1. Department of Cardiovascular Medicine, Mayo Clinic and Foundation, 200 First Street SW, Rochester, MN, USA
2. Department of Cardiology, University Medical Center Groningen, University of Groningen, Hanzeplein 1, RB Groningen, The Netherlands
3. Department of Cardiology, Institute of Clinical and Experimental Medicine - IKEM, Videnska 1958/9, Prague, Czech Republic