ATRIAL ARRHYTHMIAS AND THROMBOEMBOLIC COMPLICATIONS IN ADULTS WITH FONTAN CIRCULATION

Abstract

The Fontan operation has significantly improved survival in patients with univentricular physiology. However, in the long term, these individuals are susceptible to developing complications such as atrial arrhythmias and thromboembolism. There is a paucity of data regarding the factors associated with the development and progression of atrial arrhythmias and complications such as thromboembolism. We aimed to study the factors associated with the development, maintenance and progression of atrial arrhythmias and thromboembolism in an adult population with Fontan physiology. Single centre retrospective cohort study of clinical characteristics of all patients ≥ 18 years of age with Fontan circulation, followed for more than 12 months at a regional quaternary care centre. 93 patients were included (mean age 30.2 ± 8.8 years, 58% male). Twenty-eight (30.1%) had classic Fontan connection, 35 (37.6%) had lateral tunnel Fontan, and 29 (31.2%) had extra-cardiac Fontan pathway. After a mean of 7.27 ± 5.1 years follow-up, atrial arrhythmia was noted in 37 (39.8%) patients, of which 13 (35.1%) had atrial fibrillation, 16 (43.2%) had atrial flutter and 16 (43.2%) had ectopic atrial tachycardia. Multivariate analysis found that the number of prior cardiac surgeries/procedures (OR 1.50; 95% CI 1.06-2.12), increasing age (OR 1.10; 95% CI 1.03-1.18) and prior classic Fontan operation (OR 5.77; 95% CI 1.8-18.48) were associated with atrial arrhythmia, but not associated with gender, heart failure, hypertension, or diabetes. Forty-one thromboembolic events occurred in 31 patients: 17 (41.4%) had stroke or TIA, 11 (26.8%) had pulmonary embolism or deep venous thrombosis, five (12.0%) had a history of atrial thrombus, and the remainder had systemic thrombosis at other sites. The presence of thromboembolic events was associated with increasing age (OR 1.06; 95% CI 1.00-1.13) and hepatic cirrhosis (OR 6.28; 95% CI 1.27-31.05) in multivariate analysis. (Table 1) Atrial arrhythmias are common in adults with Fontan circulation at a relatively early age. Atrial tachycardia, flutter and atrial fibrillation are present with similar prevalence. Risk factors associated with the development of atrial arrhythmia include increasing numbers of lifetime cardiac surgeries/procedures, increasing age and classic Fontan procedure while thromboembolism was associated with increasing age and hepatic cirrhosis. Traditional risk factors such as hypertension and diabetes are not associated with atrial arrhythmia or thromboembolism in this young group of patients.