Our objective was to investigate the significance of the slow resolution of ST-segment elevation following a successful direct percutaneous transluminal coronary angioplasty (PTCA). ST-segment elevations were calculated from electrocardiograms recorded before PTCA and 1 hour after reperfusion. Forty-nine patients experiencing their first anterior acute myocardial infarction and who had undergone direct PTCA were classified into 3 groups: 17 patients with rapid ST resolution (group I), 23 patients with persistent ST elevation (group II), and 9 patients with ST reelevation (group III). Left ventricular function was evaluated by using single-plane cineventriculography performed in the acute stage, at discharge, and 4 months later. Peak creatine kinase activity was significantly increased: group III (4,046 +/- 634 IU), group II (3,336 +/- 772 IU), and group I (2,410 +/- 994 IU); p <0.05. Ejection fraction and regional wall motion in the acute stage were identical in each group. However, they were significantly higher in group I (67 +/- 6%, -1.01 +/- 0.30), followed by group II (56 +/- 6%, -1.90 +/- 0.41) and group III (38 +/- 7%, -2.79 +/- 0.46); p <0.01 4 months later. Multiple regression analysis revealed that the ST resolution was the only significant variable that indicated the recovery of regional wall motion. A good linear correlation was documented between the ST resolution and the recovery of regional wall motion. We concluded that a slow ST resolution after successful direct PTCA is a negative predictor of recovery of left ventricular function, especially when ST reelevation is evident.