1. Division of Medicine, Department of Cardiology, Akershus University Hospital, Lørenskog, Norway (P.L.M., T.O.).
2. K.G. Jebsen Center for Cardiac Biomarkers, Institute of Clinical Medicine, University of Oslo, Norway (P.L.M., T.O.).
3. Department of Internal Medicine, UT Southwestern Medical Center, Dallas, Texas (A.M.S.).