1. Contilia Heart and Vessel Centrum, Department of Cardiology and Angiology Elisabeth Hospital Essen Germany
2. Heart Centre Bonn, Department of Internal Medicine, Cardiology, Pulmonology and Angiology University of Bonn Bonn Germany
3. Heart Centre Bonn, Department of Cardiovascular Surgery University Hospital Bonn Bonn Germany
4. Heart and Vessel Medicine Mediapark, Department of Cardiology Cologne Germany