Kurose et al. report on a lower number of gaps in RF-lesions compared to Cryo-lesions as determined by late gadolinium enhancement MRI (LGE-MRI). However, unlike claimed by the authors, there is ample evidence based on LGE-MRI in this context. Most importantly we have specifically compared RF and Cryo lesions in a recent case control study on AF Ablation. In contrast to the results of Kurose et al., our study, despite larger sample size, did not detect a difference in the number of gaps between the two energy sources. While numerous factors may account for the conflicting results, two points should be considered in particular. 1. The time point of LGE-MRI at a mean of 55 days post ablation has never been validated for chronic lesion formation, and is considerably earlier than the validated and well-established 3-months timepoint chosen by most groups. In fact, according to previous reports, gadolinium enhancement at earlier time points may, at least in part, reflect a transient inflammatory response rather than chronic scar formation. 2. The method of Kurose et al. is based on the definition of an area of healthy atrial tissue in each patient as an internal reference. However, it appears almost impossible to define a truly healthy area in the atrium of patients with atrial fibrillation. Thus the method is likely to underestimate ablation-induced fibrosis in patients with advanced disease and/or underlying pathologies and to overestimate it in younger, rather healthy patients.