Background: Treatment with angiotensin converting enzyme inhibitors has been shown to be beneficial in patients with heart failure and myocardial infarction. Experimental studies have shown beneficial effects on the ischemic myocardium.
Methods and results: The effects of captopril were evaluated in 64 patients with left ventricular dysfunction after myocardial infarction. The patients were randomized at day 7 to either placebo or captopril (50 mg daily) in a double-blind parallel study over a period of 6 months. The patients were followed up by means of ambulatory ECG monitoring, bicycle ergometer testing, and echocardiographic examination. The duration of ST segment depression detected during ambulatory ECG monitoring was lower in the captopril group (87 minutes) than in the placebo group (638 minutes) (p < 0.001), and the number of patients in the captopril group with exercise-induced ST segment depression (p < 0.01) was lower at the completion of the study. The working capacity increased during the study period from 540 +/- 47 seconds to 738 +/- 41 seconds (p < 0.01) in the captopril group and was higher than that in the placebo group (530 +/- 43 seconds, p < 0.01) at the end of the study. Furthermore, a significant dilation of the left ventricular end-diastolic and end-systolic volumes was observed in the placebo group (p < 0.05); this was prevented in the captopril group where, in addition, a reduction in end-systolic volume was observed (p < 0.05).
Conclusions: Captopril has a favorable effect on the dysfunctioning myocardium after myocardial infarction inasmuch as the ischemic burden is reduced, the working capacity is increased, dilation of the left ventricle is prevented, and systolic function is improved.