1. From the Center for Clinical and Genetic Economics, Duke Clinical Research Institute (L.H.C., M.A.G., B.G.H., L.D.D., A.M.S.), and Department of Medicine (L.H.C., A.F.H.), Duke University School of Medicine, Durham, NC; and Ahmanson-UCLA Cardiomyopathy Center, Department of Medicine (G.C.F.), UCLA Medical Center, Los Angeles, Calif.