Background: The progression of atrial fibrosis long after Fontan surgery is unclear. This study aimed to evaluate the degree of atrial fibrosis long after the classic Fontan procedure and to investigate the factors associated with atrial fibrosis.
Methods: We obtained atrial free wall specimens resected at Fontan conversion from 43 patients (Fontan group) and studied the degree of atrial fibrosis, along with its association with atrial tachycardia/fibrillation (AT/AF) and other clinical parameters, compared with those of the control group without heart disease (n=6).
Results: The time after the initial Fontan procedure was 19.9 (15.9-25.3) years. Atrial fibrosis (%) was more common in the Fontan group than in the control group [24.3 (20.9-35.0)% vs. 6.2 (5.6-7.5)%, p<0.001]. The severity of atrial fibrosis was mild in 16% (n=7), moderate in 54% (n=23), and severe in 30% (n=13) of cases. Atrial fibrosis (%) was more common in the persistent/permanent AT/AF group than in the no AT/AF (p<0.001) and paroxysmal AT/AF (p<0.001) groups. The maximum atrial diameter on computed tomography (CT) (mm) significantly correlated with atrial fibrosis (%) (r=0.52, p<0.001). The maximum diameter of the right atrium (≥75 mm) on CT was a significant risk factor for severe atrial fibrosis on multivariate logistic analysis (hazard ratio=10.22, 95% confidence interval=1.04-254.8, p=0.04).
Conclusions: Atrial fibrosis was prominent long after classic Fontan surgery, especially in patients with non-paroxysmal AT/AF and dilated right atrium.
Keywords: Atrial fibrosis; Atrial myopathy; Atrial tachyarrhythmia; Fontan conversion; Fontan surgery.
Copyright © 2021. Published by Elsevier Ltd.