Impairment of Kv11.1 function by mutations in the KCNH2 gene or by a variety of drugs prolongs the QT interval of electrocardiograms leading to inherited and acquired type 2 long QT syndrome, increasing the risk of torsade de pointes arrhythmia, ventricular fibrillation and sudden cardiac death [46, 58]. This evidence concerns the gene KCNH2 and ventricular fibrillation.