To study the importance of giving an angiotensin-converting enzyme (ACE) inhibitor to patients with reduced systolic function after an infarction, the Trandodolapril Cardiac Evaluation study was designed to include the majority of patients with echocardiographic signs of left ventricular dysfunction among consecutively screened patients with infarctions. A total of 2606 consecutive patients with left ventricular systolic dysfunction corresponding to an ejection fraction < or = 35% were identified. Of these patients, 1749 (67%) were randomly assigned to receive oral trandolapril or placebo beginning on day 3 to 7 after the infarction. The follow-up period was 2 to 4 years. Trandolapril reduced all-cause mortality, with a relative risk reduction associated with trandolapril treatment of 0.78 (p = 0.0013). Benefit was seen within 1 month of treatment. Trandolapril also reduced cardiovascular death (relative risk 0.75, p = 0.001), sudden death (relative risk 0.76, p = 0.03), and progression to severe/ resistant heart failure (relative risk 0.71, p = 0.003). Recurrent myocardial infarction (fatal or nonfatal) was not significantly reduced (relative risk 0.86, p = 0.29). More than 80% of patients in both treatment groups reached the target dose of 4 mg trandolapril or placebo at the end of dose titration. Nearly half of the patients in both treatment groups discontinued taking study medication before death or trial closure. The need for open-label ACE inhibition was the reason for discontinuation for 48 and 75 patients in the trandolapril and placebo groups, respectively. In conclusion, long-term treatment with trandolapril in patients with reduced left ventricular function shortly after myocardial infarction significantly reduced mortality and morbidity. Most patients received the target dose of 4 mg trandolapril daily. The benefit observed is likely to reflect the benefit in clinical practice because the majority of eligible patients were randomized and the difference in patients leaving the trial to receive open-label ACE inhibition was moderate.