KCNJ2 variants are also associated in rare familial forms of atrial fibrillation type 9, short QT syndrome type 3 and Catecholaminergic Polymorphic Ventricular Tachycardia (CPVT) (Tester et al., 2006). Here, KCNJ2 is linked to catecholaminergic polymorphic ventricular tachycardia.