The purpose of this study is to evaluate the safety and performance of the Tendyne Mitral Valve System in the treatment of severe mitral regurgitation in patents with functional disability greater than or equal to NYHA Class II, who are not suitable candidates for surgical replacement with otherwise available devices. Follow-up evaluations will be conducted through 5 years post implantation.

Inclusion Criteria:

1. Severe mitral regurgitation of primary or secondary etiology according to MVARC (Mitral Valve Academic Research Consortium) 2015 defined as:

   • For Degenerative MR: EROA ≥ 40 mm^2 or regurgitant volume ≥ 60ml
   • For Secondary MR: EROA ≥ 20 mm^2 or regurgitant volume ≥ 30ml

2. New York Heart Association (NYHA) functional Class ≥ II while on guideline directed medical therapy (GMDT), including device therapy (CRT) if indicated.

3. Heart team determines patient is not a suitable candidate for traditional surgical treatment according to valid guidelines.

4. Age 18 years or older.

Exclusion Criteria:

1. Severe mitral annular calcification, severe mitral stenosis, valvular vegetation or mass.
2. Left Ventricle (LV) or Left Atrium (LA) thrombus.
3. Patient has a chest condition that prevents transapical access.
4. Left ventricular ejection fraction (LVEF) less than 30% by echocardiogram.
5. Left Ventricular End Diastolic Diameter (LVEDD) > 7.0 cm.
6. Prior surgical or interventional treatment of mitral or aortic valves (e.g. valve repair or replacement, MitraClip, edge to edge repair, aortic balloon valvuloplasty, etc.).
7. Any planned surgery or interventional procedure within the period of 30 days prior to 30 days following the implant procedure. This includes any planned concomitant cardiovascular procedure such as PCI, pulmonary vein ablation, left atrial appendage occlusion, septal defect repair, etc.
8. Cardiac resynchronization therapy device or implantable pulse generator implanted within three months of planned implant procedure.
9. Myocardial Infarction (MI) within 30 days of the planned implant procedure.
10. Symptomatic, unresolved multi-vessel coronary artery disease (CAD) or unprotected left main coronary artery disease requiring stenting or Coronary Artery Bypass Grafting (CABG).
11. Cerebrovascular accident (CVA) within six months of planned implant procedure.
12. Unresolved severe symptomatic carotid stenosis (> 70% by ultrasound).
13. Cardiogenic shock or hemodynamic instability requiring inotropes or mechanical support devices at the time of planned implant procedure.
14. Severe tricuspid regurgitation, tricuspid valve disease requiring surgery or severe right ventricular dysfunction.
15. Hypertrophic or restrictive cardiomyopathy, constrictive pericarditis or any other structural heart disease causing heart failure other than dilated cardiomyopathy of either ischemic or non-ischemic etiology.
16. Any of the following: leukopenia, acute anemia, thrombocytopenia, history of bleeding diathesis, or coagulopathy if cannot be adequately treated.
17. History of endocarditis within six months of planned implant procedure.
18. Active systemic infection requiring antibiotic therapy.
19. Known hypersensitivity or contraindication to procedural or post-procedural medications (e.g., contrast solution, anti-coagulation therapy) which cannot be adequately managed medically or hypersensitivity to nickel or titanium.
20. Patient is undergoing hemodialysis due to chronic renal failure.
21. Patient has pulmonary arterial hypertension (fixed PAS >70mmHg).
22. Patient has COPD and is on home oxygen.
23. Patient refuses blood transfusions.
24. Pregnant, lactating, or planning pregnancy within next 12 months.
25. Participating or planning participation in an investigational drug or another device study.
26. Patient or legal guardian unable or unwilling to give informed consent.
27. Patient unable or unwilling to comply with study required testing and follow-up visits.
28. Patients with non-cardiac co-morbidities that are likely to result in a life expectancy of less than one year.