Atrial Fibrillation/Flutter in Transthyretin Cardiac Amyloidosis

BACKGROUND: 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. OBJECTIVES: The authors aim to determine the predictors of prevalence and incidence of AF and the effect of tafamidis. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.