Prospective Evaluation of Implantable Cardioverter-Defibrillator Lead Function During and After Left Ventricular Assist Device Implantation.

Objectives: This study investigated the mechanism of lead malfunction by monitoring lead parameters throughout left ventricular assist device (LVAD) implantation.

Background: Implantable cardioverter-defibrillator (ICD) lead malfunction can occur after LVAD implantation.

Methods: ICD lead data were prospectively evaluated during and after LVAD implantation and at 12 pre-specified intraoperative time points.

Results: We prospectively evaluated 32 patients with ICDs who underwent LVAD implantation, of whom 20 patients underwent serial testing at 12 intraoperative steps. Post-operative right ventricle (RV) sensing had decreased by >50% from baseline in 7 patients (22%), with RV sensing improving at 1 to 7 weeks in 2 patients (28.6%). Nine patients (28.1%) had >10-ohm (Ω) high-voltage (HV) impedance changes from baseline to final impedance. In all 5 patients with >50% decrease in RV sensing and all 7 patients with a >10-Ω HV impedance change who underwent intraoperative testing, changes were not detected until after weaning from cardiopulmonary bypass. Patients with decreased RV lead sensing >50% (n = 7) had lower glomerular filtration rates (48.7 ± 21.9 ml/min/1.73 m vs. 68.4 ± 22.5 ml/min/1.73 m, respectively, p = 0.0489), were more likely to have undergone concomitant RVAD placement (42.9% vs. 0%, respectively, p = 0.0071), concomitant tricuspid valve surgery (57.1% vs. 16%, p = 0.0469), or to have had cardiac tamponade or unplanned return to the operating room (57.1% vs. 12%, p = 0.0258).

Conclusions: ICD lead malfunction can occur following LVAD implantation but may improve over time. Intraoperative RV sensing and HV impedance changes were not detected until after weaning from cardiopulmonary bypass, suggesting the mechanism of RV lead malfunction may be related to LV unloading and concomitant leftward septal shift. A conservative approach is warranted in many patients with ICD parameter changes after LVAD implantation because parameter abnormalities may improve over time. (Implantable Cardioverter Defibrillator (ICD) Function During Ventricular Assist Device (VAD) Implantation; NCT01576562).