Antifibrillatory agents and potassium channels in the atria: pore block versus channel trafficking

Atrial fibrillation (AF) is the most common cardiac arrhythmia. The preferred therapy for AF is sustained sinus rhythm control; however, the efficacy of currently used antiarrythmic drugs is limited by adverse side effects resulting from both a lack of ion channel selectivity and nonspecific ventricular activity. The role of the voltage-gated potassium channels in atrial myocyte repolarization and the subsequent control of action potential duration renders them attractive targets for antiarrhythmic drugs in the treatment of AF. Conventional antiarrhythmic drugs generally target the ion permeability of potassium channels. This review discusses the limitations of this traditional approach and introduces, as a novel paradigm for antiarrhythmic pharmacology, the decrease of ion channel cell surface density through the modulation of ion channel trafficking pathways.