1. Department of Cardiology, Division of Medicine, Akershus University Hospital, Lørenskog, Norway and Center for Heart Failure Research and K.G. Jebsen Cardiac Research Centre, Institute of Clinical Medicine, University of Oslo, Oslo, Norway
2. Division of Surgery, Department of Otorhinolaryngology, Akershus University Hospital, Lørenskog, Norway and Institute of Clinical Medicine, University of Oslo, Oslo, Norway
3. Division of Cardiovascular Diseases, Department of Internal Medicine, Mayo Foundation for Medical Education and Research, Rochester, MN