Implantable cardioverter-defibrillator shocks in patients with ventricular assist devices

Abstract

Purpose: Ventricular assist device (VAD) use is becoming increasingly common for patients with end-stage heart failure (HF). The majority of events seem to occur in the early post-operative period.We sought to confirm the efficacy of ICDs in a single center cohort of VAD-supported HF patients. Methods: All adult subjects who underwent VAD support since 2003 as a bridge to transplantation (BTT) were reviewed and included in the study.All subjects in the cohort received one of the following VAD systems: HeartMate XVE,Novacor LVAS,LVAD INCOR Berlin Heart,HeartWare LVAS and Berlin Heart (LVAD and BiVAD).All patients had the ICD turned off for VAD implantation, and only LVAD recipients had the ICD turned on post-operatively (routinely within 12 – 48hours).BIVAD recipients had the ICD set to monitor only. Appropriate ICD shocks for Ventricular Tachycardia (VT) and Ventricular Fibrillation (VF) were recorded.The primary outcome was survival to transplantation. Results: A total of 87 VADs were implanted for the indication of bridge to transplantation.Of these,34 were left ventricular assist devices (LVAD) and 53 were biventricular assist devices (BIVAD).57 patients had an ICD (23 LVAD, 34 BIVAD).Mean age 40±12 years,78% male,LVEF 18±9%,54% dilated.Mean length of support was 365 days (range 1–1280). Overall, 48 (56%) patients survived to transplantation.More patients with an ICD were treated with amiodarone reflecting a higher incidence of arrhythmias.Of the 23 LVAD patients with an ICD,10 received at least one ICD shock.Appropriate shocks were delivered to 7 patients after LVAD implantation (5 VT, 1 VF, 1VT and VF). The mean time to first shock after LVAD implant was 129±109 days.In the LVAD cohort, more patients had an appropriate ICD shock for VT or VF before LVAD implant than afterwards.Of great interest was the analysis of the arrhythmias detected in the BiVAD group (15 patients out of 53 had at least one event VT or VF and one of them suffered an electrical storm).In BiVAD patients detection of those arrhythmias were of great importance because a decrease in cardiac outpout was observed. Arrhythmias detected in both groups were of prognostic significance,especially in the LVAD Group (RV failure and aortic regurgitation) In addition, two patients without an ICD had ventricular arrhythmias requiring placement of an ICD after VAD placement. Conclusion: ICD shocks are common after implantation of VADs.Shock frequency decreases after VAD implantation, likely due to ventricular unloading, but appropriate ICD shocks still occur in VAD supported patients.