1. University of Belgrade, Faculty of Medicine, Belgrade, Serbia + Clinical Centre of Serbia, Cardiology Clinic, Belgrade, Serbia
2. University of Novi Sad, Faculty of Medicine, Novi Sad, Serbia + Institute of Cardiovascular Diseases of Vojvodina, Sremska Kamenica, Serbia
3. University of Defense, Medical Faculty, Belgrade, Serbia + Military Medical Academy, Belgrade, Serbia
4. University of Niš, Faculty of Medicine, Nis, Serbia + Niška Banja Institute for Treatment and Rehabilitation, Clinic of Cardiology, Niška Banja, Serbia
5. Zemun Clinical Hospital Centre, Department of Cardiology, Belgrade, Serbia
6. University of Belgrade, Faculty of Medicine, Belgrade, Serbia + Zemun Clinical Hospital Centre, Department of Cardiology, Belgrade, Serbia