1. Division of Cardiology (J.B.L., C.B.P., R.A., A.D.D.), Duke University School of Medicine, Durham, NC.
2. Duke Clinical Research Institute, Durham, NC (J.B.L., D.M.G., C.L.G., A.D.D.).
3. Department of Biostatistics and Bioinformatics (C.L.G.), Duke University School of Medicine, Durham, NC.
4. Department of Medicine, Washington University School of Medicine, St. Louis, MO (N.K.S.).
5. Department of Surgery (J.E.K., C.A.M., J.N.S.), Duke University School of Medicine, Durham, NC.