Post-extrasystolic ST, T changes in the exercise vectorcardiogram with Frank's lead.

Abstract

Post-extrasystolic ST, T changes were analyzed in the exercise vector-cardiogram, using Frank's lead system. (1) The magnitude of ST vector of the post-extrasystolic sinus beat after exercise was not changed in a normal subject, slightly increased in a hypertensive patient and a patient with aortic stenosis and insufficiency, slightly decreased in a patient with intermediate type and markedly increased in patients with angina pectoris, comparing to that of the preceding sinus beat of extrasystole. (2) The magnitude of the maximal T vector of the post-extrasystolic sinus beat after exercise was decreased in a normal subject, a hypertensive patient and a patient with aortic stenosis and insufficiency, and was increased in a patient with intermediate type. The direction of the maximal T vector of the post-extrasystolic sinus beat after exercise was not changed in non-ischemic patients and changed spatially in ischemic patients. (3) There were no marked changes in the shape of T loop of the post-extrasystolic sinus beat after exercise in non-ischemic patients and increased widening or narrowing of T loop was seen in the post-extrasystolic sinus beat of ischemic patients, comparing to T loop in the preceding sinus beat of extrasystole. (4) It is concluded that there was the specific pattern of the post-extrasystolic ST, T changes for local ischemia, that is, they occurred in a way that ST, T changes of ischemic type produced by exercise were accentuated.