1. Department of Internal Medicine, John H Stroger Jr. Hospital of Cook County, Chicago, IL 60612, USA
2. Department of Internal Medicine, Dow University of Health Sciences, Karachi 74200, Pakistan
3. Division of Cardiology, Rush University Medical Center, Chicago, IL 60612, USA
4. Department of Medicine, University of Mississippi School of Medicine, Jackson, MI 39216, USA
5. Cardiovascular Division, Beth Israel Deaconess Medical Center & Department of Medicine, Harvard Medical School, Boston, MA 02120, USA
6. Division of Cardiovascular Diseases, Mayo Clinic, Phoenix, AZ 85054, USA
7. Department of Radiology, Vancouver General Hospital, Vancouver, British Columbia, Canada