# Long-Term Outcomes of Left Bundle-Branch Pacing vs Biventricular Pacing in Heart Failure: The HeartSync-LBBP Randomized Clinical Trial

## TL;DR

This study found that left bundle-branch pacing is more effective than biventricular pacing in reducing heart failure hospitalizations and death in patients with severe heart failure and left bundle-branch block.

## Contribution

The study provides the first randomized clinical trial evidence that left bundle-branch pacing outperforms biventricular pacing in long-term outcomes for heart failure patients.

## Key findings

- Left bundle-branch pacing significantly reduced the risk of death or heart failure hospitalization compared to biventricular pacing.
- LBBP showed a higher super-response rate in improving left ventricular ejection fraction compared to BiVP.
- The study demonstrated a 36-month follow-up with strong evidence supporting LBBP as a superior pacing strategy in this patient population.

## Abstract

This study attempts to evaluate the long-term clinical outcomes of left bundle-branch pacing and biventricular pacing in patients with heart failure.

Whether left bundle-branch pacing (LBBP) yields superior clinical outcomes compared with biventricular pacing (BiVP) in patients with heart failure (HF) with left bundle-branch block (LBBB) and severely reduced left ventricular ejection fraction (LVEF)?

In this randomized clinical trial, LBBP was associated with a significantly lower risk of all-cause mortality and HF hospitalization when compared with BiVP.

These results demonstrated that LBBP was superior to BiVP in reducing the risk of death or HF hospitalization in patients with LBBB and severely reduced LVEF and might be an alternative to BiVP in this patient population.

Left bundle-branch pacing (LBBP) has been proposed as an alternative to biventricular pacing (BiVP) for patients with heart failure with left bundle-branch block (LBBB). However, robust clinical evidence from randomized clinical trials is lacking.

To evaluate the long-term clinical outcomes of LBBP and BiVP.

This multicenter, prospective, randomized clinical trial enrolled 200 patients at 6 centers in China with a left ventricular ejection fraction (LVEF) of 35% or less and LBBB from October 2020 to March 2022. This study was took place from October 2020 to September 2024. These data were analyzed September 2024 to December 2024.

Patients were randomly assigned in a 1:1 ratio to receive either LBBP or BiVP.

The primary end point was the time to death from any cause or heart failure hospitalization (HFH). The secondary end points included all-cause death, HFH, echocardiographic response (absolute increase in LVEF ≥5%), and super response (absolute increase in LVEF ≥15% or improvement of LVEF to ≥50%) rates.

Of the 200 included patients, 136 were male and 64 were female. The success rate was 98% in the LBBP group and 94% in the BiVP group (P = .28). The median follow-up duration was 36 (range, 33-39) months. The primary end point of time to death or HFH was significantly lower in the LBBP group compared with BiVP (8% vs 28%; hazard ratio [HR], 0.26; 95% CI, 0.12-0.57; P < .001). There was no significant difference in all-cause mortality between the groups (2.0% vs 5.0%; HR, 0.40; 95% CI, 0.08-2.04; P = .25). However, LBBP significantly reduced the risk of HFH (7.0% vs 28.0%; HR, 0.23; 95% CI, 0.10-0.52; P < .001). The echocardiographic response rates were similar in both groups (86.0% vs 81.0%; P = .34) but the super-response rate was higher in the LBBP group (55.0% vs 36.0%; P < .007).

In this study, LBBP was superior to BiVP in reducing the risk of death or HFH in patients with LBBB and severely reduced LVEF. Further trials are warranted in this patient population.

Chinese Clinical Trial Registry identifier: ChiCTR2000036554