University of Edinburgh, University Hospitals Plymouth NHS Trust, University Hospitals Plymouth NHS Trust - Emergency Department, University of Sheffield, University of Edinburgh, Royal Infirmary of Edinburgh - Emergency Medicine Research Group Edinburgh (EMERGE), University of Sheffield, University of Southampton - Coronary Research Group, Royal Berkshire NHS Foundation Trust - Emergency Department, Milton Keynes University Hospital NHS Foundation Trust, Torbay and South Devon NHS Foundation Trust, University of Edinburgh, University of Sheffield, University of Edinburgh, University of Edinburgh - Centre for Cardiovascular Science and Independent