1. Emergency Department, Christchurch Hospital , Private Bag 4710, Christchurch 8140 , New Zealand
2. Christchurch Heart Institute, Department of Medicine, University of Otago , Christchurch , New Zealand
3. Department of Internal Medicine III—Cardiology and Angiology, Innsbruck Medical University , Innsbruck , Austria
4. BHF Centre for Cardiovascular Science, University of Edinburgh , Edinburgh , UK
5. Usher Institute, University of Edinburgh , Edinburgh , UK