Incidence and associated factors with atrial fibrillation in patients with transthyretin amyloidosis cardiomyopathy: Insights from the multicenter REACT-SP registry.

Introduction: Atrial fibrillation (AF) presents a treatment challenge in patients with amyloidosis cardiomyopathy, particularly in transthyretin amyloidosis cardiomyopathy (ATTR-CM). Identifying factors associated with AF is important for early diagnosis and intervention. Purpose: This study aims to identify factors linked to AF in ATTR-CM patients. Methods: The REACT registry, a retrospective, multicenter cohort study, enrolled patients with TTR mutation or wild type. ATTR-CM diagnosis was based on echocardiography and pyrophosphate scintigraphy, with some cases confirmed by biopsy. Binary logistic regression and multivariate analysis were used, with ROC curve analysis determining optimal cutoff points for continuous variables. Results: The study included 273 patients, mostly male (73.2 %), with a median age of 73 years. The ATTR variant was found in 67.3 % (165 patients), and Val142Ile was the most common variant (29.3 %). AF was present in 25.2 % (59 patients). Logistic regression revealed age (per 10-year increase) and left atrial diameter (per 5-mm increase) as predictors of AF, with odds ratios of 1.714 (p = 0.009) and 1.631 (p = 0.002), respectively. ROC curve analysis identified age ≥ 70 years and left atrium > 45 mm as optimal cutoff points (AUC 0.643 and 0.727). Conclusions: In the ATTR amyloidosis registry, older age and increased left atrium size are associated with AF. These findings may help in the early diagnosis and management of AF in ATTR-CM patients.