Relationship Between Atrial Dysfunction and Atrial Arrhythmias in Adults With Fontan Palliation: Role of Atrial...

Atrial dysfunction is a risk factor for atrial arrhythmia and can be detected by atrial strain imaging in patients with biventricular circulation. However, the role of atrial strain imaging for risk stratification of atrial arrhythmia in patients with Fontan palliation has not been studied, despite the high prevalence and prognostic implications of atrial arrhythmia in this population. We hypothesized that pulmonary venous atrial strain was associated with new-onset and recurrent atrial arrhythmia in Fontan physiology.

This is a retrospective study of adults with Fontan palliation and no prior history of atrial arrhythmia who underwent atrial strain imaging by speckle tracking echocardiography (2003-2023). New-onset and recurrent atrial arrhythmias were ascertained from baseline encounter to last follow-up. Of 404 patients, atrial reservoir strain assessment was feasible in 329 patients (81%), with modest intra- and interobserver agreement. The median atrial reservoir strain was 18% (interquartile range, 13%-24%), and atrial dysfunction (atrial reservoir strain <28%) was present in 294 (89%). Atrial reservoir strain <15% was associated with new-onset atrial arrhythmia (adjusted hazard ratio [HR], 1.59 [95% CI, 1.09-2.34]; P=0.009), and recurrent atrial arrhythmia (adjusted HR, 2.01 [95% CI, 1.06-3.93]; P=0.003). Rhythm control therapy was associated with lower risk of recurrence compared with rate control therapy (adjusted HR, 0.92 [95% CI, 0.86-0.98]; P=0.003).

Atrial dysfunction was common and was associated with new-onset and recurrent atrial arrhythmias. The higher prevalence of atrial arrhythmias in patients with reduced atrial strain and the apparent protective effect of rhythm control therapy suggest that rhythm control therapy may be the preferred treatment in patients with reduced atrial strain.