1. Department of Cardiology, Castle Hill Hospital, Hull York Medical School (at University of Hull) , Kingston upon Hull, HU16 5JQ , UK
2. Cardiovascular Research Centre, University of Leicester, Glenfield Hospital , Groby Road, Leicester, LE3 9QP , UK
3. Robertson Centre for Biostatistics & Clinical Trials, University of Glasgow , Glasgow , G12 8QQ, UK
4. Faculty of Medical Science, Anglia Ruskin University , Cambridge, CB1 1PT , UK