title: [Relationship between age and the energy density distribution of fundamental and harmonic frequency component in electrocardiogram energy spectrum].
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 (21-34 yr) group and elderly (68-81 yr) group rigorously 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.
authors.affiliation: Department of Biomathematics and Biologic Information, School of Mathematics Science and Computing Technology, Central South University, Changsha 410078, China. zdz1962@163.com
authors.forename: Dianzhong
authors.initials: D
authors.lastname: Zhang
authors.forename: Xiaohong
authors.initials: X
authors.lastname: Tan
mesh_terms: D000367:Age Factors; D004562:Electrocardiography / Q000379:methods*; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D025341:Principal Component Analysis; D012815:Signal Processing, Computer-Assisted