KCNH2 and atrial fibrillation: Single-nucleotide polymorphisms in the ion channel genes including small conductance Ca2+-activated K+ channels (SK), Kv11.1 (hERG) and the α-subunit of the Nav1.5 sodium channel (SCN5A) significantly increase AF susceptibility (Remme and Bezzina, 2010; Zhang et al., 2021).