Left bundle-branch area pacing cut heart failure events over right ventricular pacing

Design

Multicentre, randomised, controlled superiority trial

Population

482 patients in China with AV block, LVEF of 50% or more and expected pacing above 40%

Primary outcome

Death, heart failure events or biventricular upgrade at 24 months

Effect

2.4% vs 12.5% (risk difference −10.1%, −16.8 to −3.4); HR 0.37 (0.19–0.73)

LEAP-Block, a randomised superiority trial at 14 Chinese hospitals published in JAMA on 28 October, compared left bundle-branch area pacing (LBBAP) with conventional right ventricular pacing in 482 patients with atrioventricular block, preserved ejection fraction and an expected pacing burden above 40%.

At 24 months, the composite of death, heart failure events or upgrade to biventricular pacing occurred in 2.4% with LBBAP and 12.5% with right ventricular pacing. Heart failure events alone were 3.4% against 11.3%. Death, upgrades and device complications did not differ significantly. Procedural success was similar.

Right ventricular pacing makes the ventricles contract out of sync, and a heavy pacing burden can weaken the heart over years. Pacing the conduction system directly keeps contraction more natural. This trial supports that approach for patients who will be paced most of the time.

For non-cardiologists, the practical point is the referral conversation: a patient with heart block facing a pacemaker can reasonably ask whether conduction-system pacing is offered.

• Patients with AV block expected to need pacing most of the time are the group that benefited.
• Conduction-system pacing is offered at many but not all centres; ask the implanting team.
• Watch for new breathlessness or falling ejection fraction in anyone with heavy right ventricular pacing.
• The benefit was driven by heart failure events, not by fewer deaths.

Why it matters

It adds randomised outcome data to a technique already spreading, for one of the commonest pacing indications.

Don't overread it

The trial was not powered for mortality, and all centres were in China with experienced operators.

The statistics, in plain English

The absolute difference was 10.1 points (95% CI 3.4 to 16.8): treating about ten patients with LBBAP rather than right ventricular pacing would prevent one composite event over two years. The hazard ratio of 0.37 (0.19 to 0.73) shows a clear effect, but with relatively few events, the true size could be smaller.

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