Ultra-high density mapping of intra-atrial reentrant tachycardia in a patient after a lateral tunnel total cavopulmonary connection.

We report a case of an 18-year-old male with a postsurgical lateral tunnel (LT) total cavopulmonary connection (TCPC) and supraventricular tachycardia (SVT). Patients after an LT TCPC have complicated suture lines and a considerable area of damaged myocardium in the LT, which could become a complex arrhythmogenic substrate of tachycardias. Detailed three-dimensional (3D) mapping of the LT and atrium is important for a successful ablation. In this patient, successful catheter ablation of two types of complex tachycardias was accomplished using an ultra-high density 3D mapping system inside the LT.