1 Department of Internal Medicine III (Cardiology and Angiology), Innsbruck Medical University, 6020 Innsbruck, Austria.
2 Division of Cardiovascular Diseases and Internal Medicine, Mayo Clinic and Medical School, Rochester, MN 55905, USA.
3 Department of Laboratory Medicine and Pathology, Hennepin County Medical Center and University of Minnesota School of Medicine, Minneapolis, MN 55415, USA.
4 Department of Medical Sciences, Uppsala Clinical Research Center, Uppsala University, 75237 Uppsala, Sweden.