Critical review of the approaches to the prevention of sudden death.

The types of cardiac rhythm in patients with sudden death may vary considerably, depending on the underlying cardiac disease. Although ventricular tachyarrhythmias are likely to be the most common causes, a significant proportion of patients may die suddenly due to asystole, electromechanical dissociation, or cardiac rupture. Therefore, the approaches to preventing sudden death may have to be multifactorial. The classic approach of arrhythmia suppression by empiric antiarrhythmic drugs has not resulted in a decrease in sudden death mortality. Although beta blockers have only a modest effect in suppressing arrhythmias, they have been clearly proven to prevent sudden death. Other promising approaches that require further evaluation include modulation of the autonomic balance between the sympathetic and parasympathetic nervous systems (perhaps by beta blockers, exercise training, or low-dose atropine or scopolamine), relief of ischemia by medical or surgical therapy, magnesium supplementation, and mechanical devices, such as the implantable defibrillator.