ICD lead parameters, performance, and adverse events following continuous-flow LVAD implantation

Ventricular arrhythmias (VAs) in the months following continuous-flow left ventricular assist devices (LVADs) implantation are common and associated with increased morbidity and mortality. We sought to evaluate for changes in implantable cardioverter defibrillator (ICD) performance following LVAD implantation.

We retrospectively reviewed the ICD interrogation reports and medical records of patients who received a continuous-flow LVAD at the University of Chicago Medical Center between January 2008 and December 2010. Patients who did not have an ICD prior to LVAD implantation were excluded.

Forty-four patients were included. Median right ventricular lead sensing amplitude decreased from 10.0 (interquartile range 7.6-13.6) mV prior to LVAD to 7.9 (5.9-9.3) mV after LVAD implantation (P < 0.01). Significant reductions in sensing threshold were associated with smaller lead diameters, smaller pace/sense electrode surface areas, and Medtronic ICD leads (Medtronic Inc., Minneapolis, MN, USA). Lead impedance and capture threshold did not change significantly. ICD-related adverse events occurred in 30% of patients and led to ICD modification in 18% of patients.

Implantation of a continuous-flow LVAD is associated with changes in the performance of preexisting ICDs. ICD-related adverse events were encountered following LVAD implantation in this cohort, and at times resulted in invasive and noninvasive ICD system modification. Reductions in ICD sensing threshold after LVAD implantation may adversely affect ICD function. Formal ICD interrogation in addition to the regular follow-up testing is warranted post-LVAD.