ABC | Volume 114, Nº4, April 2020

Short Editorial Pisani & Scanavacca MRI after AF ablation Arq Bras Cardiol. 2020; 114(4):636-637 greater extent of fibrosis after ablation. However, the study does not make it clear whether this beneficial effect was due to a lower occurrence of gaps in the induced scars or whether it was due to greater extent of ablation, for example, in other areas such as the posterior wall of the left atrium or the atrial septum. Current evidence has shown that extensive scars controlled by new technology that produces more effective and more lasting scars, with fewer reconnections, either by radiofrequency 13 or by cryoablation, 14 are currently improving the results of AF ablation. For this reason, these results should be interpreted cautiously, given that the creation of extensive atrial scarring that is not homogeneous may even lead to greater recurrence of atrial arrhythmias, especially in cases of scar-related atrial tachycardias, which, in some situations, may even be more symptomatic and complex to manage than AF itself. 8 An additional complicating factor is the lack of studies demonstrating the reproducibility of analyses of areas of atrial fibrosis when different methods of image evaluation are used, whether or not they use special software for automatic image processing. Accordingly, there are few studies comparing the observations obtained by MRI with electroanatomical maps that effectively guide AF ablations in the initial procedure and in recurrences, including some cases where there was not good agreement between the maps and the scar on MRI. 11 In conclusion, notwithstanding the great potential shown by images obtained by late gadolinium enhancement MRI, additional studies are necessary to prove its reproducibility and effectiveness for identifying and recognizing characteristics of atrial fibrosis, both during the selection of patients who will undergo AF ablation and in patients who have already undergone the procedure. 1. Haissaguerre M, Jais P, Shah DC, Takahashi A, Hocini M, Quiniou G, et al. Spontaneous initiation of atrial fibrillation by ectopic beats originating in the pulmonary veins. N Engl J Med. 1998;339(10):659-66. 2. Ouyang F, Bansch D, Ernst S, Schaumann A, Hachiya H, Chen M, et al. Complete isolation of left atrium surrounding the pulmonary veins: new insights from the double-Lasso technique in paroxysmal atrial fibrillation. Circulation. 2004;110(15):2090-6. 3. Nattel S. Paroxysmal atrial fibrillation and pulmonary veins: relationships between clinical forms and automatic versus re-entrant mechanisms. Can J Cardiol. 2013;29(10):1147-9. 4. Burstein B, Nattel S. Atrial fibrosis: mechanisms and clinical relevance in atrial fibrillation. J Am Coll Cardiol. 2008;51(8):802-9. 5. Nattel S, Dobrev D. Themultidimensional role of calcium in atrial fibrillation pathophysiology: mechanistic insights and therapeutic opportunities. Eur Heart J. 2012;33(15):1870-7. 6. Guichard JB, Nattel S. Atrial Cardiomyopathy: A Useful Notion in Cardiac DiseaseManagementoraPassingFad?JAmCollCardiol.2017;70(6):756-65. 7. Calkins H, Hindricks G, Cappato R, KimYH, Saad EB, Aguinaga L, et al. 2017 HRS/EHRA/ECAS/APHRS/SOLAECEexpertconsensusstatementoncatheter and surgical ablation of atrial fibrillation. Europace. 2018;20(1):e1-e160. 8. Verma A, Jiang CY, Betts TR, Chen J, Deisenhofer I, Mantovan R, et al. Approaches to catheter ablation for persistent atrial fibrillation. NEngl J Med. 2015;372(19):1812-22. 9. Marrouche NF, Wilber D, Hindricks G, Jais P, Akoum N, Marchlinski F, et al. Association of atrial tissue fibrosis identified by delayed enhancement MRI and atrial fibrillation catheter ablation: the DECAAF study. Jama. 2014;311(5):498-506. 10. King JB, Azadani PN, Suksaranjit P, Bress AP, Witt DM, Han FT, et al. Left Atrial Fibrosis and Risk of Cerebrovascular and Cardiovascular Events in Patients With Atrial Fibrillation. J Am Coll Cardiol. 2017;70(11):1311-21. 11. Bisbal F, Guiu E, Cabanas-Grandio P, Berruezo A, Prat-Gonzalez S, Vidal B, et al. CMR-guided approach to localize and ablate gaps in repeat AF ablation procedure. JACC Cardiovasc Imaging. 2014;7(7):653-63. 12. Correia ETO, Barbetta L, Mesquita ET. Extent of Left Atrial Ablation Lesions and Atrial Fibrillation Recurrence after Catheter Ablation - A Systematic Review and Meta-Analysis. Arq Bras Cardiol. 2020; 114(4):627-635. 13. Phlips T, Taghji P, El Haddad M, Wolf M, Knecht S, Vandekerckhove Y, et al. Improving procedural and one-year outcome after contact force- guided pulmonary vein isolation: the role of interlesion distance, ablation index, and contact force variability in the ‘CLOSE’-protocol. Europace. 2018;20(FI_3):f419-f27. 14. Kuck KH, Furnkranz A, Chun KR, Metzner A, Ouyang F, Schluter M, et al. Cryoballoon or radiofrequency ablation for symptomatic paroxysmal atrial fibrillation: reintervention, rehospitalization, and quality-of-life outcomes in the FIRE AND ICE trial. Eur Heart J. 2016;37(38):2858-65. 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