Valvular Aortic Stenosis: Study of Myocardiac Fibrosis by Magnetic Resonance Imagery

PATIENTS : Inclusion Criteria: * Echocardiography considered as normal and / or age-related * Patients who have received prior clinical examination * Patient receiving a social security scheme or entitled, or CMU * After having giving written informed consent. * Patients symptomatic with indication of surgery (group surgery) or not Exclusion Criteria: * With one of the following cardiac abnormalities: atrial fibrillation, more than moderate either aortic or mitral valve regurgitation * Heart valve surgery history (aortic, mitral, tricuspid and pulmonary). * Indication for cardiac surgery other than on the aortic valve. * Usual counter-indications of MRI: Pace-maker, defibrillator, metallic objects including gadolinium allergy. * Patients with severe renal insufficiency with a clearance \<30 ml / min estimated by the Cockcroft \& Gault formula. * Patient who cannot be followed over the duration of a year. CONTROLS (healthy volunteers) Inclusion criteria: * Normal EKG * Echocardiography considered normal and / or age-related * Patients who have received prior clinical examination * Patient receiving a french national social security * After having obtain written informed consent. Criteria for non-inclusion * History of known or detectable infarction on EKG * Known primary or secondary cardiomyopathy or detectable on echocardiography * Thoracic radiotherapy or chemotherapy history * Subject with usual contra-indications of MRI: claustrophobia, metallic objects. * Patients with significant renal insufficiency with a clearance \<90 ml / min estimated by the Cockcroft \& Gault formula. * Subject who could be planned for 2 CMR within two weeks