Sudden cardiac arrest in patients with preserved left ventricular systolic function: a clinical dilemma.

Stratifying the risk for sudden cardiac arrest (SCA) in individuals with preserved systolic function remains a pressing public health problem. Current guidelines for the implantation of cardiac defibrillators largely ignore patients with preserved systolic function, even though they account for the majority of cases of SCA. Risk stratification for such individuals may be increasingly feasible. Notably, most individuals who experience SCA have structural heart disease, even if undiagnosed. Thus, clinical risk scores have been developed to identify individuals at high risk. Moreover, there are now promising data that T-wave alternans, alone and in combination with other indices, effectively predicts SCA in this population. This article presents our current understanding of SCA caused by ventricular arrhythmias in patients with preserved left ventricular systolic function, and attempts to build a framework to predict risk in this population.