1. Department of Medical and Pediatric Sciences, University of Catania, Via Plebiscito 628, 95124 Catania, Italy
2. Clinical Echocardiography, A.U.O. Policlinic “Vittorio Emanuele”, P.O. Rodolico, Via Santa Sofia 78, 95125 Catania, Italy
3. Cardiology Unit, Ferrarotto Hospital, Via S. Citelli 6, 95124 Catania, Italy