EAM-CT Merge Guiding a Safe Transeptal Puncture in Atrial Tachycardia Ablation in a Intracardiac Fontan Patient.

A patient with tricuspid valve atresia and pulmonary artery valve stenosis underwent a total cavo-pulmonary circulation with an unfenestrated intracardiac conduit. He experienced poorly tolerated atrial tachycardia and was referred for radiofrequency catheter ablation (RFCA). No interatrial shunt was evident. Before the procedure, a computed tomography (CT) scan with 3D rendering was performed. At the time of the procedure, the 3D rendering was merged with an electroanatomical map (EAM) performed by CARTO3 in sinus rhythm (SR). The merge guided the identification of the exact target point for a safe transeptal puncture, without using intracardiac and/or transesophageal echocardiography. The EAM during the tachycardia showed a reentrant circuit with a critical isthmus in the lateral portion of the Fontan conduit, and RFCA was performed restoring SR.