Encainide: a new and potent antiarrhythmic agent.

Encainide is a potent Class I antiarrhythmic drug that prolongs conduction in the His-Purkinje system. It produces only minimal hemodynamic changes in the normal or depressed left ventricle. Studies to date demonstrate excellent effectiveness against ventricular arrhythmia, and in comparative studies with quinidine, encainide was superior in reducing the frequency and complexity of ventricular premature beats in patients late after myocardial infarction.