1. Cardiology Department, Laikon General Hospital, University of Athens Medical School, 115 27 Athens, Greece
2. First Department of Propaedeutic and Internal Medicine, University of Athens Medical School, 115 27 Athens, Greece
3. Department of Hygiene and Epidemiology, University of Athens Medical School, 115 27 Athens, Greece
4. Pulmonary Unit, Department of Therapeutics, University of Athens Medical School, 115 27 Athens, Greece