1 Department of Cardiology, Medical University of Lublin, Lublin, Poland; Clinical Department of Electrocardiology, SPSK-4 University Hospital, Lublin, Poland. Electronic address: andrzej.glowniak@umlub.pl.
2 Clinical Department of Electrocardiology, SPSK-4 University Hospital, Lublin, Poland.
3 Department of Cardiology, Ministry of Internal Affairs and Administration Hospital, Lublin, Poland.