Inclusion Criteria:

• Age ≥ 18 years
• Left ventricular ejection fraction ≥ 50%
• Grading of MR: 3+ or 4+ (effective regurgitant orifice area≥30mm2, regurgitant volume ≥45ml)
• Valve morphology: MR originating from the mid portion of the valve; mitral valve area> 4 cm2; Length of posterior leaflet ≥10 mm; Sufficient leaflet tissue for mechanical coaptation: coaptation depth< 11 mm, coaptation length> 2 mm
• Rate control in suspected AF-induced cardiomyopathy (heart rate <80 bpm at rest and <110 bpm during exercise)
• Patients must be willing to comply with all follow-up requirements

Exclusion Criteria:

• Life expectancy< 1 year due to non-cardiac conditions
• Primary mitral regurgitation: valve abnormalities including leaflet tethering from LV dysfunction, intrinsic leaflet pathology (prolapse, flail, calcification, severe thickening), mitral annular calcification (either severe or <severe but extending into the leaflets), and/or any mixed pathology
• Active endocarditis of the mitral valve or rheumatic mitral valve disease
• Hypotension (systolic pressure < 90 mmHg) or requirement for inotropic support or mechanical hemodynamic support
• Severe tricuspid regurgitation; Physical evidence of right-sided congestive heart failure with echocardiographic evidence of severe right ventricular dysfunction; Fixed pulmonary artery systolic pressure> 70 mmHg
• Stroke/TIA, TAVR, CRT/ CRT-D/ ICD, cardiac intervention or surgery within 30 days before randomization
• Any prior MV surgery or transcatheter procedure
• Need for any cardiac surgery (other than for MV disease)
• Untreated clinically significant coronary artery disease
• Echocardiographic evidence of intracardiac thrombus
• Active infections requiring current antibiotic therapy
• Patients who cannot tolerate anti-platelet/anticoagulation agents/contrast media
• Pregnancy
• Any condition making it unlikely the patient will be able to complete all protocol procedures (including compliance with medical therapy) and follow-up visits
• Patient (or legal guardian) unable or unwilling to provide written informed consent before study enrollment