2003), and a family history of early‐onset AF increases overall AF risk (Fox et al. 2004). Linkage and functional studies have revealed the mutation of several potassium channels such as KCNQ1, KCNE2, KCNH2 in rare, monogenic families with a Mendelian pattern of AF inheritance (Chen et al. 2003; Yang et al. 2004; Hong et al. 2005; Xia et al. 2005). Here, KCNE2 is linked to atrial fibrillation.