Long-Term Incidence of Arrhythmias in Extracardiac Conduit Fontan and Comparison Between Systemic Left and Right Ventricle

Aims The extracardiac conduit-Fontan (ECC) has become the preferred technique for univentricular heart palliation, but there are currently no data on the incidence of long-term arrhythmias. This study investigated the incidence of arrhythmias and relation to single ventricle morphology in the long-term follow-up in ECC. Methods and results All patients with ECC performed in our Centre between 1987 and 2017 were included (minimum follow-up 5 years). Of 353 consecutive patients, 303 [57.8% males, aging 8-50 (median 20) years at last follow-up] were considered and divided into 2 groups depending on left (194 in Group 1) or right (109 in Group 2) ventricular morphology. Eighty-five (28%) experienced ≥1 arrhythmic complications, with early and late arrhythmias in 17 (5.6%) and 73 (24.1%) patients, respectively. Notably, late bradyarrhythmias occurred after 6 years in 21 (11%) patients in Group 1, and in 15 (13.8%) in Group 2 [p=0.48]. Late tachyarrhythmias occurred in 55 (18.2%) patients after 12 years: 33 (17%) in Group 1 and 22 (20.2%) patients in Group 2 [p=0.5]. Ventricular tachycardias were documented after 12.5 years in 14 (7.2%) patients of Group 1 and 15 (13.8%) of Group 2 [p=0.06] with a higher incidence in Group 2 during the follow-up [p=0.005]. Conclusion ECC is related to a significant arrhythmic risk in the long-term follow-up, higher than previously reported. Bradyarrhythmias occur earlier but are less frequent than tachyarrhythmias. Interestingly, patients with systemic right ventricle have a significantly higher incidence of ventricular tachycardias, especially in very long follow-up.