The purpose of this study is to evaluate the safety and performance of the Harpoon Medical TSD-5. The Harpoon device will provide many significant advantages over current surgical interventions including: 1) a small minimally invasive incision, 2) no sternotomy, 3) no cardiopulmonary bypass, 4) no aortic manipulation, 5) a direct path to the valve plane, 6) performed on a beating heart, 7) real-time TEE-guided chordal length adjustment and 8) less complicated procedure that is teachable and adoptable.

The TSD-5 is intended to secure ePTFE sutures on the mitral valve for the treatment of mitral valve disease.

Inclusion Criteria:

• All subjects referred for mitral valve surgery
• Presence of severe mitral regurgitation as read on an echocardiographic study performed within 60 days prior to procedure. Assessment of mitral regurgitation will be performed by the investigational site echocardiography laboratory and confirmed by the Core Echocardiography Laboratory using an integrative method.
• Age > 18 years
• Estimated post-ePTFE cordal implantation coaptation surface is adequate in the judgment of the operating surgeon and the patient eligibility committee
• Degenerative mitral valve disease
• Subject is able to sign informed consent and able to return for follow-up and is capable of participating in all testing associated with this clinical investigation
• Women of child-bearing potential have a negative pregnancy test
• Able to sign informed consent

Exclusion Criteria:

• Age < 18 years
• Infective endocarditis
• Anterior or bileaflet prolapse
• Functional mitral regurgitation
• History of Mediastinal Radiation
• Inflammatory (rheumatic) valve disease
• Requirement for concomitant cardiac surgery (e.g., coronary artery bypass grafting (CABG), aortic valve surgery, etc.)
• Symptomatic coronary artery disease
• Cardiogenic shock at the time of enrollment
• ST segment elevation myocardial infarction requiring intervention within 30 days prior to enrollment
• Evidence of cirrhosis or hepatic synthetic failure
• Pregnancy at the time of enrollment (women of child bearing age should have negative pregnancy within 14 days of surgery)
• Severe pulmonary hypertension (PA systolic pressure > 70 mmHg)
• Previous cardiac surgery, or surgery on the left pleural space
• Left ventricular, atrial or appendage thrombus
• Severely calcified mitral leaflets
• Recent stroke (< 6 months) with permanent impairment
• EuroScore (for mitral valve repair) > 8%
• Subjects with contraindications to transesophageal echocardiography
• Severe left or right ventricular dysfunction
• NYHA Class IV
• Renal insufficiency CKD stage 3b or worse (GFR < 45 ml/min/1.73 m2)
• Patient is participating in another clinical study for which follow-up is currently ongoing. (Co-enrollment in an investigational device or interventional study)
• Patient with non-cardiac co-morbidities and life expectancy < 1 year
• Patient has a condition or conditions that, in the opinion of the Investigator, preclude participation, including willingness to comply with all follow-up procedures

Individual participant data will not be available to other researchers.

Subjects who received the Harpoon Medical Device.

Events occurring from baseline through 60 months post implant.