1. Department of Cardiology, University Hospital of Patras, 265 04 Patras, Greece
2. First Department of Cardiology, Hippocration General Hospital, National and Kapodistrian University of Athens, 157 72 Athens, Greece
3. Department of Cardiology, Tzaneio General Hospital, 185 36 Piraeus, Greece
4. First Department of Cardiology, Red Cross Hospital, 115 26 Athens, Greece
5. Department of Cardiology, Heraklion University Hospital, 715 00 Heraklion, Crete, Greece
6. Department of Cardiology, Centre Hospitalier Universitaire de Charleroi, 6042 Charleroi, Belgium