CLASS-IA ANTIARRHYTHMIC AGENTS IN THE POST-CAST ERA

One consequence of the Cardiac Arrhythmia Suppression Trial was to generate new interest in class IA antiarrhythmic agents. The drugs in this class-quinidine, procainamide, and disopyramide-are characterized by moderate depression of sodium channel conduction. Only quinidine has approval for use in the treatment of atrial arrhythmias: the three agents are equally effective in treating ventricular arrhythmias. Drugs in this group are usually preferred for patients with sustained ventricular fibrillation and tachycardia. Efficacy can be enhanced in this setting by using a class IA agent in combination with a class IB drug.