1. Department of Cardiothoracic Surgery, Landspitali University Hospital, Reykjavik, Iceland
2. Reykjalundur Rehabilitation Center, Reykjavik, Iceland
3. Faculty of Medicine, University of Iceland; Reykjavik, Iceland
4. Neskaupstadur Hospital, Neskaupstadur, Iceland
5. Department of Pulmonology, Landspitali University Hospital, Reykjavik, Iceland