Atrial fibrillation (AF) is the most common cardiac arrhythmia in adults. It is a major cause of ischemic stroke and heart failure. Intravascular cardiac ablation of the left atrium by catheter delivery is an efficient treatment to restore sinus rhythm. AF ablation is a class IIa treatment for patients with symptomatic persistent AF refractory or intolerant to antiarrhythmic medication. There are still many debates considering the ablation strategy. The pulmonary veins remain the cornerstone of AF ablation therapy, even in persistent AF. There is a large electrical remodeling occurring in the left atrium between paroxysmal AF, early persistent AF and long-standing persistent AF. However, no multicentric and randomized study has demonstrated so far the interest of targeting other left atrial substrate, such as rotors or focal sources.

Our study aims to describe with a noninvasive mapping system the arrhythmogenic substrate of persistent AF > 6 months pre- and post-cardioversion, and after pulmonary vein isolation.

Inclusion Criteria:

1. Patients with documented persistent Atrial Fibrillation lasting longer than 6 months documented by 24h holter monitoring
2. Age between 18 and 75 years
3. Efficient oral anticoagulation during at least 1 month before the procedure
4. Social security affiliation
5. Feasible patient follow-up
6. Patient willing to comply with study requirements and give informed consent to participate in this clinical study
7. Indication for Pulmonary Vein isolation

Exclusion Criteria:

1. Previous atrial fibrillation ablation
2. Previous left atrial ablation or surgery
3. Atrial fibrillation without spontaneous RR interval > 1000ms and with LVEF < 35% (measured by TTE)
4. Presence of a mechanical mitral valve
5. Current intracardiac thrombus
6. Any condition contraindicating chronic anticoagulation
7. Uncontrolled hyperthyroidism
8. Anteroposterior LA diameter > 55 mm measured by TTE
9. Body mass index ≥ 40 kg/m2