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Measurement of stroke volume with impedance cardiography
Insights
Impedance cardiography accurately tracks changes in stroke volume (SV) before and after exercise. While absolute SV values differ from dye dilution, impedance cardiography is a reliable, non-invasive method for assessing relative SV changes.
Area of Science:
- Cardiovascular Physiology
- Biomedical Engineering
- Exercise Science
Background:
- Stroke volume (SV) is a critical indicator of cardiac function.
- Non-invasive methods for measuring SV are valuable in clinical and research settings.
- Impedance cardiography (ICG) offers a non-invasive approach to assess hemodynamic parameters.
Purpose of the Study:
- To compare stroke volume (SV) measurements obtained by impedance cardiography (ICG) and the dye dilution technique.
- To evaluate the reliability and safety of ICG for measuring changes in SV before and after exercise.
- To determine the suitability of ICG for estimating absolute versus relative SV values.
Main Methods:
- Simultaneous measurement of stroke volume using impedance cardiography and dye dilution technique in 11 healthy men.
- Measurements were taken before and after exercise.
- Correlation, mean differences, and reproducibility of single measurements were analyzed.
Main Results:
- A high correlation (r=0.82) was observed between ICG and dye dilution for all measurements.
- Mean SV by ICG was significantly lower than by dye dilution (P < 0.001).
- No significant difference was found in the mean change of SV between the two methods during serial measurements; reproducibility was comparable.
Conclusions:
- Impedance cardiography is a safe, reliable, and non-invasive method for measuring changes in stroke volume in healthy individuals.
- Direct estimation of absolute stroke volume values using ICG is not recommended without calibration.
- Calibration of ICG against established techniques is necessary for accurate absolute SV determination.
Abstract:
Simultaneous determination of stroke volume with impedance cardiography and the dye dilution technique was compared in 11 healthy men before and after exercise. The correlation coefficient for all measurements was 0.82. Mean stroke volume determined by impedance cardiography was significantly (P less than 0.001) lower than mean stroke volume calculated by the dye dilution technique. However, there was no significant difference in the mean change in stroke volume determined by the two techniques during serial measurements. The reproducibility of single impedance-determined stroke volumes (6.9 ml) was not significantly different from single values obtained by dye dilution (7.3 ml). Impedance cardiography was found to be a safe, reliable, non-invasive method for the measurement of changes in stroke volume in healthy individuals before and after exercise. At present, direct estimation of absolute values of stroke volume is not recommended using impedance cardiography. Calibration of the impedance technique against other established techniques in a given application is necessary.