**Author Listing - Lead/ Submitting Author (we will be communicating with this individual): Name, Institution, City and State where the work was done. Co-authors will be added in a separate section.**
Cristhian Espinoza Romero
Heart Institute (InCor) os Hospital das Clinicas, Universidade de Sao Paulo, Brazil

**Main Body of the Abstract**
Introduction: Atrial fibrillation (AF) poses a significant challenge in amyloidosis cardiomyopathy, particularly in transthyretin amyloidosis cardiomyopathy (ATTR-CM). With AF often being an initial symptom in ATTR-CM, it is vital to identify predictors for early intervention and prevention of thromboembolic events.
Purpose: This study aims to identify predictors for AF development in patients with ATTR-CM using data from the REACT registry.
Methods: The REACT registry, a retrospective cohort and multicenter study, enrolled patients with TTR mutation or wild type. ATTR-CM diagnosis involved positive echocardiography and pyrophosphate scintigraphy, and, in some cases, cardiac or extracardiac biopsy. Binary logistic regression and multivariate analysis were employed, utilizing the LR backward method. ROC curve analysis and the Youden index determined optimal cutoff points for continuous variables.
Results: We included 273 patients with ATTR-CM diagnosis. The population, predominantly male (73.2%) with a median age of 73 years, showed a high prevalence of the ATTR variant (67.2%). Val142Ile was the most common variant (29.3%). AF prevalence was 25.2%. Binary logistic regression identified a left atrium diameter (OR 1.091, p=0.005), and age (OR 1.052, p=0.014) as AF predictors. ROC curve analysis established age ≥ 70 years and left atrium > 45 mm as optimal cutoff points (AUC 0.643 and 0.727, respectively) (see figure 1).
Conclusions: In the Brazilian ATTR amyloidosis registry, the presence of a dilated left atrium > 45 mm, and age ≥ 70 years emerged as predictors of AF, shedding light on crucial insights for early detection and management.



**Author Listing - Lead/ Submitting Author (we will be communicating with this individual): Name, Institution, City and State where the work was done. Co-authors will be added in a separate section.**
Cristhian Espinoza Romero
Heart Institute (InCor) os Hospital das Clinicas, Universidade de Sao Paulo, Brazil

**Main Body of the Abstract**
**Introduction:** Atrial fibrillation (AF) poses a significant challenge in amyloidosis cardiomyopathy, particularly in transthyretin amyloidosis cardiomyopathy (ATTR-CM). With AF often being an initial symptom in ATTR-CM, it is vital to identify predictors for early intervention and prevention of thromboembolic events.
**Purpose:** This study aims to identify predictors for AF development in patients with ATTR-CM using data from the REACT registry.
**Methods:** The REACT registry, a retrospective cohort and multicenter study, enrolled patients with TTR mutation or wild type. ATTR-CM diagnosis involved positive echocardiography and pyrophosphate scintigraphy, and, in some cases, cardiac or extracardiac biopsy. Binary logistic regression and multivariate analysis were employed, utilizing the LR backward method. ROC curve analysis and the Youden index determined optimal cutoff points for continuous variables.
**Results:** We included 273 patients with ATTR-CM diagnosis. The population, predominantly male (73.2%) with a median age of 73 years, showed a high prevalence of the ATTR variant (67.2%). Val142Ile was the most common variant (29.3%). AF prevalence was 25.2%. Binary logistic regression identified a left atrium diameter (OR 1.091, p=0.005), and age (OR 1.052, p=0.014) as AF predictors. ROC curve analysis established age ≥ 70 years and left atrium > 45 mm as optimal cutoff points (AUC 0.643 and 0.727, respectively) (see figure 1).
**Conclusions:** In the Brazilian ATTR amyloidosis registry, the presence of a dilated left atrium > 45 mm, and age ≥ 70 years emerged as predictors of AF, shedding light on crucial insights for early detection and management.



Predictors of atrial fibrillation in Brazilian patients with transthyretin amyloidosis cardiomyopathy: Insights from the REACT registry. PC79 (#526)

We invite you to attend the XIX International Symposium on Amyloidosis to be held in Rochester, MN.

This symposium is organized as a hybrid meeting (with the focus on in-person) held from Sunday, May 26 through Thursday, May 30, 2024.

Together with the ISA Board and members of Mayo Clinic, a very attractive scientific hybrid program is being planned. The program will cover a variety of types of systemic amyloidosis: ATTR (hereditary and wild-type), AL (light-chain), AA and less frequent forms. There will be key lectures, specific symposia including those company sponsored, oral presentations and poster sessions of accepted abstracts.

COURSE DESCRIPTION
This program will provide a comprehensive review of state-of-the-art education in systemic amyloidosis: basic science, pathophysiology, diagnosis, current and emerging treatments. Scientific presentations will include competitive oral and poster abstracts. The rapid evolution of scientific discovery and expanding treatment options has created tremendous interest in the field and this meeting will fill and important gap in educating scientists and clinicians.