1. Department of Cardiology, Stavanger University Hospital, Postboks 8100, 4068 Stavanger, Norway
2. Institute of Medicine, University of Bergen, Postboks 7804, 5020 Bergen, Norway
3. Cardiology Research Institute, Catholic University of Salta, España 311, A4400ANG Salta, Argentina
4. Department of Research, Stavanger University Hospital, Postboks 8100, 4068 Stavanger, Norway
5. Sigma Statistical Services, School Road, Balmullo KY16 0BJ, UK