The cox-maze procedure for lone atrial fibrillation: a single-center experience over 2 decades.

Atrial fibrillation (AF) is the most common sustained arrhythmia worldwide with an expected increase in our aging population.1 In addition to the significant morbidity and mortality secondary to hemodynamic compromise and tachycardia-induced cardiomyopathy in some patients, stroke remains the most feared complication.2 AF accounts for about 25% of strokes in patients older than 80 years and increases a person’s risk of stroke by 5-fold.3 The limitations of pharmacological therapy with failure rates as high as 60% have led to the development and proliferation of interventional approaches in the treatment of AF, including catheter ablation and surgery.4–7 In 1987, Dr. Cox introduced the maze procedure (CMP) for the surgical treatment of AF at our institution. His surgical approach was designed to block the multiple macroreentrant circuits which were the putative cause of AF.7,8 The final iteration of his cut-and-sew technique termed the CMP-III, proved to be highly efficacious with 97% freedom from symptomatic AF and became the gold standard for the surgical therapy of AF for more than a decade (Figure 1).9,10 While early follow-up was excellent and included 24-h Holter monitoring only few patients had electrocardiograms or prolonged monitoring at long-term follow-up.5,11 The endpoint was generally self-reported freedom from symptomatic AF. Moreover, this procedure was not widely adopted because of its complexity and invasiveness. Figure 1 The original cut and sew Cox-Maze Procedure III. The development of alternative energy sources has enabled surgeons to create lines of ablation to replace most incisions of the original CMP-III which shortened and simplified the procedure.12,13 In our Laboratory, bipolar radiofrequency energy was found to be able to create reliable transmural lines of ablation while minimizing the risk of collateral damage to the surrounding tissue.14–16 In 2002, our institution introduced a new iteration termed the CMP-IV, which used bipolar radiofrequency and cryoenergy to replace most of the original incisions.13 While we initially performed only a single inferior connecting lesion between the ablations isolating the right and left pulmonary veins (PVs), we implemented the final version of the CMP-IV two years later, in which the entire posterior left atrium was isolated by adding a superior connecting line, termed the box lesion-set (Figure 2 and ​and33).17 This resembled closely the original cut-and-sew lesion-set of the CMP-III. In this recent group of patients, a stricter follow-up regime was implemented with all patients having electrocardiograms or 24-h Holter monitoring at 3, 6, and 12 months and annually thereafter. Also the definition of success as outlined in recent guidelines was applied.5,11 Figure 2 The right atrial lesion set of the Cox-Maze Procedure IV. Figure 3 The left atrial lesion set of the Cox-Maze Procedure IV. While we have previously reported excellent results with the CMP, the majority of these patients underwent concomitant cardiac surgery procedures.9,10,18,19 Since 1992, our institution performed a stand-alone CMP in 212 patients, reflecting the largest series in literature. This report evaluates our experience in the surgical treatment of lone AF over two decades and compares the outcome of the original cut-and-sew CMP-III to the ablation-assisted CMP-IV.