1. Institute of Cardiovascular Science (J.A., H.S., J.C.M., R.D.A., C.M., T.A.T., R.H.D.), University College London, UK.
2. Institute of Cardiovascular and Metabolic Medicine, University of Leeds, and Leeds Teaching Hospitals NHS Trust, UK (M.G., E. Levelt, J.P.G.).
3. University of Leicester and the National Institute for Health and Care Research (NIHR) Leicester Biomedical Research Centre, Glenfield Hospital, UK (G.P.M., R.A.).
4. Institute of Cardiovascular and Medical Sciences and British Heart Foundation Glasgow Cardiovascular Research Centre (G.R., A. Morrow, K.M., C.B.), Institute of Health and Wellbeing, University of Glasgow, UK.
5. Division of Cardiovascular Medicine, Radcliffe Department of Medicine, Oxford Centre for Clinical Magnetic Resonance Research, British Heart Foundation Centre of Research Excellence, Oxford NIHR Biomedical Research Centre, University of Oxford, UK (E. Lukaschuk, M.S., S.N., S.K.P., V.M.F.).
6. Division of Cardiovascular Sciences, School of Medical Sciences, Faculty of Biology, Medicine and Health, University of Manchester, UK (C.A.M.).
7. School of Biomedical Engineering and Imaging Sciences, King’s College London, BHF Centre of Excellence and the NIHR Biomedical Research Centre at Guy’s and St Thomas’ NHS Foundation Trust, The Rayne Institute, St Thomas’ Hospital, London, UK (A.C., C.B.-D.).
8. National Heart and Lung Institute, Imperial College, London, UK (S.K.P.).
9. University of Edinburgh and British Heart Foundation Centre for Cardiovascular Science, UK (T.S., M.R.D.).
10. Royal Brompton and Harefield Hospitals and Guys’ and St Thomas NHS Trust, London, UK (C.B.-D.).
11. Bristol Heart Institute, University Hospitals Bristol and Weston NHS Trust, Bristol, UK (C.B.-D.).
12. Department of Cardiology, Aberdeen Cardiovascular and Diabetes Centre, Aberdeen Royal Infirmary and University of Aberdeen, UK (D.D.).
13. Division of Medicine, Royal Free Hospital (D.K., M.F.), University College London, UK.
14. Electrocardiology Core Laboratory (P.W.M.), Institute of Health and Wellbeing, University of Glasgow, UK.
15. Robertson Centre for Biostatistics (R.Y., A. McConnachie), Institute of Health and Wellbeing, University of Glasgow, UK.