1. Department of Cardiology, Linköping University Hospital , Garnisonsvägen 10 , 581 85 Linköping, Sweden
2. Department of Health, Medicine and Caring Sciences, Linköping University , Garnisonsvägen 10 , 581 85 Linköping, Sweden
3. Department of Clinical Physiology, Linköping University Hospital , Linköping , Sweden