,2 The mechanisms underlying ATP-induced AF involve activation of adenosine A1 receptors and G protein-coupled inwardly rectifying potassium channel subunit 4 channels, leading to membrane hyperpolarization and significant shortening of the action potential duration and effective refractory period, particularly in the RA, where these receptors and channels are more densely expressed.3 The gene discussed is ADORA1; the disease is atrial fibrillation.