Sinus Neoplasms: Tumors or cancer of the PARANASAL SINUSES.Tachycardia: 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.Electrocardiography, Ambulatory: 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.Heart Rate: The number of times the HEART VENTRICLES contract per unit of time, usually per minute.Cardiac Complexes, Premature: 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.Catheter Ablation: 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.Cardiac Pacing, Artificial: Regulation of the rate of contraction of the heart muscles by an artificial pacemaker.Maxillary Sinus Neoplasms: Tumors or cancer of the MAXILLARY SINUS. They represent the majority of paranasal neoplasms.Atrial Flutter: 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).Tachycardia, Supraventricular: A generic expression for any tachycardia that originates above the BUNDLE OF HIS.Death, Sudden, Cardiac: 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)Long QT Syndrome: 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.Heart Atria: The chambers of the heart, to which the BLOOD returns from the circulation.Sinoatrial Node: 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).Pilonidal Sinus: A hair-containing cyst or sinus, occurring chiefly in the coccygeal region.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.Heart: The hollow, muscular organ that maintains the circulation of the blood.Electric Countershock: An electrical current applied to the HEART to terminate a disturbance of its rhythm, ARRHYTHMIAS, CARDIAC. (Stedman, 25th ed)Bradycardia: 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.Defibrillators, Implantable: 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.Transverse Sinuses: The two large endothelium-lined venous channels that begin at the internal occipital protuberance at the back and lower part of the CRANIUM and travels laterally and forward ending in the internal jugular vein (JUGULAR VEINS). One of the transverse sinuses, usually the right one, is the continuation of the SUPERIOR SAGITTAL SINUS. The other transverse sinus is the continuation of the straight sinus.Dogs: 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)Electrophysiologic Techniques, Cardiac: Methods to induce and measure electrical activities at specific sites in the heart to diagnose and treat problems with the heart's electrical system.Superior Sagittal Sinus: The long large endothelium-lined venous channel on the top outer surface of the brain. It receives blood from a vein in the nasal cavity, runs backwards, and gradually increases in size as blood drains from veins of the brain and the DURA MATER. Near the lower back of the CRANIUM, the superior sagittal sinus deviates to one side (usually the right) and continues on as one of the TRANSVERSE SINUSES.Flecainide: A potent anti-arrhythmia agent, effective in a wide range of ventricular and atrial ARRHYTHMIAS and TACHYCARDIAS.Heart Block: 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.Syncope: 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)Pacemaker, Artificial: A device designed to stimulate, by electric impulses, contraction of the heart muscles. It may be temporary (external) or permanent (internal or internal-external).Action Potentials: Abrupt changes in the membrane potential that sweep along the CELL MEMBRANE of excitable cells in response to excitation stimuli.Myocardium: 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.Ventricular Dysfunction: A condition in which HEART VENTRICLES exhibit impaired function.Torsades de Pointes: 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.NAV1.5 Voltage-Gated Sodium Channel: 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.Body Surface Potential Mapping: 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)Time Factors: Elements of limited time intervals, contributing to particular results or situations.Digitalis Glycosides: 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.Atrioventricular Node: 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.Amiodarone: 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.Myocytes, Cardiac: Striated muscle cells found in the heart. They are derived from cardiac myoblasts (MYOBLASTS, CARDIAC).Models, Cardiovascular: 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.Treatment Outcome: 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.Follow-Up Studies: 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.Myocardial Ischemia: 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).Electrophysiology: 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.Atrial Premature Complexes: 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.Sinus Arrest, Cardiac: The omission of atrial activation that is caused by transient cessation of impulse generation at the SINOATRIAL NODE. It is characterized by a prolonged pause without P wave in an ELECTROCARDIOGRAM. Sinus arrest has been associated with sleep apnea (REM SLEEP-RELATED SINUS ARREST).Propafenone: An antiarrhythmia agent that is particularly effective in ventricular arrhythmias. It also has weak beta-blocking activity.Cerebral Veins: Veins draining the cerebrum.Myocardial Infarction: NECROSIS of the MYOCARDIUM caused by an obstruction of the blood supply to the heart (CORONARY CIRCULATION).Tachycardia, Ectopic Atrial: 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.Death, Sudden: The abrupt cessation of all vital bodily functions, manifested by the permanent loss of total cerebral, respiratory, and cardiovascular functions.Pericardium: 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.Aconitine: A C19 norditerpenoid alkaloid (DITERPENES) from the root of ACONITUM plants. It activates VOLTAGE-GATED SODIUM CHANNELS. It has been used to induce ARRHYTHMIAS in experimental animals and it has antiinflammatory and antineuralgic properties.Atrioventricular Block: Impaired impulse conduction from HEART ATRIA to HEART VENTRICLES. AV block can mean delayed or completely blocked impulse conduction.Myocardial Reperfusion Injury: Damage to the MYOCARDIUM resulting from MYOCARDIAL REPERFUSION (restoration of blood flow to ischemic areas of the HEART.) Reperfusion takes place when there is spontaneous thrombolysis, THROMBOLYTIC THERAPY, collateral flow from other coronary vascular beds, or reversal of vasospasm.Voltage-Sensitive Dye Imaging: Optical imaging techniques used for recording patterns of electrical activity in tissues by monitoring transmembrane potentials via FLUORESCENCE imaging with voltage-sensitive fluorescent dyes.Procainamide: A class Ia antiarrhythmic drug that is structurally-related to PROCAINE.Pulmonary Veins: The veins that return the oxygenated blood from the lungs to the left atrium of the heart.Ether-A-Go-Go Potassium Channels: A family of voltage-gated potassium channels that are characterized by long N-terminal and C-terminal intracellular tails. They are named from the Drosophila protein whose mutation causes abnormal leg shaking under ether anesthesia. Their activation kinetics are dependent on extracellular MAGNESIUM and PROTON concentration.Encainide: One of the ANTI-ARRHYTHMIA AGENTS, it blocks VOLTAGE-GATED SODIUM CHANNELS and slows conduction within the His-Purkinje system and MYOCARDIUM.Telemetry: 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)Echocardiography: Ultrasonic recording of the size, motion, and composition of the heart and surrounding tissues. The standard approach is transthoracic.Autonomic Nervous System: 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.Vagus Nerve: 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).Cardiac Electrophysiology: The study of the electrical activity and characteristics of the HEART; MYOCARDIUM; and CARDIOMYOCYTES.Sotalol: An adrenergic beta-antagonist that is used in the treatment of life-threatening arrhythmias.Heart Failure: 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.Atrial Function: The hemodynamic and electrophysiological action of the HEART ATRIA.Petrosal Sinus Sampling: Sampling of blood levels of the adrenocorticotropic hormone (ACTH) by withdrawal of blood from the inferior petrosal sinus. The inferior petrosal sinus arises from the cavernous sinus and runs to the internal jugular vein. Sampling of blood at this level is a valuable tool in the differential diagnosis of Cushing disease, Cushing syndrome, and other adrenocortical diseases.Tachycardia, Paroxysmal: Abnormally rapid heartbeats with sudden onset and cessation.Prospective Studies: 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.Quinidine: An optical isomer of quinine, extracted from the bark of the CHINCHONA tree and similar plant species. This alkaloid dampens the excitability of cardiac and skeletal muscles by blocking sodium and potassium currents across cellular membranes. It prolongs cellular ACTION POTENTIALS, and decreases automaticity. Quinidine also blocks muscarinic and alpha-adrenergic neurotransmission.Cardiomyopathies: 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).Refractory Period, Electrophysiological: 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.Wolff-Parkinson-White Syndrome: 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.Disopyramide: 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.Blood Pressure: PRESSURE of the BLOOD on the ARTERIES and other BLOOD VESSELS.Retrospective Studies: 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.Lateral Sinus Thrombosis: Formation or presence of a blood clot (THROMBUS) in the LATERAL SINUSES. This condition is often associated with ear infections (OTITIS MEDIA or MASTOIDITIS) without antibiotic treatment. In developed nations, lateral sinus thrombosis can result from CRANIOCEREBRAL TRAUMA; BRAIN NEOPLASMS; NEUROSURGICAL PROCEDURES; THROMBOPHILIA; and other conditions. Clinical features include HEADACHE; VERTIGO; and increased intracranial pressure.Recurrence: The return of a sign, symptom, or disease after a remission.Sodium Channels: Ion channels that specifically allow the passage of SODIUM ions. A variety of specific sodium channel subtypes are involved in serving specialized functions such as neuronal signaling, CARDIAC MUSCLE contraction, and KIDNEY function.Adrenergic beta-Antagonists: 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.Bundle of His: 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.Myocardial Contraction: Contractile activity of the MYOCARDIUM.Heart Diseases: Pathological conditions involving the HEART including its structural and functional abnormalities.Tetralogy of Fallot: 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.Connexin 43: A 43-kDa peptide which is a member of the connexin family of gap junction proteins. Connexin 43 is a product of a gene in the alpha class of connexin genes (the alpha-1 gene). It was first isolated from mammalian heart, but is widespread in the body including the brain.Risk Factors: 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.Maxillary Sinusitis: Inflammation of the NASAL MUCOSA in the MAXILLARY SINUS. In many cases, it is caused by an infection of the bacteria HAEMOPHILUS INFLUENZAE; STREPTOCOCCUS PNEUMONIAE; or STAPHYLOCOCCUS AUREUS.Sinoatrial Block: Disturbance in the atrial activation that is caused by transient failure of impulse conduction from the SINOATRIAL NODE to the HEART ATRIA. It is characterized by a delayed in heartbeat and pauses between P waves in an ELECTROCARDIOGRAM.Histiocytosis, Sinus: Benign, non-Langerhans-cell, histiocytic proliferative disorder that primarily affects the lymph nodes. It is often referred to as sinus histiocytosis with massive lymphadenopathy.Tachycardia, Atrioventricular Nodal Reentry: 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.Endocardium: The innermost layer of the heart, comprised of endothelial cells.Ventricular Function: The hemodynamic and electrophysiological action of the HEART VENTRICLES.Mexiletine: Antiarrhythmic agent pharmacologically similar to LIDOCAINE. It may have some anticonvulsant properties.Epinephrine: 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.Cardiomyopathy, Dilated: 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.Tomography, X-Ray Computed: Tomography using x-ray transmission and a computer algorithm to reconstruct the image.Hemodynamics: The movement and the forces involved in the movement of the blood through the CARDIOVASCULAR SYSTEM.Lidocaine: 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.Postoperative Complications: 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.Epicardial Mapping: 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.Signal Processing, Computer-Assisted: Computer-assisted processing of electric, ultrasonic, or electronic signals to interpret function and activity.Arrhythmogenic Right Ventricular Dysplasia: 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.Disease Models, Animal: 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.Potassium Channels, Voltage-Gated: Potassium channel whose permeability to ions is extremely sensitive to the transmembrane potential difference. The opening of these channels is induced by the membrane depolarization of the ACTION POTENTIAL.Pressoreceptors: Receptors in the vascular system, particularly the aorta and carotid sinus, which are sensitive to stretch of the vessel walls.Endoscopy: Procedures of applying ENDOSCOPES for disease diagnosis and treatment. Endoscopy involves passing an optical instrument through a small incision in the skin i.e., percutaneous; or through a natural orifice and along natural body pathways such as the digestive tract; and/or through an incision in the wall of a tubular structure or organ, i.e. transluminal, to examine or perform surgery on the interior parts of the body.Heart Arrest: 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.Dura Mater: The outermost of the three MENINGES, a fibrous membrane of connective tissue that covers the brain and the spinal cord.Carotid-Cavernous Sinus Fistula: An acquired or spontaneous abnormality in which there is communication between CAVERNOUS SINUS, a venous structure, and the CAROTID ARTERIES. It is often associated with HEAD TRAUMA, specifically basilar skull fractures (SKULL FRACTURE, BASILAR). Clinical signs often include VISION DISORDERS and INTRACRANIAL HYPERTENSION.Cardiac Surgical Procedures: Surgery performed on the heart.Coronary Vessels: The veins and arteries of the HEART.Mucocele: A retention cyst of the salivary gland, lacrimal sac, paranasal sinuses, appendix, or gallbladder. (Stedman, 26th ed)Otorhinolaryngologic Surgical Procedures: Surgery performed on the ear and its parts, the nose and nasal cavity, or the throat, including surgery of the adenoids, tonsils, pharynx, and trachea.KCNQ1 Potassium Channel: A voltage-gated potassium channel that is expressed primarily in the HEART.Predictive Value of Tests: 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.Propranolol: 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.Heart Defects, Congenital: Developmental abnormalities involving structures of the heart. These defects are present at birth but may be discovered later in life.Stroke Volume: 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.Purkinje Fibers: Modified cardiac muscle fibers composing the terminal portion of the heart conduction system.Ventricular Function, Left: 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.Coronary Vessel Anomalies: Malformations of CORONARY VESSELS, either arteries or veins. Included are anomalous origins of coronary arteries; ARTERIOVENOUS FISTULA; CORONARY ANEURYSM; MYOCARDIAL BRIDGING; and others.Anesthesia: 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.Stellate Ganglion: A paravertebral sympathetic ganglion formed by the fusion of the inferior cervical and first thoracic ganglia.Potassium Channels: Cell membrane glycoproteins that are selectively permeable to potassium ions. At least eight major groups of K channels exist and they are made up of dozens of different subunits.Moricizine: An antiarrhythmia agent used primarily for ventricular rhythm disturbances.Bundle-Branch Block: 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.Sinus Pericranii: Rare vascular anomaly involving a communication between the intracranial and extracranial venous circulation via diploe, the central spongy layer of cranial bone. It is often characterized by dilated venous structures on the scalp due to abnormal drainage from the intracranial venous sinuses. Sinus pericranii can be congenital or traumatic in origin.Sympathetic Nervous System: 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.Cardiac Catheterization: Procedures in which placement of CARDIAC CATHETERS is performed for therapeutic or diagnostic procedures.Perfusion: Treatment process involving the injection of fluid into an organ or tissue.Cardiotonic Agents: 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).Rhinitis: Inflammation of the NASAL MUCOSA, the mucous membrane lining the NASAL CAVITIES.Rabbits: The species Oryctolagus cuniculus, in the family Leporidae, order LAGOMORPHA. Rabbits are born in burrows, furless, and with eyes and ears closed. In contrast with HARES, rabbits have 22 chromosome pairs.Acetanilides: Compounds based on N-phenylacetamide, that are similar in structure to 2-PHENYLACETAMIDES. They are precursors of many other compounds. They were formerly used as ANALGESICS and ANTIPYRETICS, but often caused lethal METHEMOGLOBINEMIA.Respiration: The act of breathing with the LUNGS, consisting of INHALATION, or the taking into the lungs of the ambient air, and of EXHALATION, or the expelling of the modified air which contains more CARBON DIOXIDE than the air taken in (Blakiston's Gould Medical Dictionary, 4th ed.). This does not include tissue respiration (= OXYGEN CONSUMPTION) or cell respiration (= CELL RESPIRATION).Coronary Disease: 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.Ventricular Dysfunction, Left: 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.Halothane: A nonflammable, halogenated, hydrocarbon anesthetic that provides relatively rapid induction with little or no excitement. Analgesia may not be adequate. NITROUS OXIDE is often given concomitantly. Because halothane may not produce sufficient muscle relaxation, supplemental neuromuscular blocking agents may be required. (From AMA Drug Evaluations Annual, 1994, p178)Butylscopolammonium Bromide: Antimuscarinic quaternary ammonium derivative of scopolamine used to treat cramps in gastrointestinal, urinary, uterine, and biliary tracts, and to facilitate radiologic visualization of the gastrointestinal tract.Digitalis: A genus of toxic herbaceous Eurasian plants of the Plantaginaceae which yield cardiotonic DIGITALIS GLYCOSIDES. The most useful species are Digitalis lanata and D. purpurea.Central Nervous System Vascular Malformations: Congenital, inherited, or acquired abnormalities involving ARTERIES; VEINS; or venous sinuses in the BRAIN; SPINAL CORD; and MENINGES.Exercise Test: 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.Ryanodine Receptor Calcium Release Channel: 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.Digoxin: 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)Atrial Appendage: Ear-shaped appendage of either atrium of the heart. (Dorland, 28th ed)Vena Cava, Superior: The venous trunk which returns blood from the head, neck, upper extremities and chest.Electric Stimulation: Use of electric potential or currents to elicit biological responses.Isoproterenol: 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.Aprindine: A class Ib anti-arrhythmia agent used to manage ventricular and supraventricular arrhythmias.Risk Assessment: 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)Heart Septum: This structure includes the thin muscular atrial septum between the two HEART ATRIA, and the thick muscular ventricular septum between the two HEART VENTRICLES.Magnetic Resonance Imaging: Non-invasive method of demonstrating internal anatomy based on the principle that atomic nuclei in a strong magnetic field absorb pulses of radiofrequency energy and emit them as radiowaves which can be reconstructed into computerized images. The concept includes proton spin tomographic techniques.Hypokalemia: Abnormally low potassium concentration in the blood. It may result from potassium loss by renal secretion or by the gastrointestinal route, as by vomiting or diarrhea. It may be manifested clinically by neuromuscular disorders ranging from weakness to paralysis, by electrocardiographic abnormalities (depression of the T wave and elevation of the U wave), by renal disease, and by gastrointestinal disorders. (Dorland, 27th ed)Syndrome: A characteristic symptom complex.Coronary Circulation: The circulation of blood through the CORONARY VESSELS of the HEART.Tachycardia, Ectopic Junctional: 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.Incidence: The number of new cases of a given disease during a given period in a specified population. It also is used for the rate at which new events occur in a defined population. It is differentiated from PREVALENCE, which refers to all cases, new or old, in the population at a given time.Prognosis: 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.Verapamil: A calcium channel blocker that is a class IV anti-arrhythmia agent.Chronic Disease: Diseases which have one or more of the following characteristics: they are permanent, leave residual disability, are caused by nonreversible pathological alteration, require special training of the patient for rehabilitation, or may be expected to require a long period of supervision, observation, or care. (Dictionary of Health Services Management, 2d ed)Electrophysiological Phenomena: The electrical properties, characteristics of living organisms, and the processes of organisms or their parts that are involved in generating and responding to electrical charges.Cardiomyopathy, Hypertrophic: 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).Atrial Function, Right: The hemodynamic and electrophysiological action of the RIGHT ATRIUM.Parasympathetic Nervous System: The craniosacral division of the autonomic nervous system. The cell bodies of the parasympathetic preganglionic fibers are in brain stem nuclei and in the sacral spinal cord. They synapse in cranial autonomic ganglia or in terminal ganglia near target organs. The parasympathetic nervous system generally acts to conserve resources and restore homeostasis, often with effects reciprocal to the sympathetic nervous system.Potassium: An element in the alkali group of metals with an atomic symbol K, atomic number 19, and atomic weight 39.10. It is the chief cation in the intracellular fluid of muscle and other cells. Potassium ion is a strong electrolyte that plays a significant role in the regulation of fluid volume and maintenance of the WATER-ELECTROLYTE BALANCE.Monitoring, Physiologic: 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.Myocardial Reperfusion: Generally, restoration of blood supply to heart tissue which is ischemic due to decrease in normal blood supply. The decrease may result from any source including atherosclerotic obstruction, narrowing of the artery, or surgical clamping. Reperfusion can be induced to treat ischemia. Methods include chemical dissolution of an occluding thrombus, administration of vasodilator drugs, angioplasty, catheterization, and artery bypass graft surgery. However, it is thought that reperfusion can itself further damage the ischemic tissue, causing MYOCARDIAL REPERFUSION INJURY.Andersen Syndrome: 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.Nasal Polyps: Focal accumulations of EDEMA fluid in the NASAL MUCOSA accompanied by HYPERPLASIA of the associated submucosal connective tissue. Polyps may be NEOPLASMS, foci of INFLAMMATION, degenerative lesions, or malformations.Gap Junctions: Connections between cells which allow passage of small molecules and electric current. Gap junctions were first described anatomically as regions of close apposition between cells with a narrow (1-2 nm) gap between cell membranes. The variety in the properties of gap junctions is reflected in the number of CONNEXINS, the family of proteins which form the junctions.Catecholamines: A general class of ortho-dihydroxyphenylalkylamines derived from tyrosine.Heart Septal Defects, Atrial: Developmental abnormalities in any portion of the ATRIAL SEPTUM resulting in abnormal communications between the two upper chambers of the heart. Classification of atrial septal defects is based on location of the communication and types of incomplete fusion of atrial septa with the ENDOCARDIAL CUSHIONS in the fetal heart. They include ostium primum, ostium secundum, sinus venosus, and coronary sinus defects.Calcium Signaling: Signal transduction mechanisms whereby calcium mobilization (from outside the cell or from intracellular storage pools) to the cytoplasm is triggered by external stimuli. Calcium signals are often seen to propagate as waves, oscillations, spikes, sparks, or puffs. The calcium acts as an intracellular messenger by activating calcium-responsive proteins.Calcium: A basic element found in nearly all organized tissues. It is a member of the alkaline earth family of metals with the atomic symbol Ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes.Patch-Clamp Techniques: An electrophysiologic technique for studying cells, cell membranes, and occasionally isolated organelles. All patch-clamp methods rely on a very high-resistance seal between a micropipette and a membrane; the seal is usually attained by gentle suction. The four most common variants include on-cell patch, inside-out patch, outside-out patch, and whole-cell clamp. Patch-clamp methods are commonly used to voltage clamp, that is control the voltage across the membrane and measure current flow, but current-clamp methods, in which the current is controlled and the voltage is measured, are also used.Potassium Channel Blockers: A class of drugs that act by inhibition of potassium efflux through cell membranes. Blockade of potassium channels prolongs the duration of ACTION POTENTIALS. They are used as ANTI-ARRHYTHMIA AGENTS and VASODILATOR AGENTS.

Relation between mode of pacing and long-term survival in the very elderly. (1/245)

OBJECTIVES: This study analyzes the relationship between pacing mode and long-term survival in a large group of very elderly patients (> or = 80 years old). BACKGROUND: The relationship between pacing mode and long-term survival is not clear. Because the number of very elderly who are candidates for pacing is increasing, issues related to pacemaker (PM) use in the elderly have important clinical and economic implications. METHODS: We retrospectively reviewed 432 patients (mean age, 84.5+/-3.9 years) who received their initial PM (ventricular in 310 and dual chamber in 122) between 1980 and 1992. Follow-up was complete (3.5+/-2.6 years). Observed survival was estimated by the Kaplan-Meier method. Age- and gender-matched cohorts from the Minnesota population were used for expected survival. Log-rank test and Cox regression hazard model were used for univariate and multivariate analyses. RESULTS: Patients with ventricular PMs appeared to have poor overall survival compared with those with dual-chamber PMs. Observed survival after PM implantation in high grade atrioventricular block (AVB) patients was significantly worse than expected survival of the age- and gender-matched population (p < 0.0001), whereas observed survival of patients with sinus node dysfunction was not significantly different from expected survival of the matched population (p = 0.413). By univariate analysis, ventricular pacing in patients with AVB appeared to be associated with poor survival compared with dual-chamber pacing (hazard ratio [HR] 2.08; 95% confidence interval [CI] 1.33 to 3.33). After multivariate analysis, this difference was no longer significant (HR 1.41; 95% CI 0.88 to 2.27). Independent predictors of all-cause mortality were number of comorbid illnesses, New York Heart Association functional class, left ventricular depression and older age at implant. Pacing mode was not an independent predictor of overall survival. Older age at implantation, diabetes mellitus, dementia, history of paroxysmal atrial fibrillation and earlier year of implantation were independent predictors of ventricular pacemaker selection. CONCLUSIONS: After PM implantation, long-term survival among very elderly patients was not affected by pacing mode after correction of baseline differences. Selection bias was present in pacing mode in the very elderly, with ventricular pacing selected for sicker and older patients, perhaps partly explaining the apparent "beneficial impact on survival" observed with dual-chamber pacing.  (+info)

Development of sinus node disease in patients with AV block: implications for single lead VDD pacing. (2/245)

OBJECTIVE: To investigate the incidence of sinus node disease after pacemaker implantation for exclusive atrioventricular (AV) block. DESIGN: 441 patients were followed after VDD (n = 219) or DDD pacemaker (n = 222) implantation for AV block over a mean period of 37 months. Sinus node disease and atrial arrhythmias had been excluded by Holter monitoring and treadmill exercise preoperatively in 286 patients (group A). In 155 patients with complete AV block, a sinus rate above 70 beats/min was required for inclusion in the study (group B). Holter monitoring and treadmill exercise were performed two weeks, three months, and every six months after implantation. Sinus bradycardia below 40 beats/min, sinoatrial block, sinus arrest, or subnormal increase of heart rate during treadmill exercise were defined as sinus node dysfunction. RESULTS: Cumulative incidence of sinus node disease was 0.65% per year without differences between groups. Clinical indicators of sinus node dysfunction were sinus bradycardia below 40 beats/min in six patients (1.4%), intermittent sinoatrial block in two (0.5%), and chronotropic incompetence in five patients (1.1%). Only one of these patients (0.2%) was symptomatic. Cumulative incidence of atrial fibrillation was 2.0% per year, independent of the method used for the assessment of sinus node function and of the implanted device. CONCLUSIONS: In patients undergoing pacemaker implantation for isolated AV block, sinus node syndrome rarely occurs during follow up. Thus single lead VDD pacing can safely be performed in these patients.  (+info)

Cardiocirculatory coupling during sinusoidal baroreceptor stimulation and fixed-frequency breathing. (3/245)

The question of whether respiratory sinus arrhythmia (RSA) originates mainly from a central coupling between respiration and heart rate, or from baroreflex mechanisms, is a subject of controversy. If there is a major contribution of baroreflexes to RSA, cardiocirculatory coupling during breathing and during cyclic baroreflex stimulation should show similarities. We applied a sinusoidal stimulus to the carotid baroreceptors and generated heart rate fluctuations of the same magnitude as RSA with a frequency similar to, but different from, the breathing frequency (0.2 Hz, compared with 0.25 Hz), and at 0.1 Hz, in 17 supine healthy subjects (age 28-39 years). The data were analysed using discrete Fourier-transform and transfer function analysis. Respiratory fluctuations in systolic blood pressure preceded RSA with a time lag equal to that between baroreceptor stimulation and oscillations in RR interval (0.62+/-0.18 s compared with 0.57+/-0.28 s at 0.2 Hz neck suction). The response of systolic blood pressure to neck suction at 0.2 Hz was 5 times less than the respiratory blood pressure fluctuations. Neck suction at 0.1 Hz largely increased fluctuations in blood pressure and RR interval, whereas the spontaneous phase relationship between blood pressure and RR interval remained unchanged. Our results are not consistent with the hypothesis that the origin of RSA is predominantly a central phenomenon which secondarily generates fluctuations in blood pressure, but suggest that, under the condition of fixed-frequency breathing at 0.25 Hz, baroreflex mechanisms contribute to respiratory fluctuations in RR interval.  (+info)

Impact of acute hypoxia on heart rate and blood pressure variability in conscious dogs. (4/245)

To examine whether the impacts of hypoxia on autonomic regulations involve the phasic modulations as well as tonic controls of cardiovascular variables, heart rate, blood pressure, and their variability during isocapnic progressive hypoxia were analyzed in trained conscious dogs prepared with a permanent tracheostomy and an implanted blood pressure telemetry unit. Data were obtained at baseline and when minute ventilation (VI) first reached 10 (VI10), 15 (VI15), and 20 (VI20) l/min during hypoxia. Time-dependent changes in the amplitudes of the high-frequency component of the R-R interval (RRIHF) and the low-frequency component of mean arterial pressure (MAPLF) were analyzed by complex demodulation. In a total of 47 progressive hypoxic runs in three dogs, RRIHF decreased at VI15 and VI20 and MAPLF increased at VI10 and VI15 but not at VI20, whereas heart rate and arterial pressure increased progressively with advancing hypoxia. We conclude that the autonomic responses to isocapnic progressive hypoxia involve tonic controls and phasic modulations of cardiovascular variables; the latter may be characterized by a progressive reduction in respiratory vagal modulation of heart rate and a transient augmentation in low-frequency sympathetic modulation of blood pressure.  (+info)

Mechanisms of respiratory sinus arrhythmia in patients with mild heart failure. (5/245)

The high-frequency (HF) component of the heart rate variability (HRV) is regarded as an index of cardiac vagal responsiveness. However, when vagal tone is decreased, nonneural mechanisms could account for a significant proportion of the HF component. To test this hypothesis, we examined the HRV spectral power in 20 patients with mild chronic heart failure (CHF) and 11 controls before and during ganglion blockade with trimethaphan camsylate (3-6 mg/min iv). A small HF component was still present during ganglion blockade, and its amplitude did not differ between CHF patients and controls. The average contribution of nonneural oscillations to the HF component was 15% (range 1-77%) in patients with CHF and 3% (range 0. 7-30%) in healthy controls (P < 0.005). During controlled breathing at 0.16 Hz, however, it decreased to 1% (range 0.2-13%) in healthy controls and 5% (range 1-44%) in CHF patients. Our results indicate that the HF component can significantly overestimate cardiac vagal responsiveness in patients with mild CHF. This bias is improved by controlled breathing, since this maneuver increases the vagal contribution to HF without affecting its nonneural component.  (+info)

Bipolar atrial sensing thresholds in sinus rhythm and atrial tachyarrhythmias. A comparative analysis in patients with DDDR pacemakers. (6/245)

Automatic mode switching (AMS) function in dual chamber pacemakers depends on adequate detection of atrial tachyarrhythmias. There are few data on showing how intra-operative atrial signal amplititude during sinus rhythm can predict atrial tachyarrhythmias after pacemaker implantation. In 43 patients undergoing DDDR pacemaker implantation and atrioventricular nodal ablation for the treatment of drug-refractory paroxysmal atrial fibrillation, atrial sensing thresholds during sinus rhythm and during induced atrial tachyarrhythmias (24-48 h after device implantation) were analysed. Five different DDDR pacemaker systems were implanted (Chorus 7034, Ela Medical n = 13; Meta DDDR 1254, Telectronics Pacing Systems n = 12; Vigor DR 1230, Guidant n = 6; Trilogy DR 2364, Pacesetter, n = 2; Kappa DR 401, Medtronic USA n = 10). Every patient received a steroid-eluting, screwing, bipolar atrial lead (Medtronic, Capsure-Fix 4068). The mean P wave amplitude during implantation was 3.91 +/- 1.14 mV. The mean atrial sensing threshold during sinus rhythm and during all modes of induced atrial tachyarrhythmias was 3.35 +/- 1.0 mV, and 1.52 +/- 0.92 mV, respectively (P < 0.001). Atrial fibrillation was induced in 36 patients. The mean sensing threshold during sinus rhythm in this patient group was 3.39 +/- 1.01 mV, the mean sensing threshold during atrial fibrillation was 1.27 +/- 0.56 mV, reflecting a 63% reduction of sensing threshold compared with sinus rhythm (P < 0.001). Atrial flutter was induced in seven patients. The mean sensing threshold during sinus rhythm was 2.92 +/- 1.19 mV, the mean sensing threshold during atrial flutter was 2.79 +/- 1.26 mV, reflecting a reduction of 5% (ns) compared with sinus rhythm. Atrial sensing thresholds during sinus rhythm were significantly correlated with sensing thresholds during atrial tachyarrhythmias (r = 0.44; P < 0.002), but there were significant variations in intra-individual results. The reduction of atrial sensing thresholds between sinus rhythm and induced atrial tachyarrhythmias ranged from 30% to 82%. CONCLUSION: Bipolar atrial sensing thresholds during sinus rhythm are correlated with sensing thresholds during atrial tachyarrhythmias, but there is a large degree of variance in individual patients. A 4:1 to 5:1 atrial sensing safety margin based on sensing threshold during sinus rhythm is a predictor for adequate postoperative detection of atrial tachyarrhythmias and the function of AMS devices.  (+info)

Sinus node recovery time in the elderly. (7/245)

Measurement of the sinus node recovery time has been proposed as a diagnostic tool for recognition of the sick sinus syndrome. The latter is most frequently encountered in elderly patients with hypertension, coronary heart disease, and atherosclerosis. In order to provide normal values for the sinus node recovery time in this particular population group, atrial pacing studies were carried out in 30 subjects over 50 years of age, all with peripheral vascular disease and some with angina pectoris (10), residua of infarction (6), or hypertension (7). On stimulation, 7 patients maintained a I:I atrioventricular conduction up to the rate of 180/min. Second degree atrioventricular block developed in all other cases. On six occasions, Wenckebach's periods appeared at the relatively slow pacing rate of 120/min. The maximum postoverdrive pause ranged from 680 to 1600 ms with an average of 1100 ms plus or minus 190 (10). For each pacing speed, a correlation was found between the duration of the pause and the control intrinsic cardiac rate, longer pauses being associated with longer resting PP intervals. Beyond 120/min, the duration of the pause was seen to shorten progressively as the driving rate was increased. Finally, the behavior of the sinus node pacemaker following interruption of pacing showed individual variations. After pacing at relatively slow rates, a prompt return to near control values was consistently observed, whereas, after fast rates of driving, a phase of secondary depression developed in about one-half of the studied cases.  (+info)

Abnormalities of hemorheological, endothelial, and platelet function in patients with chronic heart failure in sinus rhythm: effects of angiotensin-converting enzyme inhibitor and beta-blocker therapy. (8/245)

BACKGROUND: To investigate the hypothesis that abnormalities of hemorheological (fibrinogen, plasma viscosity), endothelial (von Willebrand factor [vWF]), and platelet (soluble P-selectin) function would exist in patients with chronic heart failure (CHF) who are in sinus rhythm, we conducted a cross-sectional study of 120 patients with stable CHF (median ejection fraction 30%). We also hypothesized that ACE inhibitors and beta-blockers would beneficially affect the measured indices. METHODS AND RESULTS: In the cross-sectional analysis, plasma viscosity (P=0.001), fibrinogen (P=0.02), vWF (P<0.0001), and soluble P-selectin (P<0.001) levels were elevated in patients with CHF compared with healthy controls. Women demonstrated greater abnormalities of hemorheological indices and vWF than males (all P<0.05). Plasma viscosity (P=0.009) and fibrinogen (P=0.0014) levels were higher in patients with more severe symptoms (New York Heart Association [NYHA] class III-IV), but there was no relationship with left ventricular ejection fraction. When ACE inhibitors were introduced, there was a reduction in fibrinogen (repeated-measures ANOVA, P=0.016) and vWF (P=0.006) levels compared with baseline. There were no significant changes in hemorheological, endothelial, or platelet markers after the introduction of beta-blocker therapy, apart from a rise in mean platelet count (P<0.001). CONCLUSIONS: Abnormal levels of soluble P-selectin, vWF, and hemorheological indices may contribute to a hypercoagulable state in CHF, especially in female patients and in those with more severe NYHA class. Treatment with ACE inhibitors improved the prothrombotic state in CHF, whereas the addition of beta-blockers did not. These positive effects of ACE inhibitors may offer an explanation for the observed reduction in ischemic events in clinical trials.  (+info)

Respiratory sinus arrhythmia is not considered a major health concern. However, other arrhythmias can sometimes indicate heart disease.. An older person with a severe arrhythmia may require a pacemaker. People with sleep apnea are also more likely to experience arrhythmias, including respiratory sinus arrhythmia.. Cases of respiratory sinus arrhythmia in children and young people will often improve without treatment, as someone ages. This is because a childs heart is still growing and developing and changes to the heart can lead to respiratory sinus arrhythmia.. If a child has a respiratory sinus arrhythmia, a doctor may wish to monitor it but will probably not offer any treatment unless the problem becomes severe, causes symptoms, or continues into adolescence.. However, cases in older people are more unusual and may require further examination. If respiratory sinus arrhythmia is caused by an underlying heart disease, then that will need to be treated separately.. ...
Respiratory Sinus Arrhythmia, the variation in the heart rate synchronized with the breathing cycle, forms an interconnection between cardiac-related and respiratory-related signals. It can be used by itself for diagnostic purposes, or by exploiting the redundancies it creates, for example by extracting respiratory rate from an electrocardiogram (ECG). To perform quantitative analysis and patient specific modeling, however, simultaneous information about ventilation as well as cardiac activity needs to be recorded and analyzed. The recent advent of medically approved Electrical Impedance Tomography (EIT) devices capable of recording up to 50 frames per second facilitates the application of this technology. This paper presents the automated selection of a cardiac-related signal from EIT data and quantitative analysis of this signal. It is demonstrated that beat-to-beat intervals can be extracted with a median absolute error below 20 ms. A comparison between ECG and EIT data shows a variation in ...
What are its causes and treatment? ![Sinus arrhythmia ECG][1] [1]: https:// ... UZ2KinCsWvI/AAAAAAAAAag/08NDvy8_7vE/w535-h141-no/Sinus+arrhythmia.jpg
This article will define what a sinus arrhythmia is, what the different types are and what causes a sinus arrhythmia. It will also briefly discuss the symptoms and treatment.
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what does sinus arrhythmia non specific intraventricular conduction delay mean?what is its causes? This discussion is related to |a href=http://www.medhelp.org/posts/show/409489|abnormal ekg|/a|.
BACKGROUND:. Coronary heart disease continues to be the leading cause of death in the United States, despite risk factor reduction and technological advances in treatment options. Prospective studies implicate chronic anxiety as an independent risk factor for fatal coronary heart disease. In particular, anxiety increases the risk of sudden cardiac death substantially.. DESIGN NARRATIVE:. Nine hundred and fifty CAD patients were recruited for this study from patients hospitalized for elective cardiac catheterization. Anxiety was measured by the Hospital Anxiety Scale, the Spielberger Trait Anxiety Inventory, and the Crown-Crisp Phobic Anxiety Scale. Symptoms of depression were measured by the Montgomery-Asberg Depression Rating Scale, the Hospital Depression Scale, and the Beck Depression Inventory. Vagal control of heart rate was determined using power spectral analysis to measure two indices of vagal control: baroreceptor-mediated vagal reflex cardiac control, and respiratory sinus arrhythmia. ...
In recent years, time-varying inhomogeneous point process models have been introduced for assessment of instantaneous heartbeat dynamics as well as specific cardiovascular control mechanisms and hemodynamics. Assessment of the models statistics is established through the Wiener-Volterra theory and a multivariate autoregressive (AR) structure. A variety of instantaneous cardiovascular metrics, such as heart rate (HR), heart rate variability (HRV), respiratory sinus arrhythmia (RSA), and baroreceptor-cardiac reflex (baroreflex) sensitivity (BRS), are derived within a parametric framework and instantaneously updated with adaptive and local maximum likelihood estimation algorithms. Inclusion of second-order non-linearities, with subsequent bispectral quantification in the frequency domain, further allows for definition of instantaneous metrics of non-linearity. We here present a comprehensive review of the devised methods as applied to experimental recordings from healthy subjects during propofol ...
Choir singing is known to promote wellbeing. One reason for this may be that singing demands a slower than normal respiration which may in turn affect heart activity. Coupling of heart rate variability (HRV) to respiration is called Respiratory sinus arrhythmia (RSA). This coupling has a subjective as well as a biologically soothing effect, and it is beneficial for cardiovascular function. RSA is seen to be more marked during slow-paced breathing and at lower respiration rates (0.1 Hz and below). In this study, we investigate how singing, which is a form of guided breathing, affects HRV and RSA. The study comprises a group of healthy 18 year olds of mixed gender. The subjects are asked to; (1) hum a single tone and breathe whenever they need to; (2) sing a hymn with free, unguided breathing; and (3) sing a slow mantra and breathe solely between phrases. Heart rate (HR) is measured continuously during the study. The study design makes it possible to compare above three levels of song structure. In a
Abstract. This study examined the existence of direct maternal-infant physiological relatedness in respiratory sinus arrhythmia (RSA) when the infant was age 1, 2, 4, 8, and 12 weeks. We instructed mothers to breathe at 6, 12, 15, 20, and 6 cycles per minute while their infants lay on their body. The mother-infant ECG and respiration were registered and video recordings were made. RR-interval (RRI), respiration rate (fR) and RSA were calculated and mother-infant RSA response-patterns were analyzed. The results revealed that infants adjusted their RSA levels to their mothers levels during the first 2 months of life, but not at 3 months of age, which could be interpreted as a continuing intra-uterine effect. The attenuation between 2 and 3 months could be a reflection of the 2-month developmental shift of social orientation. ...
In this article, the design and development of a real-time heart rate (HR) and respiratory rate (RR) monitoring device is reported. The proposed device is designed to impose minimum data acquisition hazards on the subject. In standard bedside monitors, HR and RR are derived from electrocardiogram (ECG) and respiration signals, respectively, and different electrodes are required for capturing the 12-lead ECG and respiration via a chest belt, which is cumbersome for patients and healthcare providers. Respiration signal has an impact on ECG due to anatomical proximity of the heart and lung, and ECG is modulated by respiration, a phenomenon known as respiratory sinus arrhythmia (RSA). In the proposed method, the ECG signal is acquired using clip electrodes at the wrists and the respiration signal is extracted from the ECG using an Arduino Uno microcontroller-based real-time processing of ECG. RR is then derived from ECG-derived respiration (EDR). The prototype is tested on healthy subjects and ...
The neural control of the cardiovascular and respiratory systems are highly interrelated. These cardiorespiratory interactions are mediated by synaptic pathways within the CNS and are mediated largely, if not entirely, via the vagal innervation of the heart. In each respiratory cycle, the heart beats more rapidly during inspiration and slows during postinspiration and expiration (often referred to as respiratory sinus arrhythmia). The respiratory system also influences heart rate by modulating the baroreceptor and chemoreceptor input to cardiac vagal neurons. In animals and humans, the baroreceptor and chemoreceptor reflexes are inhibited during inspiration and are facilitated during postinspiration and expiration or during a maintained phase of postinspiration and apnea. As another example, stimulation of sensory laryngeal receptors evokes a prolonged apnea and a maintained and dramatic decrease in heart rate.14 This laryngeal reflex can be so exaggerated in newborns that it can lead to death ...
It has become increasingly apparent that congestive heart failure (CHF) affects not only the cardiovascular system, but every organ system involved with oxygen transport, including the respiratory system, skeletal muscles, and the hormonal and neural feedback control systems for breathing, cardiac output, blood pressure, blood volume, and distribution of blood flow. One segment of this transport system cannot be isolated from the rest. The ventilatory response to exercise in patients with CHF is augmented despite normal arterial O2 saturation and a normal or low end-tidal Pco2.1 2 3 4 5 6 The augmented ventilatory response is measured as a steep slope of the increase in ventilation with respect to CO2 output (ΔV̇e/ΔV̇co2) or as a high V̇e/V̇co2 ratio at peak exercise. The source of this ventilatory augmentation has been controversial, but its pathophysiological significance is clear. A high slope at submaximal exercise or a high V̇e/V̇co2 ratio at peak exercise is a powerful index of ...
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Jenkins, KJ et al. JTCVS 2002;123:110-8 Risk Adjusted Congenital Heart Surgery Score RACHS category 1: 1. Secundum ASD 2. Aortopexy ...
Here is the foreword to the article in Wikipedia: The Polyvagal theory (gr. polus, "many" + vagal, "vagus nerve") specifies two functionally distinct branches of the vagus, or tenth cranial nerve. It serves to identify the relationship between visceral experiences and the vagus nerves parasympathetic control of the heart, lungs, and digestive tract. The theory was introduced in 1994 by Dr. Stephen Porges, director of the Brain-Body Center at the University of Illinois at Chicago. According to the theory and its increasing evidence base, the autonomic nervous system is interconnected with and sensitive to influences that flow from the body toward the brain, called afferent influences. This effect has been observed and demonstrated by adaptive reactivity dependent on the neural circuits phylogenetical development. It builds on the study of what Charles Darwin referred to as the "pneumogastric nerve." The polyvagal theory claims that humans have physical reactions, such as cardiac and ...
Lecture 5 - Host-Parasite Coevolution II: Virulence, resistance & Tolerance I. Variation in host damage Observation: Variation in a microbes ability to damage a host exists. Microbes can be mutualistic, commensal and parasitic, even within the same genera or species. For example, Escherichia coli exhibit a large range of host interactions from mutualistic (producing vitamin K) to parasitic (producing death). Question: What causes this variation? A. Host damage is caused by a parasites pathogenicity. Pathogenicity is the parasites ability or potential to cause host damage (e.g. the mechanism of damage). B. The extent of host damage (in terms of fitness) induced by parasite pathogenicity is termed virulence (e.g. the extent of damage) II. Pathogenesis - the generation of suffering A. Impairing host capabilities 1. Direct interference - some parasites directly interfere with organ function. For example, some trematodes infect fish gills, reducing gas exchange efficiency. Also, some parasites may ...
Name : Mohammad Essa Sex : Male Nationality : Pakistani Age : 6Y Diagnosis : 1. Retinopathy 2. Sinus arrhythmia Date of Admission : Sept. 5th, 2017 Treatment hospital/period : Wu Medical Center/13 days Before treatment: The patient was born with an
The flow-induced pressure fluctuations in a door gap cavity model were investigated experimentally using a quiet wind tunnel facility. The cavity cross-section dimensions were typical of road vehicle door cavities, but the span was only 25 cm. One cavity wall included a primary bulb rubber seal. A m
Breakthrough technology that resets the neural system by Dr. Stephen Porges, father of the Polyvagal Theory. Based on four decades of research, this technology has the ability to improve stress, anxiety, or trauma-based issues. Improves resilience, social engagement, and improves ability to recover from emotional and safety triggers.
The RSA Challenge numbers are the kind we believe to be the hardest to factor; these numbers should be particularly challenging. These are the kind of numbers used in devising secure RSA cryptosystems.. This page serves as an archive for the factoring challenges conducted by RSA Laboratories through 2007.. ...
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The cardiopulmonary and respiratory laboratory studies dynamic regulation of blood flow through the lungs and how it affects human physiology and performance as it relates to pulmonary gas exchange efficiency, pulmonary artery pressure and right heart function in health and disease. The lab also studies intrapulmonary arteriovenous anastemoses and BPD (Bronchopulmonary displaysia). |meta name=msvalidate.01 content=9A2A53050FA36F851B9520901A24D4F9 /|
Heart Rate Variability, or HRV for short, is the measure of variation in timing between successive heart beats. It has been shown that heart rate and HRV are regulated by both the sympathetic (SNS) and parasympathetic (PSNS) branches of the autonomic nervous system (ANS). Only looking at total variability, or by simply reporting heart rate, it is not clear which side of the autonomic nervous system is active at a given time. Depending on what is being studied, it can be desirable to distinguish between sympathetic and parasympathetic influence.. By breaking down HRV into frequency components, it is possible to isolate a specific range of frequencies which has been shown to correlate almost exclusively to parasympathetic nervous system activity. This range of frequencies, known as high frequency HRV, is associated with a physiological phenomenon known as Respiratory Sinus Arrhythmia (RSA). This blog series is intended to discuss the process by which this and many more statistics are calculated ...
Two experiments were conducted to measure both the psychological and physiological effects of touching on the HPA axis related parts of the body. HPA stands for the hypothalamus, pituitary, and adrenal. One experiment was conducted with a group of healthy experiment participants, and another was with a group of traumatized participants who had Adverse Childhood Experiences (ACE). In the experiments, the back of an experiment participant was touched, where a kidney-adrenal was supposed to reside, and both the psychological and physiological effects were measured. As a result, respiratory sinus arrhythmia (RSA), an indicator of the parasympathetic nerve system function and, especially, an indicator of the social engagement system increased, by a statistically significant degree, as a consequence of HPA touching in both the healthy and the trauma group, in comparison with the control. The traumatized participants had a lower RSA, and this was increased by HPA touching, accompanied by a decrease of the
The present study examined the ability of a Virtual Reality (VR) public speaking task to elicit physiological arousal in adults with SAD (n=25) and Controls (n=25). A behavioral assessment paradigm was employed to address three study objectives: (a) to determine whether the VR task can elicit significant increases in physiological response over baseline resting conditions (b) to determine if individuals with SAD have a greater increase from baseline levels of physiological and self-reported arousal during the in vivo speech task as opposed to the VR speech task and (c) to determine whether individuals with SAD experience greater changes in physiological and selfreported arousal during each speech task compared to controls. Results demonstrated that the VR task was able to elicit significant increases in heart rate, skin conductance, and respiratory sinus arrhythmia, but did not elicit as much physiological or self-reported arousal as the in vivo speech task. In addition, no differences were found
A sinus rhythm is any cardiac rhythm where depolarization of the cardiac muscle begins at the sinus node. It is characterised by the presence of correctly oriented P waves on the electrocardiogram (ECG). Sinus rhythm is necessary, but not sufficient, for normal electrical activity within the heart. The term normal sinus rhythm (NSR) is sometimes used to denote a specific type of sinus rhythm where all other measurements on the ECG also fall within designated normal limits, giving rise to the characteristic appearance of the ECG when the electrical conduction system of the heart is functioning normally. However, other sinus rhythms can be entirely normal in particular patient groups and clinical contexts, so the term is sometimes considered a misnomer and its use is sometimes discouraged. Other types of sinus rhythm which can be normal include sinus tachycardia, sinus bradycardia and sinus arrhythmia. Sinus rhythms may be present together with various other cardiac arrhythmias on the same ECG. ...
Arrhythmia occurs when the hearts rhythm becomes disturbed or arrhythmic. The most common form of arrhythmia is a heart palpitation, known as sinus arrhythmia. More serious forms of heart arrhythmia include atrial fibrillation, ventricular tachycardia and ventricular fibrillation. Arrhythmia requires medical treatment; some rhythm disturbances are addressed through the use of medications, defibrillation, or a pacemaker. Natural options for heart support include fish oil, hawthorn, vitamin C and magnesium.
... is a type of slow heartbeat. A special group of cells begin the signal to start your heartbeat. These cells are in the sinoatrial (SA) node. Normally, the SA node fires at about 60 to 100 times per minute at rest. In sinus bradycardia, the node fires less than 60 times per minute.
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Dear Doctor, After feeling as if I were about to black out, I was hooked up to a Holter and these were the findings (Im 43, female, weight ok): -sinus rhythm, sinus arrhythmia, sinus tachycardia, at...
Crit care med s, . one viagra 100mg than more take to ok it is of at time? Section ii approach to the greater trochanter of the rectus sheath. Valvular and ventricular tachycardia and conduction abnormalities sinus arrhythmia demonstrates circadian modulation as does the mechanoreceptor input from the central nervous system is very often unstable. Fasciae of the moment arms of the. J clin gastroenterol , . Serour f, gorenstein a treatment for anaphylaxis includes supporting ventilation and of episodes for several months to years for a spiritual dimension to the lack of stability of the most sensitive but least sensitive guideline used by plastic surgeons as a total of mlkg of iv fluids, usually ns or lactated ringers solution, or sterile intravenous contrast with or without radiation. Moreover, the ecg tracing. To mlkghr for the most frequent transports for ages less than years old.- it appears that the newborns intake is not widely available. J biomed eng strogatz sh, abrams dm, mcrobie a, ...
http://www.nicabm.com/treating-trauma/?del=youtube The polyvagal theory is the brain child of Stephen Porges, PhD. What Dr. Stephen Porges proposes in his po...
Sinus bradycardia can be defined as a sinus rhythm with a resting heart rate of 60 beats per minute or less. However, few patients actually become symptomatic until their heart rate drops to less than 50 beats per minute.
Hi Doctor I would like to know what does it mean for the ECG findings of Marked Sinus Bradycardia and Counter Clockwise Rotation? I am a Lupus patient . Thanks . More Power ...
The tachy brady syndrome is also known as sinus node dysfunction or the sick sinus syndrome. If we were to give a simple definition of this condition, it is an | PatientHelp
When do you feel safe? When are you on guard? If you feel safe except when there is an actual threat to your safety, then you have high vagal tone. If you feel guarded most or all of the time, even when there is no actual threat to your safety, you have low vagal tone.…
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The steady lup-dup, lub-dup regularity of our hearts pumping beat is reassuring, and we dont mind it speeding up for exercise or slowing down for sleep, as long as its rhythm remains steady. Any glitch in that rhythmic throb, whether too slow or too fast, is called an arrhythmia. In either case, you can feel dizzy or lightheaded because not enough blood is getting to the brain when the heart rhythm is off-kilter. To assess and correct an arrhythmia requires a medical professional. Many times it...
The ALLMedicine™ Arrhythmias Center contains research, news, guidelines, drugs, clinical trials, and patient ed. Information related to Arrhythmias. Browse Now!
... are abnormal heartbeats usually caused by an electrical short circuit in the heart. Many are minor and not a significant health threat, but others can indicate a more serious problem.
... are abnormal heartbeats usually caused by an electrical short circuit in the heart. Many are minor and not a significant health threat, but others can indicate a more serious problem.
... are abnormal heartbeats usually caused by an electrical short circuit in the heart. Many are minor and not a significant health threat, but others can indicate a more serious problem.
With the rapidly changing lifestyle of the modern youth, occurrence of heart diseases post the age of 45 has become a common trend. One such disease is Arrhythmia which can be described as t…
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Heart rate variability (HRV), the beat-to-beat variation in either heart rate or the duration of the R-R interval - the heart period, has become a popular clinical and investigational tool. The temporal fluctuations in heart rate exhibit a marked synchrony with respiration (increasing during inspiration and decreasing during expiration - the so called respiratory sinus arrhythmia, RSA) and are widely believed to reflect changes in cardiac autonomic regulation. Although the exact contributions of the parasympathetic and the sympathetic divisions of the autonomic nervous system to this variability are controversial and remain the subject of active investigation and debate, a number of time and frequency domain techniques have been developed to provide insight into cardiac autonomic regulation in both health and disease. It is the purpose of this essay to provide an historical overview of the evolution in the concept of heart rate variability. Briefly, pulse rate was first measured by ancient Greek
The cardiovascular and respiratory systems are functionally related to each other, but the underlying physiologic mechanism of cardiorespiratory coupling (CRC) is unclear. Cardiopulmonary phase synchronization is a form of cardiorespiratory coupling. However, it is difficult to study in experimental data which are very often inherently nonstationary and thus contain only quasiperiodic oscillations. So how to enhance cardiopulmonary synchronization and quantify cardiopulmonary synchronization, the changes in cardiac function under the conditions of cardiopulmonary synchronization, and the physiological mechanisms behind them are the main issues to be discussed in this paper. The results showed that the cardiorespiratory synchronization significantly increased when breathing was controlled by heartbeat detection (p | 0.001). And the respiratory sinus arrhythmia (RSA) obviously decreased (p | 0.01) in the 2/2 mode and increased (p | 0.001) in the 4/4 mode. During the 2/2 breathing pattern compared with
Treatment strategy of sinus node dysfunction after the maze procedure is largely dictated by patients symptoms and electrocardiographic findings. Continuous monitoring of the rhythm and stand by modus of ventricular pacing "on demand" are important during the early postoperative course after the maze procedure because some of the patients may be intermittently asystole. Sinus arrhythmia, sinus tachycardia, and nonphysiological sinus tachycardia do not need pacemaker implantation (11). Sinus pause or arrest longer than 3 s is rarely an indication for pacemaker implantation in patients with the maze procedure because they were uncommonly associated with symptoms in our patients. However, in patients other than those with the maze procedure, these electrocardiographic findings may be combined with the symptoms and therefore may require pacemaker implantation (24), although some found symptoms to be uncommon during such pauses, and prognosis was not altered by cardiac pacing (25). Nevertheless, ...
Looking for sick sinus syndrome? Find out information about sick sinus syndrome. 1. inclined or likely to vomit 2. a. suffering from ill health b. : the sick 3. a. of, relating to, or used by people who are unwell b. : sickbed 4. Explanation of sick sinus syndrome
Here, we show that HCN1 channels make up a physiologically relevant component of If in the SAN. If was reduced by ≈30% in HCN1−/− SAN cells, and the activation kinetics of the remaining If was significantly slowed down. Our results also suggest that HCN1 is functionally important in spindle and elongated primary pacemaker cells of the central SAN. The main cardiac phenotype of the HCN1−/− mouse is a pronounced sinus node dysfunction characterized by impaired impulse formation and sinoatrial conduction, resulting in bradycardia, sinus arrhythmia, and recurrent sinus pauses. Hemodynamically, these changes lead to a relevant reduction in cardiac output.. Several mechanisms may contribute to this complex phenotype. First, a reduction in If density is an important factor that could contribute to or explain the bradycardia observed in HCN1−/− mice. Heterologous expression studies and analysis of neuronal hyperpolarization-activated currents predominantly carried by HCN1 revealed that the ...
Sinus Node Dysfunction - Etiology, pathophysiology, symptoms, signs, diagnosis & prognosis from the Merck Manuals - Medical Professional Version.
Ing Cardiac arrhythmia (mayayaus mu rin dysrhythmia) metung yang kataya kareng maragul at metung a lupang lupung a kabilyan nung nu atin epangkaraniwan ing kuryenting pangimut ning pusu. Ing pitig ning pusu malyaring mabilis ya o mabagal at neng misan ustu ya neng misan ali ya. Deng aliwang arrhythmias maliaring ikakamate dala at dapat idala da la keng medical emergencies at maliaring mikacardiac arrest la ampong biglaan ing pangamate da. Deng aliwa bala ra makabuysit mung symptomas. Deng aliwa naman makataid keng amanang at makamatengstroke o embolus. Deng aliwang arrhythmias maina la mu pinduan at maliari lang sabian a normal la. Ing tutu,deng aliwang tau panamdaman dang neng misan ing karelang pusu luksa ya keng kayang pitig, o neng misan naman mika masikan yang pitig nung nu dapat e dinan pagkabalisa.[1]. Ing katayang sinus arrhythmia daleraya ya keng pangkaraniwan a melayari nung nu bagyabagya ing pusu sinikad yang pasikan ampong pamangaina patse mangisnawang palub ampong palual. Keraklan ...
Several clinical and experimental studies have shown that unnecessary right ventricular pacing in sinus node disease can be detrimental. Inter- and intraventricular asynchrony imposed by right ventricular pacing may cause reduction in contractility a
Loss-of-function mutations in ANK2 can result in a broad spectrum of clinical cardiac phenotypes. Carriers of some mutations (e.g., E1425G, {106410.0001}) display QT interval prolongation, stress- and/or exercise-induced polymorphic ventricular arrhythmia, syncope, and sudden cardiac death. Patients with other variants show clinical phenotypes, sometimes mild, extending beyond LQTS, leading to the label ankyrin-B syndrome. These phenotypes include bradycardia, sinus arrhythmia, delayed conduction/conduction block, idiopathic ventricular fibrillation, and catecholaminergic polymorphic ventricular tachycardia ({1:Mohler et al., 2007 ...
Sick sinus syndrome is a type of abnormal heartbeat, or arrhythmia. If you have sick sinus, you may have episodes when your heart beats very slowly, stops beating for a short while, or beats very rapidly.
Sick sinus syndrome is a type of abnormal heartbeat, or arrhythmia. If you have sick sinus, you may have episodes when your heart beats very slowly, stops beating for a short while, or beats very rapidly.
Sick sinus syndrome, atrial fibrillation, pacemaker dependent, mild cardiomyopathy with ejection fraction 40% and no significant decompensation, and dementia of
Sick sinus syndrome (SSS) is characterized by dysfunction of the sinoatrial (SA) node that is often secondary to senescence of the SA node and surrounding atrial myocardium. Patients with SSS are typically symptomatic with fatigue, lightheadedness, p
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Learn more about Sick Sinus Syndrome at Memorial Hospital DefinitionCausesRisk FactorsSymptomsDiagnosisTreatmentPreventionrevision .....
Learn more about Sick Sinus Syndrome at TriStar Centennial Parthenon Pavilion DefinitionCausesRisk FactorsSymptomsDiagnosisTreatmentPreventionrevision ...
List of 111 causes for Collapse and Sinus bradycardia, alternative diagnoses, rare causes, misdiagnoses, patient stories, and much more.
Misdiagnosis of Sinus bradycardia including rare causes, self assessment, alternative diagnoses, differential diagnoses, and misdiagnosis.
5-Fluorouracil (5-FU) is a commonly used anti-neoplastic agent. 5-FU has been not uncommonly associated with cardiotoxicity, although the many potentially causative mechanisms are yet to be established. Here, we present the case of a 61-year-old gemstone miner who developed symptomatic sinus bradycardia while receiving a continuous 5-FU infusion combined with radiotherapy for locally advanced rectal cancer. This dysrhythmia is an unusual type of 5-FU toxicity, our case being the second described. We review the actions of 5-FU and the various proposed mechanisms of its cardiotoxic effects ...
Expert advice by veteran Family Therapist and Psychologist. Janette Strokappe - Online Counselor and Therapist. For many years, the autonomic nervous system was thought to be the sympathetic nervous system in balance with the parasympathetic nervous system. The sympathetic revved the body up and the parasympathetic calmed it down.. Dr. Stephen Porges Polyvagal Theory changed all that. As I am just summarizing the polyvagal theory, if you want more thorough information, just google Polyvagal theory.. Dr. Porges discovered that the parasympathetic system is composed of two branches of the vagus nerve which arise from different areas of the brain.. The unmyelinated branch is an ancient system found also in reptiles. Its action is below the diaphragm. Myelin is the outer coating of a nerve which allows it to transmit impulses more efficiently. This branch lacks myelin.. The ventral vagus which we are interested in is found only in mammals and it is myelinated. It arises from the brain very close to ...
The objective of the project is to study clinical and prognostic value of new echocardiographic technique, so called positive preejection velocity (+VIC), in patients with chronic ischemic left ventricular (LV) dysfunction indicated for revascularization. Pilot studies has shown high accuracy of pulsed Tissue Doppler imaging (TDI)-derived resting pattern of +VIC to detect viable myocardium in patients with both acute myocardial infarction and chronically dysfunctional myocardium. The aim of the project is to test accuracy of +VIC to predict LV remodeling and long-term prognosis after revascularization in patients with chronically dysfunctional myocardium. Study population will consist of two groups of patients with stable ischemic LV dysfunction: group A- patients indicated for revascularization (n=200), group B- matched control group treated conservatively (case-control design) (n=100). All patients will be followed for 3 years. Endpoints include: 1) LV remodeling at 6 and 24 months and 2) MACE ...
Hello MoA barflies. This is the 2nd in a series of comment I am writing about mental health and neuromodulation techniques. Before I get into writing about neuromodulation techniques and such I need to establish a knowledge base for the efforts and the last and this are parts of that base. The next subject related to my sharing of neuromodulation mental health therapy is an evolutionary digression in support of the bio-electric paradigm of dysregulation of neural networks instead of the bio-chemical one. This comment is basically a focused book report of "The Polyvagal Theory" medical text written by by Steven Porges. Mr. Porges has been studying infancy trauma since 1970 and has developed a theory around the evolution of our vegus nerve (early brain) and mental health implications.. The Porges Polyvagal Theory describes how when we were reptiles our vegus nerve gave us the ability to communicate with gill flapping and mouth contorting but our trauma response was limited to freeze/shit because ...
A Primer on Porges Polyvagal Theory, By Ron Manley, Ph.D. Although his first book on Polyvagal Theory was published in 2011, neuroscientist Stephen Porges first proposed his theory over two decades ago. It would not be...
Befriending the Nervous System: A Beginners Guide to Polyvagal Theory. This listening happens far below awareness and far away from our conscious control. Dr Porges, in understanding that this is not awareness that comes with perception, coined the term neuroception to describe the way our autonomic nervous system scans for cues of safety, danger and life-threat without involving the thinking parts of our brain. Because we humans are meaning-making beings, what begins as wordless experiencing of neuroception drives the creation of a story that shapes our daily living.. The Autonomic Nervous System. The ANS is made up of two main branches, the sympathetic and the parasympathetic and responds to signals and sensations via three pathways, each with a characteristic pattern of response. Through each of these patterns we react "in service of survival.". The SYMPATHETIC BRANCH is found in the middle part of the spinal cord and represents the pathway that prepares for ACTION. It responds to cues of ...
Question - How is rapid heart beats treated ?. Ask a Doctor about diagnosis, treatment and medication for Increased heart rate, Ask a Cardiologist
What is an arrhythmia? Well thats a very broad question. The definition is an abnormality of the heart rate what you can feel as your pulse. This can come in
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27 yrs old Male asked about Heart is beating fast, 1 doctor answered this and 94 people found it useful. Get your query answered 24*7 only on | Practo Consult
The findings of a new study suggest that there may be a connection between side effects of certain antidepressants, such as Lexapro and Celexa, and an incr
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The frequency, clinical course, and prognosis of sinus node dysfunction in 431 patients with acute myocardial infarction admitted to the coronary care unit were studied. Sinus node dysfunction occurred in 20 patients. In 13, the principal manifestation consisted of severe sinus bradycardia. In the remaining 7, periods of bradycardia alternating with episodes of supraventricular tachycardia were noted. Though several of the patients with sinus bradycardia required intravenous atropine or temporary pacing, normal sinus rhythm returned in virtually all during follow-up. The clinical course of patients with both bradycardia and tachycardia was less benign, during the acute phase and during follow-up; 5 of the 6 survivors required continued antiarrhythmic therapy or permanent pacing. The differences in the clinical course between these two groups of patients may reflect distinct underlying pathological changes. The findings in this study suggest that in contrast to sinus bradycardia, the occurrence ...
For patient information click here Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Sahar Memar Montazerin, M.D.[2] Synonyms and Keywords: Bradycardia-tachycardia syndrome, tachycardia-bradycardia syndrome, tachy-brady syndrome, sinus node dysfunction, SND, SSS, Sinus arrest, sinus bradycardia, are forms or variants of sick sinus syndrome. ...
TY - JOUR. T1 - Lung parenchymal mechanics. AU - Suki, Béla. AU - Stamenović, Dimitrije. AU - Hubmayr, Rolf. PY - 2011/7/1. Y1 - 2011/7/1. N2 - The lung parenchyma comprises a large number of thin-walled alveoli, forming an enormous surface area, which serves to maintain proper gas exchange. The alveoli are held open by the transpulmonary pressure, or prestress, which is balanced by tissues forces and alveolar surface film forces. Gas exchange efficiency is thus inextricably linked to three fundamental features of the lung: parenchymal architecture, prestress, and the mechanical properties of the parenchyma. The prestress is a key determinant of lung deformability that influences many phenomena including local ventilation, regional blood flow, tissue stiffness, smooth muscle contractility, and alveolar stability. The main pathway for stress transmission is through the extracellular matrix. Thus, the mechanical properties of the matrix play a key role both in lung function and biology. These ...
Sick sinus syndrome is an umbrella term that covers three heart rhythm problems (arrhythmias): sinus bradycardia, which causes a slow heart rate tachycardias,…
List of 77 causes for Atrial fibrillation and Sinus bradycardia, alternative diagnoses, rare causes, misdiagnoses, patient stories, and much more.
Conventional implantable dual-chamber cardiac pacemakers adjust heart rate and maintain normal atrial and ventricular contraction by tracking "native" atrial electrical activity and pacing the ventricles after a predetermined programmable atrioventricular delay. However, in patients with symptomatic bradyarrhythmias, optimal function of "atrial-tracking" devices may be limited by concomitant sinoatrial disease. Provision of chronotropic response during physical exertion or emotional stress may be achieved by using physiologic sensors to alter pacing rate independently of atrial activity. Additional systems using sensor technologies are being developed. Future pacing systems will have dual-chamber pacing capability and may use several sensors coupled synergistically in order to take advantage of particular strengths of each. Physiologic sensor technology may be of diagnostic value in both antitachycardia devices and implantable cardioverter and defibrillator systems.. [MeSH terms: arrhythmia; ...
The sinus node is a specialized group of cells in the upper chamber of the heart, the right atrium, that creates electrical signals that regulate the pace and rhythm of the heartbeat. Normally, the sinus node produces a regular, steady pattern of signals. With SSS, the pattern is irregular. The normal heart beat should increase with activity and decrease with rest and sleep. With SSS, this function is disrupted, with a heart beat that is too slow for the patients level of activity. ...
The freeMD virtual doctor has found 18 conditions that can cause Abnormally Slow Heart Beat and Worsening Confusion. There are 3 somewhat common conditions that can cause Abnormally Slow Heart Beat and Worsening Confusion. There are 5 uncommon conditions that can cause Abnormally Slow Heart Beat and Worsening Confusion. There are 10 rare conditions that can cause Abnormally Slow Heart Beat and Worsening Confusion.
Diagnosing arrhythmia can be quite difficult because the medical condition may sometimes produce few symptoms. Many physicians diagnose an arrhythmia by examining the patients medical and family history and by performing physical examinations. To diagnose an arrhythmia, physicians usually ask patients to describe their symptoms. A physician may ask the patient if he or she feels thumping in his or her chest and whether the patient feels dizzy or lightheaded. A physician may also diagnose an arrhythmia by asking a patient if his or her family has a history of arrhythmia or other heart diseases. The doctor may ask the patient if he or she is under medications including over the counter medicines and supplements. A physical exam can also serve as an important diagnostic procedure for arrhythmia. During the physical exam, the doctor will examine the patients heart rate and rhythm, and the pulse to see if they are regular. He or she will also check for swelling in the legs or swelling in the feet, ...
Radiofreqeuncy Ablation therapy for arrhythmias caused by myocardial scar. Ablation Therapy for Arrhythmias and Cardiac Arrhythmias. Read about Ablation Therapy for Arrhythmias
Cardiac arrhythmia is any of a large and heterogeneous group of conditions in which there is abnormal electrical activity in the heart. The heart beat may be too fast or too slow, and may be regular or irregular. A heart beat that is too fast is called tachycardia and a heart beat that is too slow is called bradycardia. Although many arrhythmias are not life-threatening, some can cause cardiac arrest. ...
Research on the development of emotions and their functional characteristics as regulators of behavior has grown dramatically over the past 10 years. There is currently renewed emphasis on the importance of emotion regulation and dysregulation for our understanding of normal development and the development of psychopathology.
An article by a cardiologist about PVC heart beats often felt as skipped beats and whether these are simply an annoyance or whether they are dangerous.
Arrhythmia An irregular heartbeat - too fast or too slowly. The condition is caused by changes in the hearts electrical system or a short circuit in the heart
The Report Arrhythmia Monitoring Devices Market Size, Share & Trends Analysis Report By Type (ECG, Implantable, Holter, Mobile Cardiac Telemetry), By Application, By End Use, And...
Though the feeling of an arrhythmia can be disturbing and is usually harmless, it can sometimes indicate a more serious, potentially life-threatening problem.
This is a great question to discuss with your cardiologist. In general, cigarettes smoking cannot cause an arrhythmia, it can exacerbate (or make wor
Summary Radiant Insightss latest Pharmaceutical and Healthcare disease pipeline guide Arrhythmias - Pipeline Review, H1 2017, provides an overview of the
Learn more about Arrhythmias at Grand Strand Medical Center DefinitionCausesRisk FactorsSymptomsDiagnosisTreatmentPreventionrevision ...
Historically, respiratory sinus arrhythmia was believed to be pathological, and extended bed rest was traditionally prescribed ... Feb 2004). "Respiratory sinus arrhythmia: why does the heartbeat synchronize with respiratory rhythm?". Chest. 125 (2): 683-90 ... doi:10.1111/j.1469-8986.2007.00509.x. Neff RA, Wang J, Baxi S, Evans C, Mendelowitz D (2003). "Respiratory sinus arrhythmia: ... doi:10.1111/j.1532-7795.2011.00762.x. "Respiratory sinus arrhythmia and diseases of aging: Obesity, diabetes mellitus, and ...
Generally, deviation from normal sinus rhythm is considered a cardiac arrhythmia. Thus, the first question in interpreting an ... Once sinus rhythm is established, or not, the second question is the rate. For a sinus rhythm this is either the rate of P ... In normal resting hearts, the physiologic rhythm of the heart is normal sinus rhythm (NSR). Normal sinus rhythm produces the ... If the rate is too fast then it is sinus tachycardia and if it is too slow then it is sinus bradycardia. ...
It also mediates respiratory sinus arrhythmia. When a change of blood pH is detected by central chemoreceptors or by peripheral ... or a change of blood pressure is detected by baroreceptors in the aortic sinuses or carotid sinuses, the cardiovascular centre ...
Sinus arrhythmia may also be irregularly irregular; however, one P wave morphology and PR interval are seen in this situation. ... This arrhythmia may also be confused with sinus rhythm with multifocal premature atrial contractions, although in this ... A dominant P wave (sinus or atrial) cannot be identified. The rate is less than 100 beats per minute. The RR intervals have ... Wandering atrial pacemaker (WAP) is an atrial arrhythmia that occurs when the natural cardiac pacemaker site shifts between the ...
This is often accompanied by sinus arrhythmia. The pulse of a person with athlete's heart can sometimes be irregular while at ... Among the many alternative causes are episodes of isolated arrhythmias which degenerated into lethal VF and asystole, and ... The ECG can detect sinus bradycardia, a resting heart rate of fewer than 60 beats per minute. ... ECG - typical findings in resting position are, for example, sinus bradycardia, atrioventricular block (primary and secondary) ...
... is involved in Respiratory Sinus Arrhythmia. During inhalation intrathoracic pressure decreases. It triggers ...
"Origin of Respiratory Sinus Arrhythmia in Conscious Humans." Circulation. 95:1813-1821. Retrieved 1 December 2006. Burgess, ...
Sinus Arrhythmias There are 6 different sinus arrhythmia. A normal heart should have a normal sinus rhythm, this rhythm can be ... sinus arrhythmia, atrial arrhythmia, ventricular arrhythmia. Rhythms can be evaluated by measuring a few key components of a ... Sinus arrhythmia is an irregular rhythm with a ventricular rate of 60 - 100 normally, however a slow rhythm can be ... A wondering atrial pace maker can be either normal or irregular in rate, much like a sinus arrhythmia the rate is normally ...
The upper limit of normal rate for sinus tachycardia is thought to be 220 bpm minus age. Ventricular tachycardia (VT or V-tach ... Atrial fibrillation is one of the most common cardiac arrhythmias. In general, it is an irregular, narrow complex rhythm. ... Presented order of most to least common, they are: Narrow complex Sinus tachycardia, which originates from the sino-atrial (SA ... an arrhythmia of the rapid rate type). This is why five of the aforementioned dictionaries do not enter cross-references ...
This effect is often referred to as normal sinus arrhythmia. During inspiration, intrapleural pressure decreases by up to 4 mm ...
The first, respiratory sinus arrhythmia, is usually found in young and healthy adults. Heart rate increases during inhalation ... The third, sick sinus syndrome, covers conditions that include severe sinus bradycardia, sinoatrial block, sinus arrest, and ... Pathological causes include sinus bradycardia, sinus arrest, sinus exit block, or AV block. A ventricular bradycardia, also ... The second, sinus bradycardia, is a sinus rhythm of less than 60 BPM. It is a common condition found in both healthy ...
Accelerated idioventricular arrhythmias are distinguished from ventricular rhythms with rates less than 40 (ventricular escape ... This most commonly occurs in the setting of a sinus bradycardia. Accelerated idioventricular rhythm is the most common ... Idioventricular means "relating to or affecting the cardiac ventricle alone" and refers to any ectopic ventricular arrhythmia. ... It is considered a benign arrhythmia that does not require intervention, though atrioventricular dyssynchrony can cause ...
There are two primary fluctuations: Respiratory arrhythmia (or Respiratory sinus arrhythmia). This heart rate variation is ... Activity in this range is associated with the respiratory sinus arrhythmia (RSA), a vagally mediated modulation of heart rate ... Jönsson, P. (2007). "Respiratory sinus arrhythmia as a function of state anxiety in healthy individuals". International Journal ... Because the sinus node is rich in acetylcholinesterase, the effect of any vagal impulse is brief because the acetylcholine is ...
During EPS, sinus rhythm as well as supraventricular and ventricular arrhythmias of baseline cardiac intervals is recorded.[1] ... Last, the electrophysiologist may administer various drugs (proarrhythmic agents) to induce arrhythmia (inducibility of VT/VF[3 ... Then the electrophysiologist tries to provoke arrhythmias and reproduce any conditions that have resulted in the patient's ... Management of Cardiac Arrhythmias. Contemporary cardiology. Hanumana Press. pp. 123-140. doi:10.1007/978-1-60761-161-5. ISBN ...
Cardiovascular features include hypotension, sinus bradycardia, and ventricular arrhythmias. Other features may include ... The main causes of death are ventricular arrhythmias and asystole, paralysis of the heart or of the respiratory center. The ... Other drugs used for ventricular arrhythmia include lidocaine, amiodarone, bretylium, flecainide, procainamide, and mexiletine ...
Cardiovascular features include hypotension, sinus bradycardia, and ventricular arrhythmias. Other features may include ... The main causes of death are ventricular arrhythmias and asystole, paralysis of the heart or of the respiratory center. The ... Other drugs used for ventricular arrhythmia include lidocaine, amiodarone, bretylium, flecainide, procainamide, and mexiletine ... causing arrhythmia and hypotension if not processed to degrade ester-type alkaloids like aconitine. Caffeoyl derivatives from ...
Cardiovascular features include hypotension, sinus bradycardia, and ventricular arrhythmias. Other features may include ... The main causes of death are ventricular arrhythmias and asystole, paralysis of the heart or of the respiratory center. The ... Other drugs used for ventricular arrhythmia include lidocaine, amiodarone, bretylium, flecainide, procainamide, and mexiletine ... "Malignant ventricular arrhythmias due to Aconitum napellus seeds". Circulation. 102 (23): 2907-8. doi:10.1161/01.cir.102.23. ...
Carotid sinus massage, carried out by firmly pressing the bulb at the top of one of the carotid arteries in the neck, is ... "Types of Arrhythmia". NHLBI. July 1, 2011. Archived from the original on June 7, 2015. "BestBets: Comparing Valsalva manoeuvre ... "What Are the Signs and Symptoms of an Arrhythmia?". NHLBI. July 1, 2011. Archived from the original on 19 February 2015. ... Blomström-Lundqvist ET AL., MANAGEMENT OF PATIENTS WITH Supraventricular Arrhythmias. J Am Coll Cardiol 2003;42:1493-531 " ...
... arrhythmia prevention and arrhythmia termination. Arrhythmia suppression involves the use of medications or surgical procedures ... external defibrillation can be used to restore sinus rhythm. ICDs are commonly used in patients with fainting episodes despite ... Arrhythmia termination involves stopping a life-threatening arrhythmia once it has already occurred. One effective form of ... Since the cause of arrhythmias in LQTS is EADs, and they are increased in states of adrenergic stimulation, steps can be taken ...
This symptom is usually accompanied by a loss of respiratory sinus arrhythmia - the usual change in heart rate seen with normal ...
This is a normal occurrence in healthy individuals and is known as sinus arrhythmia. Early physiologists believed the reflex ...
Introduced respiratory sinus arrhythmia as index of vagal function to the area of psychophysiology. Developed a statistic to ... 2013). Respiratory sinus arrhythmia and auditory processing in autism: Modifiable deficits of an integrated social engagement ... Demonstrated that early measures of respiratory sinus arrhythmia were related to clinical course in preterm and full term ... First to apply measures of respiratory sinus arrhythmia as an index of depth of anesthesia and as a measure of neural function ...
... its converts and maintains sinus rhythm in patients with atrial arrhythmias; and it reduces the frequency and severity of ... Most recent clinical trials have investigated the use of azimilide in reducing the frequency and severity of arrhythmias in ... ventricular arrhythmias in patients with implanted cardioverter-defibrillators. Azimilide's most important adverse effect is ... prolongation of ventricular repolarization by azimilide can result in predisposition towards severe ventricular arrhythmias. ...
... suggesting supraventricular or ventricular arrhythmias (including sinus tachycardia) and irregular "fluttering" suggesting ... Eby G, Halcomb WW (2006). "Elimination of cardiac arrhythmias using oral taurine with l-arginine with case histories: ... Medic8 Family Health Guide MedlinePlus Medical Encyclopedia, NIH Arrhythmia (palpitations) Heart Palpitations Irregular ... Hypothesis for nitric oxide stabilization of the sinus node" (PDF). Medical Hypotheses. 67 (5): 1200-4. doi:10.1016/j.mehy. ...
Sinus arrhythmia Sinus bradycardia & sinus tachycardia Sinus pause & sinoatrial arrest Sick sinus syndrome: bradycardia- ... If the rate is too fast then it is sinus tachycardia and if it is too slow then it is sinus bradycardia. If it is not a sinus ... Once sinus rhythm is established, or not, the second question is the rate. For a sinus rhythm this is either the rate of P ... Generally, deviation from normal sinus rhythm is considered a cardiac arrhythmia. Thus, the first question in interpreting an ...
... cerebral venous sinus thrombosis). Nonpenetrating and penetrating cranial trauma can also be common causes of intracerebral ... or cardiac arrhythmias Nuchal rigidity Subhyaloid retinal hemorrhages Altered level of consciousness Anisocoria, Nystagmus ...
Sinus arrhythmia is one type of arrhythmia.. In this article, we look at what a sinus arrhythmia is, how it is diagnosed, and ... this article will focus on respiratory sinus arrhythmia.. Definition and types. Sinus arrhythmia does not relate to the sinus ... Respiratory sinus arrhythmia. Respiratory sinus arrhythmia is effectively benign, meaning that it is not harmful. It occurs ... including respiratory sinus arrhythmia.. Cases of respiratory sinus arrhythmia in children and young people will often improve ...
... or arrhythmia. If you have sick sinus, you may have episodes when your heart beats very slowly, stops beating for a short while ... Sick sinus syndrome is a type of abnormal heartbeat, ... Arrhythmias What is sick sinus syndrome?. Sick sinus syndrome ( ... Living with sick sinus syndrome. The aging of your SA node causes most cases of sick sinus syndrome, and theres no way to ... How is sick sinus syndrome treated? You may have sick sinus syndrome without symptoms and not need treatment. However, if you ...
Inappropriate sinus tachycardia (IST) is a non-paroxysmal arrhythmia, characterized by a persistently high sinus heart rate (HR ... Tachycardia, Sinus. Arrhythmias, Cardiac. Heart Diseases. Cardiovascular Diseases. Pathologic Processes. Tachycardia, ... Ivabradine, a sinus rate lowering agent currently employed in Europe in the treatment of stable angina and chronic heart ... Ivabradine Versus Beta-blockers in the Treatment of Inappropriate Sinus Tachycardia (CIBIST). This study has been completed. ...
Sick sinus syndrome has multiple manifestations on electrocardiogram, including sinus bradycardia, sinus arrest, sinoatrial ... Sick sinus syndrome comprises a variety of conditions involving sinus node dysfunction and commonly affects elderly persons. ... block, and alternating patterns of bradycardia and tachycardia (bradycardia-tachycardia syndrome). Diagnosis of sick sinus ... Arrhythmias Associated with Sick Sinus Syndrome. The rightsholder did not grant rights to reproduce this item in electronic ...
Is this dangerous?? I have always had normal sinus rhythm with periods of sinus tachycardia but never sinus arrhythmia or tons ... Is this dangerous?? I have always had normal sinus rhythm with periods of sinus tachycardia but never sinus arrhythmia or tons ... Sinus arrhythmia with PACs & PVCs BlueCheetah55 Hi everyone, I am a 31 year old female with Lyme disease and Babesia since ... Sinus arrhythmia with PACs & PVCs. Hi everyone, I am a 31 year old female with Lyme disease and Babesia since April of 2008. ...
Respiratory sinus arrhythmia is a common type--an this ... Sinus arrhythmia is a common condition. There are different ... Sinus arrhythmia is a common condition. There are different types--some of which are a disease. Respiratory sinus arrhythmia is ... Respiratory sinus arrhythmia is the natural variation of heart rate with breathing. The word sinus means that the heart rhythm ... The word arrhythmia means that the heart rate is irregular--not a constant rate. Respiratory sinus arrhythmia normally occurs ...
Sick sinus syndrome is a heart-rhythm disturbance, or arrhythmia, that involves a group of symptoms, such as the heartbeat ... Arrhythmia. A type of heart disease, arrhythmia causes our hearts to beat too fast, too slow or with an irregular rhythm. Even ... Continue Learning about Arrhythmia. Heart Defects at Birth May Affect Heart Rhythm-Even Years Later ... Preparing to see a doctor about a heart arrhythmia can make you feel nervous. But if you write y... ...
what does sinus arrhythmia non specific intraventricular conduction delay mean?what is its causes? This discussion is related ... what does sinus arrhythmia non specific intraventricular conduction delay mean?. what does sinus arrhythmia non specific ... The term sinus arrhythmia refers to a normal phenomenon of mild acceleration and slowing of the heart rate that occurs with ... The term sinus arrhythmia refers to a normal phenomenon of mild acceleration and slowing of the heart rate that occurs with ...
The non respiratory form is present in diseased hearts and sometimes confused with sinus arrest (also known as sinus pause). ...
Contactless heart rate variability measurement by IR and 3D depth sensors with respiratory sinus arrhythmia ... HRV is composed of two major components: high frequency respiratory sinus arrhythmia (RSA) and low frequency sympathetic ... HRV is composed of two major components: high frequency respiratory sinus arrhythmia (RSA) and low frequency sympathetic ...
Epicardial Breakthrough Waves During Sinus Rhythm. Elisabeth M.J.P. Mouws, Eva A.H. Lanters, Christophe P. Teuwen, Lisette J.M. ... Epicardial Breakthrough Waves During Sinus Rhythm. Elisabeth M.J.P. Mouws, Eva A.H. Lanters, Christophe P. Teuwen, Lisette J.M. ... Epicardial Breakthrough Waves During Sinus Rhythm. Depiction of the Arrhythmogenic Substrate?. Elisabeth M.J.P. Mouws, Eva A.H ... EBW were referred to as sinus node breakthrough waves if they were the earliest right atrial activated site. A total of 218 EBW ...
Sinus arrhythmia in children with atrial septal defect: an analysis of heart rate variability before and after surgical repair. ... Sinus arrhythmia in children with atrial septal defect: an analysis of heart rate variability before and after surgical repair. ...
Respiratory Sinus Arrhythmia. Endogenous Activation of Nicotinic Receptors Mediates Respiratory Modulation of Brainstem ... Respiratory Sinus Arrhythmia. Endogenous Activation of Nicotinic Receptors Mediates Respiratory Modulation of Brainstem ... Respiratory Sinus Arrhythmia. Endogenous Activation of Nicotinic Receptors Mediates Respiratory Modulation of Brainstem ... Respiratory Sinus Arrhythmia. Endogenous Activation of Nicotinic Receptors Mediates Respiratory Modulation of Brainstem ...
I want to pass on the abstract from a preprint that can be downloaded here on studies correlating respiratory sinus arrhythmia ... Resting respiratory sinus arrhythmia (RSAREST) indexes important aspects of individual differences in emotionality. In the ... This change is heart rate is called respiratory sinus arrhythmia (RSA). Thus RSA serves as a measure of vagal tone. Dacher ... What happens in Vagus - compassion, positive emotion, vagal tone, and respiratory sinus arrhythmia, ...
... what the different types are and what causes a sinus arrhythmia. It will also briefly discuss the symptoms and treatment. ... This article will define what a sinus arrhythmia is, ... A sinus arrhythmia is a type of arrhythmia that is ... When diagnosing a sinus arrhythmia the doctor will first discuss the patients symptoms with them and perform a physical exam. ... Causes of Sinus Arrhythmia. written by: R. Elizabeth C. Kitchen • edited by: Leigh A. Zaykoski • updated: 9/25/2009 ...
I had two EKG one from 2009 says normal sinus rhythm with sinus arrhythmia then the second one says sinus rhythm more I had two ... Results read normal sinus rhythm with sinus arrhythmia. Possible left atrial enlargement bor more 43 year old female. Results ... Normal sinus rhythm with sinus arrhythmia Rightward axis T wave abnormality, consider anterior ischemia Abnormal more Normal ... EKG one from 2009 says normal sinus rhythm with sinus arrhythmia then the second one says sinus rhythm rightward axis ...
Phocomelia ectrodactyly deafness sinus arrhythmia information including symptoms, diagnosis, misdiagnosis, treatment, causes, ... Phocomelia ectrodactyly deafness sinus arrhythmia: Introduction. Phocomelia ectrodactyly deafness sinus arrhythmia: A very rare ... Phocomelia ectrodactyly deafness sinus arrhythmia as a symptom. Phocomelia ectrodactyly deafness sinus arrhythmia: Undiagnosed ... Phocomelia ectrodactyly deafness sinus arrhythmia *What is Phocomelia ectrodactyly deafness sinus arrhythmia? *Prevalence and ...
... is a well known cause of cardiac arrhythmias and can be a consequence of any flow abnormality in the sinus node artery (SNA). ... determine if the percentage of subjects with a positive retrospective history of supra-ventricular arrhythmias (SVA) differs in ... The ischemic damage of the sinus node (SN) ... The sinus node as a servomechanism.. Circulation Research 32: ... Early atrial arrhythmias in acute myocardial infarction. Role of the sinus node artery.. Chest 101(4):944-947 ...
Ablation within the aortic sinus of Valsalva for the treatment of ventricular arrhythmias using a standard electrophysiology ...
Eckberg DL . Point: counterpoint: respiratory sinus arrhythmia is due to a central mechanism vs. respiratory sinus arrhythmia ... Erratic sinus arrhythmia is a less well-recognized form of persistent arrhythmia that differs from ectopy in that heart beats ... Erratic sinus arrhythmia (see more information below) may also contribute to the HF band despite its non-respiratory origin.15 ... Non-sinus beat/arrhythmia identification. A central premise of HRV is that IBIs approximate SA node-firing patterns, otherwise ...
The more likely interpretation is sinus arrhythmia, also very common in young people. In a longer strip, we might be able to ... One possibility is a sinus rhythm with PACs, which would not be unexpected in a young person. ...
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Sinus Respiratory Arrhythmia. Sinus Respiratory Arrhythmia.. *When allergies tend to be the culprit, then keeping the personal ... Sinusal Arrhythmia: Treat Your Sinus Problems Right Away. There are times when you are feeling facial pain; you would think it ... Ethmoid sinuses are on either side of your nose but further back in your brain. Sphenoid sinuses are just below the ethmoid ... The frontal sinuses tend to be found in the bone merely above your eyes. The maxillary sinuses lie beneath your cheekbones. ...
... coronary sinus ostium (CS-Os), or (d) dual site right atrial pacing (CS-Os + RAA). The pacemakers (Vitatron Selection 9000 or ... To describe the atrial rhythm state, pacemaker-derived data (arrhythmia counter) were assessed for AF episodes. AF was ... incidence in patients with sinus node disease (SND). METHOD The atrial lead position is randomized to: (a) free right atrial ... pacing of the atria in sinus node disease) is a prospective and randomized trial, assessing the effect of different atrial lead ...
Conclusions Our experience with antitachycardia pacemakers in CHD patients with post-operative sick sinus syndrome after ... post-operative sinus node dysfunction and atrial tachyarrhythmias (AT) who had a new generation of DDDRP pacemakers (Model ... post-operative sinus node dysfunction and atrial tachyarrhythmias (AT) who had a new generation of DDDRP pacemakers (Model ...
  • Ivabradine, a sinus rate lowering agent currently employed in Europe in the treatment of stable angina and chronic heart failure, has recently been demonstrated to be effective and safe in the treatment of IST by a few case reports and clinical trials. (clinicaltrials.gov)
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