Atrial Fibrillation in Transthyretin Cardiac Amyloidosis: Predictors, Prevalence, and Efficacy of Rhythm Control Strategies

Objectives: This study sought to determine the incidence and prevalence of atrial fibrillation (AF) in transthyretin cardiac amyloidosis (ATTR-CA); to study the factors associated with the development of AF in this population; to study the prognostic implications of AF and maintenance of normal sinus rhythm (NSR) in patients with ATTR-CA; and to determine the impact of ATTR-CA stage on AF prevalence, outcomes, and efficacy of rhythm control strategies.

Background: AF is common in patients with ATTR-CA. The aim of this study was to determine the predictors, prevalence, and outcomes of AF in patients with ATTR-CA in addition to the efficacy of rhythm control strategies.

Methods: This was a retrospective cohort study of 382 patients with ATTR-CA diagnosed at our institution between January 2004 and January 2018. Means testing, and univariable and multivariable models were used.

Results: AF occurred in 265 (69%) patients. Factors associated with the development of AF included older age, advanced ATTR-CA stage, and higher left atrial volume index. Antiarrhythmic therapy (AAT) was used in 35% of patients with AF; cardioversion was performed in 45%, and 5% underwent AF ablation. Rhythm control strategies were substantially more effective when performed earlier in the disease course. During a mean follow-up of 35 months, no difference in mortality between patients with AF and those without AF was observed (65% vs. 49%; p = 0.76). On Cox proportional hazards analyses, maintenance of normal sinus rhythm and tafamidis use were associated with improved survival, whereas advanced ATTR-CA stage and higher New York Heart Association functional class were associated with increased mortality.

Conclusions: With advancing ATTR-CA stage, AF became more prevalent, occurring in 69% of our entire study cohort. Rhythm control strategies including AAT, direct-current cardioversion, and AF ablation were substantially more effective when performed earlier during the disease course.