Comments on “Totally Thoracoscopic Ablation for Atrial Fibrillation: All-Box Clamping”

We read the article by Doll et al[1] with great interest as they proposed a novel and refined thoracoscopic epicardial ablation procedure, totally thoracoscopic all-box clamping (TT-ABC) to treat atrial fibrillation.

The TT-ABC technique represents an innovative and optimized approach for thoracoscopic epicardial atrial fibrillation ablation. However, in our opinion, this technique still presents certain limitations and challenges. (1) Potentially increased conduction gaps: While the TT-ABC theoretically creates a closed isolation zone by connecting two C-shaped ablation lines, direct intraoperative visualization of the ablation lesions between the left and right pulmonary veins on the posterior left atrial wall remains challenging. Conduction gaps between the incompletely connected two C-shaped lesions may occur, which might disrupt the continuity of the box lesions of the Cox-Maze IV procedure and compromise ablation efficacy. Complete, continuous, and transmural lesions of the pulmonary veins and atrial wall are essential for ensuring the success of the Cox-Maze IV procedure. (2) Fewer ablation lesions: In contrast to the classic Cox-Maze IV procedure,[2] which employs independent circular ablation lesions to isolate each ipsilateral pulmonary vein separately, TT-ABC omits these lesions for the ipsilateral pulmonary veins. Although this simplified ablation box lesions may reduce the difficulty of the thoracoscopic epicardial ablation procedure, it might lead to incomplete isolation of the atrial fibrillation substrate. (3) Higher economic costs: This surgical technique requires the use of specialized bipolar ablation devices, Isolator Synergy clamps EML2 and EMR2. EML2 and EMR2 are Isolator Synergy clamps made by the AtriCure Corp., respectively for left-sided and right-sided ablation. The EML2 features a left-curved jaw design, whereas EMR2 has a right-curved jaw. However, only a few institutions in some areas have access to both EML2 and EMR2 clamps, which might limit the popularization of this technique. (4) Greater challenges in intraoperative respiratory management: Pulmonary vein isolation is performed through bilateral thoracoscopy, requiring simultaneous right and left thoracotomy incisions. This approach poses significant challenges for intraoperative respiratory management and demands a high level of technical expertise from anesthesia teams.

In our institution, we employ only the EMR2 clamp to isolate bilateral pulmonary veins. When isolating left pulmonary veins, we strategically adjust the EMR2 clamp angle and tilt it above the left atrium dome to ensure the isolation of the left pulmonary veins as well as the intersection with the right-sided ablation lesions. This strategy can contribute to addressing the four limitations mentioned above.

Despite the aforementioned limitations, the TT-ABC technique still represents a significant advancement in surgical atrial fibrillation management. By simplifying the ablation process and reducing the learning curve, this refined technique can contribute to the widespread application of thoracoscopic ablation for atrial fibrillation worldwide.

^* These authors contributed equally to this work.

Publication History

Received: 15 July 2025

Accepted: 29 August 2025

Article published online:
23 September 2025

• References

• 1 Doll N, Doll A, Horvath G. et al. Totally thoracoscopic ablation for atrial fibrillation: All-Box clamping. Thorac Cardiov Surg 2025; (e-pub ahead of print).
• 2 Ruaengsri C, Schill MR, Khiabani AJ, Schuessler RB, Melby SJ, Damiano Jr RJ. The Cox-maze IV procedure in its second decade: still the gold standard?. Eur J Cardiothorac Surg 2018; 53 (suppl_1): i19-i25