The clinical implementation of His-bundle pacing (HBP) has been limited by concern over higher capture thresholds (CTs) and lower R-wave amplitudes (RWAs), when compared with right ventricular (RV) pacing. The aim of this study was to assess the optimal pacing configuration for HBP lead when incorporated with cardiac resynchronization therapy/implantable cardioverter defibrillators (CRT-D/ICD) by testing of an integrated bipolar configuration.Methods and results
HBP was achieved in 25 CRT-D and 13 ICD patients at implantation. Their RWA, CT@0.5 ms and impedance with His-bundle (HB) tip-RV coil, and HB unipolar and bipolar (tip-ring) configurations were measured acutely. Capture threshold in CRT-D patients was that needed to ‘correct’ complete left bundle block. Among all 16 CRT-D patients with permanent HBP, their RWA, CT@0.5 ms, and pacing impedance with HBP tip-RV coil and HBP tip-ring were measured at 1 month and 3 months follow-up. Higher RWA and lower CT were achieved with HB tip-RV coil configuration than either of the other two configurations at implantation (n = 38, P < 0.05, respectively). At 1 and 3 months follow-up for patients receiving permanent HBP, RWA and CT with HB tip-RV coil configuration remained stable and better than those with HB tip-ring configuration (n = 16, P < 0.05, respectively). Furthermore, HB lead pulse energy delivered with HB tip-RV coil configuration was also less than with HB tip-ring at 3 months (n = 16, P = 0.017).Conclusion
Incorporation of HBP into a CRT-D/ICD system is feasible, and pacing thresholds/sensing can be optimized using a novel integrated bipolar configuration with the RV lead.