KCNH2 and Prolonged QT interval: A host of KCN isoforms including KV1.5, KV4.2, KV4.3, KV7.1, and KV11.1 have been implicated for their involvement in a number of cardiac arrhythmias such as atrial fibrillation [171], Long QT syndrome [172] and torsade de pointes [167,173].