What is the role of angiotensin-converting enzyme inhibitors in congestive heart failure and after myocardial infarction?

OBJECTIVE: To discuss the controversies surrounding the choice of angiotensin-converting enzyme (ACE) inhibitor, and the timing, dosage, and duration of ACE inhibitor therapy for congestive heart failure (CHF) and after myocardial infarction (MI). The beneficial effects of ACE inhibition in patients with CHF and after MI are reviewed. Human clinical trials are reviewed and their clinical implications are discussed. DATA SOURCES: MEDLINE searches (1985-1995) identified human clinical trials and review articles. DATA EXTRACTION: Landmark human clinical trials with morbidity and mortality end points were included. The validity of the study data were assessed on the basis of study methods, population characteristics, and statistical power. DATA SYNTHESIS: ACE inhibitors exert beneficial effects in patients with CHF by hemodynamic and neurohormonal mechanisms. The attenuation of ventricular remodeling that occurs with ACE inhibition does not fully explain the results of clinical trials in patients after MI. Routine determination of ejection fraction to guide ACE inhibitor therapy is not as important as the patient's clinical status. Clinicians should titrate the chosen ACE inhibitor on the basis of hemodynamic response to target doses used in major clinical trials. Because the beneficial effects of ACE inhibitors appear to be a class effect, choice of an agent should include cost considerations and the results of clinical trials. CONCLUSIONS: ACE inhibitor reduce morbidity and mortality in selected CHF and post-MI patients. Patients with symptomatic CHF benefit most from ACE inhibitor therapy, and it should be continued indefinitely. Treatment effects in asymptomatic patients are delayed. The role of ACE inhibitor therapy in preventing morbidity and morality in asymptomatic patients with preserved ventricular function requires further study.