Risk stratification of ventricular arrhythmias in patients with systolic heart failure.

PURPOSE OF REVIEW: Sudden cardiac death (SCD) accounts for an estimated 310 000 deaths in the United States each year. Implantable cardioverter defibrillator (ICD) implantation has revolutionized SCD prevention in heart failure patients, but only a minority of patients with ICDs receive appropriate therapy for ventricular arrhythmias. At present, the selection of patients for ICD is based largely on left ventricular ejection fraction and heart failure, but further risk stratification is still needed to determine which patients will derive the greatest benefit.

RECENT FINDINGS: Multicenter studies have failed to confirm the utility of microvolt T-wave alternans to predict ventricular arrhythmias in patients with ICDs. Additional risk stratification tools including resting ECG characteristics, nonsustained ventricular tachycardia, tests of autonomic function, and cardiac MRI demonstrate predictive value but have limited clinical applicability at present.

SUMMARY: Depressed ejection fraction with symptomatic heart failure remains the most powerful predictor of SCD and is the primary method currently used in patient care decisions. Progress continues in evaluation of additional risk factors and risk stratification tools, but no one test or combination of tests is definitive for prediction of arrhythmic events.