Anti-arrhythmic effects of atrial specific IKur block: A simulation study

The ultra rapid potassium current (I_Kur) is an attractive pharmacological target in atrial fibrillation (AF) management due to its atrial specific nature. An experimentally based 78% I_Kur reduction was incorporated into a human atrial action potential (AP) model under sinus rhythm (SR) and atrial fibrillation (AF) conditions. Its effects on cell and tissue level electrical activity were simulated. I_Kur block reduced AP duration (APD) and effective refractory period (ERP) under SR conditions, but prolonged APD and ERP under AF conditions. I_Kur block modulated tissue's ability to sustain high pacing rate conduction under SR and AF conditions. Vulnerability window (VW) was augmented under SR, and reduced under AF conditions. I_Kur block did not effect on re-entrant waves in 2D and 3D simulations. Simulations show pro-arrhythmic effects in SR, but anti-arrhythmic effects in AF case due to I_Kur block.