Efficacy of His Bundle Pacing on LV Relaxation and Clinical Improvement in HF and LBBB

OBJECTIVES This study aimed to compare acute hemodynamic improvements and responses to His bundle pacing (HBP) and conventional biventricular pacing (BVP). BACKGROUND HBP can correct left bundle branch block (LBBB) and may be an alternative cardiac resynchronization therapy (CRT) to BVP. METHODS Fourteen consecutive patients with heart failure (HF) and typical LBBB who required CRT were enrolled. The acute hemodynamic responses during HBP and BVP were compared using a micromanometer-tipped catheter inserted into the left ventricle (LV) before CRT. Each configuration was compared with AAI mode. A permanent HBP device was implanted when LBBB correction threshold was #1.5 Vat 1.0 ms, and remaining patients were treated with BVP. Clinical and echocardiographic improvements were assessed during a 12-month follow-up period. RESULTS The LV contractile index (positive maximal rate of LV pressure rise [dP/dtmax]) increased similarly during HBP and BVP (18.8% +/- 6.4% vs 18.0% +/- 10.2%; P = 0.810). LV relaxation indices (negative dP/dtmax and tau) were significantly improved during HBP compared with BVP (negative dP/dtmax: 14.3% +/- 5.5% vs 3.1% +/- 8.1%; P < 0.001; tau: 7.2% +/- 4.3% vs-0.8% +/- 8.1%; P = 0.001). Nine (64%) patients received permanent HBP devices, while 5 patients were treated with BVP. The New York Heart Association functional class, LV ejection fraction, LV end-systolic volume, and B-type natriuretic peptide level improved in patients treated with HBP and BVP (all P < 0.05 vs baseline). Patients treated with HBP exhibited earlier and greater improvements of the LV ejection fraction and LV end-systolic volume than did those with BVP. CONCLUSIONS HBP improves systolic function and LV relaxation in patients with HF and LBBB. CRT via HBP produced earlier and greater clinical responses than BVP. (C) 2022 by the American College of Cardiology Foundation.