1. Trent Cardiac Centre, Nottingham University Hospitals, Hucknall Rd, Nottingham, UK
2. Cardiology Department, Royal Derby Hospital, University Hospitals of Derby and Burton NHS Foundation Trust, Uttoxeter Road, Derby, UK
3. National Heart and Lung Institute, Imperial College, Guy Scadding Building, Cale Street, London, UK
4. London Health Sciences Centre, Western University, 339 Windermere Rd, London, ON, Canada