The EXERCISE FMR trial is a prospective, multi-center clinical trial.~The centers will utilize pre-screening of existing medical records to identify potentially eligible subjects. Once informed consent has been obtained, the subject will undergo standard of care assessments which include: Transthoracic echocardiography, transesophageal echocardiography (if necessary), and functional assessments (NYHA and KCCQ Quality of Life Questionnaire). Following final eligibility determination, eligible subjects will under the index procedure to implant the commercially available Carillon device (includes coronary sinus venogram) according to the Instructions for Use. Subject will be discharged following after standard of care discharge assessments are completed.~Implanted subjects will have follow-up assessments performed at 1 month, 6 months, and 12 months post index procedure. Most assessments performed as part of follow-up are intended to be standard of care at each institution. The only elements that may fall outside of standard of care would be the non-invasive assessments of TTE, 6-minute walk test and the questionnaire. Further, follow-up at 1 and 6 months may also not be common site practice.
Evaluate the hemodynamic and anatomical effect of the commercially available CMCS system within its current indication on a subset of patients with exercise induced mitral regurgitation. This will be primarily evaluated by standard of care exercise testing and echocardiography. The purpose is to evaluate HFrEF CHF patients that may have mild to moderate-severe MR at rest but aggravated upon activity.