RYR2 and atrial fibrillation: It is known that the action of flecainide on RyR can suppress triggered activity, for example, the previous studies on the flecainide therapy in catecholaminergic polymorphic ventricular tachycardia.[22, 26] Furthermore, flecainide had antiarrhythmic effects on Pitx2-induced AF due to its action on IKr by prolonging WL, decreasing susceptibility of tissue to re-entrant arrhythmias (Fig 6B).