1. Liverpool Centre for Cardiovascular Science at University of Liverpool, Liverpool John Moores University and Liverpool Heart & Chest Hospital , Liverpool , United Kingdom
2. Danish Center for Health Services Research, Department of Clinical Medicine, Aalborg University , Aalborg , Denmark
3. Heart Center, Turku University Hospital and University of Turku , Turku , Finland
4. Department of Cardiology, Aalborg University Hospital , Aalborg , Denmark