New heart ablation method's impact on heart tissue to be revealed by MRI

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: * Patient age ≥ 18 * Established diagnosis of persistent or paroxysmal atrial fibrillation with a I/IIa/IIb indication for catheter ablation (ESC 2020 guidelines) * AF ablation procedure planned using pulsed-field ablation and including at least pulmonary vein isolation and posterior wall isolation * Episode of AF documented by ECG within the last 12 months * Patient able to give written informed consent * If female of childbearing potential, have a negative serum pregnancy test and using effective contraception * Be affiliated with a French social security system or entitled Exclusion Criteria: * Only pulmonary vein isolation is scheduled * Atrial fibrillation present at ECG during the pre-ablation (V1a) visit * Contraindication to oral anticoagulation * Intracardiac thrombus * Previous ablation in the left atrium * Previous heart surgery * Significant valvular heart disease defined as any moderate (grade 3) or severe (grade 4) mitral regurgitation, mitral stenosis, aortic regurgitation, aortic stenosis, tricuspid regurgitation, or tricuspid stenosis * Contraindication to perform MRI or using the DOTAREM™ contrast product (pacemaker, defibrillator, foreign body or prosthesis, old generation heart valves, old generation ferromagnetic vascular surgical clips, percutaneous devices for endocranial aneurysms, neurosimulator, cochlear implants, automated injection device such as insulin pump, and more generally any non-removable electronic device, severe kidney disease with GFR \< 30 mL/min, documented hypersensitivity to gadoteric acid or to excipients, severe claustrophobia) * Patient on AME (state medical aid) * Pregnant or breast-feeding female * Patient protected by law (guardianship, tutelage measure, deprived of liberty) * Participation in another interventional study or being in the exclusion period at the end of a previous study.