1 Department of Cardiovascular Diseases, John Ochsner Heart and Vascular Institute, Ochsner Clinical School, University of Queensland School of Medicine, New Orleans, Louisiana.
2 Cardiac Exercise Research Group, Department of Circulation and Medical Imaging, Faculty of Medicine and Health Science, Norwegian University of Science and Technology, Trondheim, Norway.
3 John Hopkins Ciccarone Center for the Prevention of Cardiovascular Disease, Baltimore, Maryland.