1. Division of Cardiothoracic Surgery, Landspitali –The National University Hospital of Iceland, Reykjavik, Iceland;
2. Internal Medicine Services, Landspitali –The National University Hospital of Iceland, Reykjavik, Iceland;
3. Division of Cardiology, Landspitali –The National University Hospital of Iceland, Reykjavik, Iceland;
4. Division of Cardiac Surgery, Yale School of Medicine, New Haven, CT, USA;
5. Faculty of Medicine, University of Iceland, Reykjavik, Iceland