Comparison of the efficacy of propranolol and amiodarone in suppressing ventricular arrhythmias following myocardial infarction.

The purpose of this prospective randomized trial was to compare the efficacy of propranolol and amiodarone in suppressing ventricular arrhythmias during the first 6 months following myocardial infarction (MI). 97 patients were treated with either amiodarone (n = 48) or propranolol (n = 49) starting on the 9th day following MI. Holter monitoring was carried out on four occasions: on D7, D21, D90 and D180. There was no statistical difference in the incidence of 'major' arrhythmias (an average of at least 10 ventricular premature complexes (VPCs) h-1, multiform or paired VPCs or runs) between the two groups on D7. A significant difference in favour of amiodarone became apparent at D180 (P = 0.04). Patients were also classified according to whether treatment failed or was successful. 'Success' was recorded when arrhythmias remained minor or became minor (less than 10 uniform VPCs h-1) and 'failure' when arrhythmias remained major or became major, or when patients were withdrawn because of side-effects, or lost to follow-up. The difference remained in favour of amiodarone (P = 0.03 at D21; P = 0.05 at D90; P = 0.06 at D180). Evaluation of the percentage reduction in the number of VPCs at D21, D90 or D180 compared with D7 showed superiority of amiodarone at D90 (P less than 0.01) and D180 (P less than 0.04). In this study, the overall effect of amiodarone on ventricular arrhythmias following MI was shown to be superior to that of propranolol.