1. Faculty of Health and Caring Sciences, Institute of Nursing, The Sahlgrenska Academy at Göteborg University, Box 457, Göteborg SE 405 30, Sweden
2. Department of Medicine, Skellefteå County Hospital, HeartNet, Campus, Skellefteå, and Department of Public Health and Clinical Medicine, Umeå University, Sweden
3. The Cardiovascular Institute, Sahlgrenska University Hospital, Östra, Sweden
4. Department of Medicine, Sahlgrenska University Hospital, Östra, Sweden