Electrophysiological mapping and ablation of intra-atrial reentry tachycardia after Fontan surgery with the use of a noncontact mapping system

Background-Atrial tachyarrhythmias are a complication of Fontan surgery. Co nventional electrophysiological mapping and ablation techniques are limited by the complex anatomic and surgical substrate and a high arrhythmia recur rence rate. This study investigates the use of noncontact mapping to identi fy arrhythmia circuits and guide ablation in Fontan patients. Methods and Results-Eleven arrhythmias were recorded in 6 patients. Noncont act mapping improved recognition of the anatomic and surgical substrate and identified exit sites from zones of slow conduction in all clinical arrhyt hmias. Radiofrequency linear lesions were targeted across these critical zo nes in 5 patients. One patient underwent surgical cryotherapy. Although imm ediate success was achieved in 3 of 5 patients with radiofrequency ablation , 2 patients had a recurrence after a mean of 6.4 months of follow-up. The patient who underwent cryoablation remains free of arrhythmias. Conclusions-Noncontact mapping can identify arrhythmia circuits in the Font an atrium and guide placement of ablation lesions. Arrhythmia recurrence is high, possibly because of inadequate lesion creation rather than inaccurat e mapping and lesion targeting.