Coronary angioplasty is frequently performed in a vessel with corresponding regional wall motion abnormalities. However, late improvement of left ventricular function remains questionable in many cases and is difficult to predict. A retrospective analysis of 115 patients with single vessel disease and corresponding abnormal regional left ventricular function at the time of coronary angioplasty was performed. All patients had control coronary angiography and a new contrast ventriculography 5.6 +/- 3.1 months later (range 0.8-11.8 months). Among those patients, 61 (53%) showed improvement of regional left ventricular function, which was not seen in the 54 (47%) others. Global ejection fraction increased significantly in the former group, whereas it remained unchanged in the later group. Before angioplasty, patients with and without improvement of systolic left ventricular function were indistinguishable in terms of history, medication, rest and stress electrocardiogram, and angiographic characteristics. During angioplasty, angina was more frequent (65% vs. 44%, p < 0.02) in patients with subsequent left ventricular functional improvement. At follow-up study, significant angiographic restenosis was more frequently encountered (68% vs. 43%, p < 0.05) in patients with no evidence of functional improvement. Thus, coronary angioplasty in a vessel responsible for left ventricular systolic dysfunction is followed in only half the cases by improvement of this parameter. No predictor of the functional outcome of the myocardium can be pointed out before the procedure is performed.