1. Department of Cardiac and Vascular Diseases, Jagiellonian University Collegium Medicum John Paul II Hospital Prądnicka Street 80 Kraków 31‐202 Poland
2. Jagiellonian University Collegium Medicum, Students' Scientific Group at the Department of Cardiac and Vascular Diseases John Paul II Hospital Krakow Poland
3. College of Economics and Computer Science Kraków Poland