Detecting changes in cardiovascular interaction during postural stress using directed coherence
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In the study, Granger causality frequency analysis based on directed coherence is utilized to detect and quantify directional interaction among heart rate, systolic blood pressure and respiratory signal during postural stress from supine to standing and from standing to supine. The directional information flow during postural stress from supine to standing is dominant on cardiorespiratory interaction, vasculo-respiratory interaction and cardiovascular interaction. Conversely, the reverse postural stress from standing to supine resulted in a contrary effect on both cardiorespiratory and cardiovascular interactions without significant change in vasculo-respiratory interaction. Based on the power change, we observed that postural stress gets affected by both cardiorespiratory and cardiovascular but not by vasculo-respiratory system. Therefore, the directed coherence power calculated for each interaction helps to identify short-term regulatory mechanism during postural stress.
KeywordsFrequency analysis Directed coherence (DC) Cardiovascular Respiration Postural stress
Arterial blood pressure
Power spectral density
List of symbols
Model coefficient matrix
- \(\varGamma \)
- \(\gamma \)
Directed coherence power
The authors would like to thank Biomedical Instrumentation Laboratory, Department of Instrumentation and Control, Dr. B. R. Ambedkar National Institute of Technology, Jalandhar, and to all volunteers who took part in the recording.
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