1 Cardiology Department, Ospedale Civile G. Mazzini, Teramo, Italy.
2 Division of Cardiology, Department of Medicine, Karolinska Institutet, Stockholm, Sweden; Cardiology Department, Santa Maria delle Grazie Hospital, Naples, Italy.
3 Cardiology and Arrhythmology Clinic, Marche University Hospital, Ancona, Italy.
4 Department of Cardiology, Santa Chiara Hospital, APSS, 2, Largo Medaglie d'Oro, Trento 38123, Italy. Electronic address: [email protected].