A new era in the surgical treatment of atrial fibrillation: the impact of ablation technology and lesion set on procedural efficacy.

Atrial fibrillation (AF) is the most common sustained arrhythmia in the United States. Adults over the age of 40 years have a 25% risk of developing AF during their lives.1,2 Because AF has detrimental sequelae, including symptoms from tachyarrhythmias, hemodynamic compromise, and thromboembolic complications, many treatment strategies have been developed to alleviate the disease. Antiarrhythmic drugs, catheter-based ablation, and surgery have all been used with varying efficacies. Unfortunately, medical therapy has significant limitations and antiarrhythmic drugs have recurrence rates of AF of more than 60% in some series.3,4 Catheter ablation has reported short- and mid-term cure rates of 59% to 91%, respectively, at variable follow-up.5 The surgical treatment of AF has been most successful with the Cox-Maze III procedure, which has long-term cure rates over 90%.6,7 Although the Cox-Maze III procedure had excellent long-term efficacy,6 the cut-and-sew technique was technically challenging to carry out and few surgeons routinely performed the operation. Recent technologic advancements in ablation devices have provided surgeons with the possibility of performing a modified Cox-Maze procedure by replacing some or all of the traditional incisions with lines of ablation. At our institution, excellent laboratory results using a bipolar radiofrequency (RF) ablation clamp8,9 led to the development of a modification of the original cut-and-sew procedure, which was first performed in 2002. In this procedure, termed the Cox-Maze IV, many of the lesions of the conventional version are replaced with linear lines of ablation using bipolar RF energy.10 Early experience with the Cox-Maze IV procedure recorded comparable success rates to the Cox-Maze III procedure with freedom from AF at last follow-up of greater than 90%.11 The Cox-Maze procedure involved the creation of a myriad of lesions on the atria originally designed to prevent macro-reentrant circuits that were felt to be responsible for the initiation and/or maintenance of AF.12 Speculation concerning which lines of conduction block were essential for treating AF led to the development of several different operations involving limited lesion sets. These have included only left atrial lesions, right atrial lesions, pulmonary vein isolation alone, or a combination of different lesions.13,14 Using mapping techniques, some groups have found that many cases of AF initiate from ectopic beats at foci in the pulmonary veins.15–17 The use of catheter-based RF ablations to isolate the pulmonary veins and treat AF has shown short-term success rates near 80%.5 As a result, it has been suggested that pulmonary vein isolation by catheter-based RF ablation be considered as a first-line treatment of AF.18,19 Surgeons have also attempted to treat AF with fewer lesions on the atria than the traditional Cox-Maze procedure, but reports of long-term success have been scarce. The purpose of this study was to examine results using bipolar RF ablation in 130 patients undergoing a Cox-Maze IV procedure, a limited Cox-Maze procedure, or pulmonary vein isolation alone and to compare them to a historical cohort of patients undergoing a “cut-and-sew” Cox-Maze III procedure.