Can angiotensin converting enzyme (ACE) inhibitors influence the risk of sudden cardiac death in patients with heart failure?

Progression of heart failure ("expected mortality") and sudden cardiac death ("unexpected mortality"), presumably secondary to ventricular arrhythmia, are the major causes for the poor prognosis in chronic heart failure (CHF). Limitations of this classification ultimately stem from inaccuracies in establishing the mechanism of death at the time of death. Elucidation of the determinants of patients prone to sudden death and the effects of treatment modalities on the rate of sudden death remain hidden. Unexpected mortality is probably secondary to arrhythmic death but denotes only that death occurred within some brief interval (arbitrarily less than one hour in most studies) and does not exclude other causes. The demonstrated benefit of ACE inhibitors for improving total mortality as illustrated by the findings of the VHeFT, Captopril Multicenter and CONSENSUS, and the improved event-free survival shown by Munich Mild Heart Failure Trial for low-dose captopril argues strongly for their use in patients with CHF. These agents are confirmed to reduce the risk of death from pump failure; the effects on sudden death are less clear. Although many favorable effects contribute to improved hemodynamics, neuroendocrine and electrolyte status as discussed, at present, it is not possible to predict the precise mechanism by which these agents extend life and whether they reduce the frequency of "sudden" deaths.