Placement of moricizine in the selection of antiarrhythmic drug therapy.

The selection of antiarrhythmic drug therapy requires a careful assessment of the benefits of ventricular arrhythmia suppression compared with the risks of antiarrhythmic drug use. Since reduction in sudden cardiac death from ventricular arrhythmia suppression has not been demonstrated, the only indications for antiarrhythmic drug suppression involve the reduction of hemodynamic symptoms such as syncope (a major benefit) or the reduction of nonhemodynamic symptoms such as palpitations or dizziness (a minor benefit). Noncardiac adverse effects and organ toxicity as well as cardiac side effects must be considered when antiarrhythmic drug therapy is initiated. For reduction of nonhemodynamically important symptoms in patients with benign or potentially lethal ventricular arrhythmias, beta blockers are chosen as first-line therapy. Because of moricizine's relatively high effectiveness in suppressing ventricular arrhythmias and its low potential for noncardiac adverse effects and organ toxicity as well as a low incidence of induced proarrhythmia and heart failure, moricizine is selected as the next drug in line. All other class I antiarrhythmic drugs either have been shown to have the potential for increasing sudden cardiac death or have major rates of noncardiac adverse effects or organ toxicity that preclude their use in these patient groups except in special circumstances. In patients with malignant ventricular arrhythmias who present with hemodynamic consequences such as syncope or worse, moricizine also is preferred as an initial drug for consideration. When compared to drugs with class IA and IB action, moricizine has comparable efficacy yet lower rates of noncardiac adverse effects, organ toxicity, proarrhythmia and heart failure.(ABSTRACT TRUNCATED AT 250 WORDS)