1. Faculty of Materials Engineering and Metallurgy, Silesian University of Technology, Krasińskiego 8, 40-019 Katowice, Poland
2. Faculty of Biomedical Engineering, Silesian University of Technology, General de Gaulle’a 66, 41-800 Zabrze, Poland
3. Department of Electrocardiology, Medical University of Silesia, Ziołowa 45/47, 40-635 Katowice, Poland