The authors examined the effects of a long-term treatment with the angiotensin-converting enzyme inhibitor, alacepril, with respect to the reversal of left ventricular hypertrophy and the improvement of left ventricular function. Ten uncomplicated essential hypertensive patients with left ventricular hypertrophy, aged 53 +/- 8 years, were treated with alacepril alone for 12 months. All patients underwent echocardiography to assess left ventricular dimensions and function before and after the treatment. After the treatment, blood pressure was decreased significantly from 163 +/- 14.1198 +/- 4.2 to 142 +/- 20.31 86 +/- 11.0 mm Hg (each, P < .01), whereas heart rate did not change (66 +/- 6 versus 69 +/- 8 beats/min). The left ventricular mass index was decreased significantly from 146 +/- 27 to 119 +/- 29 g/m2 (P < .01). Ejection fraction, fractional shortening, peak shortening rate, and peak lengthening rate all improved significantly after the treatment. There was a significant inverse relationship between fractional shortening and end-systolic wall stress before the treatment (r = .63, P < .05), and this relationship did not change after the treatment. It is concluded that alacepril improved both left ventricular systolic and diastolic function without causing any consistent augmentation of left ventricular contractility.