Surgical Treatment of Chronic Atrial Fibrillation -Unipolar Radiofrequency Ablation versus Cryoablation, and Left Atrial versus Bi-atrial Maze Procedures-

This study evaluated the efficacy of the left atrial Maze procedure (Lt-maze) and unipolar radiofrequency (RF) ablation as an additional procedure for the surgical treatment of atrial fibrillation (AF) in patient with other cardiac disease. Methods and Results: The Maze procedure was performed in 100 consecutive patients with AF: Lt-maze, 71 patients; bi-atrial Maze (Bi-maze), 29 patients. Cryoablation and RF ablation were used in 82 and 18 patients, respectively. There were no in-hospital or early deaths. Fourteen patients (14%) experienced postoperative complications. Seventy-five patients (75%) were in sinus rhythm (SR) at discharge, 4 patients were in junctional rhythm, and 21 patients had AF. Two patients (2%) required permanent pacemaker implantation. The AF-free rate at discharge was 79%, and the AF-free rate at hospital discharge did not differ significantly between cryoablation and unipolar RF ablation (78% and 82%, respectively). There were no significant differences between these two groups in operative results, in terms of the aortic cross-clamp time, cardiopulmonary bypass time, and AF-free rate, with the AF-free rate not differing significantly in those who received single valve surgery (73% and 75% in the cryoablation and unipolar RF ablation groups, respectively). The equipment cost of the two procedures differed greatly: 14,000 yen/patient for cryoablation and 250,000 yen/patient for RF ablation. The AF-free rate did not differ significantly between Lt-maze (76%) and Bi-maze (86%), including in those who received single valve surgery (72% and 79%, respectively). The significant predictors of AF recurrence in a univariate analysis were left atrial diameter (p = 0.03), duration of AF (p < 0.01), fibrillation amplitude on ECG (p = 0.02), and cardiothoracic ratio (p < 0.01), with the duration of preoperative AF being the only significant predictor of AF in a multivariate analysis. Conclusion: In this series, unipolar RF ablation for the Maze procedure was as effective as cryoablation at eliminating AF, and Lt-maze and Bi-maze were equipotent at restoring SR at discharge.