Incidence and determinants of atrial fibrillation in patients with wild-type transthyretin cardiac amyloidosis.

BACKGROUND

Data on the incidence and factors associated with de novo atrial fibrillation (AF) in patients with wild-type transthyretin cardiac amyloidosis (ATTRwt-CA) is limited. We described the incidence and factors associated with de novo AF in patients diagnosed with ATTRwt-CA to drive tailored arrhythmia screening.

METHODS

Multicenter, retrospective, observational cohort study performed in six referral centers for CA. All consecutive patients diagnosed with ATTRwt-CA between 2004 and 2020 with >6-month follow up (FU) were enrolled and divided into three groups according to presence of AF: (1)patients with 'known AF'; (2)patients in 'sinus rhythm' and (3)patients developing 'de novo AF' during FU. Incidence and factors associated with AF in patients with ATTRwt were the primary outcomes.

RESULTS

Overall, 266 patients were followed for a median of 19 [11-33] months: 148 (56%) with known AF, 84 (31.6%) with sinus rhythm, and 34 (12.8%) with de novo AF. At Fine-Gray competing risk analysis to account for mortality, PR (sub-distribution hazard ratio [SHR] per Δms: 1.008, 95% C.I. 1.001-1.013, p = 0.008), QRS (SHR per Δms: 1.012, 95% C.I. 1.001-1.022, p = 0.046) and left atrial diameter ≥ 50 mm (SHR: 2.815,95% C.I. 1.483-5.342, p = 0.002) were associated with de novo AF. Patients with at least two risk factors (PR ≥ 200 ms, QRS ≥ 120 ms or LAD≥50 mm) had a higher risk of developing de novo AF compared to patients with no risk factors (HR 14.918 95% C.I. 3.242-31.646, p = 0.008).

CONCLUSIONS

At the end of the study almost 70% patients had AF. Longer PR and QRS duration and left atrial dilation are associated with arrhythmia onset.