1. Heart and Vascular Center, Semmelweis University , Varosmajor 68, H-1122 Budapest , Hungary
2. Department of Cardiology and Angiology, National Institute of Cardiovascular Diseases and Slovak Medical University , Bratislava , Slovakia
3. Department of Electrocardiology, Medical University of Lodz , Lodz , Poland
4. Department of Cardiology, Central Hospital of Northern Pest—Military Hospital , Budapest , Hungary
5. Gottsegen National Cardiovascular Center , Budapest , Hungary
6. Heart Institute, University of Pécs , Pécs , Hungary
7. Department of Electrocardiology and Heart Failure, Medical University of Silesia , Katowice , Poland
8. Cardiovascular Imaging Research Center, Massachusetts General Hospital, Harvard Medical School , Boston, MA , USA
9. Department of Cardiology and Electrophysiology, German Heart Center of the Charite Berlin , Berlin , Germany
10. Clinical Cardiovascular Research Center, University of Rochester , Rochester, NY , USA
11. Imperial Clinical Trials Unit, Imperial College London , London , UK
12. Physiological Controls Research Center , Budapest , Hungary
13. Cardiovascular Division, Brigham and Women's Hospital, Harvard Medical School , Boston, MA , USA