1. Department of Medicine, Skellefteå County Hospital and Umeå University, Skellefteå
2. Institute of Medicine, University of Bergen and Department of Heart Disease, Haukeland University Hospital, Bergen, Norway
3. The Heart Center, Rigshospitalet, Copenhagen, Denmark
4. Weill Cornell Medical College, New York
5. Department of Medicine, Sahlgrenska University Hospital/Östra, and University of Gothenburg, Gothenburg, Sweden
6. Department of Cardiology, Helsinki University Central Hospital, Helsinki, Finland
7. Department of Cardiology, Veterans Affairs Medical Center, Washington, DC, USA