COAST-AF trial in JAMA: extra 'low-voltage' ablation did not help persistent AF overall, but may help a subgroup

COAST-AF, a trial led by the University of Ottawa Heart Institute and published in JAMA (announced 10 November 2026), tested whether doctors should go beyond the standard procedure when treating persistent atrial fibrillation (AF), the most common sustained heart-rhythm disorder.

The question

Catheter ablation for persistent AF usually means pulmonary vein isolation, but the arrhythmia often comes back. COAST-AF asked whether also finding and ablating low-voltage areas — patches of abnormal, often scarred heart tissue — improves long-term results. It enrolled 508 patients at 14 Canadian centres.

Findings

• Across the whole study population, adding low-voltage-area ablation did not significantly improve outcomes.
• Among patients in whom low-voltage areas were actually identified, the findings suggested a lower risk of AF returning.

Lead investigator Dr. Pablo Nery said routinely adding the approach for all patients “is unlikely to provide additional benefit”, while pointing to a group that may benefit.

Limitations

• The main result was neutral; the benefit in patients with low-voltage areas comes from a subgroup analysis, which can generate hypotheses but does not prove benefit on its own.
• This summary is based on the institute’s press release; detailed effect sizes and safety data are in the JAMA paper.

Patients with AF should discuss treatment options with their cardiologist.