1. DEPARTMENT OF CARDIOLOGY AND ANGIOLOGY, SILESIAN CENTRE FOR HEART DISEASES IN ZABRZE, ZABRZE, POLAND
2. DEPARTMENT OF CARDIOLOGY AND ANGIOLOGY, SILESIAN CENTRE FOR HEART DISEASES IN ZABRZE, ZABRZE, POLAND; DEPARTMENT OF CARDIOLOGY, CONGENITAL HEART DISEASES AND ELECTROTHERAPY, FACULTY OF MEDICAL SCIENCES IN ZABRZE, MEDICAL UNIVERSITY OF SILESIA, KATOWICE, POLAND