Ventricular Assist Devices May Cause Changes In Implantable Cardioverter Defibrillator Lead Parameters

Introduction: Ventricular assist devices (VAD) are a primary method of treatment for patients with advanced heart failure. Previous studies have provided some evidence for alterations in ICD lead parameters following VAD implants, but all have had a very small sample size. Hypothesis: VAD implantation causes alterations in ICD lead parameters. Methods: Electronic medical records of a large patient cohort receiving VAD implants at Northwestern Hospital from 2012-2018 were manually reviewed. When available, high-voltage (HV) impedance, right ventricular (RV) lead pacing impedance, pacing threshold, and sensing amplitude were compared both immediately (I) and late (L), at 6-12 months follow-up after VAD implant, to baseline (B) pre-implant values. Results: A total of 271 VAD patient records were reviewed. Long-term, HV impedance changed from 51 ± 16 Ω to 49 ± 15 Ω (N=63, p=0.04), and 29% of patients had a long-term absolute change of at least 10 Ω. RV pacing impedance decreased slightly acutely from 405± 84 to 427 ±78 (N=96, p=.006), but there was no significant change long-term: 443 ± 201 Ω vs 449 ± 94 Ω (N=85, p=0.77). Yet, 19% of patients had a long-term change ≥ 100 Ω. Long-term RV pacing threshold was not significantly changed 1 ± 0.8 V to 1.1 ± 0.7 V (N=47, p=0.5), and all leads were still functional for pacing. RV sensing amplitude decreased acutely from 10.8 ± mV to 8.6 ± 4.3 mV (N=81, p<0.001). Additionally, 17% of patients had a change that was more than 50%, and new R waves below 5 mV were noted in only 13 patients (16%). Long-term RV sensing amplitude decreased from 11.3 ± 5 mV to 8.2 ± 4.3 mV (N=73, P<0.001), and 18 patients had a decrease in R wave of at least 50%. Conclusions: In conclusion, our data suggest that VAD implantation in patients with an ICD may result in immediate and long-term ICD parameter changes. For many patients, these changes may be clinically insignificant, but careful monitoring is warranted. The clinical impact of those changes merits further investigation.