Myocytes, Cardiac: Striated muscle cells found in the heart. They are derived from cardiac myoblasts (MYOBLASTS, CARDIAC).Cardiac Output: The volume of BLOOD passing through the HEART per unit of time. It is usually expressed as liters (volume) per minute so as not to be confused with STROKE VOLUME (volume per beat).Heart: The hollow, muscular organ that maintains the circulation of the blood.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.Cardiac Surgical Procedures: Surgery performed on the heart.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)Cardiomegaly: Enlargement of the HEART, usually indicated by a cardiothoracic ratio above 0.50. Heart enlargement may involve the right, the left, or both HEART VENTRICLES or HEART ATRIA. Cardiomegaly is a nonspecific symptom seen in patients with chronic systolic heart failure (HEART FAILURE) or several forms of CARDIOMYOPATHIES.Cardiac Tamponade: Compression of the heart by accumulated fluid (PERICARDIAL EFFUSION) or blood (HEMOPERICARDIUM) in the PERICARDIUM surrounding the heart. The affected cardiac functions and CARDIAC OUTPUT can range from minimal to total hemodynamic collapse.Cardiac Pacing, Artificial: Regulation of the rate of contraction of the heart muscles by an artificial pacemaker.Heart Diseases: Pathological conditions involving the HEART including its structural and functional abnormalities.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.Cardiac Catheterization: Procedures in which placement of CARDIAC CATHETERS is performed for therapeutic or diagnostic procedures.Myocardial Contraction: Contractile activity of the MYOCARDIUM.Heart Arrest: Cessation of heart beat or MYOCARDIAL CONTRACTION. If it is treated within a few minutes, heart arrest can be reversed in most cases to normal cardiac rhythm and effective circulation.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.Myoblasts, Cardiac: Precursor cells destined to differentiate into cardiac myocytes (MYOCYTES, CARDIAC).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.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).Cardiac Myosins: Myosin type II isoforms found in cardiac muscle.Cardiac Imaging Techniques: Visualization of the heart structure and cardiac blood flow for diagnostic evaluation or to guide cardiac procedures via techniques including ENDOSCOPY (cardiac endoscopy, sometimes refered to as cardioscopy), RADIONUCLIDE IMAGING; MAGNETIC RESONANCE IMAGING; TOMOGRAPHY; or ULTRASONOGRAPHY.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.Cardiac Glycosides: Cyclopentanophenanthrenes with a 5- or 6-membered lactone ring attached at the 17-position and SUGARS attached at the 3-position. Plants they come from have long been used in congestive heart failure. They increase the force of cardiac contraction without significantly affecting other parameters, but are very toxic at larger doses. Their mechanism of action usually involves inhibition of the NA(+)-K(+)-EXCHANGING ATPASE and they are often used in cell biological studies for that purpose.Heart Rate: The number of times the HEART VENTRICLES contract per unit of time, usually per minute.Echocardiography: Ultrasonic recording of the size, motion, and composition of the heart and surrounding tissues. The standard approach is transthoracic.Cardiac Output, Low: A state of subnormal or depressed cardiac output at rest or during stress. It is a characteristic of CARDIOVASCULAR DISEASES, including congenital, valvular, rheumatic, hypertensive, coronary, and cardiomyopathic. The serious form of low cardiac output is characterized by marked reduction in STROKE VOLUME, and systemic vasoconstriction resulting in cold, pale, and sometimes cyanotic extremities.Out-of-Hospital Cardiac Arrest: Occurrence of heart arrest in an individual when there is no immediate access to medical personnel or equipment.Time Factors: Elements of limited time intervals, contributing to particular results or situations.Hemodynamics: The movement and the forces involved in the movement of the blood through the CARDIOVASCULAR SYSTEM.Myocardial Infarction: NECROSIS of the MYOCARDIUM caused by an obstruction of the blood supply to the heart (CORONARY CIRCULATION).Cardiac Volume: The volume of the HEART, usually relating to the volume of BLOOD contained within it at various periods of the cardiac cycle. The amount of blood ejected from a ventricle at each beat is STROKE VOLUME.Ventricular Remodeling: The geometric and structural changes that the HEART VENTRICLES undergo, usually following MYOCARDIAL INFARCTION. It comprises expansion of the infarct and dilatation of the healthy ventricle segments. While most prevalent in the left ventricle, it can also occur in the right ventricle.Heart Transplantation: The transference of a heart from one human or animal to another.Troponin I: One of the three polypeptide chains that make up the TROPONIN complex. It inhibits F-actin-myosin interactions.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 Defects, Congenital: Developmental abnormalities involving structures of the heart. These defects are present at birth but may be discovered later in life.Stroke Volume: The amount of BLOOD pumped out of the HEART per beat, not to be confused with cardiac output (volume/time). It is calculated as the difference between the end-diastolic volume and the end-systolic volume.Blood Pressure: PRESSURE of the BLOOD on the ARTERIES and other BLOOD VESSELS.Cardiac Resynchronization Therapy: The restoration of the sequential order of contraction and relaxation of the HEART ATRIA and HEART VENTRICLES by atrio-biventricular pacing.Heart Function Tests: Examinations used to diagnose and treat heart conditions.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.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.Cardiopulmonary Resuscitation: The artificial substitution of heart and lung action as indicated for HEART ARREST resulting from electric shock, DROWNING, respiratory arrest, or other causes. The two major components of cardiopulmonary resuscitation are artificial ventilation (RESPIRATION, ARTIFICIAL) and closed-chest CARDIAC MASSAGE.Heart Neoplasms: Tumors in any part of the heart. They include primary cardiac tumors and metastatic tumors to the heart. Their interference with normal cardiac functions can cause a wide variety of symptoms including HEART FAILURE; CARDIAC ARRHYTHMIAS; or EMBOLISM.Cardiac Care Facilities: Institutions specializing in the care of patients with heart disorders.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)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.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.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).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).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.Cardiac Electrophysiology: The study of the electrical activity and characteristics of the HEART; MYOCARDIUM; and CARDIOMYOCYTES.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.Fibrosis: Any pathological condition where fibrous connective tissue invades any organ, usually as a consequence of inflammation or other injury.Rats, Sprague-Dawley: A strain of albino rat used widely for experimental purposes because of its calmness and ease of handling. It was developed by the Sprague-Dawley Animal Company.Fetal Heart: The heart of the fetus of any viviparous animal. It refers to the heart in the postembryonic period and is differentiated from the embryonic heart (HEART/embryology) only on the basis of time.Calcium: A basic element found in nearly all organized tissues. It is a member of the alkaline earth family of metals with the atomic symbol Ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes.Heart Atria: The chambers of the heart, to which the BLOOD returns from the circulation.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.Ventricular Function: The hemodynamic and electrophysiological action of the HEART VENTRICLES.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.Cells, Cultured: Cells propagated in vitro in special media conducive to their growth. Cultured cells are used to study developmental, morphologic, metabolic, physiologic, and genetic processes, among others.Heart Injuries: General or unspecified injuries to the heart.Cardiopulmonary Bypass: Diversion of the flow of blood from the entrance of the right atrium directly to the aorta (or femoral artery) via an oxygenator thus bypassing both the heart and lungs.Troponin: One of the minor protein components of skeletal muscle. Its function is to serve as the calcium-binding component in the troponin-tropomyosin B-actin-myosin complex by conferring calcium sensitivity to the cross-linked actin and myosin filaments.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.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.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.Mice, Transgenic: Laboratory mice that have been produced from a genetically manipulated EGG or EMBRYO, MAMMALIAN.Isoproterenol: Isopropyl analog of EPINEPHRINE; beta-sympathomimetic that acts on the heart, bronchi, skeletal muscle, alimentary tract, etc. It is used mainly as bronchodilator and heart stimulant.Sarcomeres: The repeating contractile units of the MYOFIBRIL, delimited by Z bands along its length.Atrial Natriuretic Factor: A potent natriuretic and vasodilatory peptide or mixture of different-sized low molecular weight PEPTIDES derived from a common precursor and secreted mainly by the HEART ATRIUM. All these peptides share a sequence of about 20 AMINO ACIDS.Muscle Proteins: The protein constituents of muscle, the major ones being ACTINS and MYOSINS. More than a dozen accessory proteins exist including TROPONIN; TROPOMYOSIN; and DYSTROPHIN.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.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.Mitochondria, Heart: The mitochondria of the myocardium.Heart Valves: Flaps of tissue that prevent regurgitation of BLOOD from the HEART VENTRICLES to the HEART ATRIA or from the PULMONARY ARTERIES or AORTA to the ventricles.Pericardium: A conical fibro-serous sac surrounding the HEART and the roots of the great vessels (AORTA; VENAE CAVAE; PULMONARY ARTERY). Pericardium consists of two sacs: the outer fibrous pericardium and the inner serous pericardium. The latter consists of an outer parietal layer facing the fibrous pericardium, and an inner visceral layer (epicardium) resting next to the heart, and a pericardial cavity between these two layers.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.Rats, Wistar: A strain of albino rat developed at the Wistar Institute that has spread widely at other institutions. This has markedly diluted the original strain.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).Edema, Cardiac: Abnormal fluid retention by the body due to impaired cardiac function or heart failure. It is usually characterized by increase in venous and capillary pressure, and swollen legs when standing. It is different from the generalized edema caused by renal dysfunction (NEPHROTIC SYNDROME).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.Mice, Inbred C57BLMagnetic Resonance Imaging, Cine: A type of imaging technique used primarily in the field of cardiology. By coordinating the fast gradient-echo MRI sequence with retrospective ECG-gating, numerous short time frames evenly spaced in the cardiac cycle are produced. These images are laced together in a cinematic display so that wall motion of the ventricles, valve motion, and blood flow patterns in the heart and great vessels can be visualized.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.Ventricular Fibrillation: A potentially lethal cardiac arrhythmia that is characterized by uncoordinated extremely rapid firing of electrical impulses (400-600/min) in HEART VENTRICLES. Such asynchronous ventricular quivering or fibrillation prevents any effective cardiac output and results in unconsciousness (SYNCOPE). It is one of the major electrocardiographic patterns seen with CARDIAC ARREST.Animals, Newborn: Refers to animals in the period of time just after birth.Coronary Circulation: The circulation of blood through the CORONARY VESSELS of the HEART.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.Myocardial Reperfusion Injury: Damage to the MYOCARDIUM resulting from MYOCARDIAL REPERFUSION (restoration of blood flow to ischemic areas of the HEART.) Reperfusion takes place when there is spontaneous thrombolysis, THROMBOLYTIC THERAPY, collateral flow from other coronary vascular beds, or reversal of vasospasm.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).Mice, Knockout: Strains of mice in which certain GENES of their GENOMES have been disrupted, or "knocked-out". To produce knockouts, using RECOMBINANT DNA technology, the normal DNA sequence of the gene being studied is altered to prevent synthesis of a normal gene product. Cloned cells in which this DNA alteration is successful are then injected into mouse EMBRYOS to produce chimeric mice. The chimeric mice are then bred to yield a strain in which all the cells of the mouse contain the disrupted gene. Knockout mice are used as EXPERIMENTAL ANIMAL MODELS for diseases (DISEASE MODELS, ANIMAL) and to clarify the functions of the genes.Ventricular Pressure: The pressure within a CARDIAC VENTRICLE. Ventricular pressure waveforms can be measured in the beating heart by catheterization or estimated using imaging techniques (e.g., DOPPLER ECHOCARDIOGRAPHY). The information is useful in evaluating the function of the MYOCARDIUM; CARDIAC VALVES; and PERICARDIUM, particularly with simultaneous measurement of other (e.g., aortic or atrial) pressures.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)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.Sarcolemma: The excitable plasma membrane of a muscle cell. (Glick, Glossary of Biochemistry and Molecular Biology, 1990)Myosin Heavy Chains: The larger subunits of MYOSINS. The heavy chains have a molecular weight of about 230 kDa and each heavy chain is usually associated with a dissimilar pair of MYOSIN LIGHT CHAINS. The heavy chains possess actin-binding and ATPase activity.Coronary Vessels: The veins and arteries of the HEART.Signal Transduction: The intracellular transfer of information (biological activation/inhibition) through a signal pathway. In each signal transduction system, an activation/inhibition signal from a biologically active molecule (hormone, neurotransmitter) is mediated via the coupling of a receptor/enzyme to a second messenger system or to an ion channel. Signal transduction plays an important role in activating cellular functions, cell differentiation, and cell proliferation. Examples of signal transduction systems are the GAMMA-AMINOBUTYRIC ACID-postsynaptic receptor-calcium ion channel system, the receptor-mediated T-cell activation pathway, and the receptor-mediated activation of phospholipases. Those coupled to membrane depolarization or intracellular release of calcium include the receptor-mediated activation of cytotoxic functions in granulocytes and the synaptic potentiation of protein kinase activation. Some signal transduction pathways may be part of larger signal transduction pathways; for example, protein kinase activation is part of the platelet activation signal pathway.Thermodilution: Measurement of blood flow based on induction at one point of the circulation of a known change in the intravascular heat content of flowing blood and detection of the resultant change in temperature at a point downstream.Diastole: Post-systolic relaxation of the HEART, especially the HEART VENTRICLES.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.GATA4 Transcription Factor: A GATA transcription factor that is expressed in the MYOCARDIUM of developing heart and has been implicated in the differentiation of CARDIAC MYOCYTES. GATA4 is activated by PHOSPHORYLATION and regulates transcription of cardiac-specific genes.Ventricular Dysfunction: A condition in which HEART VENTRICLES exhibit impaired function.Thoracic Surgery: A surgical specialty concerned with diagnosis and treatment of disorders of the heart, lungs, and esophagus. Two major types of thoracic surgery are classified as pulmonary and cardiovascular.Systole: Period of contraction of the HEART, especially of the HEART VENTRICLES.Pericardial Effusion: Fluid accumulation within the PERICARDIUM. Serous effusions are associated with pericardial diseases. Hemopericardium is associated with trauma. Lipid-containing effusion (chylopericardium) results from leakage of THORACIC DUCT. Severe cases can lead to CARDIAC TAMPONADE.NAV1.5 Voltage-Gated Sodium Channel: A voltage-gated sodium channel subtype that mediates the sodium ion PERMEABILITY of CARDIOMYOCYTES. Defects in the SCN5A gene, which codes for the alpha subunit of this sodium channel, are associated with a variety of CARDIAC DISEASES that result from loss of sodium channel function.Rabbits: The species Oryctolagus cuniculus, in the family Leporidae, order LAGOMORPHA. Rabbits are born in burrows, furless, and with eyes and ears closed. In contrast with HARES, rabbits have 22 chromosome pairs.Endomyocardial Fibrosis: A condition characterized by the thickening of the ventricular ENDOCARDIUM and subendocardium (MYOCARDIUM), seen mostly in children and young adults in the TROPICAL CLIMATE. The fibrous tissue extends from the apex toward and often involves the HEART VALVES causing restrictive blood flow into the respective ventricles (CARDIOMYOPATHY, RESTRICTIVE).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.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.RNA, Messenger: RNA sequences that serve as templates for protein synthesis. Bacterial mRNAs are generally primary transcripts in that they do not require post-transcriptional processing. Eukaryotic mRNA is synthesized in the nucleus and must be exported to the cytoplasm for translation. Most eukaryotic mRNAs have a sequence of polyadenylic acid at the 3' end, referred to as the poly(A) tail. The function of this tail is not known for certain, but it may play a role in the export of mature mRNA from the nucleus as well as in helping stabilize some mRNA molecules by retarding their degradation in the cytoplasm.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.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.Electrophysiologic Techniques, Cardiac: Methods to induce and measure electrical activities at specific sites in the heart to diagnose and treat problems with the heart's electrical system.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.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.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.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.Vascular Resistance: The force that opposes the flow of BLOOD through a vascular bed. It is equal to the difference in BLOOD PRESSURE across the vascular bed divided by the CARDIAC OUTPUT.Oxygen Consumption: The rate at which oxygen is used by a tissue; microliters of oxygen STPD used per milligram of tissue per hour; the rate at which oxygen enters the blood from alveolar gas, equal in the steady state to the consumption of oxygen by tissue metabolism throughout the body. (Stedman, 25th ed, p346)Action Potentials: Abrupt changes in the membrane potential that sweep along the CELL MEMBRANE of excitable cells in response to excitation stimuli.Muscle Cells: Mature contractile cells, commonly known as myocytes, that form one of three kinds of muscle. The three types of muscle cells are skeletal (MUSCLE FIBERS, SKELETAL), cardiac (MYOCYTES, CARDIAC), and smooth (MYOCYTES, SMOOTH MUSCLE). They are derived from embryonic (precursor) muscle cells called MYOBLASTS.Coronary Artery Disease: Pathological processes of CORONARY ARTERIES that may derive from a congenital abnormality, atherosclerotic, or non-atherosclerotic cause.Myofibrils: The long cylindrical contractile organelles of STRIATED MUSCLE cells composed of ACTIN FILAMENTS; MYOSIN filaments; and other proteins organized in arrays of repeating units called SARCOMERES .Sarcoplasmic Reticulum Calcium-Transporting ATPases: Calcium-transporting ATPases that catalyze the active transport of CALCIUM into the SARCOPLASMIC RETICULUM vesicles from the CYTOPLASM. They are primarily found in MUSCLE CELLS and play a role in the relaxation of MUSCLES.Resuscitation: The restoration to life or consciousness of one apparently dead. (Dorland, 27th ed)Endocardium: The innermost layer of the heart, comprised of endothelial cells.Adrenergic beta-Agonists: Drugs that selectively bind to and activate beta-adrenergic receptors.Troponin C: One of the three polypeptide chains that make up the TROPONIN complex of skeletal muscle. It is a calcium-binding protein.Vagus Nerve: The 10th cranial nerve. The vagus is a mixed nerve which contains somatic afferents (from skin in back of the ear and the external auditory meatus), visceral afferents (from the pharynx, larynx, thorax, and abdomen), parasympathetic efferents (to the thorax and abdomen), and efferents to striated muscle (of the larynx and pharynx).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.Ventricular Myosins: Isoforms of MYOSIN TYPE II, specifically found in the ventricular muscle of the HEART. Defects in the genes encoding ventricular myosins result in FAMILIAL HYPERTROPHIC CARDIOMYOPATHY.Receptors, Adrenergic, beta: One of two major pharmacologically defined classes of adrenergic receptors. The beta adrenergic receptors play an important role in regulating CARDIAC MUSCLE contraction, SMOOTH MUSCLE relaxation, and GLYCOGENOLYSIS.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.Organ Size: The measurement of an organ in volume, mass, or heaviness.Death: Irreversible cessation of all bodily functions, manifested by absence of spontaneous breathing and total loss of cardiovascular and cerebral functions.Cardiac Resynchronization Therapy Devices: Types of artificial pacemakers with implantable leads to be placed at multiple intracardial sites. They are used to treat various cardiac conduction disturbances which interfere with the timing of contraction of the ventricles. They may or may not include defibrillating electrodes (IMPLANTABLE DEFIBRILLATORS) as well.Ryanodine Receptor Calcium Release Channel: A tetrameric calcium release channel in the SARCOPLASMIC RETICULUM membrane of SMOOTH MUSCLE CELLS, acting oppositely to SARCOPLASMIC RETICULUM CALCIUM-TRANSPORTING ATPASES. It is important in skeletal and cardiac excitation-contraction coupling and studied by using RYANODINE. Abnormalities are implicated in CARDIAC ARRHYTHMIAS and MUSCULAR DISEASES.Advanced Cardiac Life Support: The use of sophisticated methods and equipment to treat cardiopulmonary arrest. Advanced Cardiac Life Support (ACLS) includes the use of specialized equipment to maintain the airway, early defibrillation and pharmacological therapy.Myxoma: A benign neoplasm derived from connective tissue, consisting chiefly of polyhedral and stellate cells that are loosely embedded in a soft mucoid matrix, thereby resembling primitive mesenchymal tissue. It occurs frequently intramuscularly where it may be mistaken for a sarcoma. It appears also in the jaws and the skin. (From Stedman, 25th ed)Papillary Muscles: Conical muscular projections from the walls of the cardiac ventricles, attached to the cusps of the atrioventricular valves by the chordae tendineae.Coronary Angiography: Radiography of the vascular system of the heart muscle after injection of a contrast medium.Angiotensin II: An octapeptide that is a potent but labile vasoconstrictor. It is produced from angiotensin I after the removal of two amino acids at the C-terminal by ANGIOTENSIN CONVERTING ENZYME. The amino acid in position 5 varies in different species. To block VASOCONSTRICTION and HYPERTENSION effect of angiotensin II, patients are often treated with ACE INHIBITORS or with ANGIOTENSIN II TYPE 1 RECEPTOR BLOCKERS.Dose-Response Relationship, Drug: The relationship between the dose of an administered drug and the response of the organism to the drug.Calcium Channels, L-Type: Long-lasting voltage-gated CALCIUM CHANNELS found in both excitable and nonexcitable tissue. They are responsible for normal myocardial and vascular smooth muscle contractility. Five subunits (alpha-1, alpha-2, beta, gamma, and delta) make up the L-type channel. The alpha-1 subunit is the binding site for calcium-based antagonists. Dihydropyridine-based calcium antagonists are used as markers for these binding sites.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).Purkinje Fibers: Modified cardiac muscle fibers composing the terminal portion of the heart conduction system.3-Iodobenzylguanidine: A guanidine analog with specific affinity for tissues of the sympathetic nervous system and related tumors. The radiolabeled forms are used as antineoplastic agents and radioactive imaging agents. (Merck Index, 12th ed) MIBG serves as a neuron-blocking agent which has a strong affinity for, and retention in, the adrenal medulla and also inhibits ADP-ribosyltransferase.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.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.Guinea Pigs: A common name used for the genus Cavia. The most common species is Cavia porcellus which is the domesticated guinea pig used for pets and biomedical research.Heart Valve Diseases: Pathological conditions involving any of the various HEART VALVES and the associated structures (PAPILLARY MUSCLES and CHORDAE TENDINEAE).Sodium Channels: Ion channels that specifically allow the passage of SODIUM ions. A variety of specific sodium channel subtypes are involved in serving specialized functions such as neuronal signaling, CARDIAC MUSCLE contraction, and KIDNEY function.Cardiovascular System: The HEART and the BLOOD VESSELS by which BLOOD is pumped and circulated through the body.Electric Countershock: An electrical current applied to the HEART to terminate a disturbance of its rhythm, ARRHYTHMIAS, CARDIAC. (Stedman, 25th ed)Gene Expression Regulation: Any of the processes by which nuclear, cytoplasmic, or intercellular factors influence the differential control (induction or repression) of gene action at the level of transcription or translation.Myosins: A diverse superfamily of proteins that function as translocating proteins. They share the common characteristics of being able to bind ACTINS and hydrolyze MgATP. Myosins generally consist of heavy chains which are involved in locomotion, and light chains which are involved in regulation. Within the structure of myosin heavy chain are three domains: the head, the neck and the tail. The head region of the heavy chain contains the actin binding domain and MgATPase domain which provides energy for locomotion. The neck region is involved in binding the light-chains. The tail region provides the anchoring point that maintains the position of the heavy chain. The superfamily of myosins is organized into structural classes based upon the type and arrangement of the subunits they contain.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.Norepinephrine: Precursor of epinephrine that is secreted by the adrenal medulla and is a widespread central and autonomic neurotransmitter. Norepinephrine is the principal transmitter of most postganglionic sympathetic fibers and of the diffuse projection system in the brain arising from the locus ceruleus. It is also found in plants and is used pharmacologically as a sympathomimetic.Sodium-Calcium Exchanger: An electrogenic ion exchange protein that maintains a steady level of calcium by removing an amount of calcium equal to that which enters the cells. It is widely distributed in most excitable membranes, including the brain and heart.Defibrillators: Cardiac electrical stimulators that apply brief high-voltage electroshocks to the HEART. These stimulators are used to restore normal rhythm and contractile function in hearts of patients who are experiencing VENTRICULAR FIBRILLATION or ventricular tachycardia (TACHYCARDIA, VENTRICULAR) that is not accompanied by a palpable PULSE. Some defibrillators may also be used to correct certain noncritical dysrhythmias (called synchronized defibrillation or CARDIOVERSION), using relatively low-level discharges synchronized to the patient's ECG waveform. (UMDNS, 2003)Hypothermia, Induced: Abnormally low BODY TEMPERATURE that is intentionally induced in warm-blooded animals by artificial means. In humans, mild or moderate hypothermia has been used to reduce tissue damages, particularly after cardiac or spinal cord injuries and during subsequent surgeries.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.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.Cardiology: The study of the heart, its physiology, and its functions.Emergency Medical Services: Services specifically designed, staffed, and equipped for the emergency care of patients.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)Electrophysiology: The study of the generation and behavior of electrical charges in living organisms particularly the nervous system and the effects of electricity on living organisms.Calcium Signaling: Signal transduction mechanisms whereby calcium mobilization (from outside the cell or from intracellular storage pools) to the cytoplasm is triggered by external stimuli. Calcium signals are often seen to propagate as waves, oscillations, spikes, sparks, or puffs. The calcium acts as an intracellular messenger by activating calcium-responsive proteins.Models, Animal: Non-human animals, selected because of specific characteristics, for use in experimental research, teaching, or testing.Heart Massage: Rhythmic compression of the heart by pressure applied manually over the sternum (closed heart massage) or directly to the heart through an opening in the chest wall (open heart massage). It is done to reinstate and maintain circulation. (Dorland, 28th ed)Cardiac-Gated Imaging Techniques: Timing the acquisition of imaging data to specific points in the cardiac cycle to minimize image blurring and other motion artifacts.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.Calcium-Binding Proteins: Proteins to which calcium ions are bound. They can act as transport proteins, regulator proteins, or activator proteins. They typically contain EF HAND MOTIFS.Gene Expression: The phenotypic manifestation of a gene or genes by the processes of GENETIC TRANSCRIPTION and GENETIC TRANSLATION.Rhabdomyoma: A benign tumor derived from striated muscle. It is extremely rare, generally occurring in the tongue, neck muscles, larynx, uvula, nasal cavity, axilla, vulva, and heart. These tumors are treated by simple excision. (Dorland, 27th ed; DeVita Jr et al., Cancer: Principles & Practice of Oncology, 3d ed, p1354)Perfusion: Treatment process involving the injection of fluid into an organ or tissue.Cardiography, Impedance: A type of impedance plethysmography in which bioelectrical impedance is measured between electrodes positioned around the neck and around the lower thorax. It is used principally to calculate stroke volume and cardiac volume, but it is also related to myocardial contractility, thoracic fluid content, and circulation to the extremities.Death, Sudden: The abrupt cessation of all vital bodily functions, manifested by the permanent loss of total cerebral, respiratory, and cardiovascular functions.Cardiovascular Agents: Agents that affect the rate or intensity of cardiac contraction, blood vessel diameter, or blood volume.Phosphorylation: The introduction of a phosphoryl group into a compound through the formation of an ester bond between the compound and a phosphorus moiety.Phenotype: The outward appearance of the individual. It is the product of interactions between genes, and between the GENOTYPE and the environment.Blood Circulation: The movement of the BLOOD as it is pumped through the CARDIOVASCULAR SYSTEM.Swine: Any of various animals that constitute the family Suidae and comprise stout-bodied, short-legged omnivorous mammals with thick skin, usually covered with coarse bristles, a rather long mobile snout, and small tail. Included are the genera Babyrousa, Phacochoerus (wart hogs), and Sus, the latter containing the domestic pig (see SUS SCROFA).Muscle, Skeletal: A subtype of striated muscle, attached by TENDONS to the SKELETON. Skeletal muscles are innervated and their movement can be consciously controlled. They are also called voluntary muscles.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.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.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.Postoperative Period: The period following a surgical operation.Membrane Potentials: The voltage differences across a membrane. For cellular membranes they are computed by subtracting the voltage measured outside the membrane from the voltage measured inside the membrane. They result from differences of inside versus outside concentration of potassium, sodium, chloride, and other ions across cells' or ORGANELLES membranes. For excitable cells, the resting membrane potentials range between -30 and -100 millivolts. Physical, chemical, or electrical stimuli can make a membrane potential more negative (hyperpolarization), or less negative (depolarization).Fibroblasts: Connective tissue cells which secrete an extracellular matrix rich in collagen and other macromolecules.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.Diabetic Cardiomyopathies: Diabetes complications in which VENTRICULAR REMODELING in the absence of CORONARY ATHEROSCLEROSIS and hypertension results in cardiac dysfunctions, typically LEFT VENTRICULAR DYSFUNCTION. The changes also result in myocardial hypertrophy, myocardial necrosis and fibrosis, and collagen deposition due to impaired glucose tolerance.Cardiac Output, High: A state of elevated cardiac output due to conditions of either increased hemodynamic demand or reduced cardiac oxygen output. These conditions may include ANEMIA; ARTERIOVENOUS FISTULA; THYROTOXICOSIS; PREGNANCY; EXERCISE; FEVER; and ANOXIA. In time, compensatory changes of the heart can lead to pathological form of high cardiac output and eventual HEART FAILURE.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.Potassium Channels: Cell membrane glycoproteins that are selectively permeable to potassium ions. At least eight major groups of K channels exist and they are made up of dozens of different subunits.Blotting, Western: Identification of proteins or peptides that have been electrophoretically separated by blot transferring from the electrophoresis gel to strips of nitrocellulose paper, followed by labeling with antibody probes.Heart Arrest, Induced: A procedure to stop the contraction of MYOCARDIUM during HEART SURGERY. It is usually achieved with the use of chemicals (CARDIOPLEGIC SOLUTIONS) or cold temperature (such as chilled perfusate).Patch-Clamp Techniques: An electrophysiologic technique for studying cells, cell membranes, and occasionally isolated organelles. All patch-clamp methods rely on a very high-resistance seal between a micropipette and a membrane; the seal is usually attained by gentle suction. The four most common variants include on-cell patch, inside-out patch, outside-out patch, and whole-cell clamp. Patch-clamp methods are commonly used to voltage clamp, that is control the voltage across the membrane and measure current flow, but current-clamp methods, in which the current is controlled and the voltage is measured, are also used.

Differential effects of a segment of slow conduction on reentrant ventricular tachycardia in the rabbit heart. (1/3178)

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

Junctional ectopic tachycardia evolving into complete heart block. (2/3178)

Transition from congenital junctional ectopic tachycardia to complete AV block was observed in an 8 month old girl, over a 36 hour period, during initial hospital admission. Two years later she had evidence of a rapidly increasing left ventricular end diastolic diameter, associated with lowest heart rates during sleep of < 30 beats/min. A transvenous permanent pacemaker was therefore implanted. This finding supports the idea that a pathological process in the area of the AV junction, initially presenting as junctional ectopic tachycardia may later extend to sudden complete atrioventricular block.  (+info)

Regulation of sympathetic nerve activity in heart failure: a role for nitric oxide and angiotensin II. (3/3178)

The mechanisms by which sympathetic function is augmented in chronic heart failure (CHF) are not well understood. A previous study from this laboratory (Circ Res. 1998;82:496-502) indicated that blockade of nitric oxide (NO) synthesis resulted in only an increase in renal sympathetic nerve activity (RSNA) when plasma angiotensin II (Ang II) levels were elevated. The present study was undertaken to determine if NO reduces RSNA in rabbits with CHF when Ang II receptors are blocked. Twenty-four New Zealand White rabbits were instrumented with cardiac dimension crystals, a left ventricular pacing lead, and a pacemaker. After pacing at 360 to 380 bpm for approximately 3 weeks, a renal sympathetic nerve electrode and arterial and venous catheters were implanted. Studies were carried out in the conscious state 3 to 7 days after electrode implantation. The effects of a 1-hour infusion of sodium nitroprusside (SNP; 3 microgram . kg-1. min-1) on RSNA and mean arterial pressure (MAP) were determined before and after Ang II blockade with losartan (5 mg/kg) in normal and CHF rabbits. Changes in MAP were readjusted to normal with phenylephrine. Before losartan, SNP evoked a decrease in MAP and an increase in RSNA in both groups that was baroreflex-mediated, because both MAP and RSNA returned to control when phenylephrine was administered. In the normal group, losartan plus SNP caused a reduction in MAP and an increase in RSNA that was 152.6+/-9.8% of control. Phenylephrine returned both MAP and RSNA back to the control levels. However, in the CHF group, losartan plus SNP evoked a smaller change in RSNA for equivalent changes in MAP (117.1+/-4.1% of control). On returning MAP to the control level with phenylephrine, RSNA was reduced to 65.2+/-2.9% of control (P<0. 0001). These data suggest that endogenous Ang II contributes to the sympathoexcitation in the CHF state and that blockade of Ang II receptors plus providing an exogenous source of NO reduces RSNA below the elevated baseline levels. We conclude that both a loss of NO and an increase in Ang II are necessary for sustained increases in sympathetic nerve activity in the CHF state.  (+info)

Regional differences in the recovery course of tachycardia-induced changes of atrial electrophysiological properties. (4/3178)

BACKGROUND: Regional differences in recovery of tachycardia-induced changes of atrial electrophysiological properties have not been well studied. METHODS AND RESULTS: In the control group (5 dogs), atrial effective refractory period (AERP) and inducibility of atrial fibrillation (AF) were assessed before and every 4 hours for 48 hours after complete atrioventricular junction (AVJ) ablation with 8-week VVI pacing. In experimental group 1 (15 dogs), AERP and inducibility of AF were assessed before and after complete AVJ ablation with 8-week rapid right atrial (RA) pacing (780 bpm) and VVI pacing. In experimental group 2 (7 dogs), AERP and inducibility of AF were assessed before and after 8-week rapid left atrial (LA) pacing and VVI pacing. AERP and inducibility and duration of AF were obtained from 7 epicardial sites. In the control group, atrial electrophysiological properties obtained immediately and during 48-hour measurements after pacing did not show any change. In the 2 experimental groups, recovery of atrial electrophysiological properties included a progressive recovery of AERP shortening, recovery of AERP maladaptation, and decrease of duration and episodes of reinduced AF. However, recovery of shortening and maladaptation of AERP and inducibility of AF was slower at the LA than at the RA and Bachmann's bundle. CONCLUSIONS: The LA had a slower recovery of tachycardia-induced changes of atrial electrophysiological properties, and this might play a critical role in initiation of AF.  (+info)

Mapping propagation of mechanical activation in the paced heart with MRI tagging. (5/3178)

The temporal evolution of three-dimensional (3-D) strain maps derived from magnetic resonance imaging (MRI) tagging were used to noninvasively evaluate mechanical activation in the left ventricle (LV) while seven canine hearts were paced in situ from three different sites: the base of the LV free wall (LVb), the right ventricular apex (RVa), and the right atrium (RA). Strain maps plotted against time showed the evolution of shortening over the entire LV midwall and were used to generate mechanical activation maps showing the onset of circumferential shortening. RA pacing showed rapid synchronous shortening; LVb pacing showed a wave front of mechanical activation propagating slowly and steadily from the pacing site, whereas RVa pacing showed regions of rapid and slower propagation. The mechanical (M) activation times correlated linearly with the electrical (E) activation (M = 1.06E + 8.4 ms, R = 0.95). The time for 90% activation of the LV was 63.1 +/- 24.3 ms for RA pacing, 130.2 +/- 9.8 ms for LVb pacing, and 121.3 +/- 17.9 ms for RVa pacing. The velocity of mechanical activation was calculated for LVb and RVa pacing and was similar to values reported for electrical conduction in myocardium. The propagation of mechanical activation for RVa pacing showed regional variations, whereas LVb pacing did not.  (+info)

Mechanism linking T-wave alternans to the genesis of cardiac fibrillation. (6/3178)

BACKGROUND: Although T-wave alternans has been closely associated with vulnerability to ventricular arrhythmias, the cellular processes underlying T-wave alternans and their role, if any, in the mechanism of reentry remain unclear. METHODS AND RESULTS: -T-wave alternans on the surface ECG was elicited in 8 Langendorff-perfused guinea pig hearts during fixed-rate pacing while action potentials were recorded simultaneously from 128 epicardial sites with voltage-sensitive dyes. Alternans of the repolarization phase of the action potential was observed above a critical threshold heart rate (HR) (209+/-46 bpm) that was significantly lower (by 57+/-36 bpm) than the HR threshold for alternation of action potential depolarization. The magnitude (range, 2.7 to 47.0 mV) and HR threshold (range, 171 to 272 bpm) of repolarization alternans varied substantially between cells across the epicardial surface. T-wave alternans on the surface ECG was explained primarily by beat-to-beat alternation in the time course of cellular repolarization. Above a critical HR, membrane repolarization alternated with the opposite phase between neighboring cells (ie, discordant alternans), creating large spatial gradients of repolarization. In the presence of discordant alternans, a small acceleration of pacing cycle length produced a characteristic sequence of events: (1) unidirectional block of an impulse propagating against steep gradients of repolarization, (2) reentrant propagation, and (3) the initiation of ventricular fibrillation. CONCLUSIONS: Repolarization alternans at the level of the single cell accounts for T-wave alternans on the surface ECG. Discordant alternans produces spatial gradients of repolarization of sufficient magnitude to cause unidirectional block and reentrant ventricular fibrillation. These data establish a mechanism linking T-wave alternans of the ECG to the pathogenesis of sudden cardiac death.  (+info)

Atrioventricular nodal ablation and implantation of mode switching dual chamber pacemakers: effective treatment for drug refractory paroxysmal atrial fibrillation. (7/3178)

OBJECTIVE: To assess the effect of atrioventricular node ablation and implantation of a dual chamber, mode switching pacemaker on quality of life, exercise capacity, and left ventricular systolic function in patients with drug refractory paroxysmal atrial fibrillation. PATIENTS: 18 consecutive patients with drug refractory paroxysmal atrial fibrillation. METHODS: Quality of life was assessed before and after the procedure using the psychological general wellbeing index (PGWB), the McMaster health index (MHI), and a visual analogue scale for cardiac symptoms. Nine of the patients also underwent symptom limited exercise tests and echocardiography to assess left ventricular systolic function. RESULTS: The procedure allowed a reduction in antiarrhythmic drug treatment (p < 0.01). PGWB and symptom scores improved (p < 0.01) but the MHI score did not change. Left ventricular systolic function and exercise capacity were unchanged. CONCLUSIONS: Atrioventricular node ablation and implantation of a DDDR/MS pacemaker is effective treatment for refractory paroxysmal atrial fibrillation, producing improved quality of life while allowing a reduction in drug burden. The popularity of the treatment is justified, but further studies are needed to determine optimum timing of intervention.  (+info)

Predictors of atrial rhythm after atrioventricular node ablation for the treatment of paroxysmal atrial arrhythmias. (8/3178)

OBJECTIVE: To assess the natural history of the atrial rhythm of patients with paroxysmal atrial arrhythmias undergoing atrioventricular node ablation and permanent pacemaker implantation. DESIGN AND SETTING: A retrospective cohort study of consecutive patients identified from the pacemaker database and electrophysiology records of a tertiary referral hospital. PATIENTS: 62 consecutive patients with paroxysmal atrial arrhythmias undergoing atrioventricular node ablation and permanent pacemaker implantation between 1988 and July 1996. MAIN OUTCOME MEASURES: (1) Atrial rhythm on final follow up ECG, classified as either ordered (sinus rhythm or atrial pacing) or disordered (atrial fibrillation, atrial flutter or atrial tachycardia). (2) Chronic atrial fibrillation, defined as a disordered rhythm on two consecutive ECGs (or throughout a 24 hour Holter recording) with no ordered rhythm subsequently documented. RESULTS: Survival analysis showed that 75% of patients progressed to chronic atrial fibrillation by 2584 days (86 months). On multiple logistic regression analysis a history of electrical cardioversion, increasing patient age, and VVI pacing were associated with the development of chronic atrial fibrillation. A history of electrical cardioversion and increasing patient age were associated with a disordered atrial rhythm on the final follow up ECG. CONCLUSIONS: Patients with paroxysmal atrial arrhythmias are at high risk of developing chronic atrial fibrillation. A history of direct current cardioversion.  (+info)

*John Alexander MacWilliam

Cardiac pacemaker therapy would not become reality in clinical medicine until the 1950s (transthoracic and temporary pacing) ... cardiac arrest) by causing "artificial excitation" with a series of induction shocks (rather than using constant strong ... and the 1960s (permanent pacing). During the 1960s the care of patients who suffered cardiac arrest or were thought to be at ... such as in the artificial cardiac pacemaker. MacWilliam was appointed Regius Professor of the Institutes of Medicine (later ...

*Pacing

... generally in the sense of artificial methods: Artificial pacemaker, a medical device Transcutaneous pacing, a means of making ... an energy management strategy used to manage symptoms of chronic fatigue syndrome Cardiac pacing, regulation of the heart rate ... Pacing may refer to: Pacing, an athletic technique of spreading one's effort out over longer-distance track and field and ... a means of estimating distances by counting the number of paces taken to walk a traverse Pacing, a technique in hypnosis and ...

*International Clinical Research Center

Cardiac and central nervous system electrophysiology and pacing: the development of advanced electrophysiology technologies for ... the development of novel artificial biological valves and other tissues NEUROLOGICAL PROGRAMS Neuro I - Cerebrovascular ... cardiac arrhythmias, obesity, structural heart diseases, sleep apnea, stroke, and dementia. The center located in Brno, Czech ... the development of novel technologies for advanced assessment of cardiac and brain electrophysiology Cardio V - Non-invasive ...

*Cardiac pacemaker

Sometimes an ectopic pacemaker sets the pace, if the SA node is damaged or if the electrical conduction system of the heart has ... In humans, and occasionally in animals, a mechanical device called an artificial pacemaker (or simply "pacemaker") may be used ... The contraction of cardiac muscle (heart muscle) in all animals is initiated by electrical impulses known as action potentials ... The rate at which these impulses fire controls the rate of cardiac contraction, that is, the heart rate. The cells that create ...

*Artificial cardiac pacemaker

Transvenous pacing (temporary)Edit. Main article: Transvenous pacing. Transvenous pacing, when used for temporary pacing, is an ... Transcutaneous pacingEdit. Main article: Transcutaneous pacing. Transcutaneous pacing (TCP), also called external pacing, is ... This is known as fast-pacing, overdrive pacing, or anti-tachycardia pacing (ATP). ATP is only effective if the underlying ... One lead paces the atrium and one paces the ventricle. This type more closely resembles the natural pacing of the heart by ...

*Heritage turkey

Consequently, the birds are so heavy that they are completely incapable of reproducing without artificial insemination, and ... cardiac, respiratory and leg problems. For over 35 years, the overwhelming majority of the 280 million turkeys produced in ... they reach such extreme weights so quickly their overall development fails to keep pace with their rapidly accruing muscle mass ... can reproduce without artificial insemination. More than ten different turkey breeds are classified as heritage turkeys, ...

*Third-degree atrioventricular block

Third-degree AV block can be treated by use of a dual-chamber artificial pacemaker. This type of device typically listens for a ... If these fail to respond to atropine or there is a potential risk of asystole, transvenous pacing is indicated. The risk ... Cardiac pacemaker Electrical conduction system of the heart Electrocardiogram (ECG) Atrioventricular block First-degree AV ... Mobitz Type 2 AV block is another indication for pacing. As with other forms of heart block, secondary prevention may also ...

*Artificial cardiac pacemaker

One lead paces the atrium and one paces the ventricle. This type more closely resembles the natural pacing of the heart by ... Transvenous pacing, when used for temporary pacing, is an alternative to transcutaneous pacing. A pacemaker wire is placed into ... This is known as fast-pacing, overdrive pacing, or anti-tachycardia pacing (ATP). ATP is only effective if the underlying ... North American Society of Pacing and Electrophysiology/British Pacing and Electrophysiology Group". Pacing Clin Electrophysiol ...

*Cardiac contractility modulation

Heart Cardiac cycle Heart failure Artificial cardiac pacemaker Implantable cardioverter-defibrillator NYHA classification ... Mond, H.G.; Proclemer, A. (Aug 2011). "The 11th world survey of cardiac pacing and implantable cardioverter-defibrillators: ... Since Cardiac contractility modulation signals are delivered during the absolute refractory period of the cardiac cycle, they ... In Cardiac contractility modulation therapy, electrical stimulation is applied to the cardiac muscle during the absolute ...

*Albert Hyman

Aquilina O, "A brief history of cardiac pacing Archived 2007-05-17 at the Wayback Machine.", Images Paediatr Cardiol 27 (2006 ... The first artificial pacemaker was invented by Australian anaesthesiologist Dr Mark C Lidwell, and was used by him to ... However it was Hyman who used and popularised the term "artificial pacemaker", which remains in use to this day. Lidwell did ... Furman S, Szarka G, Layvand D, "Reconstruction of Hyman's second pacemaker", Pacing Clin. Electrophysiol. 2005, May;28(5) pp ...

*Plutonium bahasa Indonesia, ensiklopedia bebas

"Trends in Cardiac Pacemaker Batteries". Indian Pacing Electrophysiol. 4 (4): 201-212. PMID 16943934. PMC 1502062. Diakses ... "Artifical radioactivity produced by neutron bombardment: Noble Lecture" (PDF). Royal Swedish Academy of Sciences. ...

*Management of heart failure

... or less and a QRS interval of 120 ms or more may benefit from cardiac resynchronization therapy (CRT; pacing both the left and ... implantation of an artificial heart. These remain the recommended surgical treatment options. However, the limited number of ... Pacing, and Defibrillation in Heart Failure (COMPANION) Investigators. (2004). "Cardiac-resynchronization therapy with or ... Cardiac Resynchronization-Heart Failure (CARE-HF) Study Investigators. (2005). "The effect of cardiac resynchronization on ...

*Morton Mower

In 1989, Mower became Vice President of Medical Science at Cardiac Pacemakers Inc. in St. Paul, Minnesota. While at Cardiac ... Method and Apparatus to Allow Cyclic Pacing at an Average Rate Just Above the Intrinsic Heart Rate so as to Maximize Inotropic ... American Society for Artificial Internal Organs. *Maryland Society of Cardiology. *American Society for Internal Medicine ... Cardiac Pacemakers, Inc. (CPI), which has since become Guidant, acquired the rights to the AICD in May 1985. The first AICD was ...

*Wilfred Gordon Bigelow

Sealy, WC (May 1989). "Hypothermia: its possible role in cardiac surgery". The Annals of thoracic surgery. 47 (5): 788-91. PMID ... was a Canadian heart surgeon known for his role in developing the artificial pacemaker and the use of hypothermia in open heart ... From Cooling Hearts to Pacing Them Canadian Medical Hall of Fame. ...

*Aortic valve replacement

Aortic valve repair Artificial heart valve Valvular heart disease Minimally invasive cardiac surgery Pericardial heart valves ... Pacing wires are usually put in place, so that the heart can be manually paced should any complications arise after surgery. ... More recently, some cardiac surgeons have been performing aortic valve replacement procedures using an approach referred to as ... These are usually removed within 36 hours while the pacing wires are generally left in place until right before the patient is ...

*Sorin Group

... benefit from technological cross fertilization and to leverage its twenty years of experience in developing artificial cardiac ... since their development would have required massive investments in R&D to keep pace with technological evolution. Moreover, ... that was its main competitor in the cardiac surgery market. This acquisition propelled Sorin Biomedica to the top of the world ... specializing in cardiac devices. Its product lines include replacement heart valves, oxygenators, perfusion tubing sets, ...

*Electrophysiology

Program Southwestern Cardiac Arrhythmia Electrophysiology Institute Cleveland Clinic Cardiac Electrophysiology and Pacing ... A BERA sensor has two parts: The consumable biorecognition elements The electronic read-out device with embedded artificial ... Neuroscience portal Bioelectrochemistry Bioelectromagnetics Cardiac electrophysiology Clinical cardiac electrophysiology ... by embedding thousands of artificial receptors into the cell membrane. While not strictly constituting an experimental ...

*Richard Crevenna

PACE - Pacing and Clinical Electrophysiology, 26 (2 I), pp. 626-629 Crevenna, R., Posch, M., Sochor, A., Keilani, M., Wiesinger ... Artificial Organs, 28 (1), pp. 99-102 Crevenna, R., Stix, G., Pleiner, J., Pezawas, T., Schmidinger, H., Quittan, M., Wolzt, M ... Electrical nerve stimulation in patients with cardiac pacemakers (2001) Physikalische Medizin Rehabilitationsmedizin ...

*Amiodarone

A 2016 review, however, found that amiodarone did not improve survival or positive outcomes in those who had a cardiac arrest. ... So-called 'acute onset atrial fibrillation', defined by the North American Society of Pacing and Electrophysiology (NASPE) in ... and second or third degree heart block who do not have an artificial pacemaker. Individuals with baseline depressed lung ... Defibrillation is the treatment of choice for ventricular fibrillation (VF) and ventricular tachycardia resulting in cardiac ...

*Paul Zoll

Ann Surg 1961; 154:338 Zoll RH, Zoll PM, Belgard AH: Noninvasive cardiac stimulation. In Feruglio GA, editor: Cardiac Pacing: ... was a Jewish American cardiologist and one of the pioneers in the development of the artificial cardiac pacemaker and cardiac ... After the war, Paul resumed his research work with coronary disease and continued to care for cardiac patients at Beth Israel ... Safety and efficacy of noninvasive pacing. A preliminary report. N Engl J Med 1983; 309: 1166-70 Zoll PM. Resuscitation of the ...

*செயற்கை இதயமுடுக்கி - தமிழ் விக்கிப்பீடியா

"Percussion pacing in a three-year-old girl with complete heart block during cardiac catheterization". Br J Anaesth 95 (4): 465- ... ஒரு இதயமுடுக்கி (pacemaker) அல்லது செயற்கை இதயமுடுக்கி(artificial pacemaker), இதயத்துடைய இயற்கையான முடுக்கியுடன் தவறாக ... North American Society of Pacing and Electrophysiology/British Pacing and Electrophysiology Group". Pacing Clin Electrophysiol ... 3.0 3.1 Mond H, Sloman J, Edwards R (1982). "The first pacemaker". Pacing and clinical electrophysiology : PACE 5 (2): 278-82. ...

*Peter Sleight

... heart and with coils aligned on the outside skin of the patient to transfer the electrical charge from the Artificial cardiac ... PACE, SCOUT, RELY, ORIGIN, GISSI-HF, ONTARGET, TRANSCEND and PrOFESS. Recent research[when?] has assessed the prognostic value ... Sleight is accredited for being the first to carry out studies of the effect of Aspirin on cardiac function and stroke ... The patient had previously spent many months connected to a filing cabinet size artificial heart machine known as the "fire ...

*Peter Allen (physician)

In early 1957, he participated in the operation where the world's first artificial cardiac pacemaker was employed by Lillehei. ... Results of Demand Pacing in Cardiac Arrhythmias - Peter Allen M.D., Eve Rotem M.D. - Annals of Thoracic Surgery, 8:2, Page 146 ... A Cardiac Surgery Anthology by C. Walton Lillehei, Page 187 1957 to 1982 Open Cardiac Surgery in British Columbia" - In the ... In 1987 and 1989 Allen was the visiting cardiac surgeon at the Ibn-al;Bitar Hospital in Baghdad, Iraq. The Hospital was built ...

*Sinus rhythm

A sinus rhythm is any cardiac rhythm where depolarization of the cardiac muscle begins at the sinus node. It is characterised ... The sinus node should pace the heart - therefore, P waves must be round, all the same shape, and present before every QRS ... Exceptions to this include complete heart block and certain ventricular artificial pacemaker rhythms, where the P waves may be ... Sinus rhythms may be present together with various other cardiac arrhythmias on the same ECG. For an ECG to be described as ...

*Adrian Kantrowitz

... , Cardiac Pioneer, Dies at 90". The New York Times. p. A33. Retrieved November 19, 2008. "About Us". World ... The device included an external control unit that could adjust the pacing rate from 64 to 120 beats per minute to allow the ... In August 1971, he implanted an artificial heart booster in a 63-year-old man whose weakened heart could not pump sufficient ... In what turned out to be a four-way race between South African cardiac surgeon Dr. Christiaan Barnard and Americans Norman ...

*William P. Murphy Jr.

... including the first physiologic cardiac pacemaker; the widely used hollow fiber artificial kidney; the first disposable medical ... the Distinguished Service Award of the North American Society of Pacing and Electrophysiology (1985), American Institute of ... Murphy's physiologic cardiac pacemaker-which is used to treat heart block-senses what a patient's heart needs and provides ...

*Medical simulation

Additional capabilities are expected to help drive this use of simulation to become common, such as Artificial Intelligence (AI ... Responds to chest compressions, defibrillation and pacing, needle decompression, chest tube insertion and intraosseous ... Advanced Cardiac Life Support simulators[50]. *Partial Human Patient Simulator (Low tech) ... Responds to clinical interventions: chest compression, pacing, defibrillation, needle decompression, and chest tube insertion ...

*Do not resuscitate

Pacing and Clinical Electrophysiology. 38 (8): 917-924. doi:10.1111/pace.12614. CS1 maint: Multiple names: authors list (link ... One fifth of the DNR patients would want resuscitation for cardiac arrest but to have care withdrawn after a week. It is ... The New Jersey Supreme Court upheld the right of Karen Ann Quinlan's parents to order her removal from artificial ventilation. ... In the United States, cardiopulmonary resuscitation (CPR) and advanced cardiac life support (ACLS) will not be performed if a ...
The focus of this thesis is the development and application of personalised computational models of cardiac electromechanics to understand and ultimately inform cardiac resynchronisation therapy (CRT). To achieve this goal, a semi-automatic pipeline for the generation and parameterisation of detailed biophysically based models using clinical data is presented and applied to a cohort of patients. Specifically, an anatomically based finite element model has been developed and applied to simulate cardiac electromechanics through the coupling of the monodomain and large deformation mechanics governing frameworks. Techniques have been implemented for tting high order representations of cardiac anatomy from MRI data, and myocardial conductivity, sti ness, contractility and boundary conditions from endocardial activation recordings and pressure volume loops respectively. Embedding these tting steps within a semi-automatic pipeline, this personalisation work ow has been applied to four CRT patient data ...
A method and apparatus for selection of one or more ventricular chambers to stimulate for ventricular resynchronization therapy. Intrinsic intracardia electrograms that include QRS complexes, are recorded from a left and right ventricle. A timing relationship between the intrinsic intracardia electrograms recorded from the left and right ventricle is then determined. In one embodiment, the timing relationship is determined using a delay between a left ventricular and a right ventricular sensed intrinsic ventricular depolarizations and a duration interval of one or more QRS complexes. In one embodiment, the duration of QRS complexes is determined from either intracardiac electrograms or from surface ECG recordings. One or more ventricular chambers in which to provide pacing pulses are then selected based on the timing relationship between intrinsic intracardia electrograms recorded from the right and left ventricle, and the duration of one or more QRS complexes.
This study demonstrates that FMD predicts clinical response to CRT, is lower at baseline in non-responders, but that FMD predicts response at 6 and 12 months. There were no significant clinical differences between the responders and non-responders at baseline; all met the current guidelines for CRT implantation. If FMD is used at baseline to discriminate responders from non-responders, then non-responders may not be exposed to potential harms from a device they will ultimately not benefit from.. It is uncertain why responders at baseline should have lower FMD, as while patients with ischaemic cardiomyopathy often have worse endothelial function, it is patients with non-ischaemic cardiomyopathy who typically demonstrate a greater response to CRT.3 ,8 It is possible that differences in endothelial function, are a result of altered haemodynamics, peripheral shear stress, cardiac loading conditions and neurohormonal activation.4 Indeed, there was no significant difference in HF aetiology between ...
Medtronic has treated more than 140,000 heart failure patients with CRT, an implantable heart device that may improve the hearts ability to pump blood.
If patients could recognise themselves, or anyone else could recognise a patient from your description, please obtain the patients written consent to publication and send them to the editorial office before submitting your response [Patient consent forms] ...
Introduction Optimal left ventricular (LV) lead placement via the coronary sinus (CS) is a critical factor in defining response to cardiac resynchronisation therapy (CRT). Using novel semi-automated ... Heart, BCS Abstracts 2011, A Shetty, S Duckett, M Ginks, Y Ma, M Sohal, P Mehta, S Hamid, J Bostock, G Carr-White, K Rhode, R Razavi, C A Rinaldi ...
Introduction Optimal left ventricular (LV) lead placement via the coronary sinus (CS) is a critical factor in defining response to cardiac resynchronisation therapy (CRT). Using novel semi-automated ... Heart, BCS Abstracts 2011, A Shetty, S Duckett, M Ginks, Y Ma, M Sohal, P Mehta, S Hamid, J Bostock, G Carr-White, K Rhode, R Razavi, C A Rinaldi ...
cardiac resynchronisation therapy and non-invasive measurement of cardiac output, heart, heart failure, chest pain, irregular heart, cardiac, cardio-vascular, cardiothoracic, aorta, heart disease, pacemaker, electrophysiology, coronary, angioplasty, stenting
The Evia HF-T and the Entovis HF-T are triple-chamber pacemakers for cardiac resynchronisation therapy (CRT-P). The objective of this study is to prove the safety and efficacy of these pacemakers. In particular, the left ventricular (LV) capture control feature is evaluated, which automatically measures the LV pacing threshold and subsequently adjusts the pacing output ...
www.heartjnl.com. These articles scored the most hits on Hearts website during November 2007. 1 JBS 2: Joint British Societies guidelines on prevention of cardiovascular disease in clinical practice. December 2005;91(suppl V):1-52. (Supplement). 2 Optimal use of echocardiography in cardiac resynchronisation therapy. GB Bleeker, C-M Yu, P Nihoyannopoulos, J de Sutter, N Van de Veire, … ...
B I V E N T R I C U L A R PAC I N G I N PAT I E N T S W I T H H E A R T FA I LU R E A N D I N T R AV E N T R I C U L A R C O N D U C T I O N D E L AY EFFECTS OF MULTISITE BIVENTRICULAR PACING IN PATIENTS WITH HEART FAILURE AND INTRAVENTRICULAR CONDUCTION DELAY SERGE CAZEAU, M.D., CHRISTOPHE LECLERCQ, M.D., THOMAS LAVERGNE, M.D., STUART WALKER, M.D., CHETAN VARMA, M ...
Big thanks to bucknike1, our latest supporter!. Were 12 people from our target today. Why dont you be one of them?. You can support NG too and get tons of perks for just $2.99.. ...
Soufi, A. and Sawasdichai, A. and Shukla, A. and Noy, P. and Dafforn, T. and Smith, C. and Jayaraman, P.-S. and Gaston, K. (2010) DNA compaction by the higher-order assembly of PRH/Hex homeodomain protein oligomers. Nucleic Acids Research, 38 (21). p. 7513. ISSN 0305-1048. ...
Evidence-based recommendations on implantable cardioverter defibrillators (ICDs) and cardiac resynchronisation therapy (CRT) for arrhythmias and heart failure
Evidence-based recommendations on implantable cardioverter defibrillators (ICDs) and cardiac resynchronisation therapy (CRT) for arrhythmias and heart failure
Comparison of pharmacological treatment alone versus treatment combined with cardiac resynchronization therapy in patients over 75 years. Cruz, Elena; Cortés, Marcelino; Farré, Jerónimo; Palfy, Julia; Ávila, Paloma; Hernández, Ignacio; Romero, Angélica; Benezet, Juan; Franco, Juan; Navas, Miguel; Hernandez, Jose; Briongos, Sem; Rubio, José // Journal of Interventional Cardiac Electrophysiology;Jun2015, Vol. 43 Issue 1, p13 Background: The role of cardiac resynchronization therapy (CRT) in patients aged ≥75 years is not well established. Methods: We identified 607 patients aged ≥75 years with left ventricular ejection fraction (LVEF) of ≤35 %, of whom 78 met the guidelines for indication of CRT.... ...
Cardiac resynchronisation therapy (CRT) with biventricular pacemakers and implantable cardiac defibrillators (ICD) has proven to be a valuable therapy in selected patients with systolic heart failure, ameliorating both morbidity and mortality. However, with current selection criteria and implant technique, about 20 to 30 % of patients remain non-responders. Non-responders might be due to failing selection criteria or methodology in casu echocardiography. However, an important number of non-responders may result of sub-optimal positioning of the left ventricular lead, remote from the site of delayed activation. Endocardial left ventricular stimulation may ameliorate the shortcomings of epicardial stimulation. The advantage of an endocardial approach is the absence of phrenic nerve stimulation which regularly complicates epicardial pacing, a more predictable pacing threshold and much less restriction to position the lead in the area of interest. Transseptal left ventricular endocardial pacing has ...
Name: Dr Munmohan Virdee, specialty: Cardiology , subspecialty: Cardiac devices ,Devices: cardiac resynchronisation therapy device (CRT) ,Devices: dual chamber pacemaker insertion ,Devices: implantable cardioverter defibrillator (ICD) ,Devices: single chamber pacemaker insertion ,Electrophysiology ,Electrophysiology complex cardiac ablation ,Electrophysiology intervention ,Electrophysiology simple cardiac ablation
Name: Dr Trevor Wistow, specialty: Cardiology ,General (internal) medicine , subspecialty: Coronary angiography ,Devices: cardiac resynchronisation therapy device (CRT) ,Devices: dual chamber pacemaker insertion ,Devices: implantable cardioverter defibrillator (ICD) ,Devices: single chamber pacemaker insertion ,Fractional flow reserve (FFR) ,Percutaneous coronary intervention with/without stenting ,Reporting of echocardiography ,Trans-oesophageal echocardiography ,Transthoracic echocardiography
A pacing system computes optimal cardiac resynchronization pacing parameters using intrinsic conduction intervals. In various embodiments, values for atrio-ventricular delay intervals are each computed as a function of an intrinsic atrio-ventricular interval and a parameter reflective of an interventricular conduction delay. Examples of the parameter reflective of the interventricular conduction delay include QRS width and interval between right and left ventricular senses.
PubMed comprises more than 30 million citations for biomedical literature from MEDLINE, life science journals, and online books. Citations may include links to full-text content from PubMed Central and publisher web sites.
TY - JOUR. T1 - Evaluation of cardiac dyssynchrony with longitudinal strain analysisin 4-chamber cine MR imaging. AU - Kawakubo, Masateru. AU - Nagao, Michinobu. AU - Kumazawa, Seiji. AU - Chishaki, Akiko S.. AU - Mukai, Yasushi. AU - Nakamura, Yasuhiko. AU - Honda, Hiroshi. AU - Morishita, Junji. PY - 2013/12. Y1 - 2013/12. N2 - Purpose: We investigated the clinical performance of evaluation of cardiac mechanical dyssynchrony withlongitudinal strain analysis using four-chamber (4CH) cine magnetic resonance imaging (MRI).Materials and methods: We retrospectively enrolled 73 chronic heart failure patients (41 men, 32 women;mean age, 57 years, NYHA 2, 3, and 4) who underwent a cardiac MRI in the present study. The left ventricu-lar dyssynchrony (LVD) and interventricular dyssynchrony (IVD) indices were calculated by longitudinalstrain analysis using 4CH cine MRI. The LVD and IVD indices were compared by the Wilcoxon rank-sumtest between the patients with indication for cardiac resynchronization ...
Then matters started to get complicated. In addition to a variety of measurements of the onset, peak, and offset of contraction, many individual centers have reported a dozen or more permutations of these measurements with different imaging modalities that could be used to predict responsiveness to CRT.1 This Tower of Babel of markers of mechanical dyssynchrony was compounded by the use of a variety of definitions of procedural success, including clinical evaluation (composite scores, New York Heart Association class, and quality-of-life scores), exercise capacity (10% improvement), and indices of left ventricular (LV) function (,15% reduction of LV volumes, ,5% increase in LV ejection fraction, decrease in Tei index, and reduction of mitral regurgitation). To the astute observer, the fecundity of this field should ring alarm bells: A truly effective modality is unlikely to beget so many variants.. With the publication of the Predictors of Response to CRT (PROSPECT) trial in this issue of ...
Heart Failure clinical trial. Clinical trial for Electrical Activation Mapping Guided Tailor Made Approach for Cardiac Resynchronization Therapy.
A cardiac rhythm management device includes a dual chamber pacemaker especially designed for treating congestive heart failure. The device incorporates a programmed microcontroller which is operative to adjust the pacing mode-AV delay of the pacemaker so as to achieve optimum hemodynamic performance. Atrial cycle lengths measured during transient (immediate) time intervals following a change in the mode-AV delay are signal processed and a determination can then be made as to which particular configuration yields optimum performance.
Process for controlling a double atrial triple chamber pacemaker having a right atrial electrode and a left atrial electrode connected to one and the same atrial circuit for the detection/stimulation of the atrium, as well as a ventricular electrode connected to a ventricular circuit for the detection/stimulation of the ventricle. The control process includes receiving at the input of the atrial circuit and the ventricular circuit a succession of depolarization signals, determining a possibly premature character of the depolarization signal sensed at the input of the atrial circuit, in case of determined prematurity, examining, during the duration of a predetermined window of listening, signals sensed at the input of the ventricular circuit and, in case of a ventricular signal reception, inhibiting all correlated atrial stimulation, and in the absence of sensing a ventricular signal, proceeding to an atrial stimulation at both atria at the end of the listening window duration, and, in the case of no
Supplier: Euro-pharmacies,EuropeChemical Name:SomatropinumComes In: 40IU dual chamber(13.2 mg) / 1 ml water solutionDosage: Men 2-6IU total dailyActive time: Varies by injection methodClass:Growth Hormone Shipping from Europe
This is a widget area - If you go to "Appearance" in your WP-Admin you can change the content of this box in "Widgets", or you can remove this box completely under "Theme Options" ...
Were back from AcadeCon again. And once again, it was a blast, and this time I didnt end up giving myself con-crud. I want to run down a handful of highlights: Highlight #1: Running a one-shot for the second time. Read More …. ...
Global Cardiac Resynchronization Therapy Device Market Professional Survey Report 2017" Purchase This Report by calling ResearchnReports.com at +1-888-631-6977.. The latest intelligence on the Cardiac Resynchronization Therapy Device market is available in the Global Cardiac Resynchronization Therapy Device Market Research report. This report is a culmination of the key events from last decade to present day, and helps to formulate the best strategy catered to both established market players and new entrants.. A birds eye view of the Cardiac Resynchronization Therapy Device industry made available in the report helps readers to understand the key drivers, restraints, challenges, and opportunities that are shaping the global Cardiac Resynchronization Therapy Device market. Furthermore, the report evaluates challenges experienced from buyers and sellers side. The report offers advice from key industry experts on how these challenges can be overcome.. A major chunk of the report talks about the ...
TY - JOUR. T1 - Association of corrected QT dispersion with symptoms improvement in patients receiving cardiac resynchronization therapy. AU - Hina, Kazuyoshi. AU - Kawamura, Hiroshi. AU - Murakami, Takashi. AU - Yamamoto, Keizo. AU - Yamaji, Hirosuke. AU - Murakami, Masaaki. AU - Hirohata, Satoshi. AU - Ogawa, Hiroko. AU - Sakane, Kohsuke. AU - Kusachi, Shozo. PY - 2008. Y1 - 2008. N2 - Cardiac resynchronization therapy (CRT) is theoretically expected to affect repolarization as well as depolarization. We studied the effects of CRT on corrected QT (QTc) dispersion in association with symptomatic improvement. QTc dispersion was analyzed in 26 consecutive patients (67 ± 6 years old, 18 men and 8 women) who underwent CRT. CRT responders and nonresponders were defined as patients showing and not showing ≥1 class New York Heart Association symptomatic improvement 3 months after CRT, respectively. QTc interval, QRS width, and QTc dispersion were measured automatically from digital data using an ...
Cardiac-resynchronization therapy (CRT) has known benefits in patients with severe left ventricular systolic dysfunction and prolonged QRS duration (,120 ms). However, up to half of patients with systolic dysfunction appear to have left ventricular dyssynchrony by echocardiographic measures, despite a QRS duration of less than 120 ms. As a result, CRT is often used for patients with echocardiographic evidence of dyssynchrony and a narrow QRS complex, despite a lack of clear benefit to this approach. The Echocardiography Guided Cardiac Resynchronization Therapy (EchoCRT) study sought to determine the effect of CRT on patient outcomes in the setting of symptomatic heart failure, echocardiographic findings of dyssynchrony, and QRS duration ,120 ms.. In this multicenter double blind trial, patients with severe symptomatic left ventricular failure (EF,35% and NYHA class III or IV) with a QRS duration of ,130ms (mean 105ms) and evidence of dyssynchrony either on tissue Doppler or speckle tracking echo ...
Introduction In selecting patients that may benefit from cardiac resynchronization therapy (CRT), dyssynchrony assessment by echocardiography based only upon the timing of regional contraction is limited by being inherently independent of underlying myocardial contractility. We hypothesised that patient selection may be enhanced using a strain-based parameter based not only on the timing of myocardial segmental motion, but also on the amplitude of contraction, a potential measure of contractile reserve. We assessed a combined early and late strain index (ELSI) to predict CRT response.. Methods Speckle tracking radial strain was performed in 42 patients scheduled for CRT (age 69 +/− 9 years, ischemic 56%, QRS 154 +/− 12ms, NYHA III/IV - 38/4, ejection fraction 23 +/− 7%). The ELSI was calculated as the sum, for each of the 12 non apical segments, of the difference in peak radial strain and strain at aortic valve closure. CRT response was defined as a ,15% reduction in LV end systolic volume ...
AIMS: Cardiac resynchronization therapy (CRT) has reportedly not been effective in the absence of electrical or mechanical dyssynchrony. We present six patients with severe left ventricular (LV) dilation, mitral regurgitation (MR), and non-ischaemic
Haemodynamic and functional effects of cardiac resynchronization therapy (CRT) have been studied mostly at rest. CRT effects on left ventricular (LV) dyssynchrony and function during stress have not been evaluated in detail. We studied the elec
Heart failure patients with a condition called heart block derive significant benefit from cardiac resynchronization therapy (CRT), according to the results of the Block HF clinical trial, presented at the American Heart Association Scientific Sessions 2012 meeting in Los Angeles. Anne B. Curtis, MD, Charles and Mary Bauer Professor and Chair of Medicine in the University at Buffalo School of Medicine and Biomedical Sciences is principal investigator of Block HF.
Care guide for Cardiac Resynchronization Therapy (Aftercare Instructions). Includes: possible causes, signs and symptoms, standard treatment options and means of care and support.
Can left bundle branch block cause chest pain? Mammen Ninan, Jonathan W Swan Exercise-induced left bundle branch block usually indicates underlying coronary artery disease or myocardial disease. Association of left bundle branch block (LBBB) with chest pain in the absence of coronary artery disease is rare. We describe the case history of a patient with chest pain associated with left bundle branch block with normal coronary arteries and review the literature on left bundle branch block associated with chest pain.. ...
We expected to see a difference, but we were struck by the magnitude of these results," said Daniel B. Kramer, M.D., M.P.H., lead author of the study and assistant professor of medicine at Harvard Medical School in Boston, Massachusetts.. "Patients functional status clearly predicts survival. Our hope would be to use activity as a factor in not just predicting outcomes but also to guide strategies that may improve outcomes. But that is much further down the line." Researchers studied the ALTITUDE registry, a nationwide database that involved 98,437 patients enrolled in a remote monitoring program. About 57 percent of the patients had received a new or replacement ICD and 43 percent had received cardiac resynchronization therapy cardiac resynchronization therapy (CRT-D) devices in 2008-12. CRT-D therapy combines an ICD with cardiac resynchronization therapy. Patients were followed for a median 2.2 years.. "What is intriguing about our results is that looking at just one piece of information ...
QRS axis -60 Interpretation: Sinus rhythm sensed by a dual chamber pacemaker with ventricular capture. A-V interval 0.19 sec. Normal pacemaker function (atrial sensing, ventricular pacing). The patient complained of dizziness and lightheadedness. Her electrocardigram showed second degree A-V block Mobitz type II, left anterior fascicular block and right bundle branch block. Dual chamber pacemaker (DDDR) has been implanted with resolution of symptoms. << back to ECG Decoder ...
The patients included in this study, who presented with a long history of apparently isolated LBBB and progressive LV dysfunction, possessed the characteristics of an original syndrome suspected from previous animal experiments, epidemiological studies, and clinical observations, though never demonstrated in individual patients. These original observations strongly support the concept of LBBB-induced cardiomyopathy treatable with CRT.. Isolated LBBB causes abnormalities of LV dysfunction, manifest by a shortening of the filling time, a decreased septal contribution to LV ejection, and a globally depressed EF, compared with normal matched controls (5). High-amplitude oscillations of the interventricular septum were also described, similar to the "septal flash," a sign of mechanical dyssynchrony (present in 4 of our 6 patients) and a putative predictor of echocardiographic response to CRT (16).. The clinical value of several techniques and measures proposed to detect and quantify LBBB-induced ...
10. The system of claim 1, wherein the processor is configured to control the electrical stimulation module to deliver the pacing stimulus to the first ventricle by at least: detecting a first atrial pace or sense event; and controlling the electrical stimulation module to deliver a first pacing stimulus after expiration of a first pacing interval from the first atrial pace or sense event, and wherein the processor is configured to determine whether the surrogate indication of intrinsic conduction from the atrium of the heart to the second ventricle of the heart of the patient is detected by at least: detecting, based on electrical cardiac activity sensed by the sensing module, a first activation of the second ventricle within the predetermined window of time immediately following delivery of the first pacing stimulus to the first ventricle; determining a first time interval between the first atrial pace or sense event and the first activation of the second ventricle and a second time interval ...
Note: This eBook sample comprises of the Cover Page, Title Page, End User License Agreement, Foreword, Preface, Table of Contents, Editors Biography and the first three pages of each chapter. These sample images are in low resolution to optimise the file size and are only to provide an overview about the scope of the eBook and highlight the layout and presentation. These images are only for website preview and not for any other use ...
Left Bundle Branch Block Differential diagnosis of left bundle branch block / causes of left bundle branch block are : -ischemic heart disease
Medtronic has treated more than 140,000 heart failure patients with CRT, an implantable heart device that may improve the hearts ability to pump blood.
This article requires a subscription or purchase to view the full text. If you are a subscriber or member, click the login link or the subscribe link in the top menu above to access this article.. ...
GlobalDatas new report, "EU5 Cardiac Rhythm Management Market Outlook to 2020", provides key market data on the EU5 Cardiac Rhythm Management Market. The report provides value, in millions of US dollars, and volume (in units) and average price data (in US dollars), within market categories - Cardiac Resynchronisation Therapy (Defibrillators and Pacemakers), Implantable Cardioverter Defibrillators, Implantable Loop Recorders and Pacemakers.. The report also provides company shares and distribution shares data for the market category, and global corporate-level profiles of the key market participants, pipeline products, and news and deals related to the Cardiac Rhythm Management Market wherever available.. The data in the report is derived from dynamic market forecast models. GlobalData uses epidemiology and capital equipment-based models to estimate and forecast the market size. The objective is to provide information that represents the most up-to-date data of the industry possible.. The ...
PubMed comprises more than 30 million citations for biomedical literature from MEDLINE, life science journals, and online books. Citations may include links to full-text content from PubMed Central and publisher web sites.
Initially, cardiac resynchronization therapy (CRT) was advocated for patients with any widened QRS complex. However, clinical evidence is increasing that left bundle branch block (LBBB) is the electrical substrate that is most amenable to CRT (1). Such improvement seems independent of the degree of heart failure or ejection fraction, in both animal (2) and clinical studies (3,4). In patients with non-LBBB patterns of activation, CRT might even worsen outcomes (1). Therefore, a proper diagnosis of the activation pattern is of great importance. Detailed electrocardiographic analysis is an important diagnostic tool that can be supported by invasive or noninvasive mapping of electrical activation. Such mapping studies have shown that "true" LBBB coincides with a U-shaped pattern of activation (5).. U-shaped activation has distinct electrical activation features: 1) prolonged transseptal conduction time or prolonged time from endocardial right ventricular activation to left ventricular (LV) ...
Heart failure (HF) has a prevalence of five million individuals in the United States. Approximately 25-30% of patients with HF due to left ventricular (LV) systolic dysfunction have prolonged QRS. Prolonged QRS duration (,120ms) on ECG in HF patients is associated with increased morbidity and mortality.. Delayed electrical activation of the LV translates to temporal delay in ventricular contraction. This is referred to as mechanical dyssynchrony. Patients with advanced HF, low ejection fraction (EF) of less than 35% and QRS of more than 120ms are indicated for cardiac resynchronization therapy (CRT). While most patients undergoing CRT implantation show dramatic improvement in HF symptoms, 30-40% of the HF patients undergoing CRT placement do not show a clinical response. The site of placement of the LV lead has been shown to be an important determinant of the effects of CRT.. Measurement of left ventricular ejection fraction (LVEF) is performed using non-invasive measures such as the MUGA. By ...
The concept of a closed - loop feedback system, that would automatically assess pacing threshold and self -adjust pacing output to ensure consistent myocardial capture, has many appeals. Enhancing patient safety in cases of an unexpected rise in threshold, reduced current drain, hence prolonging battery longevity and reducing the amount of physician intervention required are just some of the advantages. Autocapture (AC) is a proprietary algorithm developed by St Jude Medical CRMD, Sylmar, CA, USA, (SJM) that was the first to commercially provide these automatic functions in a single chamber pacemaker (Microny and Regency), and subsequently in a dual chamber pacemaker (Affinity, Entity and Identity family of pacemakers). This article reviews the conditions necessary for AC verification and performance and the problems encountered in clinical practice. ...
Evaluation of regional function with tissue Doppler or speckle tracking is currently an integral part of the assessment of cardiac dyssynchrony. Original research presented at the meeting provided additional refinement of this role. The importance of radial assessment of dyssynchrony compared with the conventional longitudinal evaluation was highlighted by a few investigations. Suffoletto et al. (20) showed that improvement in radial synchrony after cardiac resynchronization therapy (CRT) by speckle tracking was associated with longitudinal synchrony and with greater improvement in stroke volume than when radial synchrony was not optimized. The work by Seo et al. (21) demonstrated that assessment of radial dynamics is superior to longitudinal dyssynchrony in predicting the hemodynamic outcome after CRT. The greatest increase in cardiac output and dP/dt was seen in those with the most marked radial dyssynchrony.. Patients with segmental paradoxical regional expansion, assessed by strain imaging ...
With the development of Dyssynchrony Imaging, Toshiba is providing cardiologists with a new innovation that expands the quantification capabilities of ultrasound to aid in diagnosing cardiovascular disease," said Gordon Parhar, director, Ultrasound Business Unit, Toshiba America Medical Systems, Inc. "The DI method makes it easier for clinicians to determine the severity of dyssynchrony by having an automated detection of maximum values and a visual display of time to peak for each region. DI also will be a valuable tool in assessing patients for cardiac resynchronization therapy, providing clinicians with a pathway treatment from pre-implant to post implantation of the pacemaker ...
BACKGROUND: Cardiac resynchronization therapy (CRT) using biventricular pacing (BVP) is effective in patients with heart failure, bundle branch block (BBB), or right ventricular pacing. Permanent His-bundle pacing (HBP) has been reported as an alternative option for CRT. OBJECTIVE: The purpose of this study was to assess the feasibility and outcomes of HBP in CRT eligible or failed patients. METHODS: HBP was attempted as a rescue strategy in patients with failed left ventricular lead or nonresponse to BVP (group I), or as a primary strategy in patients with AV block, BBB, or high ventricular pacing burden as an alternative to BVP (group II) in patients with indications for CRT ...
A dual chamber pacemaker system is provided having an improved Wenckebach response for optimizing tracking of atrial signals having rates within a rate range above the normal tracking range, i.e., in a designated Wenckebach range. When an atrial sense occurs in the Wenckebach range, the AV delay is extended up to a predetermined maximum extension to enable delivery of a ventricular pulse at the ventricular upper rate limit (dynamic tracking limit). When the AV delay would have to be extended beyond the maximum extension in order to pace the ventricle at the dynamic tracking limit, the next ventricular stimulus is delivered asynchronously at an escape interval greater than the escape interval corresponding to the dynamic tracking limit, e.g., at a predetermined lower pacing limit.
Treatment of symptomatic bradycardia is largely algorithm-based, regardless of cause. Acting quickly to treat the bradycardia takes precedence over determining the cause. Once you have initiated treatment, proceed to determine the cause and correct, if possible (See section on "Management of Bradycardia in the OR").. Decide whether the patient has adequate or poor perfusion, since the treatment sequence is determined by the severity of the patients clinical presentation. In the OR or anesthetized patient:. * If severe hypotension, persistent poor perfusion, or low ETCO2 (,15mm Hg)-, start CPR. * Administer 100% Oxygen, assist ventilation, open IV fluids, and secure airway. * Consider 0.5mg atropine IV while awaiting pacer. May repeat to total 3mg. If ineffective, begin transcutaneous pacing.. * Consider IV bolus Epinephrine 10-100mcg. May start low dose epinephrine infusion if a response (0.05-0.10 mcg/kg/min) or dopamine (2-10mcg/kg/min). * Prepare for transcutaneous pacing: use without delay ...
Almost all attempts to improve patient selection for cardiac resynchronization therapy (CRT) using echo-derived indices have failed so far. We sought to assess: the performance of homemade software for the automatic quantification of integral 3D regional longitudinal strain curves exploring left ventricular (LV) mechanics and the potential value of this tool to predict CRT response. Forty-eight heart failure patients in sinus rhythm, referred for CRT-implantation (mean age: 65 years; LV-ejection fraction: 26%; QRS-duration: 160 milliseconds) were prospectively explored. Thirty-four patients (71%) had positive responses, defined as an LV end-systolic volume decrease ≥15% at 6-months. 3D-longitudinal strain curves were exported for analysis using custom-made algorithms. The integrals of the longitudinal strain signals (I L,peak) were automatically measured and calculated for all 17 LV-segments. The standard deviation of longitudinal strain peak (SDI L
Aims. Single-pass VDD is a physiological stimulation mode which requires a single-lead with a floating dipole to detect the atrial signal. We investigated the impact of right heart dimensions on immediate and long-term atrial sensing stability in VDD systems to draw guidelines for optimal atrial sensitivity programming.. Methods. Forty-one patients (23 males, mean age 73±11 years) with II or III degree AV block and normal sinus node function received a Thera VDD Medtronic 8948 pulse generator with Medtronic 5032 lead. Atrial sensing was evaluated at pre-discharge and during 12-months follow-up in the supine and upright positions, during normal and forced breathing. Atrial sensing variability, quantified by a D value (mV), which represents the difference between the maximum and the minimum atrial electrogram amplitude obtained during the various activities, was analyzed and related to right heart dimensions measured at echocardiography.. Results. Long-term appropriate atrial sensing was obtained ...
COSTA, Roberto et al. Permanent cardiac pacing in children with postoperative bradycardia: long-term follow-up. Rev Bras Cir Cardiovasc [online]. 2005, vol.20, n.4, pp.392-397. ISSN 0102-7638. http://dx.doi.org/10.1590/S0102-76382005000400007.. OBJECTIVE: To evaluate the long-term outcomes of children submitted to permanent cardiac pacing due to postoperative bradycardia and to identify risk factors for mortality. METHODS: From 1980 to 2004, 120 children were submitted to permanent pacemaker (PM) implantation. Interval between the defect correction and PM implantation was 1.2 ± 2.8 years, on average (median = 21 days). Atrioventricular blocks were present in 94.2% of patients. Transvenous leads (78.3%) and ventricular pacemaker systems (79.2%) were used in most of the cases. Risk factors were studied using the Cox proportional model. The Kaplan-Meier method and the Log-Rank test were used to analyze survival. RESULTS: After a mean of 5.7 ± 5.9 years (maximum = 22.5 years) of follow-up, 97 ...
Learn more about Pacemaker Insertion at St. Davids HealthCare DefinitionReasons for ProcedurePossible ComplicationsWhat to ExpectCall Your Doctorrevision ...
Arrhythmia: An irregular heartbeat that is either abnormally slow (bradycardia) or too fast (tachycardia).. Biomarker: Generally refers to a measurable indicator of some biological state or condition. Biomarkers are often measured and evaluated to examine normal biological processes, pathogenic processes, or pharmacologic responses to a therapeutic intervention.. Cardiac arrest: When the heart stops beating suddenly and respiration (breathing) and other body functions cease as a result. Without immediate treatment, the affected person will die.. Cardiac resynchronization therapy (CRT): Implantable device therapy for people with moderate to severe heart failure who also have ventricular desynchrony. Helps the lower chambers of the heart (left and right ventricles) beat together in a normal rhythm again.. Coronary artery disease: Chronic condition in which a clogged artery prevents the heart from receiving sufficient blood.. Echocardiogram (or «echo»): A cardiac imaging test that provides ...
Japans largest platform for academic e-journals: J-STAGE is a full text database for reviewed academic papers published by Japanese societies
I am a 48 year old woman who just had an ECG done that showed Left Bundle Branch Block. I think the doctor ordered the ECG to ease my mind because of what I went to see him for really had nothing to d...
Found out last year I have left bundle branch block,worked out I am running a minute a mile slower than normal,has anybody else experienced this or know anything about it?
Aims We investigated the applicability of the Ventricular Capture Control (VCC) and Atrial Capture Control (ACC) algorithms for automatic management of cardiac stimulation featured by Biotronik pacemakers in a broad, unselected population of pacemaker recipients. Methods and results Ventricular Capture Control and Atrial Capture Control were programmed to work at a maximum adapted output voltage as 4.8 V in consecutive recipients of Biotronik pacemakers. Ambulatory threshold measurements were made 1 and 12 months after pacemaker implant/replacement in all possible pacing/sensing configurations, and were compared with manual measurements. Among 542 patients aged 80 (73-85) years, 382 had a pacemaker implant and 160 a pacemaker replacement. Ventricular Capture Control could work at long term in 97% of patients irrespectively of pacing indication, lead type, and lead service life, performance being superior with discordant pacing/sensing configurations. Atrial Capture Control could work in 93% of ...
Permanent leadless cardiac pacing: results of the leadless trial. Reddy VY, Knops RE, Sperzel J, Miller MA, Petru J, Simon J, Sediva L, de Groot JR, Tjong FV, Jacobson P, Ostrosff A, Dukkipati SR, Koruth JS, Wilde AA, Kautzner J, Neuzil P. Circulation. 2014 Apr 8;129(14):1466-71.. Feasibility, safety, and short-term outcome of leadless ultrasound-based endocardial left ventricular resynchronization in heart failure patients: results of the Wireless Stimulation Endocardially for CRT (WiSE-CRT) study. Auricchio A, Delnoy PP, Butter C, Brachmann J, Van Erven L, Spitzer S, Moccetti T, Seifert M, Markou T, Laszo K, Regoli F; Collaborative Study Group. Europace. 2014 May;16(5):681-8. ...
A managed ventricular pacing (MVP) algorithm was applied, with the pacemaker working correctly (correct answer, 4). In the upper trace of the Figure, sequential pacing can be observed with an atrioventricular interval of 150 ms, except for the last beat, in which the pacemaker switches to AAI mode. The MPV algorithm periodically makes such checks.1 In the lower trace, the pacemaker is working in AAI mode with atrial pacing (asterisks) when the heart rate drops below the threshold (60 bpm). An atrial pace is present after the sixth QRS: the MVP algorithm will ensure that there is no atrioventricular conduction, but in the next complex (double arrow), the pacemaker emits a safety pace, which with this model has an atrioventricular interval of 80 ms. This is not ventricular capture failure (answers 1 and 2, incorrect) because there is no ventricular pace spike and at no point is failure of atrial capture observed (answer 3, incorrect).. ...
Pacemaker therapy has developed into one of the most successful treatment methods in the field of cardiology. Initially implanted mainly to prevent Adams-Stokes attacks and to decrease the mortality...
A pacemaker is a small electronic device that helps regulate slow electrical problems in the heart. The pacemaker is usually implanted in the chest, just below the collarbone. A pacemaker may be recommended to keep the heartbeat from slowing down to a dangerously low rate.
A pacemaker is a small electronic device that helps regulate slow electrical problems in the heart. The pacemaker is usually implanted in the chest, just below the collarbone. A pacemaker may be recommended to keep the heartbeat from slowing down to a dangerously low rate.
LBBB is a common ECG abnormality .The ECG is so classical , no one ever misses the diagnosis. But , what we miss often is the significance of it . What is the cause of LBBB in a given patient is much more important than the LBBB itself ! Though the commonest cause of LBBB…
A method and system for operating a cardiac pacemaker which employs pacing therapy to regularize the ventricular rhythm together with biventricular sensing. Biventricular sensing allows the ventricular rate regularization to be accomplished with greater hemodynamic stability.
In order to bring you the best possible user experience, this site uses Javascript. If you are seeing this message, it is likely that the Javascript option in your browser is disabled. For optimal viewing of this site, please ensure that Javascript is enabled for your browser ...
Methods, apparatus, and systems are provided to control contraction of the heart. At least one sensing element receives signals indicating electrical activity of sinus rhythm of the heart. Based on t
Biventricular Dilation Symptom Checker: Possible causes include Dilated Cardiomyopathy. Check the full list of possible causes and conditions now! Talk to our Chatbot to narrow down your search.
[19:44] |+ColinPunk| My name is Colin Kyle, Im the lead writer and designer of Axon Punk: Overdrive, which is live on Kickstarter right now (Link: https://www.kickstarter.com/projects/1877971196/axon-punk-overdrive-0)https://www.kickstarter.com/projects/1877971196/axon-punk-overdrive-0 [19:45] |+ColinPunk| The game is a combination of classic cyberpunk and hip hop. Play feels like Cowboy Bebop and Samurai Champloo, but set in the megacities of 2085. [19:46]…
Robust BVP pump drive is designed for continuous operation with a wide selection of pump heads. Equipped with a 3-digit potentiometer speed selector and an analog interface.
In recent decades, the prevalence of heart failure has steadily increased and can be considered a contemporary cardiovascular epidemic. Therefore, treatment of heart failure is a primary focus of cardiovascular disease management strategies. Cardiac resynchronization therapy: an established pacing therapy for heart failure and mechanical dyssynchrony provides basic knowledge about congestive heart failure and also covers the evolution of cardiac resynchronization therapy. State-of-the-art information and future directions of this therapeutic tool are explained. As cardiac resynchronization therapy (CRT) is a new therapy which still undergoes rapid advancement, it is imperative to provide updates on key issues. These include technological advances, the unique role of imaging to assess mechanical dyssynchrony, troubleshooting, recent key clinical trials, and the incorporation of monitoring capabilities into CRT or CRT plus defibrillation devices. Cardiac resynchronization therapy is an exciting ...
Looking for online definition of resynchronization therapy in the Medical Dictionary? resynchronization therapy explanation free. What is resynchronization therapy? Meaning of resynchronization therapy medical term. What does resynchronization therapy mean?
© 2016 American College of Cardiology Foundation. Published by Elsevier. Objectives The goal of this study was to assess the contemporary and historical success rates of transvenous left ventricular (LV) lead placement for cardiac resynchronization therapy (CRT), their change over time, and the reasons for failure. Background In selected patients, CRT improves morbidity and mortality, but the placement of the LV lead can be technically challenging. Methods A literature search was used to identify all studies reporting success rates of LV lead placement for CRT via the coronary sinus (CS) route. A total of 164 studies were identified, and a meta-analysis was performed. Results The studies included 29,503 patients: 74% (95% confidence interval [CI]: 72% to 76%) were male; their mean age was 66 years (95% CI: 65 to 67); their mean New York Heart Association functional class was 2.8 (95% CI: 2.7 to 2.9); the mean LV ejection fraction was 26% (95% CI: 25% to 28%); and the mean QRS duration was 155 ms (95%
Definition : Implantable cardiac pacemaker and/or defibrillator/cardiac pacemakers leads used for sensing cardiac bioelectric signals and delivering electrical stimuli to synchronize ventricular contractions. These leads are connected to implantable cardiac pacemakers or defibrillator/cardioverter/pacemakers for resynchronization therapy in patients with advanced heart failure (e.g., dilated cardiomyopathy) and/or serious heart-rhythm problems such as delayed ventricular activation and contraction (i.e., ventricular dysynchrony).. Entry Terms : "Biventricular Pacemaker/Implantable Cardioverter Defibrillators (Bi-V/ICDs)" , "Biventricular Pacemakers" , "Cardiac Resynchronization Therapy Leads" , "Ventricular Resynchronization Leads" , "Resynchronization Cardiac Rhythm Leads" , "Cardiac Resynchronization Therapy Defibrillator (CRT-D) Systems" , "Biventricular Pacing Devices" , "Defibrillation Electrodes" , "Electrodes, Defibrillation". UMDC code : 20377 ...
The global cardiac resynchronization therapy (CRT) market is expected to reach USD 9.2 billion by 2025, according to a new report by Grand View Research, Inc. Increasing prevalence of cardiac disorders and rising incidences of heart failure are expected to boost the CRT market growth over the forecast period.. According to statistics published by the Sudden Cardiac Arrest Foundation in 2016, about 6.0 million people within the U.S. region suffer from cardiac disorders, of which 0.8 million are affected by atrioventricular block leading to cardiac failure. Such a huge number leads to an increased cost of about USD 20.0-56.0 billion annually. CRT devices are being predominantly used to prevent the surgical cost and readmission rate in hospitals, thereby propelling its growth.. In addition, the on-going research to develop smaller, wireless/leadless and long-lasting CRT devices is expected to be a vital impact rendering driver. For instance, in September 2016, EBR Systems Inc., announced that it ...
For patient information, click here Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Mugilan Poongkunran M.B.B.S [2] Synonyms and Keywords: QRS prolongation; wide QRS; wide QRS complex; wide QRS complexes; IVCD; IVCDs; intraventricular conduction defect; non-specific intraventricular conduction delay; non-specific intraventricular conduction defect ...
TY - JOUR. T1 - Chronic exercise reduces sympathetic nerve activity in rabbits with pacing-induced heart failure. T2 - A role for angiotensin II. AU - Liu, Jun Li. AU - Irvine, Scott. AU - Reid, Ian A.. AU - Patel, Kaushik P. AU - Zucker, Irving H. PY - 2000/10/10. Y1 - 2000/10/10. N2 - Background - Chronic exercise (EX) improves the quality of life and increases the survival of patients with chronic heart failure (CHF). Because sympathetic nerve activity is elevated in the CHF state, it is possible that EX is beneficial in this disease due to a decrease in sympathetic outflow. Methods and Results - We evaluated arterial baroreflex function and resting renal sympathetic nerve activity (RSNA) in EX normal and CHF rabbits before and after angiotensin II type 1 (AT1) receptor blockade. Four groups of rabbits were studied: a normal non-EX group, a normal EX group, a CHF non-EX group, and a CHF EX group. EX lowered resting RSNA in rabbits with CHF but not in normal rabbits. In addition, EX increased ...
Looking for sick sinus syndrome? Find out information about sick sinus syndrome. 1. inclined or likely to vomit 2. a. suffering from ill health b. : the sick 3. a. of, relating to, or used by people who are unwell b. : sickbed 4. Explanation of sick sinus syndrome
LV endocardial pacing has been proposed and has been shown to be superior to conventional LV epicardial pacing in the CRT setting in computer simulations (54) and preclinical experiments (55,56). In various canine LBBB models, superiority has been shown in electrical resynchronization and acute hemodynamic response (55,56). However, clinical studies showed less reproducible differences. Derval et al. (57) was not able to show significantly better hemodynamic response between pacing in the endocardial position and immediately below the position of the coronary sinus lead, although in each patient there was an endocardial position that resulted in superior improvement in pump function. Similarly, Spragg et al. (58) found that endocardial pacing tended to be superior to epicardial pacing in patients with ischemic cardiomyopathy, but that the location of optimal LV endocardial pacing varied among patients. Shetty et al. (59) showed that LV endocardial pacing was superior to epicardial pacing and ...
In this observational analysis of a large real-world cohort of patients with NYHA class III or IV heart failure and reduced ejection fraction, we found that, compared with ICD, CRT-D was associated with a greater difference in mortality in women than in men, but this lower mortality risk was more evident in both male and female patients with LBBB. Among all LBBB patients, both women and men generally had lower mortality risks with QRS ≥130 ms; however, the mortality difference associated with CRT-D was greater in women. In the non-LBBB cohort, there was no mortality risk difference between CRT-D and ICD in women or men with RBBB or in men with IVCD. The finding that there seems to be reduced mortality in patients with LBBB and QRS 130 to 150 ms is important because professional society guidelines for CRT only assign a class I recommendation to patients with LBBB and QRS ≥150 ms.8. That CRT is effective in LBBB has been shown in recent meta-analyses of clinical trials,7,16,22 whereas other ...
what does sinus arrhythmia non specific intraventricular conduction delay mean?what is its causes? This discussion is related to |a href=http://www.medhelp.org/posts/show/409489|abnormal ekg|/a|.
Ventricular dysynchrony is something that often happens in patients who have heart failure. It is essentially the inability of the heart to beat in a coordinated fashion. This can be remedied in many cases using cardiac resynchronization therapy. This is simply a pacemaker that helps force the heart to beat in a coordinated manner. The advantages of having cardiac resynchronization therapy -- or CRT -- are that the patient can feel better, less shortness of breath, and can potentially walk farther.
Heart failure with reduced ejection fraction (HF-rEF) is responsible for high costs and increased rates of hospital admissions along with high mortality and morbidity risks. Only treatment for HF-rEF has been shown to be efficacious compared to HF-pEF which currently has no useful treatment options. Here is the latest research on HF-rEF. ...
Lancaster General Health is a comprehensive healthcare delivery system with an earned reputation for excellence, compassion, quality and cost effectiveness. Located in Lancaster, Pennsylvania.
June 23, 2009 - Today, Medtronic Inc. announced the first worldwide enrollments in the MORE-CARE (Monitoring Resynchronization in Cardiac Patients) trial, which will compare two disease management strategies for heart failure patients treated with an implantable device for cardiac resynchronization therapy. MORE-CARE aims to demonstrate that remote monitoring of these patients via the Medtronic CareLink Network is superior to in-office visits alone in terms of clinical effectiveness and healthcare system utilization.. The trial will utilize Medtronic wireless cardiac resynchronization therapy-defibrillators (CRT-Ds) equipped with OptiVol Fluid Status Monitoring and Medtronic CareAlert Notifications. The devices automatically notify a physician with a text message (SMS), e-mail or a Medtronic CareLink Web site message when certain pre-programmed thresholds are crossed without an in-office diagnosis by the physician. OptiVol CareAlert notifications are not available in the U.S., and no U.S. ...
Despite the success of CRT in clinical treatment of patients with HF and cardiac dyssynchrony,1,2 little is known about restoration of subcellular structures and functions related to EC coupling. Fluorescent labeling, 3D confocal microscopy, and image analysis provide a quantitative way of describing subcellular structures, their remodeling, and restoration. Using this approach, we demonstrated for the first time substantial remodeling of the t-system as a deleterious consequence of DHF and subsequent structural restoration of the t-system that result from CRT. In addition, we characterized the location of specific effects of DHF-associated structural remodeling of the t-system and its relationship to RyR clusters. Remodeling of t-tubules in DHF ranged from minor alterations in anterior left ventricular cells to nearly complete depletion in lateral cells. Our analyses did not reveal remodeling of the t-system by atrial tachypacing, indicating that remodeling in DHF is a consequence of cardiac ...
DISCUSSION. The greatest advantage of the S-ICD is avoiding the implantation of leads within cardiovascular system, thus preserving central venous circulation, with no risks of mechanical traumas, such as vascular damages or pneumothorax, and with a very low risk of systemic infection[8]. An important disadvantage is the impossibility of the system to provide heart pacing. For this reason, it is contraindicated for patients with indication for bradycardia pacing, cardiac resynchronization therapy or antitachycardia pacing (ATP) since S-ICD cannot provide cardiac pacing other than for a short period post-shock, when necessary[9]. Based on the benefits and after pre-selecting the patients, this new technology was chosen to be used.. After selecting the patients, they were submitted to the screening phase using a customized plastic ruler supplied by the manufacturer with the purpose of evaluating if the generated electric signal would be able to provide an appropriate functioning of the S-ICD. ...
Sick sinus syndrome is a type of abnormal heartbeat, or arrhythmia. If you have sick sinus, you may have episodes when your heart beats very slowly, stops beating for a short while, or beats very rapidly.
Sick sinus syndrome is a type of abnormal heartbeat, or arrhythmia. If you have sick sinus, you may have episodes when your heart beats very slowly, stops beating for a short while, or beats very rapidly.
A large observational study published in JAMA suggests that patients with left bundle-branch block (LBBB) and longer QRS duration derive the most benefit from a cardiac resynchronization therapy defibrillator (CRT-D). The findings appear to support current, but often criticized, guidelines from the American College of Cardiology, American Heart Association, and the Heart Rhythm Society, in which a class I […]. ...
Relative contributions of the atria and the atrioventricular (AV) node to AV conduction were studied in isolated, blood-perfused dog hearts. The functional refractory period of the atria, although shorter than that of the AV node, determined the functional refractory period of the entire transmission system in 50% of the hearts. Slow atrial conduction of early beats greatly influenced the shape of the curve used to determine the functional refractory period of the transmission system. The atrial effective refractory period was also shorter than the effective refractory period of the AV node. However, the effective refractory period of the entire transmission system was equal to that of the atrium when the driving interval was longer than 320 msec, and it decreased as the driving interval was shortened. At driving intervals of 320 msec or less, the effective refractory period of the AV transmission system abruptly increased and became equal to the effective refractory period of the node. ...
Clinical record. A 73-year-old man presented with recurrent ventricular tachycardia (VT) on a background of severe, non-ischaemic dilated cardiomyopathy (ejection fraction, 20%) and cardiac resynchronisation therapy with an implantable cardioverter defibrillator (ICD). Over the previous 6 months, he had frequent appropriate ICD shocks for VT after unsuccessful antitachycardia pacing. A coronary angiogram was normal. Amiodarone had been successful in reducing VT burden and ICD shocks, but was ceased because of amiodarone-induced thyrotoxicosis. Shortly after discontinuing amiodarone, there was a significant increase in VT burden and appropriate ICD shocks. An endocardial mapping and VT ablation procedure had been performed, but this was unsuccessful and suggested an epicardial source of VT. The patient also underwent subsequent epicardial mapping and VT ablation using a CARTO 3 (Biosense Webster) electroanatomical mapping system, which localised the source of VT to a diffuse area of the basal ...
Sick sinus syndrome comprises a variety of conditions involving sinus node dysfunction and commonly affects elderly persons. While the syndrome can have many causes, it usually is idiopathic. Patients may experience syncope, pre-syncope, palpitations, or dizziness; however, they often are asymptomatic or have subtle or nonspecific symptoms. Sick sinus syndrome has multiple manifestations on electrocardiogram, including sinus bradycardia, sinus arrest, sinoatrial block, and alternating patterns of bradycardia and tachycardia (bradycardia-tachycardia syndrome). Diagnosis of sick sinus syndrome can be difficult because of its nonspecific symptoms and elusive findings on electrocardiogram or Holter monitor. The mainstay of treatment is atrial or dual-chamber pacemaker placement, which generally provides effective relief of symptoms and lowers the incidence of atrial fibrillation, thromboembolic events, heart failure, and mortality, compared with ventricular pacemakers.
APPROVAL FOR A MODIFICATION TO THE INDICATIONS FOR USE FOR THE COGNIS CRT-D MODELS N118, N119; LIVIANCRT-D MODELS H220, H225, H227 AND H229; AND CONTAK RENEWAL 3 RF HE CRT-D MODELSH210, H215, H217, H219 CARDIAC RESYNCHRONIZATION THERAPY DEFIBRILLATORS (CRT-DS) AS FOLLOWS:THESE BOSTON SCIENTIFIC CARDIAC RESYNCHRONIZATION THERAPY DEFIBRILLATORS (CRT-DS) ARE INDICATED FOR PATIENTS WITH HEART FAILURE WHO RECEIVE STABLE OPTIMAL PHARMACOLOGIC THERAPY (OPT) FOR HEART FAILURE AND WHO MEET ANY ONE OF THE FOLLOWING CLASSIFICATIONS:1) MODERATE TO SEVERE HEART FAILURE (NYHA CLASS III-IV) WITH EF <= 35% AND QRS DURATION>= 120 MS; OR2) LEFT BUNDLE BRANCH BLOCK (LBBB) WITH QRS >= 130 MS, EF <= 30%, AND MILD (NYHACLASS II) ISCHEMIC OR NONISCHEMIC HEART FAILURE OR ASYMPTOMATIC (NYHA CLASS I)ISCHEMIC HEART FAILURE ...
article{ceee0ce3-7cdb-426b-8c17-2f62ad33a172, abstract = {,p,AIMS: To evaluate the usefulness of the signed value of monophasic action potential duration difference in analysing the cause of dispersion of ventricular repolarization.,/p,,p,METHODS AND RESULTS: Monophasic action potentials were simultaneously recorded from the right ventricular apex and outflow tract during programmed stimulation in 36 patients with ventricular arrhythmias. The time difference between the ends of repolarization on the two monophasic action potentials was used as a measure of the dispersion of ventricular repolarization, and the signed value of the monophasic action potential duration difference was used to specify the contributions of the activation time difference and the monophasic action potential duration difference to the dispersion of ventricular repolarization. During right ventricular pacing, single and double programmed stimulation and at the induction of ventricular arrhythmias, the dispersion of ...

Cardiac Pacing, Artificial | The Chopra LibraryCardiac Pacing, Artificial | The Chopra Library

Comparison of permanent cardiac pacing and cardiac pacing on demand in mixed carotid sinus syndrome. Acute- and medium-term ... Patients who needed pacing therapy because of atrial bradyarrhythmias were investigated by means of carotid sinus massage, ... The aim of the study was to evaluate the importance of atrial synchronism for pacing therapy of patients with mixed carotid ... The aim of this study was to evaluate the importance of atrial synchronism for pacing therapy of patients with mixed carotid ...
more infohttp://isharonline.org/tags/cardiac-pacing-artificial

Randomized Comparison of Endocardial Versus Epicardial - From the Coronary Sinus - Left Ventricular Pacing for...Randomized Comparison of Endocardial Versus Epicardial - From the Coronary Sinus - Left Ventricular Pacing for...

Cardiac Pacing, Artificial. cardiac resynchronization therapy. Hemodynamics. Randomized Controlled Trials. Open Study. ... pacing threshold performances of Left Ventricle pacing leads at 6 month Follow up [ Time Frame: 6-months after pacing procedure ... pacing threshold performances of left ventricle pacing leads [ Time Frame: within 7 days after pacing procedure ]. *impedances ... number of left ventricular pacing sites assessed [ Time Frame: Visit 3 : implantation day, end of pacing procedure ]. *Pacing ...
more infohttps://clinicaltrials.gov/show/NCT01260402

Ventricular Pacing Site Selection (V-PASS) - Full Text View - ClinicalTrials.govVentricular Pacing Site Selection (V-PASS) - Full Text View - ClinicalTrials.gov

Cardiac Pacing, artificial. Atrial Fibrillation. Heart failure. Pacemaker leads. Lead position. Higher degree AV-Block. ... Ventricular pacing or dual-chamber pacing for sinus-node dysfunction. N Engl J Med. 2002 Jun 13;346(24):1854-62. ... AV-Block of higher degree is the primary indication for pacing therapy for about 20% of pacemaker patients. Pacing systems with ... Patients with an expected ventricular stimulation rate of ,60% in planned pacing therapy. This will be the following pacing ...
more infohttps://clinicaltrials.gov/ct2/show/NCT00292383?recr=Open&intr=artificial+pacemaker&rank=2

NLM Classification 2015 Edition . NLM Technical Bulletin. 2015 May-JunNLM Classification 2015 Edition . NLM Technical Bulletin. 2015 May-Jun

Artificial cardiac pacing WG 168 WG 166.5.E5 Electric countershock WG 330. ... At WG 205, the caption was changed from Cardiac emergencies to Cardiac emergency treatment. ... Prosthesis implantation (General) to Artificial limbs.. *At WE 400, the caption was changed from Bursae to Synovial bursa. ... At WG 330, the caption was changed from Disorders of the heart beat to Cardiac arrhythmias (General). ...
more infohttps://www.nlm.nih.gov/pubs/techbull/mj15/mj15_nlm_classification_2015.html

Myocardial Minimal Damage After Rapid Ventricular PacingMyocardial Minimal Damage After Rapid Ventricular Pacing

... clinicaltrials.gov This study aims to investigate the impact of antitachycardia pacing ( ATP) on the myocardial tissue with ... Cardiac Resynchronization Therapy Devices. Types of artificial pacemakers with implantable leads to be placed at multiple ... Cardiac Resynchronization Therapy. The restoration of the sequential order of contraction and relaxation of the HEART ATRIA and ... More From BioPortfolio on "Myocardial Minimal Damage After Rapid Ventricular Pacing". *Related Companies*Related Events*Related ...
more infohttps://www.bioportfolio.com/resources/trial/134106/Myocardial-Minimal-Damage-After-Rapid-Ventricular-Pacing.html

Temporary transvenous cardiac pacing.Temporary transvenous cardiac pacing.

Temporary cardiac pacing in the critical care setting can be a lifesaving intervention in a number of clinical situations. A ... Cardiac Pacing, Artificial / adverse effects, methods*, standards. Critical Care*. Electrocardiography. Equipment Design / ... Temporary cardiac pacing in the critical care setting can be a lifesaving intervention in a number of clinical situations. A ... 95227 - Air entrapment as a cause of transient cardiac pacemaker malfunction.. 12049377 - Postpacemaker implant pericarditis: ...
more infohttp://www.biomedsearch.com/nih/Temporary-transvenous-cardiac-pacing/1393747.html

Cardioinhibition during tilt testing identifies patients who may benefit from pacing.Cardioinhibition during tilt testing identifies patients who may benefit from pacing.

Cardiac Pacing, Artificial*. Female. Heart / physiopathology*. Heart Rate. Humans. Male. Middle Aged. Predictive Value of Tests ... Title: Pacing and clinical electrophysiology : PACE Volume: 23 ISSN: 0147-8389 ISO Abbreviation: Pacing Clin Electrophysiol ... The test was then repeated during A-V pacing with rate hysteresis. A positive response to A-V pacing was defined as a , or = 30 ... A-V sequential pacing was successful in 13 of 17 patients with a cardioinhibitory response versus 5 of 14 patients with a mixed ...
more infohttp://www.biomedsearch.com/nih/Cardioinhibition-during-tilt-testing-identifies/11139925.html

Sensor-Triggered, Rate-Variable Cardiac PacingCurrent Technologies and Clinical Implications | Annals of Internal Medicine |...Sensor-Triggered, Rate-Variable Cardiac PacingCurrent Technologies and Clinical Implications | Annals of Internal Medicine |...

MeSH terms: arrhythmia; bradycardia; cardiac output; cardiac pacing, artificial; electric stimulation; exertion; heart atrium; ... Cardiac Pacing for Prevention of Recurrent Vasovagal Syncope Annals of Internal Medicine; 122 (3): 204-209 ... Sensor-Triggered, Rate-Variable Cardiac Pacing: Current Technologies and Clinical Implications DAVID G. BENDITT, M.D.; SIMON ... Multiple-Sensor Systems for Physiologic Cardiac Pacing Annals of Internal Medicine; 121 (12): 960-968 ...
more infohttps://annals.org/aim/article-abstract/702269/sensor-triggered-rate-variable-cardiac-pacing-current-technologies-clinical-implications

Marca-passo cardíaco definitivo em crianças com bradicardia pós-operatória: resultados tardiosMarca-passo cardíaco definitivo em crianças com bradicardia pós-operatória: resultados tardios

Keywords : Cardiac pacing [artificial]; Heart block; Pediatrics; Cardiac surgical procedures; Postoperative complications. ... COSTA, Roberto et al. Permanent cardiac pacing in children with postoperative bradycardia: long-term follow-up. Rev Bras Cir ... OBJECTIVE: To evaluate the long-term outcomes of children submitted to permanent cardiac pacing due to postoperative ...
more infohttp://www.scielo.br/scielo.php?script=sci_abstract&pid=S0102-76382005000400007&lng=en&nrm=iso&tlng=en

Boğaziçi University - The Institute of Biomedical EngineeringBoğaziçi University - The Institute of Biomedical Engineering

Cardiac pacing; defibrillators, cardiovascular prostheses and assist devices, neural assist devices, sensory and communication ... Biomaterials deal with biological materials, prosthetics, implants and artificial organs.. Code Course Title Hours/Week Cr ECTS ... Artificial kidney.. BM 632 Sensory System (3+0+0) 3 ECTS (Duyu Sistemleri). Basic psychophysics, anatomy and physiology of ... An overview of cardiac diseases which are the focus of advanced imaging systems. Detailed comparative analysis of specific ...
more infohttp://www.boun.edu.tr/en_US/Content/Academic/Graduate_Catalogue/The_Institute_of_Biomedical_Engineering

Roberts and Hedges Clinical Procedures in Emergency Medicine and Acute Care, 7th Edition - 9780323354783Roberts and Hedges' Clinical Procedures in Emergency Medicine and Acute Care, 7th Edition - 9780323354783

Emergency Cardiac Pacing. Chapter 16. Pericardiocentesis. Chapter 17. CPR and Artificial Perfusion during Cardiac Arrest ...
more infohttps://evolve.elsevier.com/cs/product/9780323354783?role=student

Patents filed at Jan 30 2018 | Cardiac pacing with anodal stimulation detection | Patents.comPatents filed at Jan 30 2018 | Cardiac pacing with anodal stimulation detection | Patents.com

System and method for assessing and selecting stimulation vectors in an implantable cardiac resynhronization... , Methods and ... Artificial airway interfaces and methods thereof. Embodiments of the present invention provide a device, system and method for ... Cardiac pacing with anodal stimulation detection. Methods and device for determining a pacing vector for delivering an ... Multi-piece dual-chamber leadless intra-cardiac medical device and method of implanting same. A leadless intra-cardiac medical ...
more infohttp://www.patents.com/isd-20180130-p74.html

Transcutaneous Cardiac Pacing: Background, Indications, ContraindicationsTranscutaneous Cardiac Pacing: Background, Indications, Contraindications

... this topic focuses on transcutaneous cardiac pacing. Newer techniques (eg, using transcutaneous ultrasound to stimulate the ... Temporary cardiac pacing can be implemented via the insertion or application of intracardiac, intraesophageal, or ... An artificial electrical pacing stimulus in the heart induces a propagating wave of cardiac action potentials. For a pacing ... Transcutaneous cardiac pacing (the fastest method of cardiac pacing) can be used until permanent pacing becomes available. ...
more infohttps://emedicine.medscape.com/article/98939-overview

Multiple-Sensor Systems for Physiologic Cardiac Pacing | Annals of Internal Medicine | American College of PhysiciansMultiple-Sensor Systems for Physiologic Cardiac Pacing | Annals of Internal Medicine | American College of Physicians

To review the status of artificial sensors in cardiac pacemakers and the rationale for developing pacing systems that use ... Articles describing clinical experience with or clinical evaluation of cardiac pacing systems using multiple artificial sensors ... Artificial sensors were created to adjust pacing rate reliably in response to changes in levels of physical exertion for ... Multiple-Sensor Systems for Physiologic Cardiac Pacing David G. Benditt, MD; Marcus Mianulli, BS, BA; Keith Lurie, MD; Scott ...
more infohttp://annals.org/aim/article-abstract/708272/multiple-sensor-systems-physiologic-cardiac-pacing

Electrical approach to improve left ventricular activation during right ventricle stimulationElectrical approach to improve left ventricular activation during right ventricle stimulation

Palabras clave : Artificial cardiac pacing; Cardiac electrophysiological study; Coronary sinus; Cardiac resynchronization ... activation time could be useful to search the optimum pacing site and would also enable detection of non-responders to cardiac ... Herein, we propose to use it to assess which right ventricular pacing modality produces the shortest left ventricular ... Finally, SEPHO resulted the best pacing modality, because it narrowed QRS-complexes and shortened left ventricular activations ...
more infohttp://www.scielo.org.ar/scielo.php?script=sci_abstract&pid=S0025-76802017000100002&lng=es&nrm=iso&tlng=en

PPT - ELECTROCARDIOGRAMs (ECGs) PowerPoint Presentation - ID:175761PPT - ELECTROCARDIOGRAMs (ECGs) PowerPoint Presentation - ID:175761

Cardiac Wellness Institute of Calgary. ELECTROCARDIOGRAMs (ECGs). Updated May 2010. Material to be Covered. ACSMs Resource ... Artificial cardiac pacing * Emphysema * Hyperkalemia * Wolff-Parkinson-White syndrome - right sided accessory pathway ... so what does a cardiac physiologist do?. ecgs ambulatory monitoring exercise testing cardiac ultrasounds (aka echocardiograms ... fast & easy ecgs - a self-paced learning program. q. i. a. atrial dysrhythmias. originate in the atrial tissue or in the ...
more infohttps://www.slideserve.com/Pat_Xavi/electrocardiograms-ecgs

Common Questions About Pacemakers - - American Family PhysicianCommon Questions About Pacemakers - - American Family Physician

Cardiac resynchronization therapy in patients with a QRS of 120 to 150 milliseconds does not reduce rates of hospitalization or ... but there is insufficient evidence to support the use of cardiac resynchronization therapy in patients with class I heart ... Cardiac resynchronization therapy improves mortality rates and some other disease-specific measures in patients who have a QRS ... Guidelines for cardiac pacing and cardiac resynchronization therapy. Europace. 2007;9(10):959-998. ...
more infohttps://www.aafp.org/afp/2014/0215/p279.html

US4091818A - Cardiac pacing apparatus with electromagnetic interference protection 
        - Google PatentsUS4091818A - Cardiac pacing apparatus with electromagnetic interference protection - Google Patents

The second channel may receive an input from either a conventional cardiac sensing and pacing electrode, or else a second ... and the pacing apparatus is switched to a safe operating rate upon the detection of electromagnetic interference having an ... an override of the conventional demand pacer inhibit function occurs and the pacing apparatus is switched to a safe operating ... A cardiac pacing apparatus of the type having a first signal processing channel which functions in the demand mode is disclosed ...
more infohttps://patents.google.com/patent/US4091818A/en

Patent US7763075 - Artificial disc prosthesis - Google PatentsPatent US7763075 - Artificial disc prosthesis - Google Patents

A visco-elastic motion-limiting artificial intervertebral disc prosthesis is provided that mimics the physiologic function of a ... Method and apparatus for placing a coronary sinus/cardiac vein pacing and defibrillation lead with adjustable electrode spacing ... Biaxial artificial disc replacement. US7291171. 7 Oct 2003. 6 Nov 2007. Ferree Bret A. Artificial disc replacement (ADR) using ... Artificial disc replacements with natural kinematics. US6723127. 21 Jun 2002. 20 Apr 2004. Spine Core, Inc.. Artificial ...
more infohttp://www.google.co.uk/patents/US7763075

DailyMed - AMLODIPINE AND BENAZEPRIL HYDROCHLORIDE- amlodipine and benazepril hydrochloride capsuleDailyMed - AMLODIPINE AND BENAZEPRIL HYDROCHLORIDE- amlodipine and benazepril hydrochloride capsule

Emergency supportive measures such as artificial ventilation or cardiac pacing should be instituted if appropriate. ... As with other calcium channel blockers, hemodynamic measurements of cardiac function at rest and during exercise (or pacing) in ... The contractile processes of cardiac muscle and vascular smooth muscle are dependent upon the movement of extracellular calcium ... with a greater effect on vascular smooth muscle cells than on cardiac muscle cells. Negative inotropic effects can be detected ...
more infohttps://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=162383ed-94ac-4220-9b28-9f7610553279

DailyMed - AMLODIPINE AND BENAZEPRIL HYDROCHLORIDE - amlodipine and benazepril hydrochloride capsuleDailyMed - AMLODIPINE AND BENAZEPRIL HYDROCHLORIDE - amlodipine and benazepril hydrochloride capsule

Emergency supportive measures such as artificial ventilation or cardiac pacing should be instituted if appropriate.. In the ... As with other calcium channel blockers, hemodynamic measurements of cardiac function at rest and during exercise (or pacing) in ... The contractile processes of cardiac muscle and vascular smooth muscle are dependent upon the movement of extracellular calcium ... with a greater effect on vascular smooth muscle cells than on cardiac muscle cells. Negative inotropic effects can be detected ...
more infohttps://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=99ed4927-9a34-4e8d-8eea-60b63c867d46

Inhibition of Unnecessary RV Pacing With AV Search Hysteresis in ICDs  - American College of CardiologyInhibition of Unnecessary RV Pacing With AV Search Hysteresis in ICDs - American College of Cardiology

Keywords: Odds Ratio, Coronary Artery Disease, Follow-Up Studies, Cardiac Pacing, Artificial, Diuretics, Heart Failure, ... but not for pacing. There are several major differences between the trials, including pacing at a lower threshold in the ... use of dual-chamber DDDR AVSH pacing was noninferior to single-chamber VVI-40 pacing for death or heart failure hospitalization ... Inhibition of Unnecessary RV Pacing With AV Search Hysteresis in ICDs - INTRINSIC RV. May 24, 2006 Share via: ...
more infohttp://www.acc.org/latest-in-cardiology/clinical-trials/2013/05/24/12/14/intrinsic-rv

The Pacing Therapies for Congestive Heart Failure (PATH-CHF) Study - American College of CardiologyThe Pacing Therapies for Congestive Heart Failure (PATH-CHF) Study - American College of Cardiology

Keywords: Cardiac Pacing, Artificial, Quality of Life, Heart Failure, Electrocardiography, Questionnaires, Cardiomyopathy, ... The patient was then randomized to univentricular or biventricular pacing. The optimal pacing site and AV delay when pacing the ... Impact of cardiac resynchronization therapy using hemodynamically optimized pacing on left ventricular remodeling in patients ... Patients were paced for 4 weeks followed by 4 weeks without pacing, and finally crossed over the the other modality ( ...
more infohttps://www.acc.org/latest-in-cardiology/clinical-trials/2010/02/23/19/14/pathchf

Patente US20040049236 - Apparatus and method for reversal of myocardial remodeling with electrical ... - Google PatentesPatente US20040049236 - Apparatus and method for reversal of myocardial remodeling with electrical ... - Google Patentes

A ventricle is paced by delivering one or more stimulatory pulses in a manner such that a stressed region of the myocardium is ... most patients can still maintain more than adequate cardiac output with artificial pacing. ... The myocardium at pacing site 210 is shown as being hypertrophied as compared to the myocardium at pacing site 220. A cardiac ... Cardiac Pacemakers, Inc.. System and method for timing synchronized pacing. US6628988 *. 27 Abr 2001. 30 Sep 2003. Cardiac ...
more infohttp://www.google.es/patents/US20040049236
  • This study sought to evaluate the clinical effect of hemodynamically optimized univentricular or biventricular pacing compared to no pacing in patients with advanced congestive heart failure. (acc.org)
  • Pacing would lead to improved clinical benefit in patients with congestive heart failure when compared to no pacing. (acc.org)
  • 1. Auricchio A, Stellbrink C, Sack S, Block M, Vogt J, Bakker P, Mortensen P, Klein H. The Pacing Therapies for Congestive Heart Failure (PATH-CHF) study: rationale, design, and endpoints of a prospective randomized multicenter study.Am J Cardiol 1999 Mar 11;83(5B):130D-135D. (acc.org)
  • There are several major differences between the trials, including pacing at a lower threshold in the present trial (60 bpm vs. 70 bpm in DAVID) and the patient population, which in INTRINSIC RV excluded patients with >20% RV pacing in the first week. (acc.org)
  • 2 . The method of claim 1 wherein the AV pacing delay interval is set to equal a linear function of the V-V interval subtracted from a measured intrinsic AV delay interval. (google.es)
  • This invention relates to cardiac pacers and relates more particularly to pacers having enhanced electromagnetic interference (EMI) protection properties. (google.com)
  • This study aims to investigate the impact of antitachycardia pacing ( ATP) on the myocardial tissue with respect to its potential micro damage measured by several myocardial markers, especially by high-sensitive TroponinT. (bioportfolio.com)
  • The optimal pacing site and AV delay when pacing the right, left, or right and left ventricles were determined using a computer generated protocol. (acc.org)
  • They were randomly assigned to 2 groups: 28 patients to no therapy (nonpacing group), and 32 to VVI (n = 18) or DDD (n = 14) pacemaker implant (pacing group). (isharonline.org)
  • AV-Block of higher degree is the primary indication for pacing therapy for about 20% of pacemaker patients. (clinicaltrials.gov)
  • This study examined whether the various hemodynamic collapse patterns observed during tilt testing in patients with suspected neurocardiogenic syncope are relevant when planning therapy, particularly whether a predominantly cardioinhibitory response predicts a beneficial response from pacing. (biomedsearch.com)
  • The second channel may receive an input from either a conventional cardiac sensing and pacing electrode, or else a second electrode, remote from the heart, may be provided for interference detection. (google.com)
  • In an alternate embodiment, the gain of the second signal processing channel is reduced with respect to that of the first channel, and the pacing apparatus is switched to a safe operating rate upon the detection of electromagnetic interference having an amplitude level above that of natural cardiac signals. (google.com)
  • A visco-elastic motion-limiting artificial intervertebral disc prosthesis is provided that mimics the physiologic function of a normal spinal disc. (google.co.uk)
  • When electromagnetic interference is detected by the second signal processing channel, an override of the conventional demand pacer inhibit function occurs and the pacing apparatus is switched to a safe operating rate, which may be either an appropriate predetermined fixed rate or a rate-limited rate synchronous with the detected electromagnetic interference. (google.com)