I would like to thank the editors for letting me review the manuscript entitled '' The long-term outcomes and durability of the Cox-Maze IV procedure for atrial fibrillation''. The authors analyzed the results and factors affecting the results of Cox Maze IV operation in 853 patients in a high volume reference center. I also would like to congratulate them for their extensive efforts to share their experiences about such a challenging surgery. It is a very well written paper but I some minor concerns that I would like to share, here are my detailed comments about the manuscript,

About the Abstarct.. It is not clear how you collect the data in the abstract section, is it a prospective, retrospective, or retrospective analyze of prospectively collected data? You may consider adding a sentence to clarify this issue. Regarding the title, Durability is one of the outcomes that all the readers wonder about the Maze operation. As you give the long term success rate and factors affecting the success in the result section, another title like, ‘’ The long-term outcomes of the Cox-Maze IV procedure for atrial fibrillation ‘’ or ‘’ The long-term outcomes and factors affecting the durability of the Cox-Maze IV procedure for atrial fibrillation’’ would be more appropriate Introduction/background, this is a very comprehensive introduction which gives detailed information about background and development of the procedure. As you already shared this information in your previous manuscripts(reference 6, 10, 14, 16…), you may consider summarizing it. Methods, Second paragraph, second sentence under the ‘’Patient Population’’ section, ‘’ In addition, this procedure can be performed via a right minithoracotomy, which is more attractive to both patients and referring physicians.’’ You already have shared this information within the previous paragraph. You may consider rewriting this as, ‘’ Performing the surgery via a right minithoracotomy, is more attractive to both patients and referring physicians.’’ ‘’Follow-up and Postoperative Care’’ section, 4th paragraph, ‘’ Throughout the entire series, the majority of patients (647/853, 76%) underwent prolonged monitoring during their follow-up.’’ Does this mean 76% of patients evaluated in each time point (at 1, 5, and 10 years) with a prolonged monitoring device? What if a patient missed the first year visit and came for fifth year? Please clarify! Statistical Analysis, I am unable to comment on the Fine-Gray regression as this is beyond the scope of my statistical knowledge. Results, Overall the results are clear and well written. I am certainly aware the importance of information that you share but you use different time points for each section. You gave the freedom from ATAs at 1,3,5,8, and 10 years in one section and 1,5 and 10 in another. This made the manuscript hard to follow and understand. You may consider using a uniform way to give this information. Use only graphs or tables for other time point results. Discussion, First paragraph, as you already stated this information in your introduction section; you may consider not repeating here. Overall the paper is well written and gives valuable information about long term outcomes of Cox-Maze IV operations. I agree with the authors about the limitations of the study especially possible overestimating the success rate because of the low prolonged monitoring. Dear Editor, This is a well written and informative manuscript from one of the biggest reference center for atrial fibrillation surgery. It has lots of limitations as well but all were clearly discussed under the limitations section. Please consider to accept the paper after minor revisions.