Related Experiment Videos
Does impedance cardiography reliably estimate left ventricular ejection fraction?
N J van der Meer1, M W Oomen, A Vonk Noordegraaf
1Department of Internal Medicine, Free University Hospital, Amsterdam, The Netherlands.
Insights
Impedance cardiography (IMP) shows promise for determining left ventricular ejection fraction (LVEF). A novel IMP calculation method offers reliable LVEF values, outperforming previous equations.
Area of Science:
- Cardiology
- Biomedical Engineering
- Medical Imaging
Background:
- Left ventricular ejection fraction (LVEF) is a critical indicator of cardiac function.
- Noninvasive methods for LVEF assessment are highly desirable in clinical practice.
- Existing impedance cardiography (IMP) formulas have shown limitations in accurately determining LVEF.
Purpose of the Study:
- To evaluate impedance cardiography (IMP) as a noninvasive method for determining left ventricular ejection fraction (LVEF).
- To introduce and validate a new IMP-based calculation for LVEF.
- To compare the accuracy of different IMP calculation methods against radionuclide ventriculography.
Main Methods:
- A study involving 24 patients with cardiotoxic chemotherapy or cardiac failure.
- Measurement of LVEF using impedance cardiography (LVEFimp) and radionuclide ventriculography (LVEFnuc).
- Calculation of LVEFimp using three distinct methods: Capan's formula (LVEFCap), Judy's ratio (LVEFJud), and a novel derived equation (LVEFimp).
Main Results:
- LVEFCap showed no significant correlation with LVEFnuc (r = 0.29).
- LVEFJud demonstrated a fair correlation with LVEFnuc (r = 0.55).
- The novel LVEFimp calculation exhibited a stronger correlation with LVEFnuc (r = 0.75).
Conclusions:
- Previous IMP-based equations for LVEF calculation require improvement.
- The newly developed IMP equation provides reliable LVEF values in the studied patient cohort.
- IMP holds potential as a valuable noninvasive tool for LVEF assessment.
Objective:
The objective of our study was to evaluate impedance cardiography (IMP) as a noninvasive method to determine the left ventricular ejection fraction (LVEF). METHODS. A total of 24 patients, 8 men and 16 women, aged 45.0 +/- 12.9 years, participated in the study. They used cardiotoxic chemotherapeutic drugs or suffered from cardiac failure. LVEF was measured by means of IMP (LVEFimp) and radionuclide ventriculography (LVEFnuc). LVEFimp was calculated in three ways. Capan and colleagues [13] proposed a formula in which LVEF (LVEFCap) can be calculated from the systolic time intervals, namely, left ventricular ejection time and preejection time. Judy and colleagues [14] described a systolic (S) and a diastolic (D) part in the first derivative curve of the impedance signal. The ratio S/D might equal the LVEF (LVEFJud). A new LVEF calculation was introduced (LVEFimp) in this study based on the first derivative of the impedance signal, the thoracic impedance, and heart rate.
Results:
Mean LVEFCap was 59.9 +/- 8.4%, which did not differ from LVEFnuc (59.9 +/- 7.1%). However the correlation between both methods was not significant (r = 0.29). Mean LVEFJud was 63.9 +/- 17.4%, which was not significantly different from LVEFnuc, with a fair correlation (r = 0.55). Mean LVEFimp was 59.2 +/- 9.4%, with a better correlation with radionuclide ventriculography (r = 0.75).
Conclusions:
The results of this study indicate that the equations that have been used until now can be improved. The new equation provides reliable LVEF values in this group of patients.