Objectives The Fontan procedure provides palliation for patients with complex congenital heart disease. A late complication is the development of a pro-arrhythmogenic environment. Modifications to the surgical technique try and reduce the incidence of late arrhythmia. This study aims to establish incidence and outcome of arrhythmias in Fontan patients with long-term follow-up.

Methods Retrospective analysis of adult patients with a Fontan circulation cared for by University Hospitals Birmingham between 2001 and 2013.

Results 166 patients, mean age 29.1 years, were identified (63% atriopulmonary (AP) Fontan, 13% lateral tunnel (LT), 24% extracardiac total cavopulmonary connection (TCPC)). The mean follow-up since Fontan surgery was 18.6 years. 42% (70 patients) had suffered at least one tachyarrhythmia, with 100% incidence of arrhythmia in AP Fontan patients surviving at least 26 years following surgery. The most common arrhythmia was intra-atrial re-entrant tachycardia (66%). There was also a significant incidence of arrhythmia in the LT and TCPC groups (23% at mean follow-up of 19.6 years and 13.6 years, respectively). 44 patients had undergone electrical cardioversion, 30 had ablations and 10 had undergone Fontan conversion surgery. Survival analysis showed only age at the time of Fontan as a significant predictor for arrhythmia onset (p<0.001) irrespective of surgical approach.

Conclusions There is a significant, increasing arrhythmia burden in adult patients with a Fontan circulation. Arrhythmia development could be regarded as an inevitable consequence of an AP Fontan. There remains a high incidence of arrhythmia with more modern surgical approaches. The long-term future of these patients is unclear and their care poses significant challenges.