1. Department of Cardiology, Policlinico Casilino , Via Casilina 1049, Roma (RM) 00169 , Italy
2. Clinica Montevergine , Mercogliano (AV) , Italy
3. Casa di Cura San Michele , Maddaloni (CE) , Italy
4. Department of Cardiac Electrophysiology and Pacing, Anthea Hospital , Bari , Italy