LEAP-Block: left bundle-branch area pacing cut heart failure events in AV block

Design

Multicentre randomised controlled superiority trial

Population

482 patients with AV block, LVEF 50% or more, expected pacing above 40%

Primary outcome

Death, heart failure events or biventricular upgrade at 24 months

Effect

2.4% vs 12.5%; difference -10.1% (95% CI -16.8 to -3.4); HR 0.37 (0.19-0.73)

LEAP-Block, published in JAMA on 28 October 2026, randomised 499 patients at 14 Chinese hospitals with atrioventricular block, LVEF of 50% or more and an expected ventricular pacing burden above 40% to left bundle-branch area pacing or right ventricular pacing. The primary analysis included 482 patients, mean age 67.

At 24 months the composite of death from any cause, heart failure events or upgrade to biventricular pacing occurred in 2.4% with left bundle-branch area pacing against 12.5% with right ventricular pacing (absolute difference -10.1%, 95% CI -16.8 to -3.4). The Kaplan-Meier estimate gave a hazard ratio of 0.37 (95% CI 0.19 to 0.73). The difference came from heart failure events, 3.4% against 11.3%. Death, biventricular upgrades, device complications and pacing-induced cardiomyopathy did not differ significantly. Implant success was similar, and left bundle-branch capture was confirmed in about 80%.

This is the clearest randomised evidence yet that conduction-system pacing protects ventricular function in patients who will be paced most of the time. It comes from experienced centres in one country and its benefit rests on the heart failure component; operator skill will matter for how well it transfers.

• Consider left bundle-branch area pacing for patients with AV block who are expected to need ventricular pacing more than 40% of the time.
• Discuss conduction-system pacing with the implanting team before the procedure rather than defaulting to a right ventricular lead.
• Confirm left bundle-branch capture at implant; it was achieved in about four in five patients.
• Follow paced patients for heart failure symptoms and ejection fraction, whatever the lead position.
• Ask where local operators have experience with the technique; results came from experienced centres.

Why it matters

Right ventricular pacing has been the default for decades; this trial shows the default carries a heart failure cost that can be avoided.

Don't overread it

The benefit came from heart failure events; the trial was not powered to show a difference in death.

The statistics, in plain English

An absolute difference of about 10 percentage points means roughly one fewer primary event for every 10 patients paced this way over two years. The confidence interval (-16.8 to -3.4) excludes no effect, but it is wide because events were few.

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