His Bundle Pacing for Newly Acquired Pacing Needs in Patients Implanted with a Sub-cutaneous Implantable Cardioverter Defibrillator: A Feasibility Study based on the Automated Screening Score and Clinical Cases.

INTRODUCTION: Management of S-ICD patients with newly acquired pacing needs remains problematic. His Bundle Pacing (HBP) allows for cardiac pacing without significant changes in the QRS morphology. We hypothesized that HBP doesn't alter S-ICD sensing and functions. METHODS: Twenty consecutive patients were implanted with a HB pacemaker. Among them, 17 demonstrated successful His recruitment and were prospectively screened with the automated screening tool (AST). Results of screenings performed immediately after implant and during follow-up, during intrinsic rhythm and while pacing from all available pacing configurations, were compared using the AST score. Positive screening tests were defined by ≥1 positive vector. RESULTS: Among the 17 patients successfully implanted (male: 41%; mean age: 73), 13 presented an indication of ventricular pacing and 4 of cardiac resynchronization. Absolute AST scores during both HBP (all configurations) and intrinsic rhythm were similar (p-value: ns). Due to LBBB correction, HBP resulted in higher number of positive vectors (AST≥100). AST scores were higher during HBP when compared to RV pacing (primary vector: 272 [16; 648] vs. 4.6 [0.8; 16.2];P=0.003; secondary vector: 569 [183;1186] vs. 1.5 [0.7;8.3];P<0.0001; alternate vector: 44 [2;125] vs. 4.8 [0.9;9.3];P=0.02) and resulted in a much higher number of positive vectors. Up to 90% of the patients had a positive screening test during HBP. This passing rate was higher when compared RVP (17%; P<0.0001). CONCLUSION: HBP restores normal intrinsic conduction and minimally modifies the surface ECG and S-EGMs. When ventricular pacing is needed, HBP might represent an ideal pacing option for patients implanted with a S-ICD. This article is protected by copyright. All rights reserved.