1. Duke Clinical Research Institute (S.A.H., D.D., Z.L., J.K.H.), Duke University Medical Center, Durham, NC.
2. Presbyterian Heart Center, Albuquerque, NM (S.A.H.).
3. University of Florida Health Science Center, Jacksonville (F.H.E.).
4. Heart Hospital Baylor Plano Research Center, TX (M.J.M.).
5. Mayo Clinic, Rochester, MN (D.R.H.).
6. Cleveland Clinic, OH (E.M.T.).
7. Emory University School of Medicine, Atlanta, GA (V.H.T.).
8. Duke University School of Medicine (J.M.B.), Duke University Medical Center, Durham, NC.