Objective: Cut and sew maze with a "box lesion" around the pulmonary veins is currently the gold standard procedure. We changed our surgical ablation of atrial fibrillation technique from standard bilateral epicardial pulmonary vein isolation with interconnecting lesions, to a "box lesion" procedure with a bipolar radiofrequency or cryo ablator. Our study describes this technique.
Methods: Between March 2009 and September 2013 we performed 131 ablations by the "box" technique. We used a combination of bipolar radiofrequency and cryo device in 90 patients and only cryo device in forty one patients. Seventy six (58%) patients had persistent and 34 (26%) long standing persistent atrial fibrillation. The left atriotomy was performed along the interatrial septum. Left atrial appendage was amputated. The "box" was made by connecting the left atriotomy to the base of the amputated appendage with lines along the transverse and oblique sinuses by epi- and endocardial application of a bipolar radiofrequency or cryo ablator. Left atrial isthmus was ablated by cryoprobe.
Results: There were no ablation-related complications. The "box" was easy to perform, with no dissection around the pulmonary veins. At 6 months, 1 year and 2 years follow-up; 123 (96%), 74 (92%) and 51 (88%) patients were in sinus rhythm correspondently. The freedom from antiarrhythmic medications in patients with sinus rhythm at 6 months, 1 year and 2 years follow-up was 82%, 87% and 83% correspondently.
Conclusions: "Box lesion" performed with bipolar radiofrequency and cryo device provided excellent freedom from atrial fibrillation. "Box lesion" may improve transmurality due to ablation of one rather than two layers of atrial wall, as in epicardial pulmonary vein isolation. Dissection around the pulmonary veins is unnecessary.
