Simulation of 'pathologic' changes in ICG waveforms resulting from superposition of the 'preejection' and ejection waves induced by left ventricular contraction
| Autor: | E V Lukoshkova, R S Sonina, V A Kolesnikov, V V Ermishkin |
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| Rok vydání: | 2013 |
| Předmět: |
Physics
History medicine.medical_specialty Aorta animal structures medicine.diagnostic_test Multifunction cardiogram Phase (waves) Computer Science Applications Education Impedance cardiography Contractility Superposition principle Amplitude Internal medicine medicine.artery medicine Cardiology Waveform Biomedical engineering |
| Zdroj: | Journal of Physics: Conference Series. 434:012007 |
| ISSN: | 1742-6596 1742-6588 |
| Popis: | The impedance cardiography (ICG) is widely used for beat-to-beat noninvasive evaluation of the left ventricular stroke volume and contractility. It implies the correct determination of the ejection start and end points and the amplitudes of certain peaks in the differentiated impedance cardiogram. An accurate identification of ejection onset by ICG is often problematic, especially in the cardiologic patients, due to peculiar waveforms. Using a simple theoretical model, we tested the hypothesis that two major processes are responsible for the formation of impedance systolic wave: (1) the changes in the heart geometry and surrounding vessels produced by ventricular contraction, which occur during the isovolumic phase and precede ejection, and (2) expansion of aorta and adjacent arteries during the ejection phase. The former process initiates the preejection wave WpE and the latter triggers the ejection wave WEj. The model predicts a potential mechanism of generating the abnormal shapes of dZ/dt due to the presence of preejection waves and explains the related errors in ICG time and amplitude parameters. An appropriate decomposition method is a promising way to avoid the masking effects of these waves and a further step to correct determination of the onset of ejection and the corresponding peak amplitudes from 'pathologically shaped' ICG signals. |
| Databáze: | OpenAIRE |
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