His bundle pacing for newly acquired pacing needs in patients implanted with a subcutaneous implantable cardioverter defibrillator: A feasibility study based on the automated screening score and clinical cases.

ABSTRACT

INTRODUCTION: Management of subcutaneous implantable cardioverter defibrillator (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 does not 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 greater than or equal to 1 positive vector. RESULTS: Among the 17 patients successfully implanted (male 41%; mean age 73), 13 presented an indication of ventricular pacing and four of cardiac resynchronization. Absolute AST scores during both HBP (all configurations) and intrinsic rhythm were similar (p NS). Due to left bundle branch block correction, HBP resulted in higher number of positive vectors (AST ≥ 100). AST scores were higher during HBP when compared with right ventricular pacing (RVP) (primary vector 272 [16; 648] vs 4.6 [0.8; 16.2]; P = .003; secondary vector 569 [183; 1186] vs 1.5 [0.7; 8.3]; P < .0001; alternate vector 44 [2;125] vs 4.8 [0.9; 9.3]; P = .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 < .0001). CONCLUSION: HBP restores normal intrinsic conduction and minimally modifies the surface electrocardiograph and subcutaneous electrograms. When ventricular pacing is needed, HBP might represent an ideal pacing option for patients implanted with a S-ICD.