Body surface distribution of exercise-induced ST depression in patients with angina pectoris.

In 38 patients with angina pectoris, 87 unipolar lead electrocardiograms were recorded from different sites over the entire thoracic surface both before and after submaximal treadmill exercise. The site of exercise-induced ST depression on the body surface was correlated with the findings of the coronary arteriography. The number of leads which showed exercise-induced ST depression was 7.2 +/- 1.8 in one vessel disease, 15.6 +/- 2.1 in two vessel disease, and 23.6 +/- 2.0 in three vessel disease (values are mean +/- SEM). Thus, the number of leads showing ST depression was proportional to the severity of the coronary artery disease. Exercise-induced ST depression was most often seen in left anterior chest leads, especially in V5 of the standard 12-ECG. However, it was not possible to identify the obstructed coronary artery from the body surface distribution of ST depression.