[17] Boersma LV, Castella M, van Boven W, Berruezo A, Yilmaz A, Nadal M et al. Atrial fibrillation catheter ablation versus surgical ablation treatment (FAST): a 2-center randomized clinical trial. Circulation 2012;125:23–30. [18] Pokushalov E, Romanov A, Elesin D, Bogachev-Prokophiev A, Losik D, Bairamova S et al. Catheter versus surgical ablation of atrial fibrillation after a failed initial pulmonary vein isolation procedure: a randomized controlled trial. J Cardiovasc Electrophysiol 2013;24:1338–43. [19] Wang SZ, Liu L, Zou CW. Comparative study of video-assisted thoracoscopic surgery ablation and radiofrequency catheter ablation on treating paroxysmal atrial fibrillation: a randomized, controlled short-term trial. Chin Med J (Engl) 2014;127:2567–70. [20] Wang J, Li Y, Shi J, Han J, Xu C, Ma C et al. Minimally invasive surgical versus catheter ablation for the long-lasting persistent atrial fibrillation. PloS ONE 2011;6:e22122. [21] De Maat GE, Van Gelder IC, Rienstra M, Quast AF, Tan ES, Wiesfeld AC et al. Surgical vs. transcatheter pulmonary vein isolation as first invasive treatment in patients with atrial fibrillation: a matched group comparison. Europace 2014;16:33–9. [22] Yilmaz A, Van Putte BP, Van Boven WJ. Completely thoracoscopic bilateral pulmonary vein isolation and left atrial appendage exclusion for atrial fibrillation. J Thorac Cardiovasc Surg 2008;136:521–2. [23] Edgerton JR, Jackman WM, Mahoney C, Mack MJ. Totally thorascopic surgical ablation of persistent AF and long-standing persistent atrial fibrillation using the ‘Dallas’ lesion set. Heart Rhythm 2009;6:S64–70. [24] Chambers D, Rodgers M, Woolacott N. Not only randomized controlled trials, but also case series should be considered in systematic reviews of rapidly developing technologies. J Clin Epidemiol 2009;62:1253–60.e4. [25] Khan AR, Khan S, Sheikh MA, Khuder S, Grubb B, Moukarbel GV. Catheter ablation and antiarrhythmic drug therapy as first- or second-line therapy in the management of atrial fibrillation: systematic review and meta-analysis. Circ Arrhythm Electrophysiol 2014;7:853–60.

eComment. Atrial fibrillation surgery: less invasive techniques, less efficient results Author: Ovidio A. Garcia-Villarreal Department of Cardiac Surgery. Hospital of Cardiology UMAE 34, IMSS, Monterrey, Mexico doi: 10.1093/icvts/ivw080 © The Author 2016. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.

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I have read with great attention the article by Kim et al [1]. In the setting of the Coxmaze III "cut-and-sew", it is clear that we need to evolve from complex original surgical techniques to easier and more feasible techniques to treat atrial fibrillation (AF). These techniques often use alternative energy sources (radiofrequency, cyolesion, microwaves, high-intensity focused ultrasound). Two examples of this are epicardial thoracoscopic ablation (TA) and endocardial catheter ablation (CA) with radiofrequency energy, both described in this meta-analysis [1]. The great concern is that both techniques here use unipolar radiofrequency (RF) ablation. It is well known that unipolar RF ablation is able to assure neither transmurality nor uniformity of the burn in the atrial tissue [2,3]. Unexpectedly, the TE was better than the CA, despite the well-known fact that the bloodstream in normothermia could cool the heat wave of RF applied from the outside. However, the lower effectiveness of CA can be explained by the difficulty in creating precise lesions within the heart without a direct view of the anatomic structures. In particular, during the course of a Cox-maze III "cut-and-sew" procedure in patients previously treated with CA, I found large areas of scarred tissue instead of a precise burn line. The techniques studied in this review [1] represent a great effort in order to reach Dr. Cox’s ideal regarding to surgery for AF. According to Cox, surgery for AF should meet the following conditions: 1) the procedure should be preferably epicardial by nature; 2) the energy source should be capable of penetrating epicardial fat and ablating all types of AF; 3) cardiopulmonary bypass must be avoided; 4) the procedure should be amenable to endoscopic or minimally invasive techniques; 5) it should be performed in less than 1 hour; 6) hospital discharge should be possible on the first postoperative day [4]. Finally, standard Cox-maze III "cut-and-sew" remains the gold standard to surgically treat AF, regardless its type [5]. Conflict of interest: none declared. References [1] Kim HJ, Kim JS, Kim TS. Epicardial thoracoscopic ablation versus endocardial catheter ablation for management of atrial fibrillation: a systematic review and meta-analysis. Interact CardioVasc Thorac Surg 2016;22:729–37. [2] Garcia-Villarreal OA. eComment. Alternative energy sources in surgery for atrial fibrillation. Interact CardioVasc Thorac Surg 2012;15:128. [3] Miyagi Y, Ishii Y, Nitta T, Ochi M, Shimizu K. Electrophysiological and histological assessment of transmurality after epicardial ablation using unipolar radiofrequency energy. J Card Surg 2009; 24: 34–40. [4] Cox JL. Atrial fibrillation II: rationale for surgical treatment. J Thorac Cardiovasc Surg 2003;126:1693–99. [5] Phan K, Xie A, Kumar N, Wong S, Medi C, La Meir M et al. Comparing energy sources for surgical ablation of atrial fibrillation: a Bayesian network meta-analysis of randomized, controlled trials. Eur J Cardiothorac Surg 2015;48:201–11.

ORIGINAL ARTICLE

H.J. Kim et al. / Interactive CardioVascular and Thoracic Surgery