Cardiology Division, Johns Hopkins University, Baltimore, Maryland; Department of Cardiology, Rikshospitalet, Oslo University Hospital and University of Oslo, Oslo, Norway. Department of Radiology, Mount Sinai School of Medicine, New York, New York. Offices of Biostatistics Research, National Heart, Lung, and Blood Institute, Bethesda, Maryland. Cardiology Division, Johns Hopkins University, Baltimore, Maryland. School of Public Health, Johns Hopkins University, Baltimore, Maryland. Department of Cardiology, Rikshospitalet, Oslo University Hospital and University of Oslo, Oslo, Norway. National Institute for Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, Maryland; Department of Radiology, Johns Hopkins School of Medicine, Baltimore, Maryland. Cardiology Division, Johns Hopkins University, Baltimore, Maryland; Department of Radiology, Johns Hopkins School of Medicine, Baltimore, Maryland. Electronic address: jlima@jhmi.edu.