Accuracy of impedance cardiography to measure cardiac output at rest in pulmonary hypertension

Introduction: Cardiac output (CO) is one of the most important prognostic factor in PH and is required for the assessment of treatment response. CO is measured invasively by right heart catheterization by thermodilution or the Fick method. Impedance cardiography (IP) measures CO and is noninvasive, simple and provides immediate results. Objectives: The main objective of this feasibility study was to assess the accuracy of of CO measures performed IP compared to the Fick method in selected patients treated for PH (Group 1 or 4). Secondary objectives were to evaluate the accuracy of CO evaluation by IP compared to thermodilution and to determine the factors that may affect the measures. Methods: Patients were recruited from the cohort of the Competence Center PH of Midi-Pyrenees, France. The three techniques (Fick, thermodilution and IP) were realized at the same time during right heart catheterization performed in the patient follow up. All patients had confirmed PH from Group 1 or group 4. Results: We had recruited 37 subjects in the study. (31 patients group 1 and 6 patients group 4). The CO measured by IP correlates with the CO measured by the Fick method: ρ=0.62 CI 95% [0.3064; 0.8124] (P Conclusion: This pilot study validates the measurement of CO by IP in patients with PH (group 1 or 4). This suggests a potential role of the non-invasive IP in the follow up of PH patients.