1. Department of Hypertensiology, Angiology and Internal Medicine, Poznan University of Medical Sciences, 61-848 Poznan, Poland
2. Department of Cardiology-Intensive Therapy and Internal Medicine, Poznan University of Medical Sciences, 60-355 Poznan, Poland
3. Institute of Physics, University of Zielona Gora, 65-516 Zielona Gora, Poland