1. Department of Cardiology, Sahlgrenska University Hospital , Gothenburg , Sweden
2. Department of Molecular and Clinical Medicine, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg , Gothenburg , Sweden
3. Department of Cardiology, Boston Veteran Affairs Healthcare , West Roxbury, MA , USA
4. Harvard Medical School , Boston, MA , USA
5. Department of Cardiothoracic Surgery, Sahlgrenska University Hospital , Gothenburg , Sweden