After cardiac surgery, vasoplegic syndrome is a hemodynamic state characterized by profound hypotension associated with a decrease in systemic vascular resistance. The care of this disease is based on the intravenous administration of a vasopressor, usually norepinephrine. During the recovery phase, weaning of norepinephrine, is an important step in which any lack of preload (blood volume) initial or secondary can be, and increase tissue malperfusion.

Inclusion Criteria:

• Major patient ≥ 18 years
• Patient operated a cardiac surgery for myocardial revascularization (CABG surgery) or surgical correction of valvular or combined surgery (CABG and valve disease) or surgery the ascending aorta and cardiac surgery with vasoplegic syndrome treated by norepinephrine
• Signed consent
• Affiliation to social assurance

Exclusion Criteria:

• Permanent atrial fibrillation
• Treatment with dobutamine and/or epinephrine
• Pregnant woman
• Patient under guardianship or private public law
• Internal pacemaker
• Hypothermia
• Patient refusal