Substrate ablation strategies in addition to pulmonary vein isolation (PVI) for the maintenance of sinus rhythm (SR) are still debated. Targeting low voltage areas (LVA) in addition to PVI may represent an efficient strategy for the ablation of persistent atrial fibrillation (AF).

SCAR-AF study (defragmentation of LVA during sinus rhythm) was a multicenter, randomized trial, evaluating the effect of defragmentation of LVA in addition to PVI for persistent AF on SR maintenance.

From September 2019 to August 2021, patients with de novo persistent AF were prospectively randomized 1:1:1 in three groups. Group 1: PVI only, without LVA: Group 2: PVI only, with LVA. Group 3 PVI, with defragmentation of LVA. PVI and LVA were guided by a 3D mapping system. LVA was defined as voltage mapping with bipolar atrial voltage<0.5mV. The primary endpoint was freedom from atrial arrhythmias, after a single ablation procedure.

A total of 212 patients (sex male: 73%, mean age 63.8±9.3 years, CHADS-VASC 2.1, long standing AF 33.5%). After 18 months FU, atrial-arrhythmia-free survival did not differ significantly between the 3 groups, 79% in Group 1, 75.7% in Group 2, 73.1% in Group 3 (Group 1 vs Group 2: HR: 1.28; 95% CI: 0.64–2.55, P=.48, Group 2 vs. Group 3: HR 95%CI: 0.67–2.45; P=.45). Multivariate analysis showed that presence of LVA was associated with age (years) (HR 1.11 CI 1.06–1.16, P<.001) and inversely with IMC (kg/m²) (HR 0.93, CI 0.87–0.99, P=0.029). CHA2DS2-VASc score was associated with AF recurrence (HR 1.66 1.30–2.12<0.001).

In this randomized trial, PVI plus defragmentation of LVA did not significantly improved outcomes in patients with persistent AF. CHA2DS2-VASc score was strongly associated with AF recurrence.