Inclusion Criteria:  In situ pulmonary artery catheter Above 16 years of age At least 36 hours of continuous hemodynamic monitoring with the pulmonary artery catheter planed  Exclusion Criteria:  Patients with: Permanent or pesisting Atrial Fibrilation or Ventricular Arrythmias Moderate to Severe Aortic Insuficiency or Aortic Stenosis Intravascular Cardiac Assist Device Planed removal of the pulmonary artery catheter <36 hours