Replacement of the Native Mitral Valve Using the ReValve System

Key Inclusion Criteria: * Symptomatic functional and/or degenerative MR (≥2+) due to ischemic and non-ischemic cardiomyopathy etiology determined by assessment of a qualifying transthoracic echocardiogram (TTE) obtained within 60 days and transesophageal echocardiogram (TEE) obtained within 90 days prior to subject registration, with MR severity based principally on the TTE study. * New York Heart Association (NYHA) Functional Class II, III or ambulatory IV. * Left Ventricular Ejection Fraction (LVEF) is ≥30% (within 90 days prior to subject registration, assessed by the site using any one of the following methods: echocardiography, contrast left ventriculography, gated blood pool scan or cardiac CT. * Age greater than 18 years. * Left Ventricular End Systolic Dimension (LVESD) is ≤ 65 mm assessed by site based on a transthoracic echocardiographic (TTE) obtained within 90 days prior to subject consent. Key Exclusion Criteria: * Untreated clinically significant coronary artery disease requiring revascularization. * Need for emergent or urgent surgery for any reason or any planned cardiac surgery within the next 12 months. * Status 1 heart transplant or prior orthotopic heart transplantation. * Cerebrovascular accident within 30 days prior to subject's consent. * Pregnant or planning pregnancy within next 12 months. * Currently participating in an investigational drug or another device study. * Evidence of LV or LA thrombus, vegetation or mass * Known hypersensitivity or contraindication to procedural, post procedural medication (e.g., contrast solution, anticoagulation therapy) or hypersensitivity to nickel or titanium.