1. Clinic of Cardiology, St. Olavs Hospital, Trondheim University Hospital , Prinsesse Kristinas gate 3, 7030 Trondheim , Norway
2. Department of Public Health and Nursing, Norwegian University of Science and Technology , Postboks 8900, Torgarden, 7491 Trondheim , Norway
3. Department of Emergency Care and Prehospital Medicine, St. Olavs Hospital, Trondheim University Hospital , Trondheim , Norway
4. Department of Circulation and Medical Imaging, Norwegian University of Science and Technology , Trondheim , Norway