**7. Resynchronization therapy on ventricular dysrhythmias after LVAD devices**

Cardiac resynchronization therapy (CRT) is recommended for symptomatic patients with HF and a QRS duration ≥150 ms and left branch bundle block QRS morphology with LVEF ≤35% despite optical treatment can improve ventricular

remodel to improve symptoms and reduce morbidity and mortality [1]. Nevertheless, its potential benefit or antiarrhythmic effect in LVAD patients remains unclear.

A prospective single-center study indicates a lower incidence of implantable cardioverter defibrillator device (ICD) therapies in the LVAD population if CRT mode was activated [40]. Richardson et al. [10] and Gopinathannair et al. [41] failed to find any differences in terms of mortality and hospitalization, but the first one corroborates the lower ICD discharges in the CRT-activated group, which could benefit from the antiarrhythmic effect of CRT.

The lack of additive effect from CRT in the LVAD population could be explained for several reasons including (i) LV unloading by LVAD surpasses the electrical correction by CRT; (ii) CRT population had a more advanced myocardiopathy to begin limiting any additive effect; (iii) CRT could improve clinical outcomes in younger patients with nonischemic dilated cardiomyopathy who receive LVAD as a bridge to recovery, but this population was not included. Muratsu et al. describe a case report of a 15-year-old male with acute decompensated heart failure and LVAD implantation as a bridge to recovery. Despite optimal treatment, a CRT was required to improve cardiac function and finally perform LVAD removal [41, 42].

More randomized studies are necessary to better know the mechanism and the benefit of maintaining CRT turned on in the LVAD population despite its use being associated with higher generator replacement rates [3].
