1. Doctoral School, Division of Medical Sciences in Zabrze, Medical University of Silesia, 40-055 Katowice, Poland
2. Department of Cardiology and Angiology, Silesian Center for Heart Diseases, 41-800 Zabrze, Poland
3. Department of Cardiology and Electrotherapy, Faculty of Medical Sciences in Zabrze, Medical University of Silesia, 40-055 Katowice, Poland