To characterize determinants of the rate of recovery of left ventricular (LV) function after exercise-induced ischemia, sequential postexercise radionuclide angiography was performed prospectively in 38 consecutive patients with documented coronary artery disease (CAD). In each patient new or increased regional asynergy developed or absolute ejection fraction decreased at least 4% during exercise. Twenty patients showed immediate recovery of LV function after exercise (group 1) and 18 showed delayed recovery (group 2). Ejection fraction in the first postexercise period was significantly greater in group 1 (65 +/- 12%) than in group 2 (55 +/- 11%) (p less than 0.01). The mean number of coronary arteries with at least 70% diameter narrowing was greater in group 2 (2.7 +/- 0.5) than in group 1 (2.0 +/- 0.9) (p = 0.026); CAD score was also greater in group 2 than in group 1 (p = 0.005). The increase in LV end-diastolic volume from rest to end exercise was greater in group 2 than in group 1 (p = 0.005); neither the change in LV volume nor the change in heart rate or blood pressure after exercise separated the groups. The only independent predictor of the rate of functional recovery was the degree of exercise-induced regional myocardial asynergy (p less than 0.001). Thus, exercise radionuclide angiography in patients with CAD provides a model for evaluating postischemic myocardial function. Delayed functional recovery is associated with extensive exercise-induced regional asynergy as a result of severe CAD and is not primarily influenced by hemodynamic changes.