1. Charité - Universitätsmedizin Berlin, Campus Benjamin Franklin, Department of Cardiology, Berlin, Germany
2. Institute of Biomaterial Science and Berlin-Brandenburg Centre for Regenerative Therapies, Helmholtz-Zentrum Geesthacht, Teltow, Germany
3. Kreiskrankenhaus Wolgast, Department of Internal Medicine, Wolgast, Germany
4. Department of Cardiology and Internal Medicine B, University Medicine Greifswald, Germany