Relation of Left Atrial Appendage Remodeling by Magnetic Resonance Imaging and Outcome of Ablation for Atrial Fibrillation.

The left atrial appendage (LAA) is a nonpulmonary vein trigger site in atrial fibrillation (AF). The association of LAA structural remodeling (SRM) identified by late gadolinium enhancement magnetic resonance imaging (LGE-MRI) and AF ablation outcome has never been described. This study sought to investigate the clinical significance of LAA-SRM in AF patients who undergo ablation therapy. Consecutive patients with AF who underwent catheter ablation therapy within 14 days following MRI scan were included in this study. LAA-SRM was assessed using LGE-MRI images to quantify the extent of LAA-LGE. Patients were followed for arrhythmia recurrence after the ablation procedure. A total of 74 patients were included in the study, 68% were male, with a mean age of 72 years. Mean LAA-LGE extent was 9%. There were 37 arrhythmia recurrences (50%) observed over a mean follow-up period of 18 months. The recurrence rate was significantly higher (73.3% vs 37.5%; p = 0.045) in patients with LAA-LGE extent in the highest tier (T4) compared with the lowest tier (T1). LAA-LGE extent was independently associated with arrhythmia recurrence (adjusted hazard ratio [HR] 1.054; 95% confidence interval [CI] 1.008 to 1.103). In addition, there was an approximately fourfold increased risk of arrhythmia recurrence (adjusted HR 4.117, 95% CI 1.260 to 13.459) in patients with advanced LAA-SRM (T4 vs T1). In conclusion, the extent of LAA-SRM identified by LGE-MRI is associated with arrhythmia recurrence after AF ablation.