**Abstract**

This chapter is developed with the intention of discussing the use of implantable defibrillator cardioverters (ICDs) in patients with left ventricular assist devices (LVADs). LVADs have become the standard treatment for patients with advanced heart failure who require prolonged mechanical circulatory support as a bridge to transplantation or as destination therapy. Patients with advanced heart failure have a major risk of sudden death due to ventricular dysrhythmias (VD) so an ICD could be indicated, but it remains unclear within the LVAD population due to several factors including sustained VD good tolerance and inappropriate therapies (due to supraventricular tachycardias or electromechanical interferences) as well as the risk of infections with complex antibiotic therapy or device replacements. Previous VD before LVAD placement, concomitant atrial fibrillation, type of LVAD device, and chronic ischemic heart disease can predict future episodes of VD. The evidence that supports ICD use in patients with LVAD is very limited, and current guidelines are based primarily on the consensus of experts and observational studies. Nowadays, an ICD implant is only recommended for LVAD patients who develop postoperative VD associated with hemodynamic collapse, and it should be programmed in a very conservative mode (higher rate and larger intervals to detection) to avoid undesirable electric shocks.

**Keywords:** implanted cardioverter defibrillator, ventricular assist device, ventricular arrhythmia, advanced heart failure, sudden death
