Symposium on the present status of electrocardiography
The T wave and ventricular repolarization

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Abstract

A detailed analysis of the genesis of the T wave comparable to that provided for a QRS complex cannot be obtained by means of direct recording of ventricular repolarization. This is mainly because of the low voltage, the slow time-course and the absence of a uniform conduction during repolarization. Determination of the excitability cycle provides an indirect measurement of local repolarization. An analysis of the recovery of excitability at several intramural and epicardial electrodes demonstrates that the T wave of the canine heart, as recorded from the epicardial surface, is determined in a larger degree by local differences in the progress of repolarization than by the intramural sequence of recovery.

The preliminary results of a new experimental method, providing immediate and synchronous activation of the ventricles in an intact dog, demonstrate an over-all direction of repolarization from the apex to the base of the heart; they support Wilson's theory of the ventricular gradient.

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