Landmark Chinese trial reveals that LBBP slashes hospitalisation

The HeartSync-LBBP trial compared left bundle branch pacing (LBBP) with traditional biventricular pacing (BVP) in heart failure patients with left bundle branch block (LBBB). Over a median follow-up of 36 months, LBBP significantly reduced the primary composite endpoint and showed better response across all pre-defined subgroups.

Cardiac resynchronisation therapy (CRT) reduces heart failure (HF) hospitalisation and all-cause mortality in HF patients with left bundle branch block (LBBB). Although biventricular pacing (BVP) is still considered the gold standard, a meta-analysis of 10 studies has shown that left bundle branch pacing (LBBP) is superior to BVP-CRT in reducing heart failure hospitalisation [1].

However, there are currently no randomised controlled studies that evaluate the long-term prognosis of LBBP and BVP. Therefore, Dr Xueying Chen (Zhongshan Hospital of Fudan University, Shanghai, China) wanted to address this gap with the HeartSync-LBBP (ChiCTR2000036554) trial, the largest (n=200) multicentre prospective randomised controlled trial aiming to evaluate the long-term clinical outcomes of BVP and LBBP among HF patients with LBBB. The primary study endpoint was the composite outcome of all-cause mortality and HF hospitalisations. The median follow-up duration was 36 months.

The intention to treat analysis showed that the incidence of the primary endpoint in the LBBP group was significantly lower, only about ¼ of that in the BVP group (HR 0.26; 95% CI 0.12-0.57; P< 0.01). Moreover, LBBP was superior across all pre-defined subgroups, e.g. age, sex, diabetes, baseline QRS duration, NYHA class and left ventricular ejection fraction (LVEF). As Dr Chen pointed out, the study included only Chinese patients so it is not sure whether these results can be transferred to other ethnic groups.

There was no difference in the response rate between the groups, but the rate of super-responders, defined as LVEF improvement ≥ 15% or LVEF ≥ 50%, was significantly higher in the LBBP-group (65% vs 44% in the BVP group; P< 0.01).

Dr Chen concluded that LBBP is a promising CRT modality, offering more physiological ventricular activation. In the HeartSync-LBBP trial, LBBP demonstrated greater electrical mechanical and haematological improvements than traditional BVP in HF patients with LBBB. [2]

Prof. Jens Cosedis Nielsen (Aarhus University Hospital, Aarhus, Denmark), the discussant of the trial, commented that the patient population of this trial was selected with a very low risk for death of 1% per year [3]. Moreover, risk of bias may be considerable in this unblinded trial. Therefore, the results have to be confirmed in further large-scale studies including different ethnic groups.

1. Parlavecchio A, et al. Pacing Clin Elecrophysiol 2023;46:432-9.
2. Chen X, et al. Long-term outcomes of LBBP and BiVP in the treatment of chronic systolic heart failure with left bundle branch block: a multicentre, prospective, randomised, controlled trial. Late-breaking science 1, EHRA 2025, 30 March –01 April, Vienna, Austria.
3. Nielsen JC. Discussant review-SWISS-APERO. Late-breaking science 1, EHRA 2025, 30 March-01 April, Vienna, Austria.

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Posted on 6 May 2025