ROLE OF DELAYED RECTIFIER POTASSIUM CHANNELS IN CARDIAC REPOLARIZATION AND ARRHYTHMIAS

Cardiac action potentials are long because the magnitude of some potas sium currents is reduced at depolarized potentials. The slow onset of repolarization is initiated by the opening of delayed rectifier potass ium channels. A decrease in function of these channels resulting from gene mutations or pharmacological block increases risk of life-threate ning ventricular arrhythmias.