REST Study: Left Ventricular Regression European Study

Inclusion Criteria: Patient requires, for the first time, isolated aortic valve replacement due to aortic stenosis or mixed aortic stenosis disease etiology when aortic stenosis is predominant and aortic regurgitation is mild. Patient is of legal age in the host country. Patient (or legal guardian) has signed a study specific informed consent form Exclusion Criteria: Patient was previously operated on with any heart surgery including heart valve replacement or coronary artery bypass graft (CABG); or underwent any form of myocardial revascularization in the past (including stents), etc. Patient requires any concomitant heart surgery other than the isolated native aortic heart valve replacement and concomitant ascending aortic replacement (e.g not allowed are: multiple valve replacements or concomitant CABG, pacemaker insertions, or severe septal hypertrophy needing surgical excision, etc.) Patient has unstable angina Patient is in New York Heart Association functional class IV Patient has significant abnormality in wall motion Patient is affected by active endocarditis. Patient has a cardiac pacemaker or automatic implanted cardiac defibrillator Patient is affected by acute aortic dissection. Patient is in chronic and persistent atrial fibrillation Patient receives hemodialysis therapy Patient has a medical condition which contraindicates implantation of the SJM Epic and Epic™ Supra Porcine Bioprosthetic Heart Valve (e.g. renal failure or abnormal calcium metabolism). Patient has aneurysmal clips or carotid artery vascular stents Patient has a neurostimulator Patient has an implanted or external drug infusion device (e.g. insulin pump) Patient has a bone growth/fusion stimulator Patient has a cochlear, otologic, or ear implant Patients with severe claustrophobia in which medical sedation is contraindicated or unable to resolve anxiety sufficiently Patients with ocular foreign body (e.g. metal shavings) Patient is pregnant or nursing