1. Cardiology Department, Royal Berkshire Hospital , Reading, RG1 5AN , UK
2. Keble College, University of Oxford , Parks Road, Oxford OX1 3PG , UK
3. Cardiothoracic Surgery Department, St Bartholomew’s Hospital , West Smithfield, London EC1A 7BE , UK
4. Sheffield Teaching Hospitals NHS Foundation Trust , Glossop Rd, Broomhall, Sheffield S10 2JF , UK
5. Royal Berkshire Hospital , Reading, RG1 5AN , UK
6. Cardiology Department, Oxford University Hospitals NHS Foundation Trust , Headley Way, Headington, Oxford OX3 9DU , UK
7. Cardiology Department, Royal Brompton Hospital , Sydney Street, London SW3 6NP , UK
8. School of Biomedical Engineering and Imaging Sciences, Kings College , Strand, London WC2R 2LS , UK