The evolution of segmental wall motion in Q and non-Q wave acute myocardial infarction was studied in detail in 15 patients without known prior ischemic events. Serial two-dimensional echocardiographic studies were performed beginning early after the onset of chest pain and continuing until 10 to 14 days after admission. An area of apparent infarction was identified on each initial study based on later correlation of ECG and echocardiographic findings. Wall motion of infarct-and noninfarct-related areas was graded in a semiquantitative fashion based on the scoring of a visual analysis. Sequential image data demonstrated significant spontaneous improvement in wall motion of the infarct area in non-Q but not in Q wave events. Patients with non-Q wave infarction and improvement in regional function were at high risk for recurrent infarction within 6 months. Improvement in wall motion inside or outside the area of infarction in Q wave events was related to future risk. We concluded that in patients with initial acute myocardial infarction, failure to develop Q waves correlated with return of function in the apparent area of infarction. Improvement in regional wall motion after the initial study suggested risk for future ischemic events in both ECG types of myocardial infarction. Serial echocardiographic imaging may be a means to identify patients at risk for infarct extension in both non-Q and Q wave events.