1. From the Division of Cardiology, Department of Medicine, Emory University School of Medicine, Atlanta, GA (H.S., P.E., M.C.M., S.S.D., L.H.T., A.A.Q.); Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA (J.S., L.H.T., D.P.G.); and Department of Health Services, University of Washington, Seattle (C.M.).