1. Heart CenterKuopio University Hospital and University of Eastern Finland Kuopio Finland
2. Heart CenterTurku University Hospital and University of Turku Turku Finland
3. Department of SurgeryOulu University Hospital Oulu Finland
4. Heart and Lung CenterHelsinki University Hospital Helsinki Finland
5. Department of Internal MedicineSouth Karelia Central Hospital Lappeenranta Finland
6. Cardiovascular MedicineBrigham and Women's Hospital, Harvard Medical School Boston Massachusetts