1. 3rd Department of Cardiology, National and Kapodistrian University of Athens, Medical School, Sotiria Chest Disease Hospital, Athens, Greece
2. 1st Department of Cardiology, National and Kapodistrian University of Athens, Medical School, Hippokration General Hospital, Athens, Greece
3. Cardiovascular Division, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
4. 1st Department of Cardiology, National and Kapodistrian University of Athens, Medical School, Hippokration General Hospital, Athens, Greece.