1. From the Cardiomyopathy Programs and Cardiovascular Divisions, Boston Medical Center, Boston, Mass (M.M.G., W.S.C.); Johns Hopkins Medical Institutions, Baltimore, Md (J.M.H.); Brigham and Women’s Hospital, Boston, Mass (M.M.G., W.S.C.); Boston University School of Medicine, Boston, Mass (M.A.C.); Johns Hopkins School of Medicine, Baltimore, Md (J.M.H.); and Harvard Medical School, Boston, Mass (M.A.C.).