This study is testing a new device called the **MR-ace Implant and Delivery System** for people with *mitral regurgitation* (a condition where the heart valve leaks). The study will see if the device helps reduce symptoms and if it's safe to use. Participants will have the device implanted and will visit the clinic at different times for check-ups over five years. They'll also fill out a survey about their quality of life. Key Points: - **Time Commitment**: This study lasts for 5 years, with follow-up visits at 30 days, 6 months, 12 months, and annually up to 5 years. - **Eligibility**: Participants must have moderate-to-severe mitral regurgitation and be unable to use other treatments. - **Risks and Benefits**: The study aims to test the device's effectiveness and safety, which might help manage symptoms of mitral regurgitation. Participants must be over 21, agree to attend follow-ups, and not have certain health conditions, like severe right ventricle dysfunction or recent heart surgery.