toSense, Inc. has developed a novel, non-invasive, body-worn sensor -CoVa Patch-that offers an alternative to invasive continuous cardiac output monitoring. To validate this new sensor's measurements of stroke volume and cardiac output, toSense, Inc. will conduct a study that compares its measurement performance to that from a pulmonary artery catheter using the thermodilution method.

This in an introductory clinical study with cardiac ICU patients featuring CoVa Patch. This is a single site, non-blinded, non-randomized study. It will employ a retrospective analysis comparing the accuracy of SV and CO. The 'test sensor', CoVa Patch, which will measure SV and CO quasi-continuously and non-invasively, approximately every 5-30 minutes for a period of time lasting approximately 12-48 hours. These measurements will be compared to those from a 'reference device', which is the pulmonary arterial catheter. It uses an invasive technique called thermodilution that will be made approximately every 4 hours. Measurements between the test and reference devices will be compared in a retrospective analysis once the study has completed.

Inclusion Criteria:

• Male or female ≥ 18 years of age at Visit X.
• Subject is a patient in the Cardiac ICU and meets the following criteria: pulmonary artery catheterization scheduled or completed.
• Written informed consent (and assent when applicable) obtained from subject or subject's legal representative and ability for subject to comply with the requirements of the study.
• Subject is not pregnant at the time of consent

Exclusion Criteria:

• Pregnant in the study.
• Presence of a condition or abnormality that in the opinion of the Investigator would compromise the safety of the patient or the quality of the data.
• Subject is unable or unwilling to wear electrode patches as required for a period between 6 to 48 hours.

Men and woman over the age of 18 years old.