Chon K H, Mullen T J, Cohen R J
Harvard-Massachusetts Institute of Technology, Division of Health Sciences and Technology, Cambridge 02139, USA.
IEEE Trans Biomed Eng. 1996 May;43(5):530-44. doi: 10.1109/10.488800.
Linear analyses of fluctuations in heart rate and other hemodynamic variables have been used to elucidate cardiovascular regulatory mechanisms. The role of nonlinear contributions to fluctuations in hemodynamic variables has not been fully explored. This paper presents a nonlinear system analysis of the effect of fluctuations in instantaneous lung volume (ILV) and arterial blood pressure (ABP) on heart rate (HR) fluctuations. To successfully employ a nonlinear analysis based on the Laguerre expansion technique (LET), we introduce an efficient procedure for broadening the spectral content of the ILV and ABP inputs to the model by adding white noise. Results from computer simulations demonstrate the effectiveness of broadening the spectral band of input signals to obtain consistent and stable kernel estimates with the use of the LET. Without broadening the band of the ILV and ABP inputs, the LET did not provide stable kernel estimates. Moreover, we extend the LET to the case of multiple inputs in order to accommodate the analysis of the combined effect of ILV and ABP effect on heart rate. Analyzes of data based on the second-order Volterra-Wiener model reveal an important contribution of the second-order kernels to the description of the effect of lung volume and arterial blood pressure on heart rate. Furthermore, physiological effects of the autonomic blocking agents propranolol and atropine on changes in the first- and second-order kernels are also discussed.
心率及其他血流动力学变量波动的线性分析已被用于阐明心血管调节机制。血流动力学变量波动的非线性作用尚未得到充分探索。本文对瞬时肺容积（ILV）和动脉血压（ABP）波动对心率（HR）波动的影响进行了非线性系统分析。为成功运用基于拉盖尔展开技术（LET）的非线性分析，我们引入了一种有效方法，即通过添加白噪声来拓宽模型中ILV和ABP输入的频谱内容。计算机模拟结果表明，利用LET拓宽输入信号的频谱带以获得一致且稳定的核估计是有效的。若不拓宽ILV和ABP输入的频带，LET无法提供稳定的核估计。此外，我们将LET扩展到多输入情况，以分析ILV和ABP对心率的联合作用。基于二阶沃尔泰拉 - 维纳模型的数据分析表明，二阶核在描述肺容积和动脉血压对心率的影响方面具有重要作用。此外，还讨论了自主神经阻滞剂普萘洛尔和阿托品对一阶和二阶核变化的生理影响。
