Dependence of Doppler echocardiographic transmitral early peak velocity on left ventricular systolic function in coronary artery disease. The influence of systolic function on pulsed Doppler echocardiographic transmitral flow velocity patterns was assessed before and after postextrasystolic (PES) potentiation in 12 normal subjects (control group) and in 25 patients with previous healed myocardial infarction (MI) group. Simultaneous high-fidelity left ventricular pressure measurements were performed in all patients. A programmed single-coupled right ventricular extrasystole was induced during echocardiographic and subsequent cineangiocardiographic recordings. Adequate angiograms for volumetric analysis in both baseline and PES beats were obtained in 23 patients (7 in the control group and 16 in the MI group). PES potentiation of contraction was more pronounced in the MI group than in the control group. PES changes in ejection fraction, stroke volume and end-systolic volume were significantly greater in the MI group than in the control group (11 vs 5%, p less than 0.005; 15 vs 5 ml/m2, p less than 0.005; and -13 vs -4 ml/m2, p less than 0.01, respectively). In contrast, PES potentiation prolonged the time constants of left ventricular pressure decline derived from exponential curve fits with a zero (Tw) and non-zero (Tb) asymptote pressure in the MI group to the same extent as in the control group (4 vs 5 ms, difference not significant [NS], and 9 vs 11 ms, NS, respectively). In the PES beat, peak E velocity remained unaltered (48 vs 49 cm/s, NS) in the control group, whereas it increased significantly (p less than 0.0001) from 47 to 51 cm/s in the MI group. 