Iatrogenic atrioventricular reentrant tachycardia following Bjork/Fontan palliation of tricuspid atresia: Electro-anatomic mapping, ablation, review and possible mechanism

This case report describes the successful ablation of an iatrogenic accessory pathway in a Fontan patient. A 15-year-old girl with tricuspid atresia was palliated with a Bjork modification Fontan procedure; six years later she developed supraventricular tachycardia. Electro-anatomic mapping during electrophysiology study localized a concealed iatrogenic atrioventricular accessory pathway and facilitated successful ablation using radiofrequency energy. This report reviews the reported cases of anomalous atrioventricular conduction (antegrade only, retrograde only [Hager, et al., J Thorac Cardiovasc Surg 2005;130:48-53], both [Liberman, et al., Pacing Clin Electrophysiol 2000;23:914-6]) after the Fontan/Bjork repair, outlines a potential pathophysiologic mechanism for the post-operative tachyarrhythmia and highlights the usefulness of electro-anatomic mapping in identifying unusual arrhythmias in post-operative patients with complex congenital heart disease.