New diagnostic evidence on the T wave map indicating involved coronary artery in patients with angina pectoris.

To define the clinical significance of T wave map changes in patients with angina at rest, body surface isopotential T distributions were obtained in 48 patients with single-vessel disease (left anterior descending artery, 34; right coronary artery, eight; left circumflex artery, six) documented angiographically and were compared with those in 120 healthy subjects and those in 19 patients with left ventricular overload whose electrocardiograms showed negative T waves accompanied by an increase in R wave amplitude in left precordial leads. The T wave map abnormalities were observed in 24 of 48 patients (50%) with angina and were classified into three types: (1) type I (18 patients, 37.5%) was characterized by a segmental negative potential in the positive area located at the left thorax and the minimum at the peak of T wave positioned in the upper portion of the left anterior chest, (2) type II (three patients, 6.3%) was characterized by a negative potential with a minimum in the inferior thorax and an indentation of negative potential at the lower margin of the positive potential located over the upper thorax, and (3) type III (three patients, 6.3%) was characterized by a negative potential with a minimum at the back throughout the period of T wave. All patients showing T wave map abnormalities of type I had a significant stenosis of the left anterior descending artery. Likewise, all patients with type II or III had single-vessel disease of the right coronary or left circumflex artery, respectively. All types of T wave map changes observed in patients with angina were different from those in patients with left ventricular overload, whose maps showed the generalized negative potential at the inferior thorax and the left back and the minima clustered at the precordium. In seven patients with lesions of the left anterior descending artery, T wave map abnormalities of type I recovered to normal after successful percutaneous transluminal coronary angioplasty. The behavior of the negative potential and its extrema on the T wave map, which was not available from routine electrocardiography, was indicative of the involved coronary artery and probably of its associated ischemic area in one-half of our patients with angina pectoris.