PeAf is more complex to treat than the simple paroxysmal AF. Several different percutaneous and surgical techniques have been proposed for its treatment, owing to the difficulties in the standardization of the ablation procedures. In addition, many reports dealing with the ablation of PeAF also include patients affected by paroxysmal and permanent fibrillation, which introduces a considerable selection bias.
As in any arrhythmia, a number of basic problems are involved in ablating the PeAF, including the following: (a) identifying the mechanism; (b) locating the source; (c) reaching the ablation area; (d) choosing the lesion set; and (e) consistently obtaining transmural lesions. As PeAf shows heterogeneity in its mechanism of origin, a simple PVI has unpredictable results. Thus, other techniques such as CFAE ablation and linear ablations, with or without substrate control, have been developed to increase the percentages of termination of the arrhythmia. Once the arrhythmia has been ablated, it can also recur in other parts of the atrium with a different mechanism, causing a high percentage of recurrent fibrillation. Recently, focal ablation and the rotor modulation technique (FIRM)  have shown promising results in a limited number of cases. Surgical ablations that de-connect a large part of the posterior left atrium, where many of the sources of the PeAF are located, have also become increasing used owing to their simple approach. Conversely, surgical procedures also are difficult to evaluate, and numerous observational studies of mixed populations without controls used different sources of energy and line combinations [15, 17, 18].
The FAST trial  was the first to compare the surgical and the percutaneous approaches, in which patients randomized to surgery had a higher rate of termination of the arrhythmia. However, their results were compromised by the incidence of complications. Many of these complications (pneumothorax, rib fracture) could be easily avoided by careful analysis of the results and by experience, which eventually results in an equivalent rate of complications between the two experiment groups. Further, the surgical ablation in that study was performed through a bilateral minimal thoracotomy. This approach was necessary to accomplish a complete surgical PVI with the use of bipolar radiofrequency delivered by the Atricure device. The bilateral approach adds time and increases the chances of complications. This can be avoided with different devices such as the Estech Cobra Fusion, which is capable of a complete electrical deconnection of the posterior left atrium, delivering bipolar radiofrequency through a single right minimally invasive approach. According to the European Guidelines , bipolar radiofrequency is the preferred source of energy for achieving a complete transmural line of ablation . The transmurality of the lesions can be consistently obtained with hybrid or simultaneous  and staged or sequential  approaches.
The hybrid simultaneous procedures have some disadvantages, in that they take time and do not allow a blank period to evaluate the clinical efficacy of surgery. The staged procedures allow a blank period of evaluation, and two modalities of ablation (surgical and percutaneous) may be used after a predetermined period or only in case of recurrences.
All of these procedures share the same basic principles. The posterior left atrium (the portion where many of the sources of PeAf are located) must be electrically separated from the base of the heart , with the addition of some endocardial lines, if necessary. In our study, we have chosen to adopt a staged approach. This has some possible advantages, including the evaluation of the efficacy of a monolateral minimally invasive approach by using bipolar radiofrequency. For this, we will use the Estech Cobra Fusion system. The ablation device encircles the posterior portion of the left atrium and allows the use of bipolar radiofrequency in a controlled protocol. Second, the procedural time is expected to be relatively short so as to avoid any ICU stay. Third, a blank period will allow a second percutaneous ablation to be performed only in patients with recurrent AF, which should reduce the total number of invasive procedures necessary to control the AF.
Finally, in our opinion, this will allow us to study the modalities of failures of the surgical approach and give valuable information in refinement of the techniques and devices.
No standard strategy is known for the percutaneous ablation of PeAF. In the PCA control group of our study, the choice of the initial technique will be left to the treating cardiologist (PVI, CFAE ablation with or without manipulation of the substrate, or rotor manipulation are frequently used in combination or in staged procedures). Insulated PVI is the least effective technique, whereas rotor modulation has been recently introduced and is not widely used. Thus, we expect that the majority of the patients in the control group will undergo a combination of PVI and CFAE ablation. In cases of failure in the surgical group, this choice will be dictated by the residual electrophysiological findings. This is a potential limitation of the study that may make comparison between the two groups difficult.