Browsing by Author "Hsu, Hung-Yi"

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A NOVEL INDEX OF PHOTOPLETHYSMOGRAPHY BY USING INSTANTANEOUS PULSE RATE VARIABILITY DURING NON-STATIONARY CONDITION
(2015)
Lin, Pei-Chen
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Huang, Po-Hsun
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Chang, Chia-Chi
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Hsu, Hung-Yi
;
Hsiao, Tzu-Chien
Heart rate variability (HRV) and pulse rate variability (PRV) have been widely used as an automatic nervous system (ANS) activities observation. Based on the timescale limitation of heart beat (for HRV) and pulse waveform (for PRV), one method of instantaneous pulse rate variability (iPRV) with photoplethysmography (PPG) had been proposed as a HRV and PRV surrogate during non-stationary condition in frequency domain. In this paper, the examination in time-domain PPG during passive leg raise (PLR) trial was studied. The 24 subjects pre-experiment resulted that iPRV and HRV are positive correlation (r-value = 0.680 +/- 0.099 in baseline; r-value = 0.688 +/- 0.096 in PLR). Furthermore, the iPRV containing much complex intrinsic components on higher frequency bands provides more intrinsic cardiovascular information for further assessment. This proposed examination in time-domain PPG is the possible leading way to more useful indicator for healthcare application.
Coefficient of Variation of Electrocardiographic R-R Intervals in Healthy Subjects and Stroke Patients
(2012)
Hsu, Hung-Yi
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Chang, Chia-Chi
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Hsiao, Tzu-Chien
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Chiang, Yi-Ying
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資訊工程學系
Frequency range extension of spectral analysis of pulse rate variability based on Hilbert-Huang transform
(2014-04-01)
Chang, Chia-Chi
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Hsiao, Tzu-Chien
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Hsu, Hung-Yi
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資訊工程學系
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友訊交大聯合研發中心
Heart rate variability (HRV) is a well-accepted indicator for neural regulatory mechanisms in cardiovascular circulation. Its spectrum analysis provides the powerful means of observing the modulation between sympathetic and parasympathetic nervous system. The timescale of HRV is limited by discrete beat-to-beat time intervals; therefore, the exploration region of frequency band of HRV spectrum is relatively narrow. It had been proved that pulse rate variability (PRV) is a surrogate measurement of HRV in most of the circumstances. Moreover, arterial pulse wave contains small oscillations resulting from complex regulation of cardiac pumping function and vascular tone at higher frequency range. This study proposed a novel instantaneous PRV (iPRV) measurement based on Hilbert-Huang transform. Fifteen healthy subjects participated in this study and received continuous blood pressure wave recording in supine and passive head-up tilt. The result showed that the very-high-frequency band (0.4-0.9 Hz) varied during head-up tilt and had strong correlation (r = 0.77) with high-frequency band and medium correlation (r = 0.643) with baroreflex sensitivity. The very-high-frequency band of iPRV helps for the exploration of non-stationary autoregulation and provides the non-stationary spectral evaluation of HRV without distortion or information loss.
Quantitative Non-stationary Assessment of Cardiovascular Diseases based on Arterial Blood Pressure Waveform by using Hilbert-Huang Transform
(2013-01-01)
Chang, Chia-Chi
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Hsu, Hung-Yi
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Hsiao, Tzu-Chien
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資訊工程學系
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Department of Computer Science
Analysis of arterial blood pressure (ABP) signal provides valuable information of cardiovascular function. But ABP\'s non-stationary characteristics are still unclear and it is hard to evaluate non-stationary characteristics by stationary analysis method, such as Fourier transform and wavelet transform. The aim of the study is to quantitatively evaluate the ABP\'s non-stationary characteristics and examine the feasibility of this method by the study of cardiovascular diseases patients. Eight ABP\'s intrinsic features were extracted by empirical mode decomposition (EMD) and were evaluated by averaged period and energy density according to the spectral integration method. In the study, 33 subjects (15 healthy subjects, 7 patients with autonomic failure, 11 patients with orthostatic tachycardia syndrome) participated in the passive head-up tilt experiment. The results showed that the characteristics of ABP fluctuation were clearly presented by the changes of IMFs and corresponding averaged periods and energy density. This method was feasible for the qualitative and quantitative assessment of ABP in normal healthy subjects and patients with impaired autonomic regulation of cardiovascular system.
Reflection Wave Analysis Based on Ensemble Empirical Mode Decomposition
(2013-01-01)
Kao, Sheng-Chi
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Hsiao, Tzu-Chien
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Chang, Chia-Chi
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Hsu, Hung-Yi
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分子醫學與生物工程研究所
In recent studies, the reflection waveform analysis (RWA) in arterial blood pressure (ABP) is the important method for cardiovascular system assessment. But conventional RWA contains some limitations during several clinical experiments, such as the unrecognizable reflection waveform morphology during Valsalva maneuver (VM). This study proposed a new RWA based on ensemble empirical mode decomposition (EEMD), which extracted the intrinsic feature of ABP waveform, including reflection wave and trend of ABP. Furthermore, the reflection time (T-r) was computed by EEMD-based RWA and the results of agreement test showed that T-r can be estimated with unrecognizable reflection waveform. It helps for the cardiovascular system assessment during specific physiological challenges, such as VM. Moreover, it helps for cardiovascular auto-regulation studies for reflection wave monitoring by VM study.
The interpretation of very high frequency band of instantaneous pulse rate variability during paced respiration
(2014-04-21)
Chang, Chia-Chi
;
Hsu, Hung-Yi
;
Hsiao, Tzu-Chien
;
分子醫學與生物工程研究所
;
資訊工程學系
Background: Pulse rate (PR) indicates heart beat rhythm and contains various intrinsic characteristics of peripheral regulation. Pulse rate variability (PRV) is a reliable method to assess autonomic nervous system function quantitatively as an effective alternative to heart rate variability. However, the frequency range of PRV is limited by the temporal resolution of PR based on heart rate and it is further restricted the exploration of optimal autoregulation frequency based on spectral analysis. Methods: Recently, a new novel method, called instantaneous PRV (iPRV), was proposed. iPRV breaks the limitation of temporal resolution and extends the frequency band. Moreover, iPRV provides a new frequency band, called very high frequency band (VHF; 0.4-0.9 Hz). Results: The results showed that the VHF indicated the influences of respiratory maneuvers (paced respiration at 6-cycle and 30-cycle) and the nonstationary condition (head-up tilt; HUT). Conclusions: VHF is as a potential indication of autoregulation in higher frequency range and with peripheral regulation. It helps for the frequency exploration of cardiovascular autoregulation.