Abstract 12093: Tafamidis Use and New Onset Atrial Fibrillation in Patients With Cardiac Amyloidosis

Introduction: Atrial fibrillation (AF) is the most common sustained arrhythmia seen in patients with cardiac amyloidosis (CA). Tafamidis, a transthyretin stabilizer, has been associated with reductions in all-cause mortality and other promising outcomes in patients with CA. However, its effect on incidence of AF still remains unknown. Hypothesis: Tafamidis therapy in patients with CA is associated with lower incidence of AF. Methods: A group of 200 patients with transthyretin CA following at our institution between 2003 and 2019 were retrospectively reviewed. Baseline characteristics, onset of AF (determined by ECG, device interrogation, or ambulatory monitoring) and tafamidis use data were collected. Patients with diagnosis of AF at baseline were excluded. Patients were matched based on age, sex, BMI, DM, HTN, ischemic heart disease, and stage of amyloid disease. Time to event analysis was performed to assess the incidence of new-onset AF in patients who had received tafamidis versus those who had not. Results: In total, 36 patients met inclusion criteria. Of these 36 patients diagnosed with incident AF, 10 received tafamidis therapy prior to AF diagnosis and 26 did not. Median time to Tafamidis initiation after diagnosis of cardiac amyloidosis was 243 [64, 776] days [IQR]. Average follow-up time was 21.8 ± 24.4 months. There were no significant differences between baseline characteristics, however there were more African Americans (27% vs. 0%) and Val122Ile mutations (23% vs. 10%) in the control group. Overall, tafamidis initiation was associated with lower incidence of new-onset AF compared to those who had not received the therapy (p=0.026). Persistent AF was the most common type of AF, no matter being on tafamidis or not. Conclusions: Tafamidis therapy in patients with CA might be associated with lower incidence of AF. The mechanism however is not clear and further studies are needed to re-examine this finding and elucidate the potential mechanism.