KCNH2 and long QT syndrome 3: The channel blocker verapamil eliminates or reduces EADs, abolishes PVCs and suppresses TdP in congenital LQTS type 1 (LQT1) or type 2 (LQT2) caused by mutations in KCNQ1 or KCNH2 encoding KV7.1 or KV11.1 subunit responsible for the slowly or rapidly activating delayed rectifier potassium currents (IKs or IKr) respectively (8, 9) and in experimental models of LQT1 and 2 (10, 11) as well as type 3 (LQT3) (12) caused by mutations in SCN5A encoding sodium channel subunit NaV1.5.