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.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.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.Echocardiography: Ultrasonic recording of the size, motion, and composition of the heart and surrounding tissues. The standard approach is transthoracic.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.Magnetocardiography: The measurement of magnetic fields generated by electric currents from the heart. The measurement of these fields provides information which is complementary to that provided by ELECTROCARDIOGRAPHY.Vectorcardiography: Recording of the moment-to-moment electromotive forces of the heart on a plane of the body surface delineated as a vector function of time.Signal Processing, Computer-Assisted: Computer-assisted processing of electric, ultrasonic, or electronic signals to interpret function and activity.Chest Pain: Pressure, burning, or numbness in the chest.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.Myocardial Infarction: NECROSIS of the MYOCARDIUM caused by an obstruction of the blood supply to the heart (CORONARY CIRCULATION).Hypertrophy, Left Ventricular: Enlargement of the LEFT VENTRICLE of the heart. This increase in ventricular mass is attributed to sustained abnormal pressure or volume loads and is a contributor to cardiovascular morbidity and mortality.Heart Rate: The number of times the HEART VENTRICLES contract per unit of time, usually per minute.Heart Auscultation: Act of listening for sounds within the heart.Heart: The hollow, muscular organ that maintains the circulation of the blood.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.Sensitivity and Specificity: Binary classification measures to assess test results. Sensitivity or recall rate is the proportion of true positives. Specificity is the probability of correctly determining the absence of a condition. (From Last, Dictionary of Epidemiology, 2d ed)Coronary Angiography: Radiography of the vascular system of the heart muscle after injection of a contrast medium.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.Dipyridamole: A phosphodiesterase inhibitor that blocks uptake and metabolism of adenosine by erythrocytes and vascular endothelial cells. Dipyridamole also potentiates the antiaggregating action of prostacyclin. (From AMA Drug Evaluations Annual, 1994, p752)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)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).Thallium: A heavy, bluish white metal, atomic number 81, atomic weight [204.382; 204.385], symbol Tl.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.Heart Diseases: Pathological conditions involving the HEART including its structural and functional abnormalities.Cardiotocography: Monitoring of FETAL HEART frequency before birth in order to assess impending prematurity in relation to the pattern or intensity of antepartum UTERINE CONTRACTION.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.Peripartum Period: The period shortly before, during, and immediately after giving birth.Kinetocardiography: The graphic recording of chest wall movement due to cardiac impulses.Dobutamine: A catecholamine derivative with specificity for BETA-1 ADRENERGIC RECEPTORS. It is commonly used as a cardiotonic agent after CARDIAC SURGERY and during DOBUTAMINE STRESS ECHOCARDIOGRAPHY.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).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.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)Cardiology: The study of the heart, its physiology, and its functions.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.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.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)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.Angina Pectoris: The symptom of paroxysmal pain consequent to MYOCARDIAL ISCHEMIA usually of distinctive character, location and radiation. It is thought to be provoked by a transient stressful situation during which the oxygen requirements of the MYOCARDIUM exceed that supplied by the CORONARY CIRCULATION.Radionuclide Ventriculography: Imaging of a ventricle of the heart after the injection of a radioactive contrast medium. The technique is less invasive than cardiac catheterization and is used to assess ventricular function.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.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.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).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.Tachycardia, Supraventricular: A generic expression for any tachycardia that originates above the BUNDLE OF HIS.Cardiology Service, Hospital: The hospital department responsible for the administration and provision of diagnostic and therapeutic services for the cardiac patient.Emergency Medical Technicians: Paramedical personnel trained to provide basic emergency care and life support under the supervision of physicians and/or nurses. These services may be carried out at the site of the emergency, in the ambulance, or in a health care institution.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.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.Troponin T: One of the three polypeptide chains that make up the TROPONIN complex. It is a cardiac-specific protein that binds to TROPOMYOSIN. It is released from damaged or injured heart muscle cells (MYOCYTES, CARDIAC). Defects in the gene encoding troponin T result in FAMILIAL HYPERTROPHIC CARDIOMYOPATHY.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).Thallium Radioisotopes: Unstable isotopes of thallium that decay or disintegrate emitting radiation. Tl atoms with atomic weights 198-202, 204, and 206-210 are thallium radioisotopes.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.Cardiovascular Abnormalities: Congenital, inherited, or acquired anomalies of the CARDIOVASCULAR SYSTEM, including the HEART and BLOOD VESSELS.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.Time Factors: Elements of limited time intervals, contributing to particular results or situations.Atrioventricular Block: Impaired impulse conduction from HEART ATRIA to HEART VENTRICLES. AV block can mean delayed or completely blocked impulse conduction.Physical Examination: Systematic and thorough inspection of the patient for physical signs of disease or abnormality.Heart Function Tests: Examinations used to diagnose and treat heart conditions.Coronary Artery Disease: Pathological processes of CORONARY ARTERIES that may derive from a congenital abnormality, atherosclerotic, or non-atherosclerotic cause.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.Electrodes: Electric conductors through which electric currents enter or leave a medium, whether it be an electrolytic solution, solid, molten mass, gas, or vacuum.Pericarditis: Inflammation of the PERICARDIUM from various origins, such as infection, neoplasm, autoimmune process, injuries, or drug-induced. Pericarditis usually leads to PERICARDIAL EFFUSION, or CONSTRICTIVE PERICARDITIS.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.Heart Murmurs: Heart sounds caused by vibrations resulting from the flow of blood through the heart. Heart murmurs can be examined by HEART AUSCULTATION, and analyzed by their intensity (6 grades), duration, timing (systolic, diastolic, or continuous), location, transmission, and quality (musical, vibratory, blowing, etc).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.Phonocardiography: Graphic registration of the heart sounds picked up as vibrations and transformed by a piezoelectric crystal microphone into a varying electrical output according to the stresses imposed by the sound waves. The electrical output is amplified by a stethograph amplifier and recorded by a device incorporated into the electrocardiograph or by a multichannel recording machine.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.Radiography, Thoracic: X-ray visualization of the chest and organs of the thoracic cavity. It is not restricted to visualization of the lungs.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)Echocardiography, Doppler: Measurement of intracardiac blood flow using an M-mode and/or two-dimensional (2-D) echocardiogram while simultaneously recording the spectrum of the audible Doppler signal (e.g., velocity, direction, amplitude, intensity, timing) reflected from the moving column of red blood cells.Death, Sudden: The abrupt cessation of all vital bodily functions, manifested by the permanent loss of total cerebral, respiratory, and cardiovascular functions.Echocardiography, Stress: A method of recording heart motion and internal structures by combining ultrasonic imaging with exercise testing (EXERCISE TEST) or pharmacologic stress.Intraoperative Complications: Complications that affect patients during surgery. They may or may not be associated with the disease for which the surgery is done, or within the same surgical procedure.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.Takotsubo Cardiomyopathy: A transient left ventricular apical dysfunction or ballooning accompanied by electrocardiographic (ECG) T wave inversions. This abnormality is associated with high levels of CATECHOLAMINES, either administered or endogenously secreted from a tumor or during extreme stress.Brugada Syndrome: An autosomal dominant defect of cardiac conduction that is characterized by an abnormal ST-segment in leads V1-V3 on the ELECTROCARDIOGRAM resembling a right BUNDLE-BRANCH BLOCK; high risk of VENTRICULAR TACHYCARDIA; or VENTRICULAR FIBRILLATION; SYNCOPAL EPISODE; and possible sudden death. This syndrome is linked to mutations of gene encoding the cardiac SODIUM CHANNEL alpha subunit.Physical Exertion: Expenditure of energy during PHYSICAL ACTIVITY. Intensity of exertion may be measured by rate of OXYGEN CONSUMPTION; HEAT produced, or HEART RATE. Perceived exertion, a psychological measure of exertion, is included.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.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.Angiocardiography: Radiography of the heart and great vessels after injection of a contrast medium.Hypertension: Persistently high systemic arterial BLOOD PRESSURE. Based on multiple readings (BLOOD PRESSURE DETERMINATION), hypertension is currently defined as when SYSTOLIC PRESSURE is consistently greater than 140 mm Hg or when DIASTOLIC PRESSURE is consistently 90 mm Hg or more.Sports: Activities or games, usually involving physical effort or skill. Reasons for engagement in sports include pleasure, competition, and/or financial reward.Prevalence: The total number of cases of a given disease in a specified population at a designated time. It is differentiated from INCIDENCE, which refers to the number of new cases in the population at a given time.Diagnosis, Computer-Assisted: Application of computer programs designed to assist the physician in solving a diagnostic problem.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.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).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.Heart Atria: The chambers of the heart, to which the BLOOD returns from the circulation.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)Tomography, Emission-Computed, Single-Photon: A method of computed tomography that uses radionuclides which emit a single photon of a given energy. The camera is rotated 180 or 360 degrees around the patient to capture images at multiple positions along the arc. The computer is then used to reconstruct the transaxial, sagittal, and coronal images from the 3-dimensional distribution of radionuclides in the organ. The advantages of SPECT are that it can be used to observe biochemical and physiological processes as well as size and volume of the organ. The disadvantage is that, unlike positron-emission tomography where the positron-electron annihilation results in the emission of 2 photons at 180 degrees from each other, SPECT requires physical collimation to line up the photons, which results in the loss of many available photons and hence degrades the image.Creatine Kinase: A transferase that catalyzes formation of PHOSPHOCREATINE from ATP + CREATINE. The reaction stores ATP energy as phosphocreatine. Three cytoplasmic ISOENZYMES have been identified in human tissues: the MM type from SKELETAL MUSCLE, the MB type from myocardial tissue and the BB type from nervous tissue as well as a mitochondrial isoenzyme. Macro-creatine kinase refers to creatine kinase complexed with other serum proteins.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.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).Cardiac Pacing, Artificial: Regulation of the rate of contraction of the heart muscles by an artificial pacemaker.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.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.Technetium Tc 99m Sestamibi: A technetium imaging agent used to reveal blood-starved cardiac tissue during a heart attack.Hematologic Tests: Tests used in the analysis of the hemic system.Reproducibility of Results: The statistical reproducibility of measurements (often in a clinical context), including the testing of instrumentation or techniques to obtain reproducible results. The concept includes reproducibility of physiological measurements, which may be used to develop rules to assess probability or prognosis, or response to a stimulus; reproducibility of occurrence of a condition; and reproducibility of experimental results.Cardiac Catheterization: Procedures in which placement of CARDIAC CATHETERS is performed for therapeutic or diagnostic procedures.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, Right: A condition in which the RIGHT VENTRICLE of the heart was functionally impaired. This condition usually leads to HEART FAILURE or MYOCARDIAL INFARCTION, and other cardiovascular complications. Diagnosis is made by measuring the diminished ejection fraction and a depressed level of motility of the right ventricular wall.Blood Pressure: PRESSURE of the BLOOD on the ARTERIES and other BLOOD VESSELS.Multidetector Computed Tomography: Types of spiral computed tomography technology in which multiple slices of data are acquired simultaneously improving the resolution over single slice acquisition technology.Hypertrophy, Right Ventricular: Enlargement of the RIGHT VENTRICLE of the heart. This increase in ventricular mass is often attributed to PULMONARY HYPERTENSION and is a contributor to cardiovascular morbidity and mortality.Heart Defects, Congenital: Developmental abnormalities involving structures of the heart. These defects are present at birth but may be discovered later in life.Echocardiography, Transesophageal: Ultrasonic recording of the size, motion, and composition of the heart and surrounding tissues using a transducer placed in the esophagus.Coronary Artery Bypass: Surgical therapy of ischemic coronary artery disease achieved by grafting a section of saphenous vein, internal mammary artery, or other substitute between the aorta and the obstructed coronary artery distal to the obstructive lesion.Natriuretic Peptide, Brain: A PEPTIDE that is secreted by the BRAIN and the HEART ATRIA, stored mainly in cardiac ventricular MYOCARDIUM. It can cause NATRIURESIS; DIURESIS; VASODILATION; and inhibits secretion of RENIN and ALDOSTERONE. It improves heart function. It contains 32 AMINO ACIDS.Preoperative Care: Care given during the period prior to undergoing surgery when psychological and physical preparations are made according to the special needs of the individual patient. This period spans the time between admission to the hospital to the time the surgery begins. (From Dictionary of Health Services Management, 2d ed)Myocardial Perfusion Imaging: The creation and display of functional images showing where the blood is flowing into the MYOCARDIUM by following over time the distribution of tracers injected into the blood stream.Evaluation Studies as Topic: Studies determining the effectiveness or value of processes, personnel, and equipment, or the material on conducting such studies. For drugs and devices, CLINICAL TRIALS AS TOPIC; DRUG EVALUATION; and DRUG EVALUATION, PRECLINICAL are available.Dyspnea: Difficult or labored breathing.Syndrome: A characteristic symptom complex.Coronary Vasospasm: Spasm of the large- or medium-sized coronary arteries.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.Chi-Square Distribution: A distribution in which a variable is distributed like the sum of the squares of any given independent random variable, each of which has a normal distribution with mean of zero and variance of one. The chi-square test is a statistical test based on comparison of a test statistic to a chi-square distribution. The oldest of these tests are used to detect whether two or more population distributions differ from one another.Myocarditis: Inflammatory processes of the muscular walls of the heart (MYOCARDIUM) which result in injury to the cardiac muscle cells (MYOCYTES, CARDIAC). Manifestations range from subclinical to sudden death (DEATH, SUDDEN). Myocarditis in association with cardiac dysfunction is classified as inflammatory CARDIOMYOPATHY usually caused by INFECTION, autoimmune diseases, or responses to toxic substances. Myocarditis is also a common cause of DILATED CARDIOMYOPATHY and other cardiomyopathies.Troponin I: One of the three polypeptide chains that make up the TROPONIN complex. It inhibits F-actin-myosin interactions.Biological Markers: Measurable and quantifiable biological parameters (e.g., specific enzyme concentration, specific hormone concentration, specific gene phenotype distribution in a population, presence of biological substances) which serve as indices for health- and physiology-related assessments, such as disease risk, psychiatric disorders, environmental exposure and its effects, disease diagnosis, metabolic processes, substance abuse, pregnancy, cell line development, epidemiologic studies, etc.Survival Analysis: A class of statistical procedures for estimating the survival function (function of time, starting with a population 100% well at a given time and providing the percentage of the population still well at later times). The survival analysis is then used for making inferences about the effects of treatments, prognostic factors, exposures, and other covariates on the function.Emergency Medical Services: Services specifically designed, staffed, and equipped for the emergency care of patients.Vasodilator Agents: Drugs used to cause dilation of the blood vessels.Hemodynamics: The movement and the forces involved in the movement of the blood through the CARDIOVASCULAR SYSTEM.Severity of Illness Index: Levels within a diagnostic group which are established by various measurement criteria applied to the seriousness of a patient's disorder.Multivariate Analysis: A set of techniques used when variation in several variables has to be studied simultaneously. In statistics, multivariate analysis is interpreted as any analytic method that allows simultaneous study of two or more dependent variables.Heart Valve Diseases: Pathological conditions involving any of the various HEART VALVES and the associated structures (PAPILLARY MUSCLES and CHORDAE TENDINEAE).Myocardial Contraction: Contractile activity of the MYOCARDIUM.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)Reference Values: The range or frequency distribution of a measurement in a population (of organisms, organs or things) that has not been selected for the presence of disease or abnormality.Ventricular Function, Right: The hemodynamic and electrophysiological action of the right HEART VENTRICLE.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.Coronary Stenosis: Narrowing or constriction of a coronary artery.Systole: Period of contraction of the HEART, especially of the HEART VENTRICLES.Age Factors: Age as a constituent element or influence contributing to the production of a result. It may be applicable to the cause or the effect of a circumstance. It is used with human or animal concepts but should be differentiated from AGING, a physiological process, and TIME FACTORS which refers only to the passage of time.Tomography, X-Ray Computed: Tomography using x-ray transmission and a computer algorithm to reconstruct the image.Cardiovascular Diseases: Pathological conditions involving the CARDIOVASCULAR SYSTEM including the HEART; the BLOOD VESSELS; or the PERICARDIUM.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.Postoperative Period: The period following a surgical operation.Acute Disease: Disease having a short and relatively severe course.Sex Factors: Maleness or femaleness as a constituent element or influence contributing to the production of a result. It may be applicable to the cause or effect of a circumstance. It is used with human or animal concepts but should be differentiated from SEX CHARACTERISTICS, anatomical or physiological manifestations of sex, and from SEX DISTRIBUTION, the number of males and females in given circumstances.Cost-Benefit Analysis: A method of comparing the cost of a program with its expected benefits in dollars (or other currency). The benefit-to-cost ratio is a measure of total return expected per unit of money spent. This analysis generally excludes consideration of factors that are not measured ultimately in economic terms. Cost effectiveness compares alternative ways to achieve a specific set of results.Pedigree: The record of descent or ancestry, particularly of a particular condition or trait, indicating individual family members, their relationships, and their status with respect to the trait or condition.Logistic Models: Statistical models which describe the relationship between a qualitative dependent variable (that is, one which can take only certain discrete values, such as the presence or absence of a disease) and an independent variable. A common application is in epidemiology for estimating an individual's risk (probability of a disease) as a function of a given risk factor.Coronary Circulation: The circulation of blood through the CORONARY VESSELS of the HEART.Diastole: Post-systolic relaxation of the HEART, especially the HEART VENTRICLES.Risk: The probability that an event will occur. It encompasses a variety of measures of the probability of a generally unfavorable outcome.Radiopharmaceuticals: Compounds that are used in medicine as sources of radiation for radiotherapy and for diagnostic purposes. They have numerous uses in research and industry. (Martindale, The Extra Pharmacopoeia, 30th ed, p1161)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.Coronary Vessels: The veins and arteries of the HEART.Statistics, Nonparametric: A class of statistical methods applicable to a large set of probability distributions used to test for correlation, location, independence, etc. In most nonparametric statistical tests, the original scores or observations are replaced by another variable containing less information. An important class of nonparametric tests employs the ordinal properties of the data. Another class of tests uses information about whether an observation is above or below some fixed value such as the median, and a third class is based on the frequency of the occurrence of runs in the data. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed, p1284; Corsini, Concise Encyclopedia of Psychology, 1987, p764-5)Case-Control Studies: Studies which start with the identification of persons with a disease of interest and a control (comparison, referent) group without the disease. The relationship of an attribute to the disease is examined by comparing diseased and non-diseased persons with regard to the frequency or levels of the attribute in each group.Ventricular Function: The hemodynamic and electrophysiological action of the HEART VENTRICLES.Algorithms: A procedure consisting of a sequence of algebraic formulas and/or logical steps to calculate or determine a given task.Cross-Sectional Studies: Studies in which the presence or absence of disease or other health-related variables are determined in each member of the study population or in a representative sample at one particular time. This contrasts with LONGITUDINAL STUDIES which are followed over a period of time.Cohort Studies: Studies in which subsets of a defined population are identified. These groups may or may not be exposed to factors hypothesized to influence the probability of the occurrence of a particular disease or other outcome. Cohorts are defined populations which, as a whole, are followed in an attempt to determine distinguishing subgroup characteristics.Thrombolytic Therapy: Use of infusions of FIBRINOLYTIC AGENTS to destroy or dissolve thrombi in blood vessels or bypass grafts.Myocardial Revascularization: The restoration of blood supply to the myocardium. (From Dorland, 28th ed)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.Cardiac Surgical Procedures: Surgery performed on the heart.Recurrence: The return of a sign, symptom, or disease after a remission.Analysis of Variance: A statistical technique that isolates and assesses the contributions of categorical independent variables to variation in the mean of a continuous dependent variable.Feasibility Studies: Studies to determine the advantages or disadvantages, practicability, or capability of accomplishing a projected plan, study, or project.Double-Blind Method: A method of studying a drug or procedure in which both the subjects and investigators are kept unaware of who is actually getting which specific treatment.Emergency Service, Hospital: Hospital department responsible for the administration and provision of immediate medical or surgical care to the emergency patient.Angioplasty, Balloon, Coronary: Dilation of an occluded coronary artery (or arteries) by means of a balloon catheter to restore myocardial blood supply.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.Family Practice: A medical specialty concerned with the provision of continuing, comprehensive primary health care for the entire family.Proportional Hazards Models: Statistical models used in survival analysis that assert that the effect of the study factors on the hazard rate in the study population is multiplicative and does not change over time.Kaplan-Meier Estimate: A nonparametric method of compiling LIFE TABLES or survival tables. It combines calculated probabilities of survival and estimates to allow for observations occurring beyond a measurement threshold, which are assumed to occur randomly. Time intervals are defined as ending each time an event occurs and are therefore unequal. (From Last, A Dictionary of Epidemiology, 1995)ROC Curve: A graphic means for assessing the ability of a screening test to discriminate between healthy and diseased persons; may also be used in other studies, e.g., distinguishing stimuli responses as to a faint stimuli or nonstimuli.Survival Rate: The proportion of survivors in a group, e.g., of patients, studied and followed over a period, or the proportion of persons in a specified group alive at the beginning of a time interval who survive to the end of the interval. It is often studied using life table methods.Stroke: A group of pathological conditions characterized by sudden, non-convulsive loss of neurological function due to BRAIN ISCHEMIA or INTRACRANIAL HEMORRHAGES. Stroke is classified by the type of tissue NECROSIS, such as the anatomic location, vasculature involved, etiology, age of the affected individual, and hemorrhagic vs. non-hemorrhagic nature. (From Adams et al., Principles of Neurology, 6th ed, pp777-810)Pilot Projects: Small-scale tests of methods and procedures to be used on a larger scale if the pilot study demonstrates that these methods and procedures can work.Mass Screening: Organized periodic procedures performed on large groups of people for the purpose of detecting disease.Sex Distribution: The number of males and females in a given population. The distribution may refer to how many men or women or what proportion of either in the group. The population is usually patients with a specific disease but the concept is not restricted to humans and is not restricted to medicine.Exercise: Physical activity which is usually regular and done with the intention of improving or maintaining PHYSICAL FITNESS or HEALTH. Contrast with PHYSICAL EXERTION which is concerned largely with the physiologic and metabolic response to energy expenditure.Regression Analysis: Procedures for finding the mathematical function which best describes the relationship between a dependent variable and one or more independent variables. In linear regression (see LINEAR MODELS) the relationship is constrained to be a straight line and LEAST-SQUARES ANALYSIS is used to determine the best fit. In logistic regression (see LOGISTIC MODELS) the dependent variable is qualitative rather than continuously variable and LIKELIHOOD FUNCTIONS are used to find the best relationship. In multiple regression, the dependent variable is considered to depend on more than a single independent variable.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.Infant, Newborn: An infant during the first month after birth.Comorbidity: The presence of co-existing or additional diseases with reference to an initial diagnosis or with reference to the index condition that is the subject of study. Comorbidity may affect the ability of affected individuals to function and also their survival; it may be used as a prognostic indicator for length of hospital stay, cost factors, and outcome or survival.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.Action Potentials: Abrupt changes in the membrane potential that sweep along the CELL MEMBRANE of excitable cells in response to excitation stimuli.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.

Investigation of the theory and mechanism of the origin of the second heart sound. (1/14381)

To investigate further the origin of the second heart sound we studied human subjects, dogs, and a model in vitro of the cardiovascular system. Intra-arterial sound, pressure, and, where possible, flow and high speed cine (2,000 frames/sec) were utilized. The closure sound of the semilunar valves was of higher amplitude in be ventricles than in their respective arterial cavities. The direction of inscription of the main components of intra-arterial sound were opposite in direction to the components of intraventricular sound. Notches, representative of pressure increments, were noted on the ventricular pressure tracings and were coincident with the components of sound. The amplitude of the closure sound varied with diastolic pressure, but remained unchanged with augmentation of forward and retrograde aortic flow. Cines showed second sound to begin after complete valvular closure, and average leaflet closure rate was constant regardless of pressure. Hence, the semilunar valves, when closed, act as an elastic membrane and, when set into motion, generate compression and expansion of the blood, producing transient pressure changes indicative of sound. The magnitude of the initial stretch is related to the differential pressure between the arterial and ventricular chambers. Sound transients which follow the major components of the second sound appear to be caused by the continuing stretch and recoil of the leaflets. Clinically unexplained findings such as the reduced or absent second sound in calcific aortic stenosis and its paradoxical presence in congenital aortic stenosis may be explained by those observations.  (+info)

Hierarchy of ventricular pacemakers. (2/14381)

To characterize the pattern of pacemaker dominance in the ventricular specialized conduction system (VSCS), escape ventricular pacemakers were localized and quantified in vivo and in virto, in normal hearts and in hearts 24 hours after myocardial infarction. Excape pacemaker foci were localized in vivo during vagally induced atrial arrest by means of electrograms recorded from the His bundle and proximal bundle branches and standard electrocardiographic limb leads. The VSCS was isolated using a modified Elizari preparation or preparations of each bundle branch. Peacemakers were located by extra- and intracellular recordings. Escape pacemaker foci in vivo were always in the proximal conduction system, usually the left bundle branch. The rate was 43+/-11 (mean+/-SD) beats/min. After beta-adrenergic blockade, the mean rate fell to 31+/-10 beats/min, but there were no shifts in pacemaker location. In the infarcted hearts, pacemakers were located in the peripheral left bundle branch. The mean rate was 146+/-20 beats/min. In isolated normal preparations, the dominant pacemakers usually were in the His bundle, firing at a mean rate of 43+/-10 beats/min. The rates of pacemakers diminished with distal progression. In infarcted hearts, the pacemakers invariably were in the infarct zone. The mean firing rates were not influenced by beta-adrenergic blockade. The results indicate that the dominant pacemakers are normally in the very proximal VSCS, but after myocardial infarction pacemaker dominance is shifted into the infarct. Distribution of pacemaker dominance is independent of sympathetic influence.  (+info)

Irbesartan reduces QT dispersion in hypertensive individuals. (3/14381)

Angiotensin type 1 receptor antagonists have direct effects on the autonomic nervous system and myocardium. Because of this, we hypothesized that irbesartan would reduce QT dispersion to a greater degree than amlodipine, a highly selective vasodilator. To test this, we gathered electrocardiographic (ECG) data from a multinational, multicenter, randomized, double-blind parallel group study that compared the antihypertensive efficacy of irbesartan and amlodipine in elderly subjects with mild to moderate hypertension. Subjects were treated for 6 months with either drug. Hydrochlorothiazide and atenolol were added after 12 weeks if blood pressure (BP) remained uncontrolled. ECGs were obtained before randomization and at 6 months. A total of 188 subjects (118 with baseline ECGs) were randomized. We analyzed 104 subjects who had complete ECGs at baseline and after 6 months of treatment. Baseline characteristics between treatments were similar, apart from a slight imbalance in diastolic BP (irbesartan [n=53] versus amlodipine [n=51], 99.2 [SD 3. 6] versus 100.8 [3.8] mm Hg; P=0.03). There were no significant differences in BP normalization (diastolic BP <90 mm Hg) between treatments at 6 months (irbesartan versus amlodipine, 80% versus 88%; P=0.378). We found a significant reduction in QT indexes in the irbesartan group (QTc dispersion mean, -11.4 [34.5] milliseconds, P=0.02; QTc max, -12.8 [35.5] milliseconds, P=0.01), and QTc dispersion did not correlate with the change in BP. The reduction in QT indexes with amlodipine (QTc dispersion, -9.7 [35.4] milliseconds, P=0.06; QTc max, -8.6 [33.2] milliseconds, P=0.07) did not quite reach statistical significance, but there was a correlation between the change in QT indexes and changes in systolic BP. In conclusion, irbesartan improved QT dispersion, and this effect may be important in preventing sudden cardiac death in at-risk hypertensive subjects.  (+info)

QT dispersion in patients with chronic heart failure: beta blockers are associated with a reduction in QT dispersion. (4/14381)

OBJECTIVE: To compare QT dispersion in patients with impaired left ventricular systolic function and in matched control patients with normal left ventricular systolic function. DESIGN: A retrospective, case-control study with controls matched 4:1 for age, sex, previous myocardial infarction, and diuretic and beta blocker treatment. SETTING: A regional cardiology centre and a university teaching hospital. PATIENTS: 25 patients with impaired left ventricular systolic function and 100 patients with normal left ventricular systolic function. MAIN OUTCOME MEASURES: QT and QTc dispersion measured by three methods: the difference between maximum and minimum QT and QTc intervals, the standard deviation of QT and QTc intervals, and the "lead adjusted" QT and QTc dispersion. RESULTS: All measures of QT/QTc dispersion were closely interrelated (r values 0.86 to 0.99; all p < 0.001). All measures of QT and QTc dispersion were significantly increased in the patients with impaired left ventricular systolic function v controls (p < 0.001): 71.9 (6.5) (mean (SEM)) v 46.9 (1.7) ms for QT dispersion, and 83.6 (7.6) v 54.3 (2.1) ms(-1-2) for QTc dispersion. All six dispersion parameters were reduced in patients taking beta blockers (p < 0.05), regardless of whether left ventricular function was normal or impaired-by 9.4 (4.6) ms for QT dispersion (p < 0.05) and by 13.8 (6. 5) ms(-1-2) for QTc dispersion (p = 0.01). CONCLUSIONS: QT and QTc dispersion are increased in patients with systolic heart failure in comparison with matched controls, regardless of the method of measurement and independently of possible confounding factors. beta Blockers are associated with a reduction in both QT and QTc dispersion, raising the possibility that a reduction in dispersion of ventricular repolarisation may be an important antiarrhythmic mechanism of beta blockade.  (+info)

Tachyarrhythmias triggered by swallowing and belching. (5/14381)

Three cases with supraventricular tachyarrhythmias related to oesophageal transit are reported. A 61 year old man had episodes of atrial tachycardia on each swallow of food but not liquid; this has been reported only rarely. A 55 year old man had atrial fibrillation initiated by drinking ice cold beverages; this has not been described previously although atrial tachycardia triggered by drinking ice cold beverages has been described once. A 68 year old man had supraventricular tachycardia initiated by belching; this has not been described previously. These cases illustrate the diversity of atrial tachyarrhythmias that can be precipitated by oesophageal stimulation and suggest that what is regarded as a very rare phenomenon may be found more commonly when sought.  (+info)

Tachycardia induced tachycardia: case report of right ventricular outflow tract tachycardia and AV nodal reentrant tachycardia. (6/14381)

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

ECG diagnosis of native heart ventricular tachycardia in a heterotopic heart transplant recipient. (7/14381)

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

Prognostic value of myocardial perfusion imaging in patients with high exercise tolerance. (8/14381)

BACKGROUND: Although high exercise tolerance is associated with an excellent prognosis, the significance of abnormal myocardial perfusion imaging (MPI) in patients with high exercise tolerance has not been established. This study retrospectively compares the utility of MPI and exercise ECG (EECG) in these patients. METHODS AND RESULTS: Of 388 consecutive patients who underwent exercise MPI and reached at least Bruce stage IV, 157 (40.5%) had abnormal results and 231 (59.5%) had normal results. Follow-up was performed at 18+/-2.7 months. Adverse events, including revascularization, myocardial infarction, and cardiac death, occurred in 40 patients. Nineteen patients had revascularization related to the MPI results or the patient's condition at the time of MPI and were not included in further analysis. Seventeen patients (12.2%) with abnormal MPI and 4 (1.7%) with normal MPI had adverse cardiac events (P<0.001). Cox proportional-hazards regression analysis showed that MPI was an excellent predictor of cardiac events (global chi2=13.2; P<0.001; relative risk=8; 95% CI=3 to 23) but EECG had no predictive power (global chi2=0.05; P=0.8; relative risk=1; 95% CI=0.4 to 3.0). The addition of Duke's treadmill score risk categories did not improve the predictive power of EECG (global chi2=0.17). The predictive power of the combination of EECG (including Duke score categories) and MPI was no better than that of MPI alone (global chi2=13.5). CONCLUSIONS: Unlike EECG, MPI is an excellent prognostic indicator for adverse cardiac events in patients with known or suspected CAD and high exercise tolerance.  (+info)

Purpose T wave inversion (TWI) is the electrical hallmark of cardiac conditions such as hypertrophic cardiomyopathy (HCM) or arrhythmogenic right ventricular cardiomyopathy (ARVC), which may be the substrate for sudden cardiac death in the young athlete. Such repolarization anomalies can feature on the ECG of an apparently healthy athlete and pose major diagnostic dilemmas in sports cardiology, as regular, prolonged high intensity, physical activity is associated with such repolarization changes. Athletes themselves are reluctant to detrain during the season, which makes interpreting any reversible effects of exercise on the ECG more difficult. This study aimed to investigate the effect of detraining on TWI in athletes. ...
Introduction: While right precordial T wave inversions (RPTWI) are associated with specific cardiomyopathic conditions including ARVC, they are common among trained athletes without underlying heart disease. RPTWI in athletes, particularly those that are not of Afro-Caribbean descent, remain poorly understood and represent a source of considerable clinical controversy. We therefore sought to examine the prevalence, training physiology specificity, and ECG correlates of RPTWI among asymptomatic Caucasian athletes.. Methods: Competitive collegiate Caucasian male endurance athletes (rowers, n=168) and strength-trained athletes (football players, n=162) underwent standard 12-lead ECG at the time of pre-participation screening. ECGs were analyzed for standard quantitative parameters and for the presence of RPTWI defined as TWI ≥2mm in ≥2 leads from V1 to V3.. Results: RPTWI were significantly more prevalent in endurance athletes (25%) than in strength-trained athletes (4%, p,0.001; Figure). ...
Introduction: While it has been proposed that T wave inversions (TWI) in the anterior precordial leads can be a normal finding in the ECGs of Afro-Caribbean athletes, it is uncertain whether this holds true for African-Americans. Hypothesis: TWI in the anterior precordial leads can be a non-specific marker of cardiac disease, and as a result, assuming a benign nature for TWI in the anterior leads in African-American athletes may not be appropriate. Methods: To begin to investigate this notion, we evaluated the incidence of cardiovascular death (CVD) in apparently healthy African- Americans with anterior TWI over an 11 year period. We analyzed the ECGs and CV deaths in 5334 ambulatory African Americans (average age 50 years, 8% female, average follow up of 8 years) seen at the Palo Alto VA Health Care system from 1986 until 1997. T waves were coded as inverted in V2, V3, V4 and V5 if TWI were noted to be more than 1 mm below the PR segment. The leads coded as inverted were summed to create a ...
OBJECTIVE: To investigate the value of a giant negative T wave (, or = 1.0 mV) in precordial leads of 12-lead electrocardiograms in the acute phase of Q wave myocardial infarction as a predictor of myocardial salvage. METHODS: Coronary angiographic and electrocardiographic findings, left ventricular ejection fraction in the chronic stage, and levels of cardiac enzymes were compared in patients with myocardial infarction with (group GNT, n = 31) and without (group N, n = 20) a giant negative T wave. GNT patients were divided into two subgroups according to the presence (GNT:R[+], n = 10) or absence (GNT: R[-], n = 21) of R wave recovery with an amplitude , or = 0.1 mV in at least one lead that had shown Q waves. RESULTS: The maximum level of creatine kinase and the total creatine kinase were lower in group GNT compared with group N (P , 0.05). The left ventricular ejection fraction was higher in group GNT than in group N (P , 0.05). The maximum creatine kinase and total creatine kinase were lower ...
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You systematically review the EKG. The heart rate is normal. There is a p wave before every QRS complex, but the p-wave axis is abnormal (negative in lead II). There is now an extreme rightward axis as the QRS is negative in leads I, II and avF. As you analyze the ST segments for evidence of ischemia, there appears to be T wave inversions in the inferior distribution of II, III, and avF. You start considering the differential of ectopic atrial rhythm, right axis deviation, and T wave inversions including PE or ischemia but stop yourself. You think "did someone switch the leads?" You take a brief look at aVR and see that the P, QRS and T waves are positive, making you even more suspicious ...
Alteration in ventricular repolarization occurs during changes in ventricular activation as may occur with ventricular pacing, bundle branch block and various arrhythmias. This may result in T wave abnormalities which persist following cessation of pacing, resolution of bundle branch block or resolution of arrhythmia. Such changes may be confused with ischemia. The phenomenon, known as cardiac memory, is reviewed here in the American Journal of Emergency Medicine. ...
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A method of gathering electrocardiographic data is disclosed wherein the EKG data is collected by sequentially monitoring the difference in electrical potential measured at each of at least three patient leads for a time period greater than 15 seconds, preferably for equal time periods of 20 seconds each. Although more than three leads and longer monitoring time periods may be used, a 60-second three-lead EKG data sample in accordance with the present invention is clinically sufficient to monitor cardiac function and to diagnose most cardiac dysfunctions. A system for collecting such electrocardiographic data is also disclosed. The system allows the collected data to be stored for later translation and interpretation. The stored data may also be communicated over phone lines for translation and interpretation at a remote site by trained individuals.
In this chapter, we investigate the most recent automatic detecting algorithms on abnormal electrocardiogram (ECG) in a variety of cardiac arrhythmias. We present typical examples of a medical case study and technical applications related to diagnosing ECG, which include (i) a recently patented data classifier on the basis of deep learning model, (ii) a deep neural network scheme to diagnose variable types of arrhythmia through wearable ECG monitoring devices, and (iii) implementation of the health cloud platform, which consists of automatic detection, data mining, and classifying via the Android terminal module. Our work establishes a cross-area study, which relates artificial intelligence (AI), deep learning, cloud computing on huge amount of data to minishape ECG monitoring devices, and portable interaction platforms. Experimental results display the technical advantages such as saving cost, better reliability, and higher accuracy of deep learning-based models in contrast to conventional schemes on
ECG in hypertrophic cardiomyopathy with atrial fibrillation: Atrial activity is seen as irregular fibrillary waves suggesting atrial fibrillation. The QRS complexes have a large amplitude in chest leads overlapping between the leads. Tall R waves in lateral leads and deep S waves in anterior leads along with gross ST segment depression with T wave inversion in lateral leads are suggestive of severe left ventricular hypertrophy. The QRS width is also increased to about 120 msec mimicking left bundle branch block. The ECG is from a case of advanced hypertrophic cardiomyopathy with atrial fibrillation. Development of atrial fibrillation leads to cardiac decompensation in hypertrophic cardiomyopathy due to loss of atrial kick. In a hypertrophied ventricle the booster effect of atrial contraction is very important for diastolic filling. Even though the contribution of atrial contraction to ventricular filling in a normal person is about 15 - 20 %, it may be over 30% in an individual with diastolic ...
The discrepancy between the relatively better early outcomes and the similar or even worse long-term prognoses in patients with non-Q wave versus Q wave infarction has led to a more aggressive approach in the management of this group of patients ([3, 5, 10]). Our findings conflict somewhat with reports from the prethrombolytic era ([3-5, 9, 17-19]), in which 1-year mortality was similar or even higher in the non-Q wave infarction populations. The difference could be related to the heterogeneity of the populations, the definitions used and the use of thrombolysis ([3-9, 11]).. Another possible explanation for this disagreement is the initial ST segment deviation. In most studies of Q wave or non-Q wave infarction, the initial ST segment shift was seldom considered a prognostic marker. The observation that patients with initial ST segment depression have a worse prognosis than those with ST segment elevation and either Q wave or non-Q wave infarction ([20-23]), with the additional evidence that ...
The correlation between persistent negative T wave on basal electrocardiogram and coronary anatomy or global and regional left ventricular function was investigated in 34 patients with unstable angina defined as new onset (| 2 months), crescendo or rest angina. The patients with history of previous myocardial infarction, pathological Q waves on electrocardiogram or documented elevation of CPK were excluded. Eighteen patients (group A) showed T wave inversion (| 1 mV) in at least two leads on the basal electrocardiogram, persisting for at least 48 hours before coronary arteriography. In 16 patients (group B) the basal electrocardiogram was normal. Left ventricular volumes and ejection fraction were calculated and the regional systolic wall motion was analyzed using the area method in the 30 degrees right anterior oblique view. Hypokinesis was defined as more than 2 standard deviation below the mean value calculated in 24 normal subjects. No difference was present for age (A: 61 +/- 9 vs B: 57 +/- 9 yrs)
GREAT case! My initial impression looking at the initial ECG was that the leads (especially leads III and aVF) just "looked funny" - almost as if there was some type of lead misplacement. That is, the amount of T wave inversion (especially in lead III) looked extreme - albeit both QRS and ST-T wave appearance in lead III was indeed the precise "mirror-image" of the QRST & ST-T wave in lead aVL …But there is no lead misplacement - as the P wave in lead II is upright, and there is global negativity in lead aVR as there is expected to be. Looking next at the chest leads - not only R wave progression, but also R wave amplitude looks uncharacteristically reduced - which if not due to large body habitus (I dont think this patients body habitus was described … ?) should raise the question if loss of R wave on this initial ECG is the result of an acute ongoing event. Regardless of questions raised by these findings - there is little doubt (as recognized by the treating ED physician) that T wave ...
Background:. The importance of ischemic ECG changes including St segment elevation, ST segment depression or T wave inversion that indicate myocardial ischemia are well established and require appropriate investigation and treatment.. However, there is an abundance of clinical situation, with apparently ischemic ECG change not indicate traditionally coronary artery related ischemia and therefore require prompt recognition and treatment of underlying condition, that may be serious and life-threatened. For example of such conditions are pericarditis, myocarditis, aortic dissection, electrolyte abnormalities, intracranial hemorrhage and hypothermia.. Together with them, an ECG ST segment changes may appeared in abdominal serious illness such as pancreatitis and cholecystitis(17,18,19,20,23). Whereas in pancreatitis various vasoactive and toxic for myocardium substances released, the cause of ST segment changes in cholecystitis are discussed and includes tachycardia , vagal reflexes, changed in ...
Background:. The importance of ischemic ECG changes including St segment elevation, ST segment depression or T wave inversion that indicate myocardial ischemia are well established and require appropriate investigation and treatment.. However, there is an abundance of clinical situation, with apparently ischemic ECG change not indicate traditionally coronary artery related ischemia and therefore require prompt recognition and treatment of underlying condition, that may be serious and life-threatened. For example of such conditions are pericarditis, myocarditis, aortic dissection, electrolyte abnormalities, intracranial hemorrhage and hypothermia.. Together with them, an ECG ST segment changes may appeared in abdominal serious illness such as pancreatitis and cholecystitis(17,18,19,20,23). Whereas in pancreatitis various vasoactive and toxic for myocardium substances released, the cause of ST segment changes in cholecystitis are discussed and includes tachycardia , vagal reflexes, changed in ...
Early repolarization pattern (ERP) on the 12-lead electrocardiogram (ECG) is associated with sudden cardiac death (SCD) and increased mortality in certain populations. The mechanism of this association has been hypothesized to relate to regional heterogeneity of epicardial and endocardial repolarization. However, whether differences in subclinical left ventricular wall thickness may affect this association is unknown (1). Individuals with ERP are more likely to meet Sokolow-Lyon ECG criteria for left ventricular hypertrophy (LVH-SL) but are paradoxically less likely to meet Cornell voltage criteria (LVH-C) (2,3). Studies to date are limited by use of ECG measurements to define LVH and are thus not sufficient to determine whether there is a relationship between left ventricular mass (LVM) and ERP. We hypothesized that participants with ERP have a higher LVM and a greater prevalence of cardiac magnetic resonance imaging-determined LVH (LVH-CMR) compared with those without ERP.. The ...
Have recently had ECG done following chest pain.Tracing showed T wave inversion and ST wave inversion in lead 3. Have then had normal Echo, stress ECG and 24 hour Holter monitor. What could be the reas...
Intraventricular conduction delays such as LBBB and the associated ST segment-T wave abnormalities can mimic both acute and chronic ischaemic changes. Much has been written about the evaluation of the ST segment elevation in the presence of LBBB1,8; considering chest pain patients in the ED, LBBB is responsible for 15% of STE syndromes and is the second most frequently encountered electrocardiographic pattern responsible for non-ischaemic STE.17,18 LBBB, however, can also cause significant ST segment depression, and it is imperative that these electrocardiographic changes be distinguished from those that occur in the presence of ACS.3 The "rule of appropriate discordance" states that in LBBB, ST segment-T wave configurations are directed opposite from the major, terminal portion of the QRS complex. As such, leads with either QS or rS complexes should have significantly elevated ST segments mimicking an AMI while leads with a large monophasic R wave demonstrate ST segment depression. T waves in ...
I will commit myself to commenting before reading Dr. Smiths Blog. I see sinus bradycardia with 1st degree AV block and LBBB. Without yet knowing the history - I see several findings of concern that transcend need (in my opinion) for numerical criteria ... These include: i) ST coving and slight-but-real elevation in leads III and aVF - associated with fairly deep T wave inversion in these leads that is NOT what I expect with typical LBBB; ii) Subtle-but-real ST segment coving that should-not-be-there with simply LBBB in lead II - that supports i) findings; iii) J-point depression with uncharacteristically FLAT ST segment in leads I,aVL (whereas with typical LBBB the ST segment isnt flat, but slowly upsloping) - associated with an upright terminal T wave in these leads (!) that is the mirror-image opposite of what I see in leads III, aVF; iv) An uncharacteristic-for-LBBB takeoff of the ST segment in lead V2 (is typically not so straight at takeoff); and v) 1-2mm of J-point ST depression in ...
article{3004d42f-c464-4188-bf60-ba0491925d72, author = {Bennhagen, Rolf and Sörnmo, Leif and Pahlm, Olle and Pesonen, Erkki}, issn = {1399-3046}, language = {eng}, number = {6}, pages = {773--779}, publisher = {Wiley-Blackwell}, series = {Pediatric Transplantation}, title = {Serial signal-averaged electrocardiography in children after cardiac transplantation.}, url = {http://dx.doi.org/10.1111/j.1399-3046.2005.00384.x}, volume = {9}, year = {2005 ...
This comprehensive 50 hour EKG Technician Certification Program prepares students to function as an EKG Technician. This course will include important practice and background information on anatomy of the heart and physiology, medical disease processes, medical terminology, medical ethics, legal aspects of patient contact, the Holter monitor, electrocardiography and echocardiography.. Additionally, students will practice with equipment and perform hands-on labs including introduction to the function and proper use of the EKG machine, the normal anatomy of the chest wall for proper lead placement, 12-lead placement and other clinical practices. EKG Technicians also analyze printed readings of EKG tests, measuring various "cardiac intervals and complexes" and determining normal vs. abnormal EKG.. EKG Technician Course Outline. ...
The QED 2000 is a complete 12 Lead Electrocardiograph (ECG) solution with ECG interpretation software. Designed to assist health care professionals in delivering the utmost quality care to patients, the ECG reading can be easily and accurately acquired, analyzed, stored and printed in one touch. With features designed to enhance portability, streamline workflow and assist in a physicians diagnosis, the QED 2000 12 Lead ECG is suitable for many environments.. The built-in ECG interpretation software assists in healthcare professionals diagnosis and screening. Our patented ECG interpretation software is a unique algorithm which analyzes the frequency components of a 10 second 12 lead resting ECG reading. Clinically tested and with a high sensitivity/specificity rate, the ECG interpretation offers a reliable and accurate analysis to support a physicians diagnosis. Segment and waveform measurement, rhythm interpretation, and myocardial ischemia sensitivity probability is generated by the QED 2000 ...
A 42-year-old man with acute renal failure is confused. His serum potassium is 8.1 mEq/L . The most likely abnormal ECG finding is: a) T wave inversion b) PR interval of 300ms c) QT interval of 0.4s d) U wave e) Tall tented T waves The correct answer is E The earliest ECG evidence of [...]. ...
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Here is a good organized approach to master ECG interpretation. Learning the art of ECG interpretation requires intellect, commitment, effort and - perhaps most importantly - an organized approach.
Signal-averaged electrocardiography (SAECG) is a special electrocardiographic technique, in which multiple electric signals from the heart are averaged to remove interference and reveal small variations in the QRS complex, usually the so-called "late potentials". These may represent a predisposition towards potentially dangerous ventricular tachyarrhythmias. A resting electrocardiogram (ECG) is recorded in the supine position using an ECG machine equipped with SAECG software; this can be done by a physician, nurse, or medical technician. Unlike standard basal ECG recording, which requires only a few seconds, SAECG recording requires a few minutes (usually about 7-10 minutes), as the machine must record multiple subsequent QRS potentials to remove interference due to skeletal muscle and to obtain a statistically significant average trace. For this reason, it is important for the patient to lie as still as possible during the recording. SAECG recording yields a single, averaged QRS potential, ...
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QRS width and morphology is in a gray zone. Precise answer really requires review after conversion to sinus rhythm. That said, the QRS looks supraventricular. While one can debate if QRS width is 0.11 vs 0.12 ... the width of the monophasic R wave in lateral leads is not overly wide; the initial r in V1,2,3 is larger than is usual in lbbb; and the QRS just looks supraventricular. Remember that BOTH LAHB and LVH may slightly widen the QRS - and that is my strong hunch of what we have here - :). Delete ...
Even though the electrocardiogram (ECG) is the standard diagnostic test for the evaluation of symptoms of acute myocardial ischemia or infarction, the prognostic value of various ECG features of cardiac ischemia is ill-defined. Savonitto and colleagues conducted a retrospective study of the ECG findings among patients in the Global Use of Strategies to Open Occluded Arteries in Acute Coronary Syndromes (GUSTO-IIb) trial.. A total of 12,142 patients were enrolled in the GUSTO-IIb trial. To be enrolled in the study, patients had to have ECG signs of myocardial ischemia, including transient or persistent ST-segment elevation or depression of more than 0.05 mV or persistent and definite T-wave inversion of more than 0.1 mV. All patients had to have reported symptoms of cardiac ischemia at rest within 12 hours of hospital admission. Since the GUSTO-IIb trial was a comparison of heparin and desirudin, patients were excluded if they had active bleeding, a history of stroke, an elevated serum creatinine ...
TY - JOUR. T1 - Fragmented QRS on twelve-lead electrocardiogram predicts arrhythmic events in patients with ischemic and nonischemic cardiomyopathy. AU - Das, Mithilesh. AU - Maskoun, Waddah. AU - Shen, Changyu. AU - Michael, Mark A.. AU - Suradi, Hussam. AU - Desai, Mona. AU - Subbarao, Roopa. AU - Bhakta, Deepak. PY - 2010/1. Y1 - 2010/1. N2 - Background: Myocardial scar is a substrate for reentrant ventricular arrhythmias and is associated with poor prognosis. Fragmented QRS (fQRS) on 12-lead ECG represents myocardial conduction delays due to myocardial scar in patients with coronary artery disease (CAD). Objective: The purpose of this study was to determine whether fQRS is associated with increased ventricular arrhythmic event and mortality in patients with CAD and nonischemic dilated cardiomyopathy (DCM). Methods: Arrhythmic events and mortality were studied in 361 patients (91% male, age 63.3 ± 11.4 years, mean follow-up 16.6 ± 10.2 months) with CAD and DCM who received an implantable ...
Electrocardiography is a simple investigation to perform, but accurate interpretation can be challenging. This book takes a logical and systematic approach to ECG interpretation, beginning with the basics of normal variations and dealing in turn with atrial abnormalities, ventricular enlargement, ventricular conduction defects and ischemic heart disease ...
Electrocardiography and Dysrhythmia Monitoring Unit 4 chapter 32 Nursing Care of Clients with Cardiovascular Disorders SectionDiagnostic and Therapeutic Procedures Chapter 32 Electrocardiography and Dysrhythmia Monitoring Overview в-Џв-Џ Cardiac electrical activity can be monitored by using an ECG. The heart’s electrical activity can be monitored by a standard 12-lead ECG (resting ECG), ambulatory ECG (Holter monitoring), continuous cardiac monitoring, or by telemetry. View Media Supplement: в-Џв-Џ в-Џв-Џ ECG Strip (Image) Cardiac dysrhythmias are heartbeat disturbances (beat formation, beat conduction, or myocardial response to beat). Nurses should be familiar with cardioversion and defibrillation procedures for treating dysrhythmias. Electrocardiography в-Џв-Џ Electrocardiography uses an electrocardiograph to record the electrical activity of the heart over time. The electrocardiograph is connected by wires (leads) to skin electrodes placed on the chest and limbs of a ...
... - EKG Ruler. The EKG Heart Rate Calculator Ruler is specifically design to help you determine patients heart rates and interval lengths on EKGs.EKG Heart Rate Calculator Ruler - EKG RulerMDpocket has created a pocket EKG H
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Learning the art of ECG interpretation requires intellect, commitment, effort and perhaps most importantly...an organized approach. I personally have spent thousands of hours (yes thousands) looking at 12-lead ECG tracings, studying ECGs for the cardiology boards, interpreting ECGs for direct patient care and developing the ECG tutorials and quizzes of LearnTheHeart.com ...
It is now time to "solve" the laddergram. We accomplish this by filling in the AV nodal tier for those beats we had been uncertain about. It should be emphasized that we are not necessarily certain about the mechanism of the arrhythmia at this point (If we were, we wouldnt be doing this laddergram). Instead - We are looking for a plausible theory to explain the problematic elements of the rhythm strip. In this case - this entails explaining: i) WHY beats #2,5,8 occur early; ii) HOW the P waves immediately following these beats can occur right on time; and iii) WHY no QRS complex is seen after these non-conducted P waves ...
The Welch Allyn 12-Lead Resting Electrocardiograph, CP150AW-1ENB is a comprehensive ECG (EKG) machine that will help you improve workflow, save time, and manage patient information most efficiently.
Question - Abnormal ECG. What should we express concern over? Translate it?. Ask a Doctor about when and why Electrocardiography is advised, Ask a Radiologist
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12 Lead ECG Interpretation: Color Coding for MI s Anna E. Story, RN, MS Director, Continuing Professional Education Critical Care Nurse Online Instructional Designer – A free PowerPoint PPT presentation (displayed as a Flash slide show) on PowerShow.com - id: 3c58de-YjQxZ
Basic ECG interpretation is important to understand as a nurse. What does it mean when different waves do not look how they should? Here is a guide to common ECG abnormalities and what to look out for.
ECG Interpretation. Arrhythmias of Formation Chapters 4-5. Types of Arryhthmias:. Sinus Problems: Formed in the sinus node, but irregular Ectopic Problems: Formed outside of the sinus node Conduction Problems: Formed in the sinus node, but conduction in error Slideshow 172476 by Ava
A long philosophical introduction that places electrocardiography in its proper perspective among the cardiological diagnostic techniques makes for enjoyable reading of this primer right from the beginning.. The analogy of the lead systems used to investigate the electrophysiology of the heart to blind men observing an elephant inside a box is quite appropriate.. A brief history of electrocardiography and an introduction into anatomy, physiology, and electrophysiology precede chapters on the normal electrocardiogram, arrhythmias, atrioventricular and intraventricular conduction defects, muscle injury and death, and atrial and ventricular enlargement.. Clearly, the emphasis is on presenting concepts in a simplified but up-to-date manner. ...
Conventional 12-lead electrocardiography, the most widely used diagnostic approach for analyzing ECG changes in patients with suspected acute myocardial infarction (AMI), has a clinical sensitivity of 80% and specificity of 95% in patients with anterior AMI from occlusion of the left anterior descending coronary artery (2). These percentages are lower when investigating other coronary arteries, such as the circumflex coronary artery and right coronary artery (clinical sensitivity, 53%; specificity 98%) (2). The differences in the reliability of ECG in detecting AMI depend on the different left ventricular mass, producing electrical abnormalities in 12-lead ECG and on differences in electrode location. Sensitivity can be enhanced if 24 or 19 leads are used. The location of AMI involving a small (,2 cm) area of the midbasal interventricular septum may be overlooked in the ECG in terms of ST-segment elevation, showing only an isolated QS complex on V1 and V2 with a small R wave. The ECGs (Fig. 1) ...
With adenosine, the rhythm stopped briefly, but then immediately reinitiated. The EKG, however, changed considerably to this EKG. (Beta blockers were administered and had little affect on the patients tachycardia rate. Note that the 5th and 7th beats of the subsequent EKG have the same morphology as the wide complex beats seen in the first EKG, except the 7th beat is somewhat narrower, making it consistent with a fusion beat between the narrow-complex rhythm and a PVC. Hence, the wide complex beats in the original EKG are from a ventricular source (ventricular bigeminy) and the narrow-complex beats are being driven by a long-RP supraventricular tachycardia (the second rhythm of the tango ...
... (ECG or EKG[a]) is the process of recording the electrical activity of the heart[4] over a period of time ... Electrocardiography Vectorcardiography. Holter monitor. Implantable loop recorder. Cardiac stress test Bruce protocol. ... Cooper JK (1986). "Electrocardiography 100 years ago. Origins, pioneers, and contributors". N Engl J Med. 315 (7): 461-64. doi: ... Pediatric and Fundamental Electrocardiography. Developments in Cardiovascular Medicine. 56. pp. 315-327. doi:10.1007/978-1-4613 ...
Electrocardiography[edit]. ECG pattern in Brugada syndrome. According to consensus guidelines, Type 1 ST segment elevation, ...
Retrieved from "https://en.wikipedia.org/w/index.php?title=P_wave_(electrocardiography)&oldid=842471189" ...
Main article: Electrocardiography. Cardiac cycle shown against ECG. Using surface electrodes on the body, it is possible to ...
In 1913, he published the book Clinical Electrocardiography, the first treaty on electrocardiography. Lewis was elected a ... Accordingly, Lewis is considered the "father of clinical cardiac electrophysiology". The first use of electrocardiography in ... employed electrocardiography to diagnose heart block.[12] In 1909, with James MacKenzie, Lewis founded the journal Heart: A ... the Dutch physiologist Willem Einthoven concerning the latter's invention of the string galvanometer and electrocardiography, ...
Electrocardiography Vectorcardiography. Holter monitor. Implantable loop recorder. Cardiac stress test Bruce protocol. ... In medicine, a Holter monitor (often simply Holter) is a type of ambulatory electrocardiography device, a portable device for ... 12-lead Holter electrocardiography. Review of the literature and clinical application update. Su L1, Borov S, Zrenner B. ... The Holter's most common use is for monitoring ECG heart activity (electrocardiography or ECG). Its extended recording period ...
Shvilkin, Ary L. Goldberger, Zachary D. Goldberger, Alexei (2013). Goldberger's Clinical Electrocardiography: A Simplified ... Wagner, Galen S. (2001). Marriott's Practical Electrocardiography (10th ed.). Philadelphia, PA: Williams & Wilkins. ISBN ...
Electrocardiography. ...
The presence of LBBB results in that electrocardiography (ECG) cannot be used to diagnose left ventricular hypertrophy or Q ... "Electrocardiography > Left Bundle Branch Block (LBBB)". SIU School of Medicine. Retrieved 2015-07-02. Stevenson WG, Hernaddez ...
"Electrocardiography". Wikipedia. 2017-07-21. Huff, Jane (2012). ECG Workbook. 323 Norristown Road, suite 200, ambler, PA 19002- ...
EKG [Electrocardiography]: Alexander Muirhead (1911) [189]. *Discovering secretin, the first hormone, and its role as a ... EKG [Electrocardiography]: Alexander Muirhead (1911) [182]. *Pioneering the use of surgical anaesthesia with Chloroform: Sir ...
It can affect electrocardiography (ECG) findings. An ECG with right ventricular hypertrophy may or may not show a right axis ...
Conover, Mary Boudreau (2003). "Bedside Diagnosis". Understanding electrocardiography. St. Louis: Mosby. p. 82. ISBN 0-323- ...
Conover, Mary Boudreau (2003). Understanding Electrocardiography. Elsevier Health Sciences. pp. 117-118. ISBN 0323019056. ...
Wenger, R; Massumi, RA; Kuramoto, K (1955). "A comparative study of esophageal and direct auricular electrocardiography in dog ... Fisch, Charles (1973). Complex electrocardiography. Philadelphia: F.A. Davis. ISBN 978-0-8036-3555-5. LCCN 73082285. [page ... "Complex Electrocardiography". He was a driving force behind the field's understanding of Prinzmetal-Massumi syndrome, a rare ... "A Comparative Study of Esophageal and Direct Auricular Electrocardiography in Dog". Cardiology. 26 (4): 193-208. doi:10.1159/ ...
Dynamic Electrocardiography. Elmsford (NY): Blackwell Futura. p. 291-300. ISBN 1405119608 Antzelevitch C (2002). "Cellular ... "Long-Term Outcome Associated with Early Repolarization on Electrocardiography". New England Journal of Medicine. 361: 2529-2537 ...
... is an imaginary formation of three limb leads in a triangle used in electrocardiography, formed by the two ... p. 4. ISBN 0-323-01905-6. Silverman, M. E. (1992-10-01). "Willem Einthoven--the father of electrocardiography". Clinical ... p. 5. ISBN 978-1-60547-476-2. Understanding Electrocardiography. Elsevier Health Sciences. 2003. ...
Chugh, S. N. (2014-05-14). Textbook of Clinical Electrocardiography. Jaypee Brothers Publishers. ISBN 9789350906088. Burns, Ed ... Conover, Mary Boudreau (2003-01-01). Understanding Electrocardiography. Elsevier Health Sciences. ISBN 0323019056. Kossmann, ...
"An introduction to clinical electrocardiography - Supraventricular Arrhythmias". ECG Learning Center. University of Utah.. ...
Electrocardiography (1963, 1964). ...
Levine, Shel; Coyne, Brian J.; Colvin, Lisa Cooper (2015-02-13). Clinical Exercise Electrocardiography. Jones & Bartlett ...
"ECG Learning Center - An introduction to clinical electrocardiography". Library.med.utah.edu. Retrieved 2013-04-24.. ...
Wilson in the field of electrocardiography. All of his work in this domain was done primarily in an effort to explain why ... Wilson's time in the last years of his active service was devoted to informal teaching of electrocardiography to doctors who ... Wilson's life was dedicated primarily to electrocardiography he had many other interests and hobbies. Both he and his wife ... Burch, George Edward; DePasquale, Nicholas P. (1990). A History of Electrocardiography. Norman Publishing. pp. 91-. ISBN ...
2002-03-02). "ABC of clinical electrocardiography". Retrieved 2008-04-28. ...
Besterman E, Creese R. (July 1979). "Waller--pioneer of electrocardiography". British Heart Journal. 42 (1): 61-64. doi:10.1136 ...
Electrocardiography (ECG or EKG[a]) is the process of recording the electrical activity of the heart[4] over a period of time ... Electrocardiography Vectorcardiography. Holter monitor. Implantable loop recorder. Cardiac stress test Bruce protocol. ... Cooper JK (1986). "Electrocardiography 100 years ago. Origins, pioneers, and contributors". N Engl J Med. 315 (7): 461-64. doi: ... Pediatric and Fundamental Electrocardiography. Developments in Cardiovascular Medicine. 56. pp. 315-327. doi:10.1007/978-1-4613 ...
Retrieved from "https://en.wikipedia.org/w/index.php?title=P_wave_(electrocardiography)&oldid=842471189" ...
Fundamentals of electrocardiography interpretation. Anesth Prog. 2006;53:53-64.CrossRefPubMedPubMedCentralGoogle Scholar ... Miwa S., Mieszczanska H.Z. (2018) Cardiac Electrocardiography. In: Mieszczanska H., Budzikowski A. (eds) Cardiology Consult ... acute ischemia/infarction a scientific statement from the American Heart Association Electrocardiography and Arrhythmias ... associated with cardiac chamber hypertrophy a scientific statement from the American Heart Association Electrocardiography and ...
encoded search term (What is electrocardiography (ECG)?) and What is electrocardiography (ECG)? What to Read Next on Medscape. ... What is electrocardiography (ECG)?. Updated: Mar 11, 2019 * Author: Tarek Ajam, MD, MS; Chief Editor: Terrence X OBrien, MD, ... electrocardiography diagnostic statement list a scientific statement from the American Heart Association Electrocardiography ... ABC of clinical electrocardiography. Conditions affecting the left side of the heart. BMJ. 2002 May 25. 324 (7348):1264-7. [ ...
UNIPOLAR ELECTROCARDIOGRAPHY. Br Med J 1958; 1 doi: https://doi.org/10.1136/bmj.1.5084.1399-a (Published 14 June 1958) Cite ...
Electrocardiography with Music. Br Med J 1964; 2 doi: https://doi.org/10.1136/bmj.2.5422.1464-c (Published 05 December 1964) ...
Electrocardiography, method of tracing the electric current of a heartbeat to provide information on the heart. ... Electrocardiography, method of graphic tracing (electrocardiogram; ECG or EKG) of the electric current generated by the heart ... In addition, electrocardiography can be used to determine whether a slow heart rate is physiological or is caused by heart ... During the late 1960s, computerized electrocardiography came into use in many of the larger hospitals. ...
Electrocardiography (ECG or EKG) is the process of recording the electrical activity of the heart over a period of time using ... Cooper JK (1986). "Electrocardiography 100 years ago. Origins, pioneers, and contributors". N Engl J Med. 315 (7): 461-4. doi: ... Though the basic principles of that era are still in use today, many advances in electrocardiography have been made over the ... One additional form of electrocardiography is used in clinical cardiac electrophysiology in which a catheter is used to measure ...
An improved electrocardiography system displays and records electrocardiograph (ECG) signals provided on multiple pickup leads ... Typically, in such electrocardiography systems, a large number of electrode leads are connected to the patient, but only a few ... 8. An electrocardiography system for displaying, in accordance with an operator input provided via control console switches, ... An electrocardiography system for displaying, in accordance with an operator input provided via control console switches, ...
This book deals with the basic concepts of high resolution electrocardiography: the electrophysiological basis of late ... arrhythmia electrocardiogram (ECG) electrocardiography electrophysiology myocardial infarction physiology Editors and ... 2.Section of Electrocardiography and ElectrophysiologyMount Sinai Medical CenterNew YorkUSA ... This book deals with the basic concepts of high resolution electrocardiography: the electrophysiological basis of late ...
... add an essential health care service to your repertoire with knowledge of electrocardiography.. ...
Electrocardiography PR interval QRS complex QT interval ST segment T wave U wave Longmore, Murray (2004). Oxford Handbook of ...
... set purposes have been achieved by providing a device allowing easy and quick positioning of electrodes for Electrocardiography ...
Electrocardiography for the anaesthetist by W. N. Rollason; 4 editions; First published in 1964; Subjects: Anesthesia, ... Are you sure you want to remove Electrocardiography for the anaesthetist from your list? ...
Spatial Vector Electrocardiography. The Clinical Characteristics of S-T and T Vectors. ROBERT P. GRANT, E. HARVEY ESTES, JOSEPH ...
Implications for Pre-Participation Cardiovascular Evaluation Using Electrocardiography Nabeel Sheikh, Michael Papadakis, Aneil ...
Make research projects and school reports about electrocardiography easy with credible articles from our FREE, online ... Electrocardiography Gale Encyclopedia of Medicine, 3rd ed. COPYRIGHT 2006 Thomson Gale. Electrocardiography. Definition. ... Electrocardiography Encyclopedia of Public Health COPYRIGHT 2002 The Gale Group Inc.. ELECTROCARDIOGRAPHY. The ... Electrocardiography. Definition. Electrocardiography is a commonly used, noninvasive procedure for recording electrical changes ...
Electrocardiography Basics is a new infographic science illustration poster design by Eleanor Lutz at TabletopWhale.com for ... Source: http://www.coolinfographics.com/blog/2016/10/20/electrocardiography-basics.html ...
Maximal Treadmill Exercise Electrocardiography. Correlations with Coronary Arteriography and Cardiac Hemodynamics. CARROLL M. ...
Electrocardiography. ECG findings include prolonged QTc interval, elevated ST segments, and inverted T waves. [14] Although ...
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... embedded into an electrocardiography monitor (12), which correlates syncope events and electrocardiographic data. Physiological ... an abnormal electrocardiography baseline module configured to detect (242) whether an abnormal electrocardiography baseline is ... an abnormal electrocardiography baseline module configured to detect (242) whether an abnormal electrocardiography baseline is ... electrocardiography monitor 14. Other types of battery compartment are possible. The battery contained within the battery ...
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Electrocardiography. Twelve-lead electrocardiographic (ECG) features of patients with Ebstein anomaly include the following:. * ...
  • Standards for Analysis of Ventricular Late Potentials using High-Resolution or Signal-Averaged Electrocardiography: A statement by a task force committee of the European Society of Cardiology, the American Heart Association, and the American College of Cardiology. (cogprints.org)
  • Serial signal-averaged electrocardiography in children after cardiac transplantation. (lu.se)
  • Signal-averaged electrocardiography in 27 patients showed late potentials in three of 11 patients with repetitive ventricular arrhythmias and was negative in 15 of 16 patients without these arrhythmias. (eurekamag.com)
  • A report of the American College of Cardiology/American Heart Association Task Force on Assessment of Diagnostic and Therapeutic Cardiovascular Procedures (Committee on Electrocardiography). (medscape.com)
  • The more optimal prognostic efficiency of thallium-201 scintigraphy is due in part to the fact that the error rate in falsely classifying patients at low risk is substantially smaller with scintigraphy than with stress electrocardiography. (biomedsearch.com)
  • The present study was designed to determine the prognostic significance of the signal average electrocardiography and to evaluate the possible value of this technique as a noninvasive tool for monitoring of coronary occlusion and reperfusion. (koreamed.org)
  • However, the prognostic value of such electrocardiography is still not clear. (eur.nl)
  • This EKG/EMG shield allows Arduino boards to capture Electrocardiography/Electromyography signals, so you can experiment with biofeedback. (microcontrollershop.com)
  • This short-term training program is designed to prepare students to perform non-invasive electrocardiography procedures, identify rhythms, and perform 12-lead electrocardiograms (ECG, or EKG). (jjc.edu)
  • Learning to perform non-invasive electrocardiography procedures and identifying rhythms will be a valuable addition to the skill set of today's healthcare worker. (jjc.edu)
  • 2. An ambulatory, extended-wear electrocardiography and syncope sensor monitor recorder (14) according to Claim 1, wherein the syncope sensor comprises at least one of a patient-mediated tactile feedback syncope button (66) and an actigraphy-based syncope sensor (64). (google.co.uk)
  • 3. An ambulatory, extended-wear electrocardiography and syncope sensor monitor recorder (14) according to Claim 2, wherein the syncope events comprise at least one of a syncope event identified by a patient (10,11) and a syncope event identified by the actigraphy-based syncope sensor (64) based on actigraphy filtering criteria comprising at least one of a falling event and a postural change event. (google.co.uk)
  • METHODS: Signal averaging was performed by using a signal average electrocardiography with bidirectional filterings before coronary artery occlusion, at 5 minutes after coronary occlusion and on reperfusion in 20 cats. (koreamed.org)
  • Electrocardiography ( ECG or EKG [a] ) is the process of recording the electrical activity of the heart over a period of time using electrodes placed over the skin. (wikipedia.org)
  • In addition, electrocardiography can be used to determine whether a slow heart rate is physiological or is caused by heart block . (britannica.com)
  • The overall goal of performing electrocardiography is to obtain information about the structure and function of the heart. (wikipedia.org)
  • Electrocardiography is a commonly used, noninvasive procedure for recording electrical changes in the heart. (encyclopedia.com)
  • Electrocardiography (ECG) is a simple, fast test to check the electrical activity of your child's heart as blood moves through it. (ahealthyme.com)
  • This indicates that pre-hospital electrocardiography offers a more timely diagnosis and has the potential to reduce ischemic time and limit heart muscle damage. (ucsd.edu)
  • Bolanos, M., Nazeran, H. and Haltiwanger, E. (2006) Comparison of Heart Rate Variability Signal Features Derived from Electrocardiography and Photoplethysmography in Healthy Individuals. (scirp.org)
  • Electrocardiography (ECG), introduced in 1902 by Einthoven, is the most commonly used procedure for the diagnosis of heart disease. (scribd.com)
  • Patients were screened before surgery by type of surgery, cardiovascular risk factors (history of coronary heart disease, heart failure, diabetes mellitus, renal dysfunction, and stroke), and preoperative electrocardiography. (eur.nl)
  • Electrocardiography (ECG) - a diagnostic study method that reflects the dynamics of the functioning of the heart over a certain period of time using a graphic image that displays the electrical activity of the organ. (sanatorii.by)
  • Electrocardiography is based on a rather elementary principle, which is based on the ability of the device to pick up electrical impulses in the heart and, after processing, record them in the form of a graph. (sanatorii.by)
  • Heart ailments have become common globally, and this is one of the reasons why 2 out of 10 patients are prescribed electrocardiography to ensure proper working of the heart. (marketdataforecast.com)
  • Electrocardiography market report shows often use of this device to check the condition of the heart among individuals. (marketdataforecast.com)
  • Root mean square electrocardiography (RMS ECG) provides a novel alternative measure of ventricular repolarization. (doaj.org)
  • Hence, the need of innovation in diagnostics for detection of disease progression increases thereby leading to a positive impact on diagnostic electrocardiography (ECG) devices market. (grandviewresearch.com)
  • In the initial section on electrocardiography, Dr. Spodick reviews our present day physiologic and pathophysiologic understanding of systolic time intervals, and how they are affected by a variety of cardiac disease states and pharmacologic agents. (magrudy.com)
  • An improved electrocardiography system displays and records electrocardiograph (ECG) signals provided on multiple pickup leads attached to a patient. (google.com)