Impaired left ventricular diastolic function is often found preceding systolic functional abnormality in coronary artery disease. To assess whether captopril improves diastolic function, radionuclide ventriculography was performed before and 1 h after captopril administration in 10 stable effort angina patients with severe isolated stenosis of the left anterior descending coronary artery and in 8 controls. Resting global peak filling rate (PFR) was significantly (p < 0.05) reduced in association with significantly (p < 0.01) increased left ventricular diastolic asynchronous index (delta t) in patients with angina pectoris. Neither global PFR nor regional cardiac function was affected by captopril, although delta t was significantly (p < 0.05) reduced from 70 +/- 18 (SD) to 51 +/- 25 ms in patients with angina pectoris. A significant (p < 0.01) correlation was observed between percentage changes in peak ejection rate and in PFR in all subjects. Thus, captopril improves left ventricular asynchrony in patients with stable angina, although global diastolic function affected by systolic function remains unchanged.