Effects of captopril on ventricular arrhythmias in the early and late phase of suspected acute myocardial infarction: Randomized, placebo-controlled substudy of ISIS-4

The antiarrhythmic effect of oral captopril was studied during the early (day 3) and late (day 14) phase of acute myocardial infarction among 304 patients in a randomized placebo-controlled substudy of ISIS-4. Ventricular arrhythmias (ventricular ectopic beats per hour) occurred significantly less frequently among captopril-allocated patients than among those allocated placebo at day 3 (logarithmic scale: 0·48 ± 0·8 captopril vs 0·84 ± 1·3 placebo; P<0·003) and at day 14 (0·51 ± 1·0 vs 0·77 ± 1·3; P<0·05). The number of patients with frequent ventricular arrhythmias (more than 10 ventricular ectopic beats per hour) was also significantly lower among those allocated captopril at day 3 (7·3% vs 14·4% P<0·05) and at day 14 (7·3% vs 14·8%; P<0·05). These results support the hypothesis that the activation of the renin-angiotensin-aldosterone and sympathetic system may underlie heart rhythm disturbances in acute myocardial infarction, and that early use of converting enzyme inhibitor therapy may ameliorate these disturbances. (Eur Heart J 1996; 17: 1506–1510)