Abstract 17144: Architecture of Atrial Fibrosis is Associated With Increased Risk of Recurrence Post Af Treatment

Abstract

Background: Previous studies reported the association between left atrial (LA) fibrosis as assessed by delayed enhancement (DE)-MRI and arrhythmia recurrence post AF ablation. In this study we report the significance of atrial fibrotic infiltrations architecture in predicting treatment failure. Methods: 271 patients (mean age was 59 years, 64% had paroxysmal AF) from the multicenter prospective DECAAF study were included in this sub-analysis. We assessed the location and size of patchy fibrotic atrial tissue infiltrations (figure 1) in all patients who underwent ablation of AF. Due to the strong correlation between LA fibrosis and the largest patch(r=0.875, P<0.001), a Z-transformation of LA fibrosis and the sum of LA fibrosis and largest patch was performed. This allowed direct comparison of hazard ratios (HR) in a Cox proportional hazard model. Results: Mean LA fibrosis score was 18%, the mean largest patch was 21.5 cm2. AF recurrences were associated with the largest patch size per quartile: Q1: 15%, Q2: 28%, Q3: 34%, Q4: 45%, P<0.001. The HR for the standardized LA fibrosis was 1.317, P=0.009.compared to 1.437 for the standardized sum of LA fibrosis and largest patch size, demonstrating that the addition of largest patch to the LA fibrosis score improved the predictive properties of the model. In a multivariate model with age, AF type and LA volume, the standardized sum of LA fibrosis and largest patch size was significantly associated with AF recurrences post-ablation (HR 1.404, P=0.001). Conclusion: From our preliminary data not only the quantity but also the architectural presentation of atrial tissue fibrotic infiltrations was significantly associated with AF treatment failure. This finding would help better understand the severity of AF in addition to improving patient selection undergoing various treatments of AF.