1. Duke Clinical Research Institute, Duke University School of Medicine, Durham, NC (A.L., K.P.A., N.J.P., C.L.H., B.A., D.B.M., P.S.D.).
2. Vanderbilt University Medical Center (A.L.).
3. Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN (P.A.P.).
4. National Heart, Lung, and Blood Institute, Bethesda, MD (L.S.C.).
5. Massachusetts General Hospital, Harvard Medical School, Boston (U.H.).