1. Cardiology Unit; S. Maria Annunziata Hospital; Florence Italy
2. Epidemiology Unit; Local Health Unit; Florence Italy
3. Department of Cardiology; Careggi Hospital; Florence Italy
4. Department of Cardiovascular Sciences; Division of Cardiology; European Hospital; Rome Italy
5. Division of Cardiology; Northwestern University Feinberg School of Medicine; Chicago Illinois USA
6. Department of Cardiology; Local Health Unit; Florence Italy