1 Department of Cardiology, Alexandrovska University Hospital, Faculty of Medicine, Medical University of Sofia, Bulgaria. monika_shumkova@yahoo.com.
2 Department of Cardiology, Alexandrovska University Hospital, Faculty of Medicine, Medical University of Sofia, Bulgaria.
3 Mossakowski Medical Research Centre, Polish Academy of Sciences, Poland Department of Invasive Cardiology, Central Clinical Hospital of the Ministry of the Interior, Warszawa, Poland.