Predictors of the efficacy of AV-optimised His bundle pacing in patients with a prolonged PR interval: a stratified analysis of the HOPE-HF clinical trial

Abstract

Abstract Funding Acknowledgements Type of funding sources: Foundation. Main funding source(s): British Heart Foundation. Background HOPE-HF was a randomised, placebo-controlled, cross-over trial of AV-optimised His bundle pacing in patients with heart failure (LVEF ≤40%), a PR interval (≥200ms) and without left bundle branch block.1,2. In this analysis we studied the impact of baseline PR interval and acute blood pressure change at the optimal AV-delay on the placebo-controlled effect of His bundle pacing on the trial endpoints of peak VO2 (primary) and patient symptoms (using the Minnesota Living with Heart Failure Questionnaire). Methods and Results 167 patients were successfully implanted and randomised to 6 month blocks of pacing and placebo. We performed a non-invasive, high-precision protocol to calculate the optimal AV delay and associated acute blood-pressure response at randomisation. To test the impact of the baseline PR interval and acute BP response on the placebo-controlled effect of AV-optimised His bundle pacing on endpoints we compared Bayesian ordinal regression models and the relative explained variance (REV) of variables in the model. There was weak evidence that His-bundle pacing improved peak VO2 across all patients (OR 1.31, 95% CrI 0.86 to 2.01, Pr(OR > 1)=89%). The baseline PR interval had little impact on this benefit (REV 0%), and the blood pressure response was more likely (88% vs 12%) to be predictive. However, there was strong evidence that overall AV-optimised His-bundle pacing improved patient symptoms as compared to placebo (OR 1.58, 95% CrI 1.04 to 2.40, Pr(OR>1)=98%). Again, the baseline PR interval had little impact on this benefit (REV 0%) and the blood pressure response was much more likely (97% vs 3%) to be predictive. Higher acute BP increments led to greater placebo-controlled improvements in MLWHF at 6-months. Conclusion An individual’s acute BP response with AV-optimised His-pacing is a powerful predictor of their placebo-controlled improvement in symptoms (MLWHF) at 6-months. This can form the basis of patient selection for future studies and clinical practice.