Surgical Treatment of Atrial Fibrillation

Abstract

Atrial fibrillation (AF) is now commonly treated at the time of valvular heart surgery or coronary artery bypass grafting. Surgical ablation of AF, which is predicated upon the Maze procedure, includes creation of lines of conduction block and excision of the left atrial appendage. A full bi-atrial lesion set is associated with success in 80% to 95% of patients and virtually eliminates the risk of late stroke. A complex but safe operation, the classic cut-and-sew Maze procedure has been applied by relatively few surgeons. However, recent advances in understanding of the pathogenesis of AF and development of new ablation technologies enable surgeons to perform pulmonary vein isolation, create linear left and right atrial lesions, and remove the left atrial appendage rapidly and safely. Lesions are created under direct vision, minimizing the risk of damage to the pulmonary veins and adjacent mediastinal structures. Recently developed instrumentation now enables thoracoscopic and keyhole approaches, facilitating extension of epicardial AF ablation and excision of the left atrial appendage to patients with isolated AF and no other indication for cardiac surgery. In addition, novel devices designed specifically for minimally invasive epicardial exclusion of the left atrial appendage will broaden the range of treatment options for patients with AF, possibly eliminating the need for anticoagulation in selected patients.

Figure 1.. Left atrial lesion set of the Cox-Maze III procedure. Schematic illustration of the posterior left atrium. White ovals represent mitral valve, and sets of 4 black ovals represent pulmonary veins. Dashed lines indicate surgical incisions. The pulmonary veins are encircled by a surgical incision, and there is a connecting incision to the mitral valve annulus. The left atrial appendage is excised, and this incision is connected to the pulmonary vein encircling incision.

Figure 2.. Left atrial lesion set of the Cox-Maze III procedure. Schematic illustration of the posterior left atrium. White ovals represent mitral valve, and sets of 4 black ovals represent pulmonary veins. Dashed lines indicate surgical incisions. The pulmonary veins are encircled by a surgical incision, and there is a connecting incision to the mitral valve annulus. The left atrial appendage is excised, and this incision is connected to the pulmonary vein encircling incision.

Figure 3.. Left atrial appendage clip. A cloth-covered, nitinol and titanium clip has been applied to the epicardial aspect of a canine left atrial appendage.