Simulation of ventricular rate control during atrial fibrillation using ionic channel blockers

BACKGROUND The atrioventricular (AV) node is the only compartment that conducts an electrical impulse between the atria and the ventricles. The main role of the AV node is to facilitate efficient pumping by conducting excitation slowly between the two chambers as well as reduce the ventricular rate during atrial fibrillation (AF). METHODS Using computer simulations, we investigated excitation conduction from the right atrium to the bundle of His during high-rate atrial excitation with or without partial blocking of the calcium or potassium ionic current. RESULTS Our simulations revealed differences in rate reduction and repolarization effects between calcium and potassium current blocking and high degree of potassium current blocking required to reduce the ventricular rate during AF. CONCLUSIONS Our simulation results explain why potassium current blockers are not recommended for controlling ventricular rate during AF.