NCIt definition : A class IA anti-arrhythmic agent with cardiac depressant property. Disopyramide blocks
the fast sodium channel in normal cardiac cell membranes within atrial and ventricular
tissues. This slows the rate and amplitude of phase 0 depolarization and thus prolongs
the duration of the action potential, thereby reducing cell excitability and conduction
velocity. Further, disopyramide directly decreases the rate of diastolic (phase 4)
depolarization in cells with normal or augmented automaticity. Disopyramide also blocks
potassium channel and results in prolonged QT interval, thus increases the effective
refractory period. This agent also possesses anticholinergic property.;