Combined Atrial Volume is Associated with Significant Atrial Arrhythmias in Total Cavopulmonary Connection Fontan Patients

Atrial arrhythmias are a common late manifestation after Fontan palliation and are known to contribute to significant morbidity and mortality. Atrial volume by cardiac magnetic resonance imaging has been increasingly used in patients with congenital heart disease with no reports in those with Fontan palliation. In acquired heart disease, left atrial volume has been shown to be a strong predictor of outcomes of sustained atrial arrhythmias, including recurrence of atrial fibrillation. We hypothesized that combined atrial volume (CAV) in patients with total cavopulmonary connection (TCPC) Fontan palliation may be associated with increased risk of significant atrial arrhythmias (SAA). This is a single center retrospective case–control study. Cases were defined as patients with TCPC Fontan palliation ≥ 18 years of age, with SAA requiring intervention. Only those with advanced imaging for 3D rendering between 2013 and 2022 were included. CAV was analyzed from a 3-dimensional (3D) data set, including both the left and right atria, excluding the Fontan baffle. Seventeen TCPC Fontan case patients and 17 control patients were included. There was no difference in age between the two groups. There was no difference between gender, type of Fontan palliation, atrio-ventricular valve regurgitation, or combined ventricular function between the two groups. CAV was higher in SAA group compared to controls, and all control patients had indexed CAV ≤ 80 mL/kg. This is the first data suggesting CAV is associated with SAA in TCPC Fontan patients. Indexed CAV ≥ 80 mL/kg may be a valuable marker for SAA risk.