1. Primary Care Unit, Department of Public Health & Primary Care, University of Cambridge , Forvie Site, Robinson Way, Cambridge CB2 OSR , UK
2. Department of Cardiology, Royal Papworth Hospital NHS Foundation Trust, Papworth Road, Cambridge Biomedical Campus , Cambridge CB2 0AY , UK
3. The Healthcare Improvement Studies Institute, Department of Public Health & Primary Care, University of Cambridge , Forvie Site, Robinson Way, Cambridge CB2 OSR , UK
4. Physiotherapy Department, Cambridge University Hospital NHS Foundation Trust , Addenbrookes, Cambridge CB2 OQQ , UK
5. Medical Library, University of Cambridge, Cambridge University Hospital NHS Foundation Trust , Addenbrookes, Cambridge CB2 OQQ , UK
6. University of Cambridge School of Clinical Medicine, Cambridge University Hospital NHS Foundation Trust , Addenbrookes, Cambridge CB2 OQQ , UK