Duke Clinical Research Institute, Duke University Medical Center, Durham, North Carolina; Division of Cardiology, Department of Medicine, Duke University Medical Center, Durham, North Carolina. Electronic address: robert.mentz@duke.edu. Duke Clinical Research Institute, Duke University Medical Center, Durham, North Carolina. Duke Clinical Research Institute, Duke University Medical Center, Durham, North Carolina; Division of Cardiology, Department of Medicine, Duke University Medical Center, Durham, North Carolina. Department of Medical and Surgical Specialties, Radiological Sciences, and Public Health, University of Brescia, Brescia, Italy. Department of Cardiology, University Medical Center Groningen, University of Groningen, Groningen, the Netherlands. Canadian VIGOUR Centre, Edmonton, Alberta, Canada; Division of Cardiology, Department of Medicine, University of Alberta, Edmonton, Alberta, Canada. Division of Cardiology, Department of Medicine, University of Alberta, Edmonton, Alberta, Canada. Heart and Vascular Institute, Cleveland Clinic, Cleveland, Ohio.