Cardiology Department, Athens General Hospital "G. Gennimatas", Athens, Greece. Electronic address: ggiann@med.uoa.gr. Second Department of Cardiology, School of Medicine, National and Kapodistrian University of Athens, Athens, Greece. Cardiology Department, Athens General Hospital "G. Gennimatas", Athens, Greece. Second Department of Cardiology, Evangelismos General Hospital, Athens, Greece. First Department of Cardiology, School of Medicine, National and Kapodistrian University of Athens, Athens, Greece.