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Primary prevention of sudden cardiac death in heart failure and cardiomyopathy

Joseph E Marine, MD, FACC, FHRS
Andrea M Russo, MD, FACC, FHRS
Section Editors
Samuel Lévy, MD
Bradley P Knight, MD, FACC
Deputy Editor
Brian C Downey, MD, FACC


Life-threatening ventricular arrhythmias, including sustained ventricular tachycardia (VT) and ventricular fibrillation (VF), are common in patients with systolic heart failure (HF) and dilated cardiomyopathy and may lead to sudden cardiac death (SCD). Primary prevention of SCD refers to medical or interventional therapy undertaken to prevent SCD in patients who have not experienced symptomatic life-threatening sustained VT/VF or sudden cardiac arrest (SCA) but who are felt to be at an increased risk for such an event. The primary prevention of SCD in patients with HF and cardiomyopathy with reduced ejection fraction, either due to coronary heart disease or a dilated nonischemic etiology, will be reviewed here with emphasis on the role of implantable cardioverter-defibrillators (ICDs). The different types of ventricular arrhythmias, the effects of HF therapy on ventricular arrhythmias, the role of electrophysiologic testing, and the secondary prevention of SCD are discussed separately. (See "Ventricular arrhythmias in heart failure and cardiomyopathy" and "Secondary prevention of sudden cardiac death in heart failure and cardiomyopathy".)

The approaches to the treatment of ventricular arrhythmias related to specific heart muscle diseases or primary electrical system diseases such as hypertrophic cardiomyopathy, arrhythmogenic right ventricular cardiomyopathy, isolated left ventricular noncompaction, Brugada syndrome, long QT Syndrome, and other channelopathies are discussed elsewhere. (See "Hypertrophic cardiomyopathy: Assessment and management of ventricular arrhythmias and sudden cardiac death risk" and "Arrhythmogenic right ventricular cardiomyopathy: Treatment and prognosis" and "Isolated left ventricular noncompaction" and "Prognosis and management of congenital long QT syndrome" and "Brugada syndrome: Prognosis, management, and approach to screening".)


While the exact percentages and mode of death in patients with HF vary with HF class and type of cardiomyopathy, progressive pump failure, unexpected SCD, and SCD during episodes of clinical worsening of HF each account for approximately one-third of deaths in HF patients. Ventricular tachycardia (VT) and ventricular fibrillation (VF) are the most common arrhythmic causes of SCD, although bradyarrhythmias and pulseless electrical activity (PEA) are responsible in 5 to 33 percent of cases. These issues are discussed in greater detail elsewhere. (See "Secondary prevention of sudden cardiac death in heart failure and cardiomyopathy", section on 'Causes of death in heart failure'.)

Patients with New York Heart Association (NYHA) class IV HF have a very high mortality from progressive HF unless they are candidates for either cardiac transplantation, ventricular assist device implantation, or cardiac resynchronization therapy (CRT). Therefore, such patients are not usually considered appropriate candidates for implantable cardioverter-defibrillator (ICD) therapy unless this is used as a bridge to transplantation or implanted in conjunction with CRT. The mode of death in patients with HF is more likely to be "sudden" in patients with class II or III HF, while the mode of death is more likely to be related to "pump" failure in patients with class IV HF (figure 1) [1]. Therefore, primary prevention ICD trials (in the absence of CRT) have excluded patients with NYHA class IV HF. In fact, the 2008 ACC/AHA/HRS Device-Based Guidelines state that "ICD therapy is not indicated for NYHA Class IV patients with drug-refractory congestive HF who are not candidates for cardiac transplantation or CRT-D," listing this as a class III indication [2]. (See 'Class IV heart failure' below and "Indications and contraindications for cardiac transplantation in adults" and "Cardiac resynchronization therapy in heart failure: Indications".)


While implantable cardioverter-defibrillators (ICDs) are highly efficacious in the treatment of ventricular tachyarrhythmias and prevention of SCD, they are costly, require ongoing follow-up, and have numerous risks (eg, infection, device and lead malfunction, etc). In addition, only a subset of patients with cardiomyopathy develops sustained ventricular tachyarrhythmias or SCD. As such, the risk stratification of patients prior to ICD therapy is important for providing therapy to patients at highest risk of SCD and minimizing the number of ICD implantations in patients who are unlikely to benefit.

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Literature review current through: Nov 2017. | This topic last updated: Nov 03, 2017.
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