KCNA5 and atrial fibrillation: In patients with atrial fibrillation, decreased expression of L-type Ca 2 + channel, ryanodine receptor (RyR2), potassium voltage-gated channel subfamily A member 5 (KCNA5), sarcoplasmic reticular Ca2+-ATPase (SERCA2), the beta-subunit MinK (KCNE1) and MIRP2 (KCNE3) [7], and increased expression of hyperpolarization-activated cation channel two associated with the pacemaker current I (f) (HCN2) were observed [8].