1. Division of Cardiology, Azienda Ospedaliero-Universitaria Policlinico “G. Rodolico—San Marco”, University of Catania, Via S. Sofia, 78, 95123 Catania, Italy
2. Bristol Heart Institute, Bristol National Institute of Health Research (NIHR) Biomedical Research Centre, University Hospitals Bristol NHS Trust and University of Bristol, Terrell St, Bristol BS2 8ED, UK