Cardiac Surgical Treatment by Radiofrequency Ablation on Valvular Patients: Efficacy at 3 Months

Inclusion Criteria: * Adult patients with no age limit, presenting a chronic atrial fibrillation and planned to undergo a surgical intervention on mitral valve (valve replacement or plasty) associated or not with myocardial revascularization or replacement/plasty of another valve (aortic, tricuspid) * The chronic atrial fibrillation is defined as a continuous atrial fibrillation more than 1 month before the surgery despite all anti-arrhythmia treatments including cardioversion ; the atrial fibrillation can be associated to another rhythm trouble except the severe ventricular rhythm troubles. * The indication for surgery is performed using the clinical evaluation : NYHA \>2 and the usual echocardiography criteria (mitral regurgitation \> grade 3, mitral gradient \>10 mm Hg or valve surface \< 1,5 cm2) * Patients with a vital prognosis not compromised by comorbidity in the next 2 years and with a mental state enabling to give informed consent * Patients agreeing to take part in the study and having signed the informed consent form. For the part of the study pursued in open independent to the actual protocol, patients having signed the modified informed consent with approval of the new study procedure not yet published. Exclusion Criteria: * Paroxystic atrial fibrillation or atrial fibrillation for less than 1 month * Atrial fibrillation never treated by cardioversion or pharmacology before surgery. * Contra-indication to surgery, i.e. severe respiratory failures, multivisceral deficiencies (renal, cardiac or hepatic), rapidly evolutive or metastatic cancers, malignant hemopathies not stabilized by chemotherapy * Contra-indication to the following arrhythmia treatments: class III (amiodarone) associated to contra-indication to class II (beta blockers) or to class Ic (flecainide, propafenone, cibenzoline). * Severe decompensated heart failure. * Uncontrolled, repetitive, severe documented ventricular arrhythmia (ventricular tachycardia, ventricular fibrillation episodes) * Contra indication to epicardic ablation procedure (pericardic adhesions, intra-atrial thrombus) In these cases the ablation could be only an endocardic ablation but it does not necessarily exclude the patient. * Ventricular "ejection fraction " \< 40% * Impossibility to follow the pre-inclusion phases i.e. emergency surgery for mitral break or evolutive endocarditis. * Patients with disabled mental status * Patient participating in another clinical study