1. Heart and Vascular Center, Semmelweis University , Varosmajor 68, H-1122 Budapest , Hungary
2. Department of Cardiology and Angiology, National Institute of Cardiovascular Diseases, Slovak Medical University , Bratislava , Slovakia
3. Department of Electrocardiology, Medical University of Lodz , Lodz , Poland
4. Department of Cardiology, Gottsegen National Cardiovascular Center , Budapest , Hungary
5. Department of Cardiology, Central Hospital of Northern Pest—Military Hospital , Budapest , Hungary
6. Cardiovascular Division, Brigham and Women's Hospital, Harvard Medical School , Boston, MA , USA
7. Clinical Cardiovascular Research Center, University of Rochester , Rochester, NY , USA