Clinical relevance of exercise-induced S-T segment elevation.

Patients with exercise-induced S-T elevation or S-T depression were evaluated with demographic, treadmill and angiographic data. When 541 patients with S-T depression were compared with 109 patients with S-T elevation, a greater proportion of the former had chest pain (71 versus 58 percent) and a normal-sized ventricle (86 versus 61 percent) with normal wall motion (54 versus 30 percent). A greater proportion of patients with S-T elevation had had a previous myocardial infarction (61 versus 33 percent). Among patients without prior infarction (360 with S-T depression and 42 with S-T elevation), these differences disappeared. In this group of 42 patients with S-T elevation, 83 percent had a normal-sized ventricle, 64 percent had normal contractility and none had a ventricular aneurysm; the severity of coronary disease and ventricular dysfunction did not differ from the severity in patients with S-T depression. Thus, in patients without prior myocardial infarction, the cause of the development of S-T elevation or S-T depression during exercise does not appear to be related to the severity of the coronary lesions, ventricular function or wall abnormalities at rest. In patients with prior myocardial infarction, exercise-induced S-T elevation appears to be a marker of depressed left ventricular function.