Current clinical perspectives on antiarrhythmic drug therapy

The approach of arrhythmia evaluation and therapy is rapidly changing because of new diagnostic approaches and new antiarrhythmic agents, and because of evolving concepts about arrhythmia risk. Ventricular arrhythmias and the degree of associated heart disease define three broad risk categories: benign, potentially lethal, and lethal arrhythmia groups. Benign arrhythmias require therapy only if symptomatic, and arrhythmias with lethal potential should always be aggressively treated. The approach to potentially lethal arrhythmias remains problematic. It is now clear that complex arrhythmias in the presence of advanced heart disease (e.g., myocardial infarction) signify an increased risk (two- to fourfold). The optimal approach to risk reduction, however, is uncertain, and empirical therapy with standard antiarrhythmic agents alone appears inadequate. Antiarrhythmic drugs may be classified into four groups based on electrophysiological and pharmacological effects, and class I (membrane-active) agents are now divided into three subgroups (classes IA, IB, and IC). Current agents are far from ideal. Four new agents, however, are becoming available: tocainide (1984) and mexiletine (1985-1986) (class IB, lidocaine congeners); flecainide (1985) (class IC); and amiodarone (1986) (class III). These agents will extend the current scope of antiarrhythmic therapy. Novel nonpharmacological therapies are also becoming increasingly important, including surgical and catheter ablation procedures after electrophysiological mapping, advanced pacemaker/cardioverter units for tachyarrhythmia termination, and automatic implantable defibrillator devices. These new developments promise more specific and successful arrhythmia management in the future.