1. Division of Cardiology and Angiology, Department of Internal Medicine, Magdeburg University, Leipziger Str. 44, D-39120 Magdeburg, Germany
2. Institute of Biometry and Medical Informatics, Magdeburg University, D-39120 Magdeburg, Germany
3. Department of Cardiology, Leiden University Medical Center, 2333 ZA Leiden, The Netherlands