• Patients who voluntarily participate and sign the informed consent form and can cooperate with the completion of the entire trial process;

• Age ≥ 18 years old;

• Moderate-severe or severe mitral regurgitation (≥3+); Note 1: Patients with ischemic or non-ischemic heart disease induced symptomatic secondary mitral regurgitation as the primary cause must be treated for at least 1 month after optimal guideline medical therapy (GDMT). Echocardiography should be performed 3 months after cardiac resynchronization therapy and 1 month after coronary revascularization to assess the degree of regurgitation.

• Note 2: For patients with primary mitral regurgitation, the multidisciplinary cardiac team of the research center needs to use a standard scoring system, considering multiple factors such as complications, frailty, and disability, ensuring the enrolled with a high risk of surgery.

• Patients with New York Heart Association (NYHA) functional ratings are Class II, III, or ambulatory Class IV;

• Anatomically appropriate for treatment with the HighLife Transcatheter Mitral Valve Replacement System.