1. Department of Internal Medicine, Catholic University Medical School, Rome, Italy;
2. Critical Care Medicine Department, National Institutes of Health, Bethesda, Maryland;
3. Department of Medicine, Cardiology Division, Johns Hopkins Hospital, Baltimore, Maryland;
4. MedStar Cardiovascular Research Network, Washington, DC;
5. Department of Pharmacology, Catholic University Medical School, Rome, Italy; and
6. Department of Internal Medicine, University of Tor Vergata, Rome, Italy