1. Department of Cardiology, City Hospital Zurich Triemli , Birmensdorferstr. 497 , 8063 Zurich, Switzerland
2. Departement of Cardiac Surgery, City Hospital Zurich Triemli , Birmensdorferstr. 497 , 8063 Zurich, Switzerland
3. Departement of Cardiac Surgery, University Hospital Zurich , Rämistrasse 100 , 8091 Zurich, Switzerland