1 Electrophysiology Department, Barts Heart Centre, St. Bartholomew's Hospital, London, United Kingdom.
2 1(st) Cardiology Department, Athens University Medical School, Hipporkation Hospital, Athens, Greece.
3 Electrophysiology Department, Barts Heart Centre, St. Bartholomew's Hospital, London, United Kingdom; Institute of Cardiovascular Science, University College London, London, United Kingdom. Electronic address: drnpapageorgiou@yahoo.com.