The effect of medical treatment without reperfusion therapy on the long-term recovery of regional wall motion was evaluated retrospectively in 28 patients with transmural acute anterior myocardial infarction who had coronary angiography and left ventriculography at 1-6 months after the onset of the episode and were followed for a mean of 65 months. In all patients, initial coronary angiography revealed significant stenosis in only the left anterior descending artery (LAD). All patients were treated medically without reperfusion therapy (such as thrombolytic therapy, angioplasty, or bypass grafting). The regional wall motion in the LAD territory was measured by the centerline method using the right anterior oblique projection. Long-term improvement in anterior wall motion is unlikely in patients with patent LAD or underdeveloped collaterals to the LAD (38%). However, subsequent anterior wall motion frequently improved among patients with severely stenotic or occluded LAD (63%) and well-developed collaterals (73%). Therefore, the anterior wall motion of some LAD-related infarctions improves spontaneously, the extent of coronary collaterals is an important determinant of long-term improvement, and the improvement in wall motion is completed within the early period of acute anterior infarction in patients with patent LAD.