Box lesion in the open left atrium for surgical ablation of atrial fibrillation

Cut-and-sew maze with a box lesion around the pulmonary veins is currently the criterion standard procedure for surgical ablation of atrial fibrillation. Recently, we changed our technique from standard bilateral epicardial pulmonary vein isolation with interconnecting lesions to a box lesion procedure with a bipolar radiofrequency ablation device. Our study describes this technique.

Between March 2009 and June 2012, we performed 90 ablations by the box technique with a bipolar radiofrequency device. Fifty-five patients (61%) had persistent atrial fibrillation, and 21 (23%) had long-standing persistent atrial fibrillation. The left atriotomy was performed along the interatrial septum and the left atrial appendage 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 epicardial and endocardial application of a bipolar radiofrequency ablation device. The left atrial isthmus was ablated by cryoprobe.

There were no ablation-related complications. The box was easy to perform, with no dissection around the pulmonary veins. At 6-month, 1-year, and 2-year follow-ups, 80 (94%), 69 (93%), and 47 (91%) patients, respectively, were in sinus rhythm. Freedoms from antiarrhythmic medications in patients in sinus rhythm at 6 months, 1 year, and 2 years were 78%, 88%, and 85%, respectively.

The box lesion provided excellent freedom from atrial fibrillation and may improve transmurality through ablation of 1 rather than 2 layers of atrial wall, as in epicardial pulmonary vein isolation. With the box lesion, dissection around the pulmonary veins is unnecessary.