1. Heart Center, Satakunta Central Hospital, Pori, Finland;
2. Heart Center, Turku University Hospital, Turku, Finland;
3. Department of Cardiology, Brighton and Sussex University Hospital NHS Trust, Brighton, UK;
4. Medical Research Center, Oulu University Hospital, and University of Oulu, Oulu, Finland;
5. Department of Cardiology, Kokkola Central Hospital, Kokkola, Finland;
6. Helsinki University Hospital, Helsinki, Finland