Mutations in KCNQ1 causing loss‐of‐function and gain‐of‐function can lead to type 1 LQTS, AF, and even fatal arrhythmia when calcium channels are reactivated causing early afterdepolarizations (Chen, Xu, & Bendahhou, 2003; Keating & Sanguinetti, 2001). Here, KCNQ1 is linked to atrial fibrillation.