Inclusion Criteria:
1. Age 18 years or older(≥ 18 years)
2. Subject has severe MR (Grade lll or greater per the ASE criteria, which includes severity grades of 3+ and 4+). Severity grades (3+)/ (4+) MR confirmed by core lab review on transthoracic or transesophageal echocardiography.
For patients with primary mitral regurgitation: Deemed high or prohibitive surgical risk (STS score 8 for valve replacement or \> 6 for valve repair or determined by the site heart team due to documented surgical risk factors) For patients with secondary mitral regurgitation: undergone optimal guideline-directed medical therapy (GDMT) for at least one month as determined by the local heart team; coronary revascularization, and cardiac resynchronization therapy (CRT) if clinically indicated, all of which have proven to be ineffective. Local heart team has determined that mitral valve surgery is not an option.
3. Anatomically suitable for TEER with GeminiOne device as confirmed by site investigators, core lab, and eligibility committee.
4. Feasible transseptal catheterization and femoral vein access.
5. Written informed consent from subject or legal representative.
Exclusion Criteria:
1. History of heart transplantation, prior mitral valve replacement surgery, or transcatheter mitral valve procedure.
2. Leaflet anatomy that precludes optimal positioning of the GeminiOne device, as determined by site investigators, core lab, and eligibility committee.
3. Evidence of severe calcification or significant cleft in the grasping area of the mitral valve leaflets.
4. Left ventricular ejection fraction (LVEF)\< 20%
5. Left ventricular end-systolic diameter(LVESD)\> 60mm
6. Mobile leaflet length less than 10mm
7. Mitral valve effective orifice area (EOA) \< 3.5cm or a high risk of mitral stenosis developing after device implantation, as judged by site investigators, core lab, and eligibility committee.
8. Echocardiographic evidence of intracardiac mass, thrombus, or vegetation.
9. Presence of severe non-mitral valve disease requiring intervention.
10. Severe pulmonary artery hypertension(sPAP \>70mmHg).
11. Severe right ventricular dysfunction. 12, Active endocarditis or history of mitral valve endocarditis. Active rheumatic heart disease or leaflets severely degenerated from rheumatic disease.
13\. Severe untreated coronary artery stenosis requiring revascularization or other cardiovascular disease requiring surgery.
14.Patents with extreme frailty. 15.Hypertrophic cardiomyopathy, restrictive cardiomyopathy, constrictive pericarditis, or any other structural heart disease causing heart failure besides dilated cardiomyopathy.
16\. Severe renal insufficiency with estimated glomerular filtration rate (eGFR) \< 25 mL/min.
17\. Blood cachexia including granulocytopenia(WBC\<3x10\^9/L),acute anemia(HB \<90g/L)thrombocytopenia (PLT \<50x10\^9/L), severe coagulopathy, or contraindications to anticoagulant and antiplatelet therapy.
18\. Evidence of an acute myocardial infarction within the past 4 weeks. 19.Evidence of stroke within the prior 90 days. 20. Any percutaneous cardiac intervention, carotid surgery, or any cardiac surgery within 30 days prior to procedure.
21\. Severe symptomatic carotid artery stenosis exceeding 70% confirmed by imaging.
22\. Subjects with underlying medical or psychiatric conditions that may interfere with trial evaluation (e.g. cancer, infection, severe metabolic disease). Additionally, any case deemed unsuitable for the study by the local heart team.
23.Life expectancy of less than 12 months. 24. Participation in another investigational drug or device study within the past 1 month.
25\. Subjects deemed unlikely to complete the trial due to potential non-compliance, as judged by the investigator.
26\. Any anatomic characteristic or presence of atrial septal occluders, which would preclude the performance of the transseptal approach.
