Electroanatomic mapping system guided His bundle pacemaker implantation: experience of the His bundle registry graz
Authors: Benedikt M , Rohrer U , Prenner G , Sereinigg M , Zweiker D , Manninger M , Bisping E , Eberl A , Riedlbauer R , Lercher P , Zirlik A , Scherr D 
Published: May 2023

Abstract

Funding Acknowledgements
Type of funding sources: None.

Background
Electric conduction disturbances are very common, however, patients in need for ventricular pacing may suffer from pacing-induced heart failure due to unphysiological pacing by the right ventricular lead. Conducting system pacing allows to overcome this common issue with a more physiologic approach, but real-life procedural data using this technology is scarce.

Methods
We report a single centre experience of the first 63 consecutive patients being implanted with a His-bundle-based pacemaker 09/2020-11/2022 per 3D-mapping guided implantation due to bradyarrhythmia, or for cardiac resynchronisation therapy in heart failure combined with a left-ventricular lead (HOT-CRT) ± a right ventricular defibrillator lead. The identification of the His-bundle-location was done with a 3D electroanatomic mapping system via an introducing sheath that is provided with electrodes at its tip.

Results
Mean age was 71 [18;87] years, 18/63 (29%) patients were female, mean baseline LVEF was 46±15%. Baseline ECG was captured before implantation: QRS width was 127±34ms, with typical LBBB in 19/63 (30%), typical RBBB in 5/63 (8%), alternating BBB in two patient (3%) and either no BBB or ventricular escape rhythm in 37/63 (59%). Indications for implantation were AV-block grade II-III in 31/63 (49%), primary prophylactic ICD indication in HFrEF in 18/63 (29%), atrial fibrillation with bradycardic conduction in 8/63 patients (13%), sick-sinus-syndrome in 4/63 (7%) and secondary prophylactic ICD indication in one patient (2%). In 57/63 (90,5%) a primary device was implanted, in 6/63 (9,5%) a pre-existent device was upgraded with a HB lead.
Therefore, 23 dual-chamber-pacemaker, 5 single-chamber-pacemaker, 10 single-chamber CRT-P, 17 dual-chamber CRT-P, 4 single-chamber CRT-D, 4 dual-chamber CRT-D were implanted. In 63 patients his bundle pacing was attempted, while in 6/63 (9%) patients outside of this analysis the attempt was not successful, these patients were consecutively implanted with a non-HBP-device and therefor excluded from the further analysis.
In the 63 patients included in this analysis with a primary successful pacing at the his-position, 5/63 (8%) his-bundle-leads dislocated within the first 48 hours, leading to a secondary success rate of 92%. There were two post-procedural pneumothorax that needed drainage, no major procedure-related complications occurred.
Median skin-to skin procedure time was 111±47 minutes in his-bundle-device-implantation.
The paced QRS width at the post-implantation follow up was 113±27ms with a change in QRS width of -15±39ms (+72; -92ms). The mean his-bundle sensing was 5,38±5,6mV and the mean threshold 1,1±0,86V over 1,0±0,5ms (0,4;1,5ms). The proportion of ventricular pacing was 75±36%.

Conclusion
Electroanatomic-guided His bundle pacing as a new innovative technic for physiological pacing is viable including high implantation success rate as well as electric impact, both regarding QRS width and pacing threshold.