1. Department of Medicine and Vetinary Medicine, The University of Edinburgh Medical School, Edinburgh BioQuarter, 49 Little France Crescent, Edinburgh, EH16 4TJ, UK
2. Bristol Heart Institute, Bristol Medical School, University of Bristol, Bristol, BS2 8HW, UK
3. Department of Cardiology, Royal Infirmary of Edinburgh, Edinburgh BioQuarter, 51 Little France Crescent, Edinburgh, EH16 4SA, UK