The Annals of Thoracic Surgery, Vol 51, 81-85, Copyright © 1991 by The Society of Thoracic Surgeons
Amiodarone versus bretylium for suppression of reperfusion arrhythmias in dogs
A Rosalion, NJ Snow, TP Horrigan, DL Noon and ND Mostow
Department of Surgery, MetroHealth Medical Center, Cleveland, Ohio 44109.
Reperfusion arrhythmias are an important complication of interventions to
limit infarct size. Recently, amiodarone has been shown to be rapidly
effective in suppressing sustained, incessant ventricular tachycardia and
ventricular fibrillation in this setting. This study evaluated the time
course of arrhythmia suppression and comparative efficacy of amiodarone
versus bretylium in a canine model of reperfusion arrhythmias. Of 23 dogs
subjected to a Harris two-stage coronary artery ligation followed by
release, 18 demonstrated clinically significant ventricular arrhythmias and
received either intravenous amiodarone, 5 mg/kg (9 dogs), or intravenous
bretylium, 5 mg/kg (9 dogs). Direct-current shocks for sustained
ventricular tachycardia or ventricular fibrillation were administered as
necessary. Amiodarone rapidly suppressed sustained ventricular tachycardia
and ventricular fibrillation in this model with no dog in the amiodarone-
treated group requiring cardioversion after completion of the 15-minute
infusion versus 4 of 9 dogs in the bretylium-treated group (p less than
0.05). Amiodarone was more effective than bretylium in suppressing episodes
of sustained ventricular tachycardia/ventricular fibrillation, episodes of
nonsustained ventricular tachycardia, and premature ventricular complexes.
The blood pressure and heart rate decreased more after amiodarone
administration than after bretylium administration. We conclude that, in
the canine reperfusion arrhythmia model, amiodarone is rapidly effective in
suppressing ventricular arrhythmias and is more effective than bretylium.
