1. Second Department of Cardiology; Laboratory of Cardiac Electrophysiology; “Evangelismos” General Hospital of Athens; Athens Greece
2. Department of Cardiology; “G. Gennimatas” General Hospital of Athens; Athens Greece
3. Hellenic Center for Disease Control and Prevention; Athens Greece
4. Department of Cardiology; University Hospital of Ioannina; Ioannina Greece
5. “Dromokaiteio” Psychiatric Hospital of Attica; Attica Greece