Comparison of Arrhythmia Prevalence and Incidence in Adult Patients with Lateral Tunnel and Extra-Cardiac Fontan Circulation.

Although patients with total cavopulmonary connection (TCPC) Fontan are known to have a lower incidence of arrhythmias compared with atriopulmonary Fontan, there is debate about long-term prevalence of arrhythmia in the TCPC population or about the differences in arrhythmia burden between patients with lateral tunnel (LT) and extra-cardiac (EC) Fontan circulations. A retrospective cohort of 341 patients with LT and EC Fontan operations was identified in a single adult congenital heart disease (ACHD) center. Arrhythmias and related procedures were recorded. Logistic regression was used to determine factors affecting arrhythmia prevalence. Arrhythmia incidence was compared using interval-censored Cox regression. Of 341 patients, 254 (74.5%) had LT Fontan and 87 (25.5%) had EC Fontan. Patients with LT Fontan were older at their last ACHD follow-up (29 versus 25 years). Arrhythmia occurred in 52.2% of patients, 57.9% of the LT and 35.6% of the EC Fontan group. Compared to EC Fontan patients, patients with LT were both more likely to have an arrhythmia (OR 1.84, 95% CI 1.04-3.24) and at a higher risk of developing a new arrhythmia (HR 1.67, 95% CI 1.10-2.54). Patients with LT had more cardioversions, ablations, and revisions compared with EC Fontan patients. However, a similar proportion in each group were treated with antiarrhythmics and had a pacemaker. We summarize arrhythmia burden in a large single-center adult cohort of patients with TCPC Fontan, demonstrating increased arrhythmia in patients with LT. This work can inform screening protocols and risk assessment for this growing population.