【摘要】 对长时间心电图能量谱中的心率基频及其谐频成分能量密度的分布,用一个指数函数进行最小二乘拟合,函数中引入的分布指数用来量化能量密度分布分散与集中的程度。用该函数对年轻(21~34岁)与年老(68~81岁)二组经过严格筛选的健康人心电图数据的能量谱进行局部拟合,计算出每个个体的心率基频及其谐频成分的中心频率f0、在中心频率f0处的能量密度、谐频与基频成分能量密度的比值、谐频与基频成分分布指数的比值以及可识别出的谐频个数等特征参数值。结果:分布指数是年轻组明显大于年老组(P<0.01),谐频与基频能量密度的比值是年轻组明显小于年老组(P<0.01),可识别出的谐频个数是年轻组明显少于年老组(P<0.01),f0及在f0处的能量密度在二个不同年龄组之间没有差异。这些结果预示着在本研究中提出的特征参数值可作为心率波动的一种新的度量。更多还原

【Abstract】 In a least square method,an exponential function fits the energy density distribution of fundamental and harmonic frequency component in a long-term ECG energy spectrum.A distributing index of the function was used to quantify divergence and convergence degree of energy density.The function fits locally the ECG energy spectrum data that were collected from the young（2134 yr） group and elderly（68-81 yr） group rigorously screened healthy subjects. The characteristic parameter values of all subjects were calculated which are center frequency f₀ of fundamental and harmonic frequency component,energy density at center frequency f₀,energy density ratio of the harmonic to fundamental frequency component,distributing index ratio of the harmonic to fundamental frequency component and recognizability number of harmonic frequency component.The results showed the distributing index was significantly greater in the young group than in the elderly group（P<0.01）,the energy density ratio of the harmonic to fundamental frequency component and recognizability number of harmonic frequency component were significantly less in the young group than in the elderly group（P<0.01）,the center frequency f₀ and energy density at center frequency f₀ did not differ between the two age groups.These data indicate that the characteristic parameter values presented in this study can serve as a new measurement of heart rate fluctuations.更多还原