Collaborative work in a complex case of Fontan for treating intra-atrial reentrant tachycardia and severe aortic stenosis: a case report.

Background: Intra-atrial reentrant tachycardia (IART) is a frequent arrhythmia in patients with Fontan circulation. Although its supraventricular origin, such arrhythmia can be poorly tolerated as it leads to haemodynamic impairment. Concomitant assessment of pressure/volume overload of cardiac chambers due to valvular disease or residual shunts is necessary.

Case Summary: We report the case of a 33-year-old male with Fontan extracardiac conduit, suffering from IART with initial poor haemodynamic tolerance. He had a medical history of pulmonary atresia with intact ventricular septum and Type 0 bicuspid aortic valve, with a total of four cardiac surgeries. Echocardiography demonstrated a severe impairment of the univentricular ejection fraction and a critical aortic stenosis. Given the limited medical treatment options of the arrhythmia and the risks of another heart surgery, both IART ablation and transcatheter aortic valve replacement (TAVR) were performed during the same procedure. The IART critical isthmus located in the antero-lateral region of the extracardiac conduit was effectively treated with radiofrequency. Rapid pacing during TAVR was provided by a catheter placed in the unique ventricle via a transconduit puncture. The aortic valve was deployed with minimal para-valvular regurgitation and a satisfactory transvalvular gradient. At follow-up, the univentricular ejection fraction normalized and no arrhythmic episode was recorded in absence of anti-arrhythmic drugs.

Discussion: This case highlights the need of a collaborative approach for treating complex cases of adult congenital heart disease, suffering from both electrophysiological and haemodynamic disorders. This combination offered an elegant and safest solution for treating concomitantly a life-threatening arrhythmia and an aortic stenosis.