Sudden Death in Heart Failure: Risk Stratification and Treatment Strategies

Attempting a careful evaluation of the incidence of sudden death (SD) in congestive heart failure is inevitably a complex and imprecise task. In particular, this is due to the difficulties in defining and understanding the baseline mechanisms underlying SD. “Sudden” death is commonly regarded as a synonym of “cardiac arrest due to ventricular fibrillation,” which is in turn considered to be a merely arrhythmic phenomenon occurring during apparent wellbeing, and without any precipitating cause other than an extrasystole or a sustained ventricular tachycardia. Cardiac arrest may also be the terminal event during refractory pulmonary edema and/or cardiogenic shock in a patient with end-stage heart failure, a pulmonary embolism in a patient with severe biventricular dysfunction, bradyarrhythmia due to advanced atrioventricular (AV) block, electrical asystole, ventricular fibrillation secondary to myocardial ischemia or infarction, or secondary to a noncardiac event such as a cerebro vascular accident or a ruptured aortic aneurysm. Pratt et al.[1] analyzed a population of 834 patients with an automatic implantable cardioverter defibrillator (ICD) implanted for ventricular tachycardia or sustained ventricular tachycardia. During follow-up 109 patients died (17 died “suddenly”). Autopsy findings revealed a nonarrhythmic cause (pulmonary embolism, ruptured aortic aneurysm, stroke, acute myocardial infarction) in 7/17 patients. Postmortem analysis of the ICD memory revealed ventricular tachyarrhythmias preceding death in only 7/17 patients.