1. Cardiology Unit, S. Maria Nuova Hospital, 42100 Reggio Emilia, Italy
2. Arrhythmologic Center, Lavagna Hospital, 16033 Lavagn, Italy
3. Guglielmo da Saliceto Hospital, 29121 Piacenza, Italy
4. Cardiogy Unit, University Hospital of Ferrara, 8-44124 Cona, Italy
5. Electrophysiology and Cardiac Pacing, Division of Cardiology, Cardio-Thoracic Department, University Hospital of Verona, 1-37126 Verona, Italy