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Comparison of cardiac time intervals between echocardiography and impedance cardiography at various heart rates

Maureen A.J.M. van Eijnatten
Maureen A.J.M. van Eijnatten
, 
Michael J. van Rijssel
Michael J. van Rijssel
, 
Rob J.A. Peters
Rob J.A. Peters
, 
Rudolf M. Verdaasdonk
Rudolf M. Verdaasdonk
 and 
Jan H. Meijer
Jan H. Meijer
   | Apr 15, 2014
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Article Category: Articles
Published Online: Apr 15, 2014
Page range: 2 - 8
Received: Sep 23, 2013
DOI: https://doi.org/10.5617/jeb.690
Keywords
© 2014 Maureen A.J.M. van Eijnatten, Michael J. van Rijssel, Rob J.A. Peters, Rudolf M. Verdaasdonk and Jan H. Meijer, published by Sciendo
This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Fig.1

ISTI is defined as the dime delay between the R-peak of the ECG signal and the C-point in the ICG registration.
ISTI is defined as the dime delay between the R-peak of the ECG signal and the C-point in the ICG registration.

Figure 2

Positioning of the ultrasound transducer for the three views.
Positioning of the ultrasound transducer for the three views.

Figure 3

Electrode configuration. A small current (i) is applied through the outer two electrodes I1 and I4. The inner two electrodes I2 and I3 measure the impedance induced voltage difference (V) over the heart (indicated with an oval). The ECG is obtained from these inner electrodes simultaneously.
Electrode configuration. A small current (i) is applied through the outer two electrodes I1 and I4. The inner two electrodes I2 and I3 measure the impedance induced voltage difference (V) over the heart (indicated with an oval). The ECG is obtained from these inner electrodes simultaneously.

Figure 4

Typical example of results from a subject: the moments of occurrence for each heart cycle marker are presented at various RR-intervals. Shown are from bottom to top: opening aortic valves, C-point ICG, maximum diameter aortic arch, maximum diameter descending aorta and closing aortic valves. Least squares linear regression was used to fit the data. All coefficients of correlation were r > 0.97 (p<0.005). The error bars of C-point indicate the standard deviation at a constant heart rate. For all other markers, the error bars indicate the measurement’s time resolution.
Typical example of results from a subject: the moments of occurrence for each heart cycle marker are presented at various RR-intervals. Shown are from bottom to top: opening aortic valves, C-point ICG, maximum diameter aortic arch, maximum diameter descending aorta and closing aortic valves. Least squares linear regression was used to fit the data. All coefficients of correlation were r > 0.97 (p<0.005). The error bars of C-point indicate the standard deviation at a constant heart rate. For all other markers, the error bars indicate the measurement’s time resolution.

Figure 5

Typical example of the relationships of the time interval between the start of the ejection phase (opening aortic valves) and the heart cycle markers. Data from the same subject as in Figure 4 were used.
Typical example of the relationships of the time interval between the start of the ejection phase (opening aortic valves) and the heart cycle markers. Data from the same subject as in Figure 4 were used.

Subjects' characteristics (mean ± S.D.).

SubjectsTotal (N=16)
Age (years)22 ± 2
Male (m) / Female (f)9 m / 7 f
Height (cm)177 ± 10
Body mass (kg)69 ± 12

The mean slopes and their standard deviations (SD) of the regression lines describing the time interval between the start of the ejection phase and the corresponding heart cycle marker. All slopes were found to differ from zero, except for the C-point.

Slope ofMean ± SDp-value
C-point0.02 ± 0.060.255
Aortic arch maximum0.07 ± 0.06< 0.001
Descending aorta maximum0.17 ± 0.07< 0.001
Aortic valves close0.16 ± 0.06< 0.001

Moment of occurrence of the C-point compared with all other heart cycle markers in all 16 subjects. Paired 2-sided t-tests were applied to the C-point and all other markers to compare the means, both in rest and after exercise. All markers differed from the moment of the C-point, except the moment of maximum diameter of the aortic arch.

C-point compared withp-value
Rest (RR=1000 ms)Aortic valves open< 0.001
Aortic arch maximum> 0.05
Descending aorta maximum< 0.001
Aortic valves close< 0.001
Exercise (RR=500 ms)Aortic valves open< 0.001
Aortic Arch maximum> 0.05
Descending aorta maximum< 0.05
Aortic valves close< 0.001
eISSN:
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Language:
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Journal Subjects:
Engineering, Bioengineering and Biomedical Engineering, Biomedical Electronics, Life Sciences, Biophysics, Medicine, Biomedical Engineering, Physics, Spectroscopy and Metrology
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