Background Late gadolinium enhancement magnetic resonance imaging is an effective tool for assessment of atrial fibrosis. The degree of left atrial fibrosis is a good predictor of atrial fibrillation ( AF ) ablation success at 1 year, but the association between left atrial fibrosis and long-term ablation success has not been studied. Methods and Results Late gadolinium enhancement magnetic resonance images of sufficient quality to quantify atrial fibrosis were obtained before the first AF ablation in 308 consecutive patients. Left atrial fibrosis was classified in 4 Utah stages (I, 0-10%; II , 10-20%; III , 20-30%; and IV , >30%). Patients were followed up for up to 5 years until the time of first arrhythmia recurrence or second ablation. A total of 308 patients were included; the mean age was 64.5±12.1 years, and 63.4% were men. During follow-up, 157 patients experienced an arrhythmia recurrence and 106 patients underwent a repeated ablation. A graded effect was observed in which patients with more advanced atrial fibrosis were more likely to experience recurrent AF (hazard ratio for stage IV versus stage I, 2.73; 95% confidence interval, 1.57-4.75) and undergo a repeated ablation (proportional odds ratio for stage IV versus stage I, 5.19; 95% confidence interval, 2.12-12.69). Conclusions The degree of left atrial fibrosis predicts the success of AF ablation at up to 5 years follow-up. In patients with advanced atrial fibrosis, AF ablation is associated with a high procedural failure rate.
Keywords: ablation; atrial fibrillation; fibrosis; magnetic resonance imaging.