Conduction system pacing was non-inferior to biventricular pacing after AV node ablation

Design

Investigator-initiated multicentre randomised non-inferiority trial

Population

82 patients with refractory AF, LVEF <50% and narrow QRS undergoing AV node ablation

Primary outcome

Change in LVEF at 6 months, core laboratory

Effect

36%→46% vs 34%→46%; difference 0.4 points (95% CI −3.1 to 3.8), non-inferior

CONDUCT-AF was an investigator-led trial at 10 European centres. It randomised 82 patients with refractory atrial fibrillation, heart failure with an ejection fraction below 50%, a narrow QRS of 120 ms or less and NT-proBNP above 600 ng/L to left bundle branch area pacing or biventricular pacing, both alongside AV node ablation. The mean age was 72.

At six months, ejection fraction rose from 36% to 46% with conduction system pacing and from 34% to 46% with biventricular pacing, assessed by an independent core laboratory. The difference of 0.4 percentage points (95% CI −3.1 to 3.8) met non-inferiority. Volumes, symptoms and the composite of worsening heart failure or cardiovascular death were similar. Paced QRS was 14 ms narrower, and procedure and fluoroscopy times were shorter.

This was a small trial powered for an echocardiographic endpoint, so it cannot settle clinical outcomes. But for the 'ablate and pace' patient it supports left bundle branch area pacing as a reasonable first choice where operators are experienced, with a simpler procedure and no need for a coronary sinus lead.

• Consider left bundle branch area pacing as an alternative to biventricular pacing when planning ablate-and-pace
• Reserve this approach for centres with experience in conduction system lead placement
• Expect an ejection fraction gain of about 10 points at six months with either strategy in this population
• Recheck ejection fraction by echocardiography at about six months after the procedure
• Keep a coronary sinus lead as the fallback if conduction system capture cannot be achieved

Why it matters

It offers the same ventricular recovery with a simpler procedure, which matters where coronary sinus leads are difficult or costly.

Don't overread it

With 82 patients and an echocardiographic endpoint, the trial was not powered to compare death or hospital admission.

The statistics, in plain English

Non-inferiority means the new approach was shown not to be meaningfully worse, within a margin set in advance. The confidence interval for the difference (−3.1 to 3.8 points) sits close to zero on both sides, so the two strategies performed very similarly for this endpoint.

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