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Time-Frequency Analysis of Cardiovascular and Cardiorespiratory Interactions During Orthostatic Stress by Extended
Sonia Charleston-Villalobos1, Sina Reulecke1, Andreas Voss2
1Department of Electrical Engineering, Universidad Autónoma Metropolitana, Mexico City 09340, Mexico.
Entropy (Basel, Switzerland)
|December 3, 2020
Summary
Orthostatic intolerance (OI) patients exhibit altered cardiovascular and cardiorespiratory interactions during head-up tilt tests. The extended partial directed coherence (ePDC) method revealed significant dynamic changes, highlighting impaired autonomic regulation in OI.
Area of Science:
- Cardiovascular Physiology
- Autonomic Nervous System Function
- Systems Biology
Background:
- Orthostatic stress challenges the cardiovascular system, revealing autonomic regulation.
- Orthostatic intolerance (OI) is characterized by symptoms upon assuming an upright posture.
- Understanding cardiorespiratory interactions is crucial for diagnosing and managing OI.
Purpose of the Study:
- To investigate the temporal dynamics of cardiovascular and cardiorespiratory interactions during head-up tilt (HUT) tests in healthy individuals and OI patients.
- To identify gender differences in cardiorespiratory interactions during orthostatic stress.
- To evaluate the utility of the extended partial directed coherence (ePDC) method for causality analysis in OI.
Main Methods:
- Application of the linear method of extended partial directed coherence (ePDC) for causality analysis.
- Analysis of 20 five-minute windows during a 70° HUT test, from baseline (BL) to 18 minutes of the orthostatic phase (OP).
- Inclusion of both healthy subjects and patients with OI, stratified by gender.
Main Results:
- Gender differences in cardiorespiratory interactions were observed in healthy controls during the orthostatic phase.
- Patients with OI displayed significant dynamic alterations in cardiovascular and cardiorespiratory interactions throughout the HUT test.
- In young female OI patients, altered information flow was noted: increased heart rate to systolic blood pressure modulation pre-tilt, increased neural baroreflex during OP, and decreased respiratory sinus arrhythmia during the entire HUT test.
Conclusions:
- Cardiovascular interactions are impaired in patients with orthostatic intolerance.
- The ePDC method is effective for analyzing dynamic causality in cardiorespiratory interactions during orthostatic stress.
- Findings underscore the complex interplay of autonomic regulation in OI pathophysiology.
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