AMADEUS was a single-arm, first-in-human study designed to evaluate the safety and feasibility of the Carillon system. The study utilized several independent bodies to minimize bias and increase rigor, including a blinded echo core lab, clinical events committee, and data and safety monitoring board. Key inclusion criteria included moderate to severe FMR, NYHA class II-IV, LVEDD >55mm, and ejection fraction <40% receiving sustained stable and optimal HF medication regimen. The study enrolled 48 patients with the device successfully implanted in 30 patients. At six months, the degree of FMR reduction among five different quantitative echo measures ranged from 22-32%.