The observation of reduced KCNK13 mRNA levels in patients with chronic AF or heart failure, which could also be recapitulated in a porcine large animal model of combined AF and heart failure might point towards a physiological role of K2P13.1 (THIK-1) currents in regulating atrial electrophysiology [10,40,129]. The gene discussed is KCNK13; the disease is atrial fibrillation.