The purpose of this study was to assess altered left ventricular diastolic filling by noninvasive means in patients with coronary artery disease and normal systolic pump function. Mitral inflow velocity was measured by pulsed Doppler, and left ventricular volumes were obtained from cross-sectional echocardiography at rest and during upright bicycle exercise. Peak and integrated early and late diastolic filling velocities were calculated from Doppler-derived time-velocity curves. Studies were performed in normal subjects (group I, n = 8) and in patients with angiographically proven coronary artery disease (Group II, n = 18). The ejection fraction was not significantly different in group II as compared to group I (group I, 60 +/- 7%; group II, 55 +/- 11%). During exercise, ejection fraction increased significantly in group I by 7.6%, but did not increase in group II. In all cases, diastolic filling showed a biphasic pattern. At rest, the major part of diastolic filling occurred during early diastole: the ratio of early filling velocity integral (E) to the late filling velocity integral (L) was significantly greater in group I than in group II (group I, 1.74 +/- 37; group II, 1.19 +/- 3, P less than 0.001). During exercise, early diastolic filling was unchanged in normal subjects but decreased in patients, with a significant decrease in E/L index of 34% (P less than 0.001). Thus, pulsed Doppler echocardiography provides a useful method for assessing noninvasively exercise-induced changes in left ventricular diastolic filling dynamics in patients with coronary artery disease.