1. Clinic for Electrophysiology, Herz- und Diabeteszentrum NRW, Ruhr-Universität Bochum, Georgstr.11, 32545 Bad Oeynhausen, Germany
2. Electrophysiology Center Bremen, Bremen, Germany
3. Department of Cardiology, Asklepios Klinik St. Georg, Hamburg, Germany
4. Department of Cardiology and Pneumology, University Medical Center, Goettingen, Germany
5. Department of Cardiology, University Heart Center Luebeck, Luebeck, Germany