We performed postexercise two-dimensional echocardiography in 21 patients with sarcoidosis but no signs of ischemic heart disease and in 24 normal control subjects. This was done to assess global and regional left-ventricular (LV) function and to try to identify the presence of occult myocardial involvement among sarcoidosis patients. All 21 sarcoidosis patients had a normal resting left-ventricular ejection fraction (LVEF) and echocardiogram. An abnormal LV response to exercise was detected in 10 sarcoidosis patients in the form of a significant decrease in mean LVEF with exercise without concomitant clinical and ECG evidence of myocardial ischemia. Seven of these 10 patients were found to have a pathological increase in LV and systolic volume with exercise, although it did not achieve statistical significance. In addition, markedly abnormal regional septal wall motion was noted in two of these patients. In the remaining 11 sarcoidosis patients, mean LVEF increased significantly with exercise. This is the normal ejection fraction response to stress. These 11 patients also showed that LV end-systolic volume decreased with exercise; the decrease was from 40.8 to 27.9 ml (P = 0.0004). In the control group, the mean LVEF increased from 69.5 +/- 7.2 at rest to 78.5 +/- 7.6 with exercise (P less than 10(-6)). We conclude that postexercise echocardiography is a noninvasive, simple, and safe method to detect and to follow the course of possible occult myocardial sarcoidosis.