LAUSR

Background Transvenous Cardiac Defibrillators (ICDS) are frequently present at the time of Ventricular Assist Device (VAD) implantation. Many of these patients have underlying rhythms which depend on the pacing function of these devices or derive benefit from cardiac resynchronization therapy. Furthermore, adequate ventricular lead function is critical for the detection and treatment of tachyarrhythmias. Previous studies have shown decreased right ventricular sensing thresholds in patients undergoing earlier generation axial-flow VAD placement. Heartmate 3 (HM3) and Heartware (HVAD) are two of the newer-generation VADs whose unique use of a magnetically-levitated rotor and intrapericardial placement may result in increased interference with nearby right ventricular device leads. Methods A retrospective analysis of all patients with a PPM or ICD who underwent implantation of an HM3 or HVAD between 2015-2019 was performed. We examined the device interrogations of patients immediately before and after device implantation, as well as a third most recent interrogation if available. A significant change in ventricular pacing threshold was defined as an increase in 2V in either of the post VAD interrogations. Results 52 patients with HM3 and 16 patients with HVADs who had ICDs in place at the time of LVAD implant were identified, 46 of whom had both pre and post VAD interrogation reports available. 10 patients (21%) met the criteria for significant increase in RV pacing threshold (mean threshold = .98V pre-VAD vs 4.79V post-VAD, P Conclusion RV pacing and sensing thresholds significantly increased after implantation of a HVAD or HM3 in more than one-fifth of patients with existing transvenous ICDs. The magnitude and frequency of these changes appear to greater than previously described with earlier-generation axial VADs. The etiology of this change in pacing performance warrants further investigation as it may result in adverse clinical events in this highly susceptible patient population.