1. Department of Cardiology, Sorlandet Hospital , Postboks 416 Lundsiden, 4604 Arendal , Norway
2. Department of Cardiology, Oslo University Hospital Ullevaal , Oslo , Norway
3. Institute of Clinical Medicine, University of Oslo , Oslo , Norway
4. Department of Medical Research and Department of Internal Medicine, Vestre Viken Hospital Trust, Baerum Hospital , Rud , Norway
5. Department of Cardiac Rehabilitation, LHL-hospital Gardermoen , Jessheim , Norway
6. Faculty of Engineering and Science, University of Agder , Grimstad , Norway
7. Clinic of Cardiology, St. Olavs Hospital , Trondheim , Norway
8. Department of Circulation and Medical Imaging, Norwegian University of Science and Technology , Trondheim , Norway