1. 3rd Department of Cardiology, University of Athens, Sotiria Hospital, 11527 Athens, Greece
2. 1st Department of Cardiology, University of Athens, Hippokration Hospital, 11527 Athens, Greece
3. Cardiology Department, Aghios Loukas Hospital, 55236 Thessaloniki, Greece
4. Cardiology Department, Hgeia Hospital, 15123 Athens, Greece
5. Cardiology Department, Interbalkan Medical Center, 55535 Thessaloniki, Greece