Criterion for Maximum Entropy Spectral Analysis of Heart Rate Diurnal Rhythm in a Horse

Abstract

The application of the maximum entropy spectral analysis to the chronotropisms of heart rate diurnal rhythm in a horse was examined. As the sampling interval and the order of the autoregressive model (model order) had to be determined before the estimate by maximum entropy method (MEM), these parameters were examined. As the results, 5-or 10-minute interval and N (the number of data)/2 for the estimate of over a 6-hour period and N/5 for that of the 1-to 6-hour period were adequate for the sampling interval and the model order. It was presumed that by the MEM using these parameters, the heart rate diurnal rhythm of this horse had approximately 1-, 4-, 5-, 9-, and 26-hour periods.

An Ambulatory Data-logger Apparatus for Determining Heart Rate of Horses Grazed on Pastures.

“…A telemetry system for monitoring the heart rate is not well suited to large fields, because the range of a standard medical telemetry system in Japan is limited [8]. The Holter electrocardio graph is used for monitoring the electrocardio gram or heart rate in the field of veterinary medicine [13], but the data-analysis is expensive , and the data-analyzing software is not necessarily suited to various kinds of domestic animals. In recent years portable heart rate meters have been developed, and used in studies of exercising horses [1,2,14], but they cannot measure the R-R interval, and also cannot be connected to another measuring apparatus.…”

Diurnal Rhythms of R-R Interval and R-R Interval Variability in the Young Thoroughbred Horse.

“…The fluctuation in the heart rate has many types of periodicity such as circadian and ultradian rhythms, and indicates the variability of the balance between sympathetic and parasympathetic nervous activity in humans [13,18]. We have already reported a periodic analysis of the diurnal rhythm of the equine heart rate by means of maximum entropy spectral analysis (MESA) [17]. As MESA is able to detect the characteristics of the fluctuation in the diurnal rhythm of the heart rate, we expected that the frequency and power calcu-lated from the MESA spectrum reflect the autonomic nervous function.…”