Department of Clinical Medicine

BACKGROUND: His bundle pacing (HBP) is a novel treatment with limited knowledge on long-term outcome. We aimed to assess long-term safety and effectiveness of HBP in patients with atrioventricular block treated with HBP and a back-up right ventricular pacing (RVP) lead.

METHODS: We included 38 patients from a completed single-center, randomized controlled cross-over trial designed to compare left ventricular (LV) function after 12 months of HBP vs. RVP conducted between September 2007 and August 2011. Lead performance beyond the 2-year study period was assessed based on a retrospective review of capture thresholds, sensing, impedance, energy consumption, and rate of HBP interruption.

RESULTS: Patients were followed for a mean of 7 ± 4 years. Both at baseline and during follow-up, HBP leads displayed significantly higher capture thresholds than RVP leads (P < 0.001), multifold higher energy consumption (P < 0.001), and lower sensing amplitudes (P < 0.001). During follow-up, 17 (53%) HBP leads were deactivated or abandoned. The principal cause for HBP interruption was high pacing thresholds in patients with preserved LVEF during RVP. Device longevity was shorter than that of contemporary cohorts treated with dual-chamber pacing or CRT, and time to first device exchange was 6.8 ± 1.5 years. No lead dislodgements occurred, but four patients (10%) developed device-related infections requiring device extraction.

CONCLUSION: HBP was interrupted in > 50% of patients during long-term follow-up. The principal cause was unacceptably high capture thresholds and no significant difference in LV function with HBP compared with RVP. Device longevity was shorter, and infection rates were higher than anticipated.