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