Kowalski, Oskar, Department of Cardiology, Congenital Heart Disease and Electrotherapy, Medical University of Silesia, Silesian Center for Heart Diseases, Zabrze, 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 Kozhuharov, Nikola Koziara, Dariusz Kozicka, Urszula, Institute of Cardiology, ul. Alpejska 42, 04-628 Warsaw Koziel, Dorota Kozieł, Paweł Kozieł, Paweł (Poland) Kozinski, Lukasz Koziński, Marek Koziński, Marek, Department of Cardiology and Internal Diseases, Collegium Medicum, Nicolaus Copernicus University, Bydgoszcz, Poland Koziński, Marek, Department of Cardiology and Internal Diseases, <i>Collegium Medicum</i> Nicolaus Copernicus University, Bydgoszcz, Poland