1. Internal Medicine, Syncope Unit, IRCCS Humanitas Research Hospital, 20089 Milan, Italy
2. IBM, 20100 Milan, Italy
3. Department of Medicine and Surgery, University of Milano-Bicocca, 20100 Milan, Italy
4. Emergency Department, IRCCS Humanitas Research Hospital, 20089 Milan, Italy
5. Department of Biomedical Sciences, Humanitas University, 20072 Milan, Italy
6. Emergency Department, Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico, Università Degli Studi Di Milano, 20100 Milan, Italy
7. Emergency Medicine Unit, Luigi Sacco Hospital, ASST Fatebenefratelli Sacco, 20100 Milan, Italy