1. Department of Cardiovascular Sciences, Fondazione Policlinico Universitario A. Gemelli IRCCS, L.go A. Gemelli, 1-00168 Rome, Italy
2. Department of Cardiovascular and Pulmonary Sciences, Catholic University of the Sacred Heart, Rome, Italy
3. Cardiology Division, Massachusetts General Hospital, Harvard Medical School, 55 Fruit Street, GRB 800, Boston, MA 02114, USA