Prevention of Atrial Flutter With Cryoablation May Be Proarrhythmogenic

Background Atrial flutter is a serious problem after surgery for congenital heart disease. Methods We performed an intraoperative linear one-minute cryolesion between a right atriotomy and the tricuspid annulus to prevent atrial flutter in 17 consecutive adult patients undergoing surgery for congenital heart disease. Coronary angiography and electrophysiology study using an electroanatomic mapping system to assess the conduction across the line and to try to induce atrial flutter were performed three months after the operation in 15 patients. Results Eleven patients had bidirectional block in the cryolesion, four patients did not, and two patients refused the electrophysiology study and coronary angiography. All patients with terminal temperature below −151°C had bidirectional block, while only one patient with terminal temperature above −151°C had bidirectional block. No patient with bidirectional block and all patients without bidirectional block had inducible or spontaneous atrial flutter (p = 0.0007). No lesion of the right coronary artery was detected at coronary angiography. Conclusions The success rate was suboptimal and the intervention is potentially proarrhythmogenic in patients without block. Preventive strategies targeting atrial flutter should be validated with regard to the block rate achieved.