1. Department of Medicine, Section of Cardiology, Baylor College of Medicine, Houston, TX, USA;
2. Department of Clinical Physiology, Lund University and Lund University Hospital, Lund, Sweden;
3. Department of Cardiology, The Heart Centre, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark;
4. Department of Cardiology, Division of Medicine, Oslo University Hospital and Institute of Clinical Sciences, University of Oslo, Oslo, Norway;
5. Department of Medicine, Division of Cardiology, Nykøbing Falster Hospital, Nykøbing Falster, Denmark;
6. Institute of Regional Health Research, University of Southern Denmark, Odense, Denmark;
7. Department of General and Interventional Cardiology, University Heart Center Hamburg, Hamburg, Germany