1. Division of Cardiology, Department of Medicine (N.A.N., A.C.C., W.E.K., J.P.P., J.P.D., A.Y.S., S.H.S.), Durham, NC.
2. Department of Medicine (J.W.A.), Durham, NC.
3. Duke Molecular Physiology Institute, Duke University School of Medicine (L.C.K., W.E.K., S.H.S.), Durham, NC.
4. Duke Clinical Research Institute (J.P.P.), Durham, NC.