1. Department of Medical and Surgical Sciences, Institute of Cardiology, University of Bologna, Policlinico S.Orsola-Malpighi , via Massarenti 9, Bologna 40138 , Italy
2. IRCCS, Policlinico S. Orsola-Malpighi, U.O.C. di Cardiologia , via Massarenti 9, Bologna 40138 , Italy
3. Cardiology Division, Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, Policlinico di Modena , Modena , Italy