1. From the Duke Clinical Research Institute, Durham, NC (A.D.D., M.C., Z.J.E., E.D.P., A.F.H.); Department of Medicine, Duke University School of Medicine, Durham, NC (A.D.D., Z.J.E., E.D.P., A.F.H.); Department of Medicine, Veterans Affairs Palo Alto Health Care System, CA (P.A.H.); Stanford University, CA (P.A.H.); Ahmanson-UCLA Cardiomyopathy Center, University of California, Los Angeles (G.C.F.); and Division of Cardiology, Northwestern University, Feinberg School of Medicine, Chicago, IL (C.W.Y.).