1. From the Exercise Physiology Laboratory University of Louisville, Louisville, KY (A.M.S.); Duke Clinical Research Institute, Durham, NC (J.H.); Division of Cardiovascular Sciences, (J.L.F., L.C.) and Office of Biostatistics Research, (E.L.), National Heart, Lung, and Blood Institute, Bethesda, MD; Ahmanson UCLA Cardiomyopathy Center, Los Angeles, CA (G.C.F.); Division of Cardiovascular Medicine, Department of Medicine, Henry Ford Hospital, Detroit, MI (S.K.); University of Pennsylvania, Philadelphia...