Learning Curve and Initial Experience With Implementation of a His-Bundle Pacing Program in an Australian Setting.

Background: His-bundle pacing (HBP) has emerged as a promising technique to avoid pacing complications associated with dyssynchrony from right ventricular pacing, but data are limited to experienced operators and centres. We aimed to evaluate the implementation and outcomes of an HBP program in an Australian setting.

Methods: Data were retrospectively collected on 140 consecutive HBP procedures attempted at three centres from March 2018 to September 2019. The cohort was divided into three groups (early: procedures 1-47, middle: 48-94, late: 95-140) to determine changes in procedural success in relation to operator experience.

Results: Median age was 76 years (IQR 68-80 yrs); 69% were male. Atrial fibrillation was present in 59%, left ventricular ejection fraction (LVEF) ≤40% in 25%, and left and right bundle branch blocks present in 23% and 16% respectively, and atrioventricular (AV) block was present in 26%. Overall procedural success was 87%, median implant threshold 0.8V@1 ms, and QRS duration improved in 64% of procedures. Procedural success (early 83%, middle 89%, late 89%, p=0.58) was not different, while median procedural time (early 98 mins, middle 83 mins, late 70 mins, p<0.001) improved across operator experience groups. Lower success rates were identified for patients with AV block (73% vs. 92%, p<0.01), a previous device (69% vs. 89%, p=0.02), moderate-severe TR (69% vs. 88%, p=0.04), and when right-sided access was required (25% vs. 89%, p<0.01).

Conclusions: His-bundle pacing is a feasible procedure with continued improvement in procedural measures of success after an early learning period. The presence of AV block, a previous device, significant tricuspid regurgitation, or right-sided access may affect procedural success.