Corresponding Author:
Lee Man Young ,Tel: 2-3779-1135, Fax: 2-780-3132, Email: myleecardio@catholic.ac.kr
Received: February 20, 2017. Accepted: April 5, 2017.
Abstract
The T wave in surface ECG means the diastolic phase in cardiac cycle. Even though the cellular basis of the T-wave morphology of surface ECG remains controversial in clinical cardiology, the morphology of T wave is suggested to be determined by transmural voltage gradient during repolarization period which underlie the changes of T wave and QT interval. The heterogeneous distribution of electrophysiological behavior across the heart is essential for normal cardiac function. If this heterogeneity becomes excessive it may contribute to arrhythmogenesis and sudden cardiac death. This paper will give an overview of T wave genesis and action potential duration (APD) contribution, in which ion channels involved in repolarization period of the cardiac action potential with special emphasis on potassium channels involved in phase 3 repolarization. These channels are primarily Kv11.1 (hERG1), Kv7.1 (KCNQ1) and Kir2.1 (KCNJ2) being the responsible a-subunits for conducting IKr, IKs and IK1. The alteration of T waves and QT interval affected by both loss and gain of function of these currents are associated with various arrhythmogenic diseases. This review also briefly mention the arrhythmogenesis in diseases which are manifested by changes in T wave QT interval.