Letter regarding the article ‘Predictors of the efficacy of His bundle pacing in patients with a prolonged PR interval: A stratified analysis of the HOPE ‐ HF randomized controlled trial’

Predictors of the efficacy of His bundle pacing in patients with a prolonged PR interval: A stratified analysis of the HOPE-HF randomized controlled trial'We read with great interest the recently published article by Keene et al. 1 regarding the predictors of response to His bundle pacing (HBP) in patients with prolonged PR intervals.According to this study, a subset of patients with heart failure (HF) and narrow QRS complex could benefit from HBP.While in the HOPE-HF study pacing did not improve the primary outcome of peak oxygen uptake in patients with ejection fraction below 40%, PR interval above 200 ms and narrow QRS or right bundle branch block, this stratified analysis showed that acute haemodynamic improvement after pacing was a reliable predictor of positive response.1,2 No such interaction was observed for the extent of PR interval prolongation or transmitral E and A wave fusion.The targeted pathophysiological substrate in this group of patients is atrioventricular (AV) dyssynchrony.AV dyssynchrony occurs when there is a delay between the atrial and ventricular contractions, leading to a time interval between the end of atrial systole and the onset of ventricular contraction.This 'lost time' can result in diastolic mitral regurgitation and decreased ventricular