Surgical treatment of atrial fibrillation: State of the art, 2012

The development and introduction of radiofrequency ablation devices allowed maze procedure to be performed safely and easily, further enabling off-pump pulmonary vein isolation through mini-thoracotomy or thoracoscopy. The outcomes of the maze procedure include the prevention of stroke and other complications related to atrial fibrillation (AF), improvement in cardiac performance, and relief of symptoms. The indications for the maze procedure have been discussed on the basis of available evidence. Pulmonary vein isolation has been shown to be effective in most patients with paroxysmal AF, and can be performed with both endocardial catheter ablation and minimally invasive epicardial ablation. These 2 modalities should be compared in terms of the success rate, occurrence of cerebral microembolic signals, capability adding other lesions indicated for persistent or long-standing persistent AF, and closure of the left atrial appendage. Noncontinuous or nontransmural lines of conduction block as a result of incomplete ablation can result in the recurrence of AF and induction of atrial tachycardia. Intraoperative verification of a conduction block across the ablation lines is recommended to prevent these complications. Volume reduction of the enlarged left atrium or a box lesion to isolate the entire posterior left atrium may be effective in patients with a dilated left atrium, but the potentially impaired atrial transport function should be considered. Mapping of active ganglionated plexi and their ablation may improve the outcome of the procedure; however, the long-term effect on AF and autonomic nerve activities should be examined. Because the mechanism underlying AF varies in each patient, a tailor-made therapy, using a stepwise approach, with a hybrid procedure combining epicardial and endocardial ablation offers promising prospects in the nonpharmacological treatment of AF.