1. From the Duke Clinical Research Institute (A.F.H., B.G.H., S.M.A., C.M.O., K.A.S., E.D.P., L.H.C.) and Department of Medicine (A.F.H., S.M.A., C.M.O., K.A.S., E.D.P., L.H.C.), Duke University School of Medicine, Durham, NC; Ahmanson-UCLA Cardiomyopathy Center, UCLA Medical Center (G.C.F.), Los Angeles, Calif; and Division of Cardiology, Baylor University Medical Center (C.W.Y.).