Intraoperative Three-Dimensional Mapping of Supraventricular Tachycardia in a Young Fontan Patient.

Preoperative tachycardia is uncommon before an initial Fontan procedure. Catheter intervention can risk complications in small patients. A patient with fetal tachycardia and double inlet left ventricle underwent Norwood and bidirectional Glenn procedures. She had persistent tachycardia. A three-dimensional electroanatomic mapping system was modified for the operative procedure; it was used to identify the arrhythmia substrate and cryoablate an atrioventricular nodal tachycardia. Mapping added 20 minutes to the operation. She is arrhythmia-free and off medication after 4 months. This three-dimensional system was successfully adapted for an intraoperative SVT ablation in this small patient, and it may be useful in other settings.