Inclusion Criteria:  Weight >50 kg Veno-arterial ECMO with impending removal (for recovery, heart transplantation or LVAD/BIVAD implantation or support futility) Venous catheter tip positioned in the superior vena cava or right heart Arterial line for blood pressure monitoring Given informed consent  Exclusion Criteria:  Pregnancy Absence of arterial line or central venous catheter Hemodynamic instability under ECMO support Malposition of ECMO venous canula