Lian JF
The rapid activating delayed rectifier K-current (Ikr) plays a crucial role in the phase 3 repolarization of action potential of human myocardial cells. The Ikr channel is composed by the αsubunits which encoded by the human ether-a-go-go related gene (HERG). HERG mutation with Ikr channel current reduction leads to type II hereditary long QT syndrome, which is characterized by a prolonged QT interval, an abnormal T wave on the electrocardiogram (ECG), a high risk of syncope, and sudden cardiac death due to underlyinglife-threatening torsade de pointes (Tdp) arrhythmias, particularly in young patients . There are several hundred HERG mutations having been identified, with majority causing LQT2 due to trafficking deficiency of HERG proteins
