BACKGROUND AND OBJECTIVES: Angiotensin converting enzyme inhibitor and aniotensin II receptor blocker have been used in the treatment of heart failure. However, the effects of both agents are not known exactly in patients with ischemic heart failure. The clinical effects of Imidapril, Losartan and its combination on ischemic heart failure were observed after percutaneous coronary interventions (PCI). METHODS: Thirty six patients (58+/-8.8 year-old, 30 male) with myocardial infarction who underwent PCI with ejection fraction less than 45% by echocardiogram were included. The patients were divided into four groups; low (5 mg) and high (10 mg) doses of Imidapril (Group I: 58+/-6.1 years, M:F=:2 and II: 61+/-6 years, M:F=:1), combination of low dose Imidapril and 50 mg Losartan (Group III: 56+/-13 years, M:F=:0), and Losartan alone (Group IV: 57+/-9.3 years, M:F=:3). Clinical symptoms of angina and dyspnea, laboratory changes, exercise tolerance by treadmill test, and left ventricular function with dimension, and wall motion score by echocardiogram were observed at 4-week interval for 12 weeks. RESULTS: There were no significant differences among 4 groups in baseline clinical characteristics. In Group I, dyspnea and ejection fraction improved 12 weeks after therapy. Dyspnea and exercise tolerance improved in Group II. However, dyspnea and left ventricular function were unchanged in Group III, and 4 of them developed hypotension. In Group IV, left ventricular ejection fraction improved after therapy. Dry cough observed in 3 of Imidapril-treated patients, but withdrawal of drug was performed only in one of Group II. CONCLUSIONS: Monotherapy of Imidapril or Losartan is effective in the management of ischemic heart failure, but its combination shows no additional benefit.