1. Royal Brompton and Harefield Hospitals, Guys’ & St Thomas NHS Trust , Sydney St, London SW3 6NP , UK
2. Department of Neuroscience, Imaging and Clinical Sciences, ‘G. d’Annunzio’ University of Chieti-Pescara , Chieti , Italy
3. Department of Biomedical and Dental Sciences and of Morphological and Functional Images, University of Messina , Messina , Italy
4. Department of Experimental and Clinical Medicine, Magna Graecia University , Catanzaro, Italy
5. Department of Cardiovascular and Pulmonary Sciences, Catholic University of the Sacred Heart , Rome , Italy
6. Postgraduate School of Cardiovascular Medicine, University of Trieste, Italy
7. Department of Clinical and Experimental Medicine, University of Messina , Messina , Italy
8. School of Biomedical Engineering and Imaging Sciences, Faculty of Life Sciences and Medicine, King’s College University , Strand, London WC2R 2LS , UK
9. National Heart, Lung and Blood Institute, National Institutes of Health , Bethesda, MD , USA