1. Department of Cardiothoracic Surgery, The Heart Centre, Rigshospitalet, Copenhagen University Hospital , Blegdamsvej 9, 2100 Copenhagen , Denmark
2. Department of Cardiology, The Heart Centre, Rigshospitalet, Copenhagen University Hospital , Blegdamsvej 9, 2100 Copenhagen , Denmark
3. Department of Cardiology, Bispebjerg University Hospital , Bispebjerg Bakke 23, 2400 Copenhagen , Denmark
4. Department of Cardiology, Odense University Hospital , J. B. Winsløws Vej 4, 5000 Odense , Denmark
5. Department of Cardiothoracic and Vascular Surgery, Odense University Hospital , J. B. Winsløws Vej 4, 5000 Odense , Denmark
6. Department of Cardiology, Sahlgrenska University Hospital , Blå Stråket 5, 413 45 Gothenburg , Sweden