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Assessing cardiac preload by the Initial Systolic Time Interval obtained from impedance cardiography

Jan H. Meijer
Jan H. Meijer
, 
Annemieke Smorenberg
Annemieke Smorenberg
, 
Erik J. Lust
Erik J. Lust
, 
Rudolf M. Verdaasdonk
Rudolf M. Verdaasdonk
 and 
A. B. Johan Groeneveld
A. B. Johan Groeneveld
   | Dec 10, 2010
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Article Category: Articles
Published Online: Dec 10, 2010
Page range: 80 - 83
Received: Nov 04, 2010
DOI: https://doi.org/10.5617/jeb.141
Keywords
© 2010 Jan H. Meijer, Annemieke Smorenberg, Erik J. Lust, Rudolf M. Verdaasdonk and A. B. Johan Groeneveld , published by Sciendo
This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Fig.1

Electrode configuration. A small alternating electrical current of 0.3 mA r.m.s. and 64 kHz was applied to the thorax by means of the two outer electrodes. The two inner electrodes measured the subsequent electrical voltage difference over the heart. From the time course of this voltage signal the impedance signal was obtained.
Electrode configuration. A small alternating electrical current of 0.3 mA r.m.s. and 64 kHz was applied to the thorax by means of the two outer electrodes. The two inner electrodes measured the subsequent electrical voltage difference over the heart. From the time course of this voltage signal the impedance signal was obtained.

Fig.2

A typical example of simultaneous registration of an Impedance CardioGram (ICG) and an ElectroCardioGram (ECG) (arbitrary units). The marker points R in the ECG and C in the ICG are indicated. From the time difference between these points the Initial Systolic Time Interval (ISTI) is determined, which can be considered as a measure of the time lag between the electrical and mechanical activity of the heart.
A typical example of simultaneous registration of an Impedance CardioGram (ICG) and an ElectroCardioGram (ECG) (arbitrary units). The marker points R in the ECG and C in the ICG are indicated. From the time difference between these points the Initial Systolic Time Interval (ISTI) is determined, which can be considered as a measure of the time lag between the electrical and mechanical activity of the heart.

Fig.3

A significant relationship between the Initial Systolic Time Interval (ISTI) and the Cardiac Output (CO) was found before and after intravenous administration of 2x250 ml of a Gelofusine® solution in two steps of 250 ml each.
A significant relationship between the Initial Systolic Time Interval (ISTI) and the Cardiac Output (CO) was found before and after intravenous administration of 2x250 ml of a Gelofusine® solution in two steps of 250 ml each.

Mean values (± S.D.) of the Cardiac Output (CO), Pulse Transit Time (PTT) and Initial Systolic Time Interval (ISTI) at three moments, before and after intravenous administration of a Gelofusine® solution in two steps of 250 ml each.

momentCO (L/min)PTT (ms)ISTI (ms)
before infusion4.7 ± 1.2190 ± 9148 ± 30
after 250 ml4.9 ± 1.3184 ± 10151 ± 28
after 500 ml4.9 ± 1.3179 ± 9151 ± 26

Relationships between the Initial Systolic Time Interval ISTI (ms) and the Cardiac Output CO (L/min) at the three moments before, after the first and after the second intravenous fluid administration of 250 ml (N = 16). The coefficients of correlation r and the levels of significance p are also given. The last row gives the relationship for the pooled data (N = 48)..

momentrelationship ISTI =rp
before infusion-13.5·CO + 2110.5453< 0.025
after 250 ml-10.1·CO + 2010.4920< 0.05
after 500 ml-9.5·CO + 1970.4609< 0.05
pooled data-10.7·CO + 2020.4917< 0.005
eISSN:
1891-5469
Language:
English
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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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