Left ventricular (LV) filling as assessed by Doppler transmitral flow velocity measurements was studied in 20 male patients with coronary artery disease (CAD) and in 18 normal individuals. Stroke volume, blood pressure and heart rate in the two groups were not significantly different. Compared to normals, the ratio between early and atrial-induced peak velocities was significantly lower in the patients (1.2 +/- 0.3 vs. 1.40 +/- 0.3, P = 0.01), as was the fraction of transmitral filling during the first 1/3 of diastole (45 +/- 7% vs. 50 +/- 4%, P less than 0.001). Isovolumic relaxation time (IV R) was 96 +/- 13 ms in patients vs. 74 +/- 12 ms in normals (P less than 0.001). The CAD patients were treated with atenolol for 13-24 days. The velocity ratio increased by 30% (P less than 0.001) due to a 12% increase in early (P = 0.004) and an 11% decrease in atrial-induced peak velocities (P = 0.01). Filling fraction and deceleration rate of early inflow both increased by 22% (P less than 0.001). IV R decreased by 8% (P = 0.01). After atenolol treatment, heart rate and blood pressure decreased by 23% and 10% (P less than 0.001), respectively, whereas stroke volume increased by 14% (P less than 0.001). Thus, CAD was associated with Doppler indices of retarded LV filling and myocardial relaxation. After atenolol treatment, significant increases in velocity ratio and filling fraction indicated a shift of filling from late towards early diastole, suggesting improved diastolic function. However, different factors related to beta-adrenergic blockade may have contributed to the observed changes.