ASSESSMENT OF FREQUENCY-SHIFTS IN R-R INTERVAL VARIABILITY AND RESPIRATION WITH COMPLEX DEMODULATION
ASSESSMENT OF FREQUENCY-SHIFTS IN R-R INTERVAL VARIABILITY AND RESPIRATION WITH COMPLEX DEMODULATION
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DOI：
10.1152/jappl.1994.77.6.2879
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发表时间：
1994-12-01
影响因子：
3.3
通讯作者：
FUJINAMI, T
中科院分区：
文献类型：
--
作者：
HAYANO, J;TAYLOR, JA;FUJINAMI, T
提出了一种复杂解调（CDM）方法，用于连续评估预定义频带中存在的节律分量的频移和随时间变化的幅度变化，并将其应用于 R-R 间期的高频（HF）和低频（LF）分量分析以及通过阻抗呼吸图分析呼吸。仿真研究表明，这种 CDM 技术提供了非常适合研究非平稳 R-R 间隔信号的数学特征，并且可以描绘幅度和频率的时间相关波动，从而准确地区分高频和低频分量。对不同呼吸频率下定速呼吸期间的数据分析表明，估计的 HF 分量和呼吸频率忠实地反映了定速呼吸频率。对增加工作量（20 W/min）的动态运动期间的数据分析表明，高频分量的频率随着运动而升高，并且高频和低频幅度随着负荷的增加而逐渐减小。 CDM 衍生的呼吸频率和幅度与直接每次呼吸的呼吸频率和潮气量测量高度相关。我们的结论是，这种方法可以为连续评估心血管和呼吸变化的时间依赖性变化提供强大的手段。
A complex demodulation (CDM) method for continuous assessment of frequency shifts and time-dependent changes in amplitude in the rhythmic components existing in predefined frequency bands was proposed and applied to the analysis of high-frequency (HF) and low-frequency (LF) components of the R-R interval and to the analysis of respiration via impedance spirogram. Simulation studies revealed that this CDM technique furnishes mathematical features well suited to the investigation of non stationary R-R interval signals and can delineate time-dependent fluctuations in both amplitude and frequency, accurately differentiating between HF and LF components. Analysis of data during paced breathing at different respiratory frequencies revealed that the estimated frequency of the HF component and respiration faithfully reflected the frequency of paced breathing. Analysis of data during dynamic exercise with in creasing workload (20 W/min) showed that the frequency of the HF component was elevated with exercise and that both HF and LF amplitudes were reduced progressively with advancing load. CDM-derived frequency and amplitude of respiration were highly correlated to direct breath-by-breath respiratory frequency and tidal volume measurements. We conclude that this method could provide a powerful means for continuously assessing time-dependent changes in both cardiovascular and respiratory variations.