USE OF INTRAOPERATIVE MAPPING TO OPTIMIZE SURGICAL ABLATION OF ATRIAL-FLUTTER

The purpose of this study was to develop a surgical treatment for atri al flutter using intraoperative activation sequence mapping to minimiz e the surgical procedure necessary to ablate the flutter. A canine mod el (n = 10) of left atrial enlargement was developed by creating a shu nt from the left subclavian artery to the left superior pulmonary vein . Sustained atrial flutter was easily induced in this model. The flutt er consisted of a single reentrant circuit that rotated around one or two anatomic obstacles linked by a region of functional block. Epicard ial templates, consisting of 252 bipolar electrodes, were used to reco rd activation time maps. After localization of the reentrant circuit, surgical incisions were placed to interrupt the pathways. In all 10 an imals, flutter could be induced and intraoperative mapping localized t he reentrant circuit, Seven circuits were in the right atrium and thre e were in the left atrium. The operation ablated all of the preoperati ve circuits. However, in 5 of the animals, flutter originating from a new circuit could be induced. Activation sequence mapping before and a fter operation demonstrates that there are multiple potential reentran t pathways in this canine model of atrial flutter. Therefore, all pote ntial pathways must be surgically interrupted to prevent inducibility of atrial flutter.