1. HUCH Heart and Lung Center, Helsinki University Hospital and University of Helsinki, Helsinki, Finland;
2. Department of Clinical Physiology, Tampere University Hospital, Tampere, Finland;
3. Science Service Center, Kuopio University Hospital, Kuopio, Finland;
4. Department of Clinical Physiology, Central Finland Health Care District, Jyväskylä, Finland;
5. Department of Clinical Physiology and Nuclear Medicine, Kuopio University Hospital and University of Eastern Finland, Kuopio, Finland