Converting enzyme inhibition and heart failure.

Angiotensin converting enzyme inhibitors are known to improve cardiac performance in patients with severe heart failure, and are probably safer and more effective than other vasodilators. Less is known about their effects in mild and moderate heart failure. Results at one year are presented about an ongoing double-blind, placebo-controlled parallel-group study on 94 outpatients in New York Heart Association functional class II and III. After a three-week period during which appropriate doses of digoxin were administered and a stable response to exercise was obtained, diuretic therapy was withdrawn if in use and captopril or placebo treatment was assigned randomly. The assessment of patients was performed by symptom history, clinical examination, New York Heart Association functional class, chest radiograph, 12-lead electrocardiogram, 24-hour Holter monitoring, M-mode echocardiography, and bicycle exercise at the time of random selection and at specified times during a two-year follow-up. Preliminary data after one year suggest that patients receiving placebo may have a greater tendency to need diuretics and may improve New York Heart Association functional class less often than those receiving captopril. No statistically significant treatment differences were found for the noninvasive test results. Detailed analysis suggests that treatment with an angiotensin converting enzyme inhibitor may be more advantageous than that with placebo for some groups of patients. Investigations are under way to determine which patients might benefit most from angiotensin converting enzyme inhibitors.