1. Department of Cardiology, Division of Medicine, Akershus University Hospital, Postbox 1000, 1478 Lørenskog, Norway
2. Center for Heart Failure Research, Faculty of Medicine, University of Oslo, Postbox 1078 Blindern, 0316 Oslo, Norway
3. Department of Medical Research, Bærum Hospital, Vestre Viken Hospital Trust, Postbox 800, 3004 Drammen, Norway