Adhering to the principles of surgical ablation.

The surgical treatment of atrial fibrillation (AF) has evolved since Dr James Cox introduced the maze procedure in 1987. The advent of innovative technologies for endocardial and epicardial ablation endeavouring to replicate Cox-maze III surgical lesions has ushered in a new era of innovative operations to address AF. The current report by Fengsrud et al. [1] elegantly demonstrates the technique of right monolateral thoracoscopic creation of an isolated pulmonary vein encircling box lesion using the Cobra Adhere XL radiofrequency device (Estech, Inc., San Ramon, CA, USA). In their preliminary experience with 10 stand-alone cases for AF of varying type and duration, they had no mortality, 1 re operation for bleeding and an average length of stay of 5.6 days. They performed guideline-directed Holter monitoring in 8 patients. Though 7 of 10 were free of AF at 12 months, only 4 were free from antiarrhythmic medications. The development of this technique started nearly a decade ago with the introduction of microwave epicardial ablation [2], demonstrating excellent safety and short-term efficacy. However, late results revealed that these outcomes were not effective in sustaining curative intent [3]. The result was the abandonment of the ablation technology but not the approach. Several others have replicated and modified the epicardial thoracoscopic procedure by making this a monolateral right-sided procedure. Initial experience with the epicardial Cobra Adhere XL vacuum-assisted radiofrequency ablation (Estech, Inc.) revealed good outcomes [4]. Applying rigorous monitoring, this technique demonstrated respectable freedom from paroxysmal AF and helped establish a hybrid approach to ablation that includes a secondary percutaneous endocardial mapping and ablation with an electrophysiology partnership [5–7]. The challenge with right mono-lateral approaches is the inability to surgically address the left atrial appendage (LAA). Though the necessity of LAA exclusion or excision is debated by authors of the current report [1], many surgeons and cardiologists continue to feel that addressing the LAA is a fundamental principle in the surgical approach to AF [8]. As we innovate with different ablative technologies, can we adhere to the principles of surgical ablation? Though definitions may evolve over time, these include a low morbidity procedure that durably restores sinus rhythm documented by Holter or continuous monitoring over 1 year, one that enables freedom from antiarrhythmic medications and one that mitigates the occurrence of stroke and improves quality of life. This latter point often relates to patients safely stopping anticoagulation. This is often not possible for several months or longer when the LAA remains intact post-ablation. Non-sternotomy approaches to treat AF include monoor bilateral thoracosopic or mini-thoracotomy, on-pump endocardial or off-pump epicardial surgical ablation. Each approach has demonstrated clinical effectiveness in several excellent centres worldwide [7]. However, a recent comparison between mini-right thoracotomy open Cox-maze, epicardial ablation and epicardial hybrid ablation with percutaneous treatment revealed that operations most closely following the full Cox-maze procedure may afford the best long-term results [9]. Regardless of the surgical approach or institutional expertise, when innovating with surgical ablation, being dedicated to the rigours of monitoring, follow-up, drug-free morbidity reduction and complete ablation, should be among the principles we adhere to for our patients and our specialty.