Porta A, Baselli G, Caiani E, Malliani A, Lombardi F, Cerutti S
Dipartimento di Bioingegneria, Politecnico di Milano, Italy.
Med Biol Eng Comput. 1998 Jan;36(1):27-34. doi: 10.1007/BF02522854.
A dynamic linear parametric model is designed to quantify the dependence of ventricular repolarisation duration variability on heart period changes and other immeasurable factors. The model analyses the beat-to-beat series of the RR duration and of the interval between R- and T-wave apexes (RT period). Directly from these two signals, a parametric identification procedure and spectral decomposition techniques allow RT variability to be divided into RR-related and RR-unrelated parts and allow the RT-RR transfer function to be calculated. RT variability is driven by RR changes at low frequency (LF, around 0.1 Hz) and high frequency (HF, at the respiratory rate), whereas, at very low frequencies, the RR-unrelated contribution to the total RT variability is remarkable. During tilt at LF the RR-related RT percentage power increases (p < 0.02), the RR-unrelated RT percentage power remains unchanged, the gain of the RT-RR relationship largely increases (p < 0.001), and the phase is not significantly modified. Both the RR-related and the RR-unrelated RT percentage powers at LF are not affected by controlled respiration, and an increase in the RT-RR gain at HF is observed (p < 0.02). The proposed analysis may help to describe the regulation of the ventricular repolarisation process and to extract indexes quantifying the coupling between heart period and ventricular repolarisation interval changes.
设计了一种动态线性参数模型，用于量化心室复极持续时间变异性对心动周期变化及其他不可测量因素的依赖性。该模型分析RR间期和R波与T波顶点之间的间期（RT间期）的逐搏序列。直接从这两个信号出发，通过参数识别程序和频谱分解技术，可以将RT变异性分为与RR相关和与RR无关的部分，并计算RT-RR传递函数。RT变异性在低频（LF，约0.1Hz）和高频（HF，呼吸频率）时受RR变化驱动，而在极低频时，与RR无关的部分对总RT变异性的贡献显著。在LF倾斜期间，与RR相关的RT百分比功率增加（p<0.02），与RR无关的RT百分比功率保持不变，RT-RR关系的增益大幅增加（p<0.001），且相位无显著改变。LF时与RR相关和与RR无关的RT百分比功率均不受控制呼吸的影响，且观察到HF时RT-RR增益增加（p<0.02）。所提出的分析可能有助于描述心室复极过程的调节，并提取量化心动周期与心室复极间期变化之间耦合的指标。
