1. Cardiology Section, Wake Forest School of Medicine, Winston-Salem, NC 27157, USA
2. General Internal Medicine Division, San Francisco VA Medical Center and the University of California San Francisco, San Francisco, CA 94143, USA
3. Department of Preventive Medicine and Division of Nephrology and Hypertension, Loyola University Medical Center, Maywood, IL 60153, USA
4. Department of Radiology, John Hopkins University, Baltimore, MD 21205, USA