eComment. Pulmonary vein isolation is not enough to treat long-standing persistent atrial fibrillation

I have read with great attention the article by Fengsrud et al. [1]. In spite of the good results shown in this paper, I would like to highlight several points. In accordance with the genesis of atrial fibrillation (AF), there are micro re-entrant circuits (triggers) located in the pulmonary veins (PV), and macro re-entrant circuits in both atria. AF is a self-sustaining arrhythmia independent of focal discharges from PV. Indeed, macro re-entrant circuits have the ability to sustain themselves, especially in cases of long-standing persistent AF. Consequently, the success rate of PV isolation (including antrum) in long-standing persistent AF may be very low [2]. The maze procedure has been designed to surgically treat any type of AF [3]. The “real” maze procedure must include a full bi-atrial lesion pattern, i.e. PV isolation (box lesion), left atrial (LA) appendage exclusion (preferably removal), joining incision between the LA appendage and PV isolation, LA isthmus incision, and all right atrial (RA) incisions (intercaval, mid-RA incision including counter-lesion reaching tricuspid annulus, and finally incision joining mid-RA incision with RA appendage tip). Cryoprobe must be applied on coronary sinus and tricuspid annulus. The only alternative energy sources with proven effectiveness in producing true transmural lesions are cryolesion and bipolar radiofrequency applied by intraoperative clamp. Unfortunately, unipolar radiofrequency ablation cannot consistently produce transmural lesions [4]. In order to prove how effective pulmonary vein isolation is, I have surgically isolated the PV in 100 cases of mitral valve disease with long-standing persistent AF. Freedom of AF was observed in 53% at 1 year follow-up. However, in a larger follow-up only 30% of patients were free of AF at 5 years [5]. I congratulate the authors for these good results. However, a longer follow-up is needed in order to safely assess these findings. Conflict of interest: none declared.