1. University Hospital of Patras, Department of Cardiology , Patras , Greece
2. National & Kapodistrian University of Athens Medical School, First Department of Cardiology, Hippocration General Hospital , Athens , Greece
3. National & Kapodistrian University of Athens Medical School , Athens , Greece
4. CHU Charleroi, Department of Cardiology , Charleroi , Belgium
5. Sant'Eugenio Hospital, Department of Cardiology , Rome , Italy