Efficacy of additional ExTRa Mapping-guided substrate ablation beyond pulmonary vein isolation in persistent atrial...

There are currently no established effective additional substrate ablation strategies beyond pulmonary vein isolation (PVI) for persistent atrial fibrillation (AF).

This randomized clinical trial evaluated the efficacy of a novel substrate ablation technique using the ExTRa Mapping system, which visualizes rotational activation during AF rhythm.

This study included 80 patients undergoing initial catheter ablation for persistent AF. Eighty patients whose AF persisted after PVI and ExTRa Mapping were randomly assigned in a 1:1 ratio to either PVI alone or PVI plus ExTRa Mapping-guided substrate ablation targeting areas with high non-passively activated ratio(%NP)( ≥ 35%)(ExTRa group). The primary outcome measure was recurrence of atrial tachyarrhythmias after a 90-day blanking period postablation.

Post-PVI ExTRa Mapping assessed a median of 36 sites per patient in both atria. Baseline characteristics were comparable between groups. The ExTRa group showed higher event-free survival from the primary outcome compared to the PVI alone group (85.0% vs. 67.5% at 1-year, p = 0.07). This favorable prognosis was more pronounced for patients with a large( ≥ 12 sites) area of rotational activation area (81.0% vs. 57.9% at 1-year, p = 0.01). Multivariable analysis identified the number of high %NP areas as an independent risk factor for recurrent tachyarrhythmias (HR 1.13, 95%CI 1.03-1.23, p = 0.005), while ExTRa Mapping-guided substrate ablation emerged as a unique protective factor (HR 0.38, 95%CI 0.13-0.99, p = 0.047).

While the reduction in atrial tachyarrhythmia recurrence of persistent AF patients did not reach statistical significance, the addition of ExTRa Mapping™-guided substrate ablation beyond PVI demonstrated promising potential, especially in patients with larger rotational activation areas.