MMP9 and atrial fibrillation: In this trial we hypothesize that several imaging markers associated with cardiac structural alteration, provided by CMR (such as LA, LV fibrosis, atrial volumes or the amount of epicardial fat), associated with serum inflammatory biomarkers (IL-6, MMP-9, hsCRP) could form a powerful prediction panel to predict the risk of AF recurrence in the post ablation period, reflecting the impact of inflammatory-mediated myocardial fibrosis on the risk of arrhythmia.