For a study, researchers sought to determine the efficacy and side effects of targeting atrial fibrosis (AF) observed on magnetic resonance imaging (MRI) in minimizing atrial arrhythmia recurrence in patients with persistent AF.

The Efficacy of Delayed Enhancement-MRI-Guided Fibrosis Ablation versus Conventional Catheter Ablation of Atrial Fibrillation trial was a multicenter, randomized clinical experiment launched by 44 academic and non-academic facilities in ten countries. From July 2016 to January 2020, 843 patients with symptomatic or asymptomatic persistent AF and receiving AF ablation were included, with follow-up until February 19, 2021. Patients with persistent AF were randomly randomized to either PVI + MRI-guided atrial fibrosis ablation (421 patients) or PVI alone (422 patients). Delayed-enhancement MRIs were done in both groups before the ablation surgery to determine baseline atrial fibrosis and three months afterward to test for ablation scar. The primary endpoint was the time to the first recurrence of atrial arrhythmia after a 90-day blanking period following ablation. The primary safety composite outcome was defined as one or more of the following events occurring within 30 days of the procedure: stroke, PV stenosis, bleeding, heart failure, or death.

About 815 (96.9%) of the 843 randomized patients (mean age 62.7 years; 178 [21.1%] women) completed the 90-day blanking period and participated in the effectiveness analyses. There was no significant difference in the recurrence of atrial arrhythmia between groups (fibrosis-guided ablation with PVI patients, 175 [43.0%] vs. PVI-only patients, 188 [46.1%]; hazard ratio [HR], 0.95 [95% CI, 0.77-1.17]; P=.63). Patients in the fibrosis-guided ablation + PVI group had a greater risk of adverse events (9 [2.2%] vs. 0 in the PVI group; P=.001). About 6 patients (1.5%) in the fibrosis-guided ablation with the PVI group experienced an ischemic stroke, but none in the PVI-only group did. The first death in the fibrosis-guided ablation plus PVI group was presumably due to the operation. 

There was no significant difference in atrial arrhythmia recurrence between MRI-guided fibrosis ablation plus PVI and PVI catheter ablation alone in individuals with persistent AF. The findings did not support using MRI-guided fibrosis ablation to treat chronic AF.