Stem cells derived from heart failure patients' own bone marrow improved the function of the left ventricle, the heart's pumping chamber. In this video, Robert Simari, M.D., a cardiologist at Mayo Clinic in Rochester, Minn., discusses these finding and their implications for developing new treatments for heart disease. The research team also found that patients with certain types of the stem cells had the greatest improvement, another intriguing fact for further study.