Long QT syndrome (LQTS) is a disorder of impaired ventricular repolarization that predisposes individuals to the development of lethal arrhythmic episodes (Keating & Sanguinetti 2001): congenital LQTS is predominantly caused by loss-of-function mutations in HERG or KCNQ1 K+ channel genes (Keating & Sanguinetti 2001). The gene discussed is KCNH2; the disease is familial long QT syndrome.