Left ventricular ejection fraction for the risk stratification of sudden cardiac death: friend or foe?

More than 450000 Americans die suddenly each year from sustained ventricular tachycardia or fibrillation. A correct identification of these patients is crucial for a rational clinical management, because the demonstrated effectiveness of implantable cardioverter-defibrillators (ICD) on the reduction of sudden cardiac death. Basing on the results of multiple clinical trials, left ventricular systolic function, measured as ejection fraction, is currently the only recommended tool to identify patients at higher risk of sudden death that would benefit from a prophylactic ICD. However, the systematic implementation of prophylactic ICD recommendations results in a substantial number of inappropriate ICD implantations, while failing to prevent the majority of sudden deaths occurring in the general population. That has been the case implementing arrhythmic risk stratification with a rough arrhythmic risk marker, such as ejection fraction, that lacks sensitivity and specificity in the prediction of sudden cardiac death. The aim of this viewpoint is to critically revise the value of ejection fraction in the identification of patients at risk of sudden cardiac death.