Efficacy of Delayed Enhancement MRI-Guided Ablation vs Conventional Catheter Ablation of Atrial Fibrillation

This proposal is aiming at modifying and improving persistent AF management guidelines by evaluating targeting DE-MRI detected atrial fibrosis during AF ablation and its related effect on procedural outcome. OBJECTIVES: Primary Objective: To examine the efficacy of targeting atrial fibrosis tissue during an ablation procedure in treating persistent AF. Results from the DECAAF study show that one of the most important predictors of ablation outcome was the degree of ablation of the fibrotic tissue; the more fibrotic tissue that was overlapped with scar during ablation, the better the outcome. These results were the impetus for the primary outcome of DECAAF II. Patients will be randomized to receive conventional pulmonary vein isolation (PVI) ablation or PVI + fibrosis-guided ablation. The investigators will follow patients longitudinally to assess the primary outcome identified as recurrence of persistent atrial arrhythmias (AA) (atrial fibrillation, atrial flutter or atrial tachycardia as defined by recent guidelines \[2\]). The investigators hypothesize that patients receiving fibrosis-guided ablation in addition to conventional PVI ablation will have fewer AA recurrences than those who receive PVI ablation alone. The investigators will also examine the efficacy of the fibrosis-guided ablation intervention on a number of secondary or exploratory outcomes including the individual components of the primary outcome (atrial fibrillation, atrial flutter and atrial tachycardia), symptomatic atrial arrhythmia, AF cycle length/regularity/termination, cardiovascular (CV)-related hospitalization, CV-related mortality, quality of life measurements (University of Toronto Atrial Fibrillation Severity Scale (AFSS), and AF burden. The safety of the two interventions will be evaluated by evaluating peri-procedural complications including stroke, peripheral vascular stenosis, bleeding, esophageal injury, cardiac perforation, heart failure, and death.