For patients with heart failure (HF) and left bundle-branch block (LBBB), left bundle-branch pacing (LBBP) has been proposed as an alternative to the standard biventricular pacing (BiVP).¹ A new randomised trial, HeartSync-LBBP, has found that LBBP leads to superior long-term clinical outcomes compared with BiVP in this patient population.²
Methodology
The HeartSync-LBBP trial was a multicentre, prospective, randomised clinical study conducted at six centres in China. It enrolled 200 patients with a left ventricular ejection fraction (LVEF) of 35% or less, complete LBBB, and New York Heart Association (NYHA) functional class II to IV symptoms.
Participants were randomly assigned in a 1:1 ratio to receive either LBBP or BiVP. The primary endpoint was the time to a composite of death from any cause or heart failure hospitalisation (HFH). Secondary endpoints included all-cause death, HFH, and echocardiographic response, defined as an absolute LVEF increase of ≥5%, and super-response, defined as an absolute LVEF increase of ≥15% or an LVEF improvement to ≥50%.
Results
Over a median follow-up of 36 months, the primary endpoint occurred in significantly fewer patients in the LBBP group compared to the BiVP group (8.0% vs 28.0%; hazard ratio [HR] 0.26; 95% CI 0.12–0.57; p<0.001).
This result was primarily driven by a significant reduction in the risk of HFH with LBBP (7.0% vs 28.0%; HR 0.23; 95% CI 0.10–0.52; p<0.001). There was no significant difference in all-cause mortality between the two groups (2.0% vs 5.0%; HR 0.40; 95% CI 0.08–2.04; p=0.25).
While the overall echocardiographic response rates were similar (86.0% for LBBP vs 81.0% for BiVP; p=0.34), the rate of super-response was significantly higher in the LBBP group (55.0% vs 36.0%; p=0.007). The implant success rate was high in both arms (98% for LBBP and 94% for BiVP), with no major complications reported in the LBBP group.
In Practice
These long-term results from a randomised trial suggest a clear benefit for LBBP over traditional BiVP for patients with HF, severely reduced LVEF, and LBBB. The authors concluded that, “In this study, LBBP was superior to BiVP in reducing the risk of death or HFH in patients with LBBB and severely reduced LVEF.” The findings suggest LBBP may be a preferable alternative for cardiac resynchronisation therapy in this patient population.
Next Steps
The study authors note that while these findings are significant, further trials are warranted to confirm the benefits of LBBP in more diverse patient populations.
This study was funded by the National Nature Science Foundation of China, the Shanghai Clinical Research Center for Interventional Medicine, and the Clinical Research Special Fund of Zhongshan Hospital, Fudan University.
Disclaimer
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References
1. Chung MK, Patton KK, Lau CP, et al. 2023 HRS/APHRS/LAHRS Guideline on cardiac physiologic pacing for the avoidance and mitigation of heart failure. Heart Rhythm. 2023;20(9):e17-e91. https://doi.org/10.1016/j.hrthm.2023.03.1538
2. Chen X, Liu X, Li R, et al. Long-Term Outcomes of Left Bundle-Branch Pacing vs Biventricular Pacing in Heart Failure: The HeartSync-LBBP Randomized Clinical Trial. JAMA Cardiol. Published online March 11, 2026. https://doi.org/10.1001/jamacardio.2026.0083