1. Märkische Kliniken GmbH; Department of Cardiology and Angiology; Klinikum Lüdenscheid; Ludenscheid Germany
2. Department of Cardiology; Witten / Herdecke University; Witten Germany
3. Division of Electrophysiology; Department of Cardiovascular Medicine; University of Münster; Münster Germany
4. Department of Cardiology; Helios Klinikum Wuppertal; Wuppertal Germany
5. Orthopedics and Traumatology; University Clinic Patras; Patras Greece
6. Spine-Center; Asklepios Clinic Lindenlohe; Schwandorf Germany