1. Clinical Cardiology Center, National Institute of Medicine MSWiA , Wołoska 137, 02-507 Warsaw , Poland
2. Center for Postgraduate Medical Education , Marymoncka 99, 01-813 Warsaw , Poland
3. Department of Cardiology, KU Leuven , Leuven , Belgium
4. Department of Cardiology, University Hospital of Wales , Cardiff , UK