1. Medical School of Athens, National and Kapodistrian University of Athens, 15772 Athens, Greece
2. Department of Cardiology, University Hospital of Larissa, 41110 Larissa, Greece
3. Department of Cardiology, Hygeia Hospital, 15123 Athens, Greece
4. Attikon University Hospital, Medical School of Athens, National and Kapodistrian University of Athens, 12462 Athens, Greece