Comparison of cardiac electrophysiologic effects of experimental hypothyroidism and chronic oral amiodarone administration in dogs.
A comparative study on ventricular electrophysiologic effects of experimental hypothyroidism and chronic oral amiodarone administration was made in canine models, with the application of electrical stimulation and monophasic action potential recording. The results showed similar effects possessed by hypothyroidism and amiodarone, which included prolongations in ventricular repolarization and refractoriness, an increase in ventricular fibrillation threshold, and a decrease in the incidence of reperfusion ventricular fibrillation. The differences were that hypothyroidism primarily lengthened phase 2 repolarization and had no effects on intraventricular conduction time, whereas amiodarone lengthened both phase 2 and phase 3 repolarization and suppressed myocardial conduction velocity.
Liu
P M
PM
Department of Medicine, Sun Yat-sen Memorial Hospital, Sun Yat-sen University of Medical Sciences, Guangzhou.
Zhang
X M
XM
Wu
W
W
Li
J M
JM
Tang
Y
Y
D000638:Amiodarone / Q000008:administration & dosage / Q000494:pharmacology; D000818:Animals; D004285:Dogs; D004562:Electrocardiography; D004594:Electrophysiology; D005260:Female; D006329:Heart Conduction System / Q000187:drug effects / Q000503:physiopathology*; D007037:Hypothyroidism / Q000503:physiopathology*; D008297:Male; D011897:Random Allocation; D014693:Ventricular Fibrillation / Q000517:prevention & control
D000638:Amiodarone