Profiling risk from arrhythmic or hemodynamic death.

Congestive heart failure is increasing in prevalence and, despite recent advances in therapy, mortality remains high. Sudden cardiac death (SCD) represents a significant percentage of overall mortality, accounting for almost 1 in 2 deaths in patients with congestive heart failure. In patients with asymptomatic left ventricular dysfunction or mild degrees of functional impairement, overall annual mortality is low, although a significant portion of the deaths are sudden; on the other hand, in advanced heart failure annual mortality increases, but SCD contributes to it to a lesser degree. The mechanisms of SCD in heart failure are multiple, including ventricular tachycardia/ventricular fibrillation, bradyarrhythmias, electromechanical dissociation, acute coronary events, and thromboembolic events. Only a minority of patients with advanced heart failure or on the waiting list for heart transplant experience SCD as a consequence of ventricular tachycardia (VT) or ventricular fibrillation (VF). The availability of effective therapies to prevent sudden arrhythmic death, such as that provided by automatic implantable cardioverter defibrillators, may help to reduce the burden of SCD in congestive heart failure, but major efforts will be needed to identify the candidates who may benefit from this approach.