RESUMO
A 33-year-old man, who had undergone atriopulmonary connection Fontan procedure (AP Fontan) for double outlet right ventricle, suffered from heart failure due to atrial tachycardia at 27â¯years old. Atrial tachycardia was suppressed after amiodarone administration. At 32â¯years old, atrial tachycardia recurred, and short palpitations gradually increased. Cardiac computed tomography showed that coronary sinus (CS) was perfused into the pulmonary venous atrium, and catheter insertion to CS from the systemic venous atrium was impossible. We performed an electrophysiology study (EPS) and radiofrequency catheter ablation (RFCA) under local anesthesia. An esophageal electrode catheter was inserted as a potential reference for ultra-high density three-dimensional (3D) mapping system. Two types of atrial tachycardia were induced by EPS. Ultra-high-density 3D mapping system revealed an intra-atrial reentrant pattern around the scar area on the lower right atrium in both atrial tachycardias; therefore, we diagnosed intra-atrial reentrant tachycardia (IART). The low voltage area and inferior vena cava during IART were ablated linearly, and IART was terminated.In conclusion, a CS electrode catheter cannot be inserted in a patient with AP Fontan, and ultra-high-density 3D mapping using the esophageal electrode catheter as a potential reference enables accurate and rapid mapping and is very effective for RFCA. Learning objective: The incidence of intra-atrial reentrant tachycardia (IART) is high in patients with late after Fontan procedure, and the treatment may be difficult. Ultra-high-density three-dimensional mapping can perform accurate mapping of IART and rapid detection of low voltage areas effective for radiofrequency catheter ablation. An esophageal electrode catheter can be the reference potential for accurate activation mapping in Fontan patients where coronary sinus electrode catheter insertion may be impossible from a systemic venous atrium.