1. Clinical Ergospirometry, Exercise & Rehabilitation Laboratory, Evaggelismos Hospital, National and Kapodistrian University of Athens, 10676 Athens, Greece
2. Cardiac Surgery Intensive Care Unit, Onassis Cardiac Surgery Center, 17674 Kallithea, Greece
3. Heart Failure, Transplant and Mechanical Circulatory Support Units, Onassis Cardiac Surgery Center, 17674 Athens, Greece