# Atrial Fibrillation/Flutter in Transthyretin Cardiac Amyloidosis: Prevalence, Incidence, Clinical Predictors, and Effect of Tafamidis

## TL;DR

This study finds that over half of patients with a specific heart condition have atrial fibrillation, which is linked to disease severity and a drug called tafamidis may help prevent it.

## Contribution

The study identifies new predictors of atrial fibrillation in transthyretin cardiac amyloidosis and evaluates the protective effect of tafamidis.

## Key findings

- Atrial fibrillation was present in 58% of patients with transthyretin cardiac amyloidosis at baseline.
- Higher Columbia score and left atrial volume index were associated with prevalent atrial fibrillation.
- Tafamidis and hereditary amyloid transthyretin were protective against new-onset atrial fibrillation.

## Abstract

Atrial fibrillation/flutter (AF) is common in transthyretin cardiac amyloidosis (ATTR-CA). The CHARGE-AF score has not been validated in ATTR-CA. The Columbia staging system is prognostic for survival, but its utility in predicting incident AF is unknown.

The authors aim to determine the predictors of prevalence and incidence of AF and the effect of tafamidis.

This is a retrospective cohort study of 419 patients with ATTR-CA. AF was ascertained from review of electrocardiograms, extended rhythm, device interrogations, and charted history. Binary logistic regression assessed for factors associated with prevalent AF. Cox regression time-to-event analysis assessed for factors associated with incident AF.

AF was present in 58% (n = 244) of ATTR-CA at baseline. On multivariable logistic regression, higher Columbia score (OR: 1.48; 95% CI: 1.25-1.75) and higher left atrial volume index (LAVI) (OR: 1.05; 95% CI: 1.02-1.08) were associated with prevalent AF, whereas hereditary amyloid transthyretin (ATTRv) (OR: 0.19; 95% CI: 0.07-0.55) was protective (all P < 0.05). AF developed in 71 (41%) subjects without prior AF, over a median follow-up 2 years. On Cox regression, higher Columbia score (HR: 1.18; 95% CI: 1.01-1.38; P = 0.035) was associated with new onset AF, whereas CHARGE-AF and LAVI were not. ATTRv (HR: 0.44; 95% CI: 0.23-0.87; P = 0.017) and tafamidis (HR: 0.54; 95% CI: 0.30-0.95; P = 0.034) were protective.

More than half of the ATTR-CA patients have AF, which was associated with wild-type amyloid transthyretin, greater Columbia stage, and increased LAVI. About half of the ATTR-CA individuals developed AF after 2 years, which was predicted by the Columbia score, but not the CHARGE-AF score. ATTRv and tafamidis were protective against incident AF.