Kowalska, Monika Kowalska, Wiktoria Kowalska, Wiktoria (Poland) Kowalski, Jan Kowalski, M. Kowalski, Marcin Kowalski, Mirosław Kowalski, Mirosław, Department of Congenital Heart Diseases, Institute of Car diology Warsaw (Poland) Kowalski, Oskar Kowalski, Oskar, I Katedra i Oddział Kliniczny Kardiologii Śląskiej Akademii Medycznej, Śląskie Centrum Chorób Serca w Zabrzu Kowalski, Oskar, Department of Cardiology, Congenital Heart Disease and Electrotherapy, Medical University of Silesia, Silesian Center for Heart Diseases, Zabrze, Poland (Poland) Kowalski, Oskar, Department of Cardiology, Congenital Heart Disease and Electrotherapy, Silesian Medical University, Silesian Centre for Heart Diseases, Zabrze, Kowalski, Oskar, Department of Cardiology, Congenital Heart Diseases and Electr otherapy, Silesian Medical University, Silesian Center for Heart Diseases Zabrze Kowalski, Oskar Kowara, Michał Koyama, Yasushi Koyi, Hirsh, Karolinska Institutet Koza, Konrad Kozak, Karol Kozakiewicz, Krystyna Kozakiewicz, Krystyna Kozanecki, Kozanecki, Department of Cardiac and Vascular Diseases, John Paul II Hospital, Krakow, Poland Kozar-Kamińska, Katarzyna Kozaryn, Radoslaw, Department of Cardiovascular Surgery, Medical University of Gdansk Kozela, Magdalena, Department of Epidemiology and Population Studies, Institute of Public Health, Faculty of Health Sciences, Jagiellonian Univer sity Medical College, Krakow, Poland