1. Division of Cardiology; Fondazione IRCCS Policlinico San Matteo; Pavia Italy
2. Center for Scientific Documentation; Fondazione IRCCS Policlinico San Matteo; Pavia Italy
3. Coronary Care Unit; Fondazione IRCCS Policlinico San Matteo; Pavia Italy
4. Service of Clinical Epidemiology and Biostatistic; Fondazione IRCCS Policlinico san Matteo; Pavia Italy