Abstract
In order to investigate the clinical significance of exercise-induced ST changes in patients with prior myocardial infarction, we performed an exercise tolerance test using bicycle ergometer, coronary arteriography and left ventriculography in 77 patients with prior myocardial infarction and compared exercise-induced ST changes with coronary arteriographic and left ventriculographic findings. At end-point time in the exercise test, we observed abnormal ST elevation in 36 patients (46.7%), ST depression in 11 (14.3%) and no significant ST changes in the remaining 30 (39.0%). After exercise, 29 out of 48 patients (60.4%) with prior anterior myocardial infarction had significant ST elevation, 9 (18.8%) had ST depression, and 10 patients (20.8%) had no significant ST changes. Of the 29 patients with exercise-induced ST elevation, 26 (89.6%) had no significant coronary lesion or simply had single vessel disease, and 6 of 9 patients with ST depression (66.7%) had multiple vessel disease. Furthermore, 18 of 29 patients with exercise-induced ST elevation (62.1%) had dyskinesis, 8 (27.6%) had akinsesis and only 3 (10.3%) had hypokinesis. On the other hand, only 2 of 9 patients with exercise-induced ST depression (22.2%) had dyskinesis, 5 had akinesis, and 2 had hypokinesis. Only 7 out of 29 patients (24.1%) with prior inferior myocardial infarction had ST elevation, 2 (6.9%) had ST depression, and no significant ST changes were observed in the remaining 20 (69.0%). No significant correlation was obtained between exercise-induced ST changes and coronary arteriographic and left ventriculographic findings. These findings strongly suggest that exercise-induced ST elevation is commonly observed in patients with anterior myocardial infarction and correlated with the severity of abnormal left ventricular wall movement, and ST depression is related with the extent of coronary artery lesion.
