channel, preventing the movement of sodium ions into the cardiac cell. This decreases the rate of depolarization of the cell membrane as well as the action potential amplitude, but has no effect on the overall duration of the action potential. Suppression of the depolarization rate is use-dependent, and therefore inhibition increases with increased stimulation. Pilsicainide also causes delayed impulse conduction through the myocardium in a dose-dependent manner. The effects of pilsicainide have a slow rate of onset and offset resulting in a prolonged recovery time. This contributes to its potent blocking activity and its classification as a class 1c antiarrhythmic agent. References Antiarrhythmic agents Pyrrolizines Acetanilides