1. Electrophysiology Laboratory; First Department of Cardiology; “Hippokration” General Hospital; National and Kapodistrian University of Athens; Athens Greece
2. Second Department of Cardiology; Laboratory of Cardiac Electrophysiology; “Evangelismos” General Hospital of Athens; Athens Greece
3. Department of Cardiology; University General Hospital of Heraklion; Heraklion Greece
4. State Department of Cardiology; “Hippokration” General Hospital; Athens Greece
5. Department of Cardiology; “Konstantopouleio” General Hospital; Athens Greece
6. Department of Cardiology; University General Hospital of Ioannina; Ioannina Greece