Dissociation between regional myocardial dysfunction and ECG changes during myocardial ischemia induced by exercise in patients with angina pectoris.

In order to investigate the relation between regional myocardial function and electrical changes during myocardial ischemia in humans, left ventricular echocardiogram and ECG were recorded during supine ergometer exercise in 16 patients with coronary artery disease until angina or ischemic ECG appeared. During exercise in 13 patients a decrease of left ventricular posterior wall excursion or of interventricular septum excursion occurred earlier than the appearance of ST-T change on ECG. In two patients the excursion decreased at the same time as the ST-T change. Significant regional myocardial dysfunction occurred at 30 +/- 15 seconds and ECG changes occurred at 90 +/- 60 seconds (p less than 0.001). Percent systolic wall thickening occurred in similar fashion. Results support the hypothesis that regional contractile abnormalities may provide a more sensitive indicator of myocardial ischemia than ST-T changes in humans.