Can cardiac resynchronization therapy be used as a tool to reduce sudden cardiac arrest risk?

Patients with cardiomyopathy and reduced left ventricular (LV) ejection fraction are at risk of heart failure (HF) symptoms and sudden cardiac arrest (SCA). In selected HF patients, cardiac resynchronization therapy (CRT) provides LV reverse remodeling and improves the cellular and molecular function. However controversial results have been published regarding the effect of CRT on the residual ventricular arrhythmia risk. Indeed, the decrease in SCA risk is inconsistent and some factors strongly influence the residual post implantation arrhythmic risk. Conversely, proarrhythmic effect of CRT has been previously described. In this review we aim to describe the relationship between CRT implantation and the SCA risk decrease and discuss the patients who only require cardiac resynchronization therapy-pacemaker and those who need a concomitant implantable cardioverter defibrillator.