sodium-ethylxanthate and Arrhythmias--Cardiac

Topics: Adult; Aging; Animals; Arrhythmias, Cardiac; Autonomic Nervous System; Cardiovascular Physiological Phenomena; Catecholamines; Female; Gonadal Steroid Hormones; Humans; Male; Middle Aged; Myocardial Ischemia; Obesity; Sex; Vasomotor System

There is increased awareness of the impact of gender and gonadal steroids on human cardiac rhythm and arrhythmias; e.g., drugs that prolong repolarization induce torsades de pointes (TdP) more frequently in women than men; female gender is an independent risk factor for syncope and sudden death in the congenital long QT syndrome; and the higher propensity toward arrhythmia in normal females is associated with fundamental differences in repolarization such that rate-corrected QT intervals are longer in females than males. Mechanisms underlying these differences are incompletely defined but are believed to involve gonadal steroids. This review discusses recent advances and prospects for further elucidation of the influence of gender and gonadal steroids on ventricular repolarization and arrhythmias.

Topics: Aging; Animals; Arrhythmias, Cardiac; Electrocardiography; Electrophysiology; Female; Gonadal Steroid Hormones; Humans; Ion Channels; Long QT Syndrome; Male; Myocardium; Phenethylamines; Potassium Channel Blockers; Rabbits; Receptors, Androgen; Receptors, Estrogen; Sex; Sulfonamides

Repolarization-prolonging drugs induce torsades de pointes (TdP) in females more than males. The action potential plateau and the early afterdepolarizations that induce TdP are determined, in part, by L-type calcium current (I(Ca,L)). Therefore, we studied gender- and hormone-related differences in I(Ca,L) in age-, and weight-matched normal male, female and hormonally-treated, castrated rabbits.. Oophorectomized (OVX) or orchiectomized (ORCH) 50- to 60-day-old rabbits were subcutaneously implanted with pellets impregnated with placebo (PLA), 5 alpha-dihydroxytestosterone (DHT), or 17 beta-estradiol (EST). Four to five weeks later, epicardial and endocardial myocytes were isolated from the left ventricle. Patch clamp technique was performed to assess I(Ca,L).. I(Ca,L) density (measured as peak current density [pA/pF] at +15 mV, V(h)= -40 mV), was greater in female epicardium (-7.4 +/- 0.9) than endocardium (-5.6 +/- 0.7, P<0.05), while male epicardial I(Ca,L) density (-6.5 +/- 0.7) did not differ from endocardial (-5.9 +/- 1.0, P>0.05). OVX-female, DHT and EST-treated groups had epicardial I(Ca,L) density (-5.6 +/- 0.6, and -5.9 +/- 0.7, respectively) greater than endocardial (-4.3 +/- 0.3, and -3.6 +/- 0.4, P<0.05). However, OVX-females had hormone levels not significantly different from female controls and EST-treated females had non-physiological levels of estradiol. There were no differences between endocardial and epicardial I(Ca,L) activation and inactivation. In contrast, epicardial-endocardial differences in I(Ca,L) density in EST-treated OVX-females were associated with epicardial-endocardial differences in I(Ca,L) activation and conductance; in DHT-treated OVX-females only epicardial-endocardial activation differed. The other groups, showed no I(Ca,L) transmural gradient, or differences in activation, inactivation or conductance.. The greater dispersion in I(Ca,L) density of OVX-DHT and OVX-EST than OVX-PLA suggests both hormones can modulate I(Ca,L) density in females. That gonadal steroids had no effect on I(Ca,L) dispersion in males suggests gender differences in mechanism of action of both hormones. The greater I(Ca,L) dispersion in females may contribute to gender differences in repolarization.

Topics: Analysis of Variance; Animals; Arrhythmias, Cardiac; Calcium Channels, L-Type; Dihydrotestosterone; Endocardium; Estradiol; Female; Gonadal Steroid Hormones; Male; Myocardium; Orchiectomy; Ovariectomy; Patch-Clamp Techniques; Pericardium; Rabbits; Sex

Topics: Adult; Aged; Alcoholism; Arrhythmias, Cardiac; Asian People; Female; Humans; Japan; Male; Middle Aged; Myocardial Infarction; Sex; Smoking

Topics: Adult; Aged; Aging; Arrhythmias, Cardiac; Female; Glucose; Heart Failure; Humans; Insulin; Male; Middle Aged; Myocardial Infarction; Potassium; Sex; Shock

Topics: Adrenalectomy; Animals; Arrhythmias, Cardiac; Body Temperature; Cardiac Complexes, Premature; Cats; Female; Heart; Heart Rate; Heart Ventricles; Hexamethonium Compounds; Male; Ouabain; Reserpine; Sex; Sympathetic Nervous System; Ventricular Fibrillation

Topics: Adolescent; Adult; Aging; Arrhythmias, Cardiac; Electrocardiography; Geriatrics; Health Surveys; Heart Block; Humans; Hyperglycemia; Hypertension; Michigan; Sex; Statistics as Topic

The mortality from acute myocardial infarction has remained unchanged over the past three decades. The records of 200 patients hospitalized because of acute myocardial infarction were analyzed at St. Paul's Hospital, Vancouver. Criteria for diagnosis were autopsy evidence and electrocardiographic evidence of acute muscle necrosis. Sixty-two patients died, 30 in the first three days and 41 in the first week; 33 of these deaths were due to cardiac arrhythmias, cardiac arrest or hypotension. Anticoagulants improved the mortality, but the degree of control was not a factor. Thromboembolism was significantly decreased by anticoagulants. Forty-nine patients died in shock; pressor amines did not improve the mortality in such cases. This study emphasizes the need for intensive care during the early critical period of the illness. Prompt adequate therapy of shock may improve the prognosis.

Topics: Acute Disease; Aging; Anterior Wall Myocardial Infarction; Anticoagulants; Arrhythmias, Cardiac; Critical Care; Diagnosis; Drug Therapy; Electrocardiography; Geriatrics; Heart Arrest; Humans; Hypotension; Intensive Care Units; Mortality; Myocardial Infarction; Sex; Shock; Statistics as Topic; Sympathomimetics; Thromboembolism

Topics: Arrhythmias, Cardiac; Cholesterol; Diabetes Mellitus; Epidemiology; Follow-Up Studies; Humans; Hungary; Hypertension; Myocardial Infarction; Nutritional Physiological Phenomena; Nutritional Sciences; Obesity; Occupations; Prognosis; Prothrombin; Sex; Smoking; Statistics as Topic

Topics: Arrhythmias, Cardiac; Arteriosclerosis; Atrial Fibrillation; Atrial Flutter; Cardiac Complexes, Premature; Cardiomegaly; Coronary Disease; Geriatrics; Heart Block; Heart Diseases; Heart Failure; Hypertension; Myocardial Infarction; Obesity; Sex; Statistics as Topic

Topics: Adolescent; Aortic Valve Stenosis; Arrhythmias, Cardiac; Biomedical Research; Digitalis; Digitalis Glycosides; Drug Therapy; Drug Tolerance; Electrocardiography; Humans; Mitral Valve Insufficiency; Mitral Valve Stenosis; Rheumatic Heart Disease; Sex; Toxicology

Topics: Arrhythmias, Cardiac; Biometry; Geriatrics; Heart Diseases; Humans; Incidence; Sex; Statistics as Topic

Topics: Adrenal Cortex Hormones; Anticoagulants; Arrhythmias, Cardiac; Cerebrovascular Disorders; Drug Therapy; Estrogens; Geriatrics; Heart Arrest; Heart Block; Heart Failure; Heart Massage; Humans; Hypertension; Italy; Mortality; Myocardial Infarction; Occupations; Oxygen Inhalation Therapy; Pacemaker, Artificial; Prognosis; Sex; Statistics as Topic; Thromboembolism; Thrombophlebitis