To evaluate the time course of spontaneous changes in wall motion following anterior infarction, we prospectively performed serial apical four-chamber two-dimensional echocardiography on 45 consecutive long-term survivors of initial transmural anterior infarction. Studies were performed on admission (1 +/- 1 days), 1 week after admission (6 +/- 2 days), at discharge (15 +/- 8 days), and at long-term follow-up (235 +/- 186 days). Ventricular size was expressed as end-diastolic area in square centimeters. Wall motion for this tomographic section was evaluated as the percent change in left ventricular area from end diastole to end systole (% LVA). Patients were grouped on the basis of significant differences for %LVA between the first and fourth studies. Group I (n = 14) had improved wall motion (23 +/- 5% to 38 +/- 9%); group II (n = 23) did not change (22 +/- 9% to 23 +/- 11%); and group III (n = 8) had worsened wall motion (28 +/- 6% to 18 +/- 7%). End-diastolic area did not change over the study period for groups I and II but increased significantly for group III (30 +/- 6 to 35 +/- 4 cm2, p less than 0.05). Most of the increase in end-diastolic area for group III was between the third and fourth study. The percent improvement (%IMP) in wall motion for patients in group I who did not have ventricular fibrillation outside the hospital expressed in days (t) following infarction fit an exponential curve (%IMP = 100-100e-(.108t) that predicts that 70% of eventual recovery will occur in the first 15 days post-infarction. We conclude that changes in left ventricular size and wall motion occur following anterior infarction with improvement or worsening occurring spontaneously in some patients. If improvement occurs, it should be evident within 2 weeks of infarction; infarct expansion in this select group of long-term survivors occurred primarily after discharge.