Re: Prospective randomized comparison of left atrial and biatrial radiofrequency ablation in the treatment of atrial fibrillation

We read the article by Wang et al. [1] with great interest. In our opinion, a few points ought to be addressed.

The authors describe two different surgical techniques for surgical atrial fibrillation ablation therapy, the left atrial and the biatrial ablation approach; the LA approach requiring cavotricuspid isthmus ablation in the RA in order to achieve bidirectional block. For better understanding of the well conducted study it would have been of some help if the authors would have mentioned the rationale for performing an atrial ablation line on the right atrial side which in accordance to the guidelines is only recommended in patients with a history of typical atrial flutter or inducible cavotricuspid dependent atrial flutter [2]. The authors also do not explain why the additional opening of the right atrium is regarded as ‘left’ sided. In accordance with others [3] we believe that standardization of ablation therapies is of great help for better understanding, since this is of utmost importance for further scientific comparison of different ablation strategies. By calling a two sided ablation therapy a one sided therapy, confusion might arise. In addition, it is beneficial to use a common nomenclature when reporting on ablation issues [2]. The term ‘permanent’ atrial fibrillation describes that group of patients where a decision has been made not to pursue restoration of sinus rhythm by any means, thus the term ‘longstanding persistent’ would have been appropriate for the patients being studied. Furthermore, there is a need for specification when defining the kind of surgical ablation technique; the term ‘Maze procedure’, as stated by Ad [4], should only be used to describe the procedure as it was developed by Cox et al.

The authors well describe the patients’ heart rhythm status and AF recurrence in the early postoperative period. However, a high incidence of atrial fibrillation recurrence (35–40%) due to inflammation occurs within the first three months after ablation and is not related to long-term success. Therefore, in order to avoid confusion, this time period ought to be omitted in the outcome analysis of ablation therapy [2]. For further evaluation of post-ablation heart rhythm, and this is regarded as a ‘minimal monitoring strategy’, regular intervals of 24 h Holter monitoring (24 HM) for one to two years are strongly recommended [2]. In case of ‘rhythm at last follow-up’, an overestimation of procedural success is inevitable. There is an agreement that the most appropriate heart rhythm documentation after ablation therapy is accomplished when using continuous rhythm surveillance as achieved with implantable devices [2]. We were able to show that the sensitivity of quarterly performed 24 HM after surgical ablation therapy reaches only 60% with a negative predictive value of 64% when intraindividually compared to continuous heart rhythm monitoring [5]. Thus, in our opinion, for further more ‘real life’ reports after ablation therapy and thus gaining more certainty about the procedural success, long-term continuous rhythm surveillance as well as usage of a defined nomenclature might be of an additional benefit.

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