1. First Department of Cardiology, University of Ioannina Medical School, Ioannina, Greece;
2. Second Department of Cardiology, Laboratory of Cardiac Electrophysiology, "Evangelismos" General Hospital of Athens, Athens, Greece;
3. Third Department of Cardiology, Hippokration Hospital, Medical School, Aristotle University of Thessaloniki, Thessaloniki, Athens, Greece;
4. Department of Medicine and Therapeutics, Chinese University of Hong Kong, Hong Kong, P. R. China;
5. Li Ka Shing Institute of Health Sciences, Faculty of Medicine, Chinese University of Hong Kong, Hong Kong, China;
6. Department of Cardiology, Tianjin Institute of Cardiology, Second Hospital of Tianjin Medical University, Tianjin, P. R. China