Spectral Analysis of Heart Rate Without Resampling
Harvard-M.I.T. Division of Health Sciences and Technology, Cambridge, MA, USA
| This article originally appeared
in Computers in Cardiology 1993, vol. 20, pp. 715-718 (IEEE Computer
Society Press). Please cite this publication when referencing this material.
Also available are PostScript and PDF versions of this article, a portable C implementation of the
spectral analysis algorithm described below, and a brief user's guide. The algorithm for
deriving instantaneous heart rate, as provided in the article (following the
bibliography) is a simplified version of ihr, for which a brief user's guide is available here.
Standard methods of estimating the power spectral density (PSD)
of irregularly sampled signals such as instantaneous heart rate (HR)
require resampling at uniform intervals and replacement of unusable
samples. The Lomb periodogram is a means of obtaining PSD estimates
directly from irregularly sampled time series, avoiding these
requirements. This paper compares Fourier, autoregressive, and Lomb
PSD estimates from synthetic, real, and noise-corrupted real heart
rate time series, and examines systematic differences among these
estimates. An algorithm is presented for obtaining a heart rate time
series suitable for Lomb PSD estimation from an RR interval time
series with included ectopic beats and erroneous measurements. The
paper concludes with a brief survey of other applications of the
technique, such as estimation of respiratory frequency from a time
series of beat-by-beat measurements of the mean electrical axis.
George B. Moody