1. Department of Cardiology and Angiology II, University Heart Center Freiburg - Bad Krozingen, Bad Krozingen, Germany
2. Institute of Medical Biometry and Statistics (IMBI), Albert-Ludwigs-University Freiburg, Freiburg, Germany
3. Department of Cardiovascular Surgery, University Heart Center Freiburg - Bad Krozingen, Bad Krozingen, Germany