1 Department of Cardiology, The Cardiovascular Research Centre, Herlev and Gentofte Hospital, University of Copenhagen, Hospitalsvej 1, 2900 Hellerup, Denmark.
2 Department of Cardiology, The Heart Centre, Rigshospitalet, University of Copenhagen, Blegdamsvej 3B, 2100 Copenhagen, Denmark.
3 Cardiovascular Division, Brigham & Women's Hospital, 75 Francis St, Boston, MA 02115, USA.