INTRODUCTION: Multiple CMR-derived indices of atrial fibrillation (AF) substrate have been shown in isolation to predict long-term outcome following catheter ablation. Left atrial (LA) fibrosis, LA volume, LA ejection fraction (EF), LVEF, LA shape (sphericity) and pulmonary vein anatomy have all been shown to correlate with late AF recurrence. This study aimed to validate and assess the relative contribution of multiple indices in a long-term single-center study.
METHODS AND RESULTS: 89 patients (53% PAF, 73% male) underwent comprehensive CMR study prior to first-time AF ablation (median follow-up 726days (IQR 418-1010days)). 3D LGE acquisition (1.5T, 1.3x1.3x2mm) was quantified for fibrosis, LA volume and sphericity assessed on manual segmentation at atrial diastole, LA and LV ejection fraction (EF) quantified on multi-slice cine imaging. AF recurred in 43 patients (48%) overall (31 at one year). In the recurrence group, LA fibrosis was higher (42% vs 29%, HR 1.032, p=0.002), LAEF lower (25% vs 34%, HR 0.063, p=0.016) and LVEF lower (57% vs 63%, HR 0.011, p=0.008). LA volume (63 vs 61 ml/m2) and sphericity (0.819 vs 0.822) were similar. Multivariate Cox regression analysis was adjusted for age and sex (model 1), additionally AF type (model 2) and combined (model 3). In models 1 and 2, LA fibrosis, LAEF and LVEF were independently associated with outcome, but only LA fibrosis was independent in model 3 (HR 1.021, p=0.022).
CONCLUSIONS: LAEF, LVEF and LA fibrosis differed significantly in the AF recurrence cohort. However, on combined multivariate analysis only LA fibrosis remained independently associated with outcome. This article is protected by copyright. All rights reserved.
- atrial fibrillation
- atrial fibrosis
- cardiac magnetic resonance imaging
- catheter ablation
- structural remodeling