BACKGROUND: Ventricular remodeling after acute myocardial infarction (AMI) is associated with increased morbidity and mortality. ELITE II study showed that losartan, an angiotensin receptor blocker, shows a survival benefit to the same degree as captopril, an angiotensin-converting enzyme inhibitor, does in patients with heart failure. However, recent OPTIMAAL study showed that clinical outcomes after losartan are not superior to those after captopril in patients with AMI. We examined the effect of losartan on ventricular remodeling after AMI comparatively with that of enalapril. METHODS: We enrolled 203 consecutive patients with AMI (mean age 62 +/- 11 years). All patients underwent primary percutaneous coronary intervention and were randomly assigned to losartan (25-50 mg, n = 101) or enalapril (2.5-10 mg, n = 102) treatment. Biplane left ventriculography was performed just after primary percutaneous transluminal coronary angioplasty (acute phase) and 6 months after the onset of AMI. RESULTS: Any of the maximal creatine kinase level, left ventricular end-diastolic volume index, end-systolic volume index, and ejection fraction measured at acute phase was not different between losartan and enalapril groups. However, changes in left ventricular end-diastolic index (18 +/- 25 vs 8 +/- 24 mL/m2) and left ventricular end-systolic volume index (10 +/- 20 vs 2 +/- 18 mL/m2) from acute phase to 6 months were significantly greater in losartan than in enalapril group. Change in left ventricular ejection fraction (0.2% +/- 10.3% vs 3.4% +/- 11.6%) from acute phase to 6 months was significantly smaller in losartan than in enalapril group. The plasma level of brain natriuretic peptide at 6 months was significantly higher in losartan than in enalapril group (all P < .05). CONCLUSION: These indicate that enalapril suppresses ventricular remodeling after AMI more effectively than losartan.