Most of these studies show that gain- or loss-of-function mutations in the genes encoding proteins contributing to cardiac depolarization, e.g. SCN1-3B (involved in INa) [6,9], or cardiac repolarisation, e.g. KCNQ1 (IKs), KCNH2 (IKr), KCNJ2 (IK1) can lead to increased susceptibility to AF [6]. Here, KCNJ2 is linked to atrial fibrillation.