1. Department of Cardiology, University Hospital Bern; Switzerland
2. Hanseatisches Herzzentrum; Asklepios Klinik St. Georg; Hamburg Germany
3. Division of Electrophysiology; Department of Cardiology/Angiology; University of Münster; Germany
4. Universitäres Herzzentrum; Hamburg Germany
5. Kerckhoff-Klinik GmbH, Bad Nauheim; Germany
6. Institute for Clinical and Experimental Medicine, Prague; Czech Republic
7. Herz-und Gefäss-Klinik; Bad Neustadt; Germany
8. Aarhus University Hospital; Skejby Sygehus; Aarhus, Denmark