To determine the effects of changes in coronary stenosis on left ventricular diastolic filling, diastolic filling was serially examined before and after percutaneous transluminal coronary angioplasty using pulsed Doppler echocardiography in 50 patients with stable exertional angina pectoris. Peak rapid filling velocity and the ratio of peak atrial filling to peak rapid filling velocities were measured from the transmitral flow velocity pattern before and 2 and 9 days after coronary angioplasty. Peak rapid filling velocity increased and the ratio of peak atrial filling to peak rapid filling velocities decreased gradually after coronary angioplasty. The improvement in left ventricular diastolic filling was greater in patients with severe (greater than 90%) coronary stenosis than in patients with mild (less than or equal to 90%) coronary stenosis. In the long-term follow-up period, the improved left ventricular diastolic filling worsened in only 11 patients with marked progression to greater than 90% coronary stenosis. Thus, left ventricular diastolic filling improved gradually after coronary angioplasty, possibly reflecting post-ischemic "stunned" myocardium. Serial examinations of left ventricular diastolic filling with pulsed Doppler echocardiography may be a means of noninvasively assessing the temporal changes in the coronary stenosis and predicting the occurrence of coronary restenosis after coronary angioplasty.