A Randomized Trial of His Pacing Versus Biventricular Pacing in Symptomatic HF Patients With Left Bundle Branch Block
Michael Vinther1, Niels Risum1, Jesper Hastrup Svendsen2
1Department of Cardiology, The Heart Center, Copenhagen University Hospital-Rigshospitalet, Copenhagen, Denmark.
Insights
His-bundle pacing (His-CRT) and biventricular pacing (BiV-CRT) offer similar clinical improvements for heart failure patients with left bundle branch block (LBBB). His-CRT requires higher pacing thresholds but may improve ejection fraction in per-protocol analysis.
Area of Science:
- Cardiology
- Electrophysiology
- Heart Failure Management
Background:
- Cardiac resynchronization therapy (CRT) is used for symptomatic heart failure (HF) patients with left bundle branch block (LBBB).
- His-bundle pacing (His-CRT) offers an alternative to traditional biventricular pacing (BiV-CRT) for CRT.
- This study represents the largest randomized comparison of His-CRT and BiV-CRT to date.
Purpose of the Study:
- To compare the efficacy and outcomes of His-CRT versus BiV-CRT in patients with symptomatic HF and LBBB.
- To evaluate changes in left ventricular ejection fraction (LVEF), clinical parameters, and physical function.
- To assess pacing thresholds associated with each CRT method.
Main Methods:
- Fifty patients with symptomatic HF, LVEF ≤35%, and LBBB were randomized 1:1 to His-CRT or BiV-CRT.
- Patients were followed for 6 months, with assessments of LVEF, clinical status, and physical function.
- Pacing thresholds were measured at implantation and at 6-month follow-up.
Main Results:
- Intention-to-treat analysis showed no significant difference in LVEF improvement between His-CRT and BiV-CRT.
- Per-protocol analysis revealed significantly higher LVEF and lower end-systolic volume in the His-CRT group.
- His-CRT was associated with significantly higher pacing thresholds compared to BiV-CRT at both implantation and follow-up.
Conclusions:
- His-CRT provides comparable clinical and physical improvements to BiV-CRT in HF patients with LBBB.
- The primary limitation of His-CRT is the requirement for higher pacing thresholds.
- Per-protocol results suggest potential benefits of His-CRT on LVEF and ventricular volumes.
Objectives:
This study sought to compare 2 ways of achieving cardiac resynchronization.
Background:
Cardiac resynchronization therapy (CRT) in patients with symptomatic heart failure and left bundle branch block (LBBB) can be achieved with His-bundle pacing correcting the bundle branch block (His-CRT). The present study is the largest randomized study comparing His-CRT and biventricular pacing (BiV-CRT) to date.
Methods:
Fifty patients with symptomatic heart failure, left ventricular ejection fraction (LVEF) ≤35% and LBBB according to electrocardiography were randomized 1:1 to His-CRT or BiV-CRT and followed for 6 months. At implantation, 7 patients crossed over from His-pacing to LV-pacing in the His-CRT group and 1 patient crossed over from LV-pacing to His-pacing in the BiV-CRT group.
Results:
His-corrective pacing was achieved in 72% of the patients in the His-CRT group. Intention-to-treat 6-month follow-up LVEF increased by 16 ± 7% in the His-CRT group compared with 13 ± 6% in the BiV-CRT group (nonsignificant) and improvements were seen in clinical and physical parameters in both treatment arms with no significant differences between the groups. Pacing thresholds were higher for His-CRT compared with BiV-CRT both at implantation (1.8 ± 1.2 V vs. 1.2 ± 0.8 V; p < 0.01) and at 6-month follow-up (2.3 ± 1.4 V vs. 1.4 ± 0.5 V; p < 0.01). The per-protocol LVEF was significantly higher at 6 months (48 ± 8% vs. 42 ± 8%; p < 0.05) and the end-systolic volume was lower (65 ± 22 ml vs. 83 ± 27 ml; p < 0.05) in His-CRT patients compared with BiV-CRT.
Conclusions:
In heart failure patients with LBBB, His-CRT provided similar clinical and physical improvement compared with BiV-CRT at the expense of higher pacing thresholds.
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