Transthoracic percutaneous access for electroanatomic mapping and catheter ablation of atrial tachycardia in patients with a lateral tunnel Fontan.

Background: The incidence of atrial tachycardia following Fontan surgery is high, but access to the pulmonary venous atrium, a frequent site of arrhythmia origin, is limited.

Objectives: The purpose of this study is to report our results with a novel transthoracic percutaneous technique that provides direct access to the pulmonary venous atrium for electrophysiologic procedures.

Methods: Six transthoracic ablation procedures were performed in five patients (age 1.2-17 years, weight 9.2-68.4 kg) with a lateral tunnel Fontan. Under biplane fluoroscopy, a percutaneous needle was advanced at the selected intercostal space toward the pulmonary venous atrium. Once access was confirmed, a sheath was placed over a wire and a Navistar CARTO catheter advanced for mapping and ablation. Additional catheters were placed in the baffle and esophagus for pacing and reference. Atrial tachycardia was induced, electroanatomic mapping performed, and candidate areas tested with entrainment techniques. Radiofrequency ablation was performed and success defined as the inability to reinduce tachycardia using the initiating protocol.

Results: All tachycardias were ablated. Procedure time ranged from 3.7 to 4.9 hours, and fluoroscopy time ranged from 31 to 70 minutes. Hospital stay was 2 days. One patient had a pneumothorax and two had a hemothorax that was drained. Tachycardia recurred in one patient at 3 months. Ablation was repeated successfully. Four patients are free of tachycardia at follow-up ranging from 6 to 29 months. Follow-up is not available for one child.

Conclusion: Transthoracic percutaneous access provided a direct route to the pulmonary venous atrium for successful mapping and radiofrequency ablation in Fontan patients.