Comparison of different threshold values r for approximate entropy: application to investigate the heart rate variability between heart failure and healthy control groups

Liu, Chengyu, Liu, Changchun, Shao, Peng, Li, Liping, Sun, Xin, Wang, Xinpei and Liu, Feng (2011) Comparison of different threshold values r for approximate entropy: application to investigate the heart rate variability between heart failure and healthy control groups. Physiological Measurement, 32 2: 167-180. doi:10.1088/0967-3334/32/2/002


Author Liu, Chengyu
Liu, Changchun
Shao, Peng
Li, Liping
Sun, Xin
Wang, Xinpei
Liu, Feng
Title Comparison of different threshold values r for approximate entropy: application to investigate the heart rate variability between heart failure and healthy control groups
Journal name Physiological Measurement   Check publisher's open access policy
ISSN 0967-3334
Publication date 2011-02-01
Year available 2010
Sub-type Article (original research)
DOI 10.1088/0967-3334/32/2/002
Open Access Status Not yet assessed
Volume 32
Issue 2
Start page 167
End page 180
Total pages 14
Place of publication United Kingdom
Publisher Institute of Physics Publishing Ltd.
Language eng
Subject 1304 Biophysics
1314 Physiology
2204 Biomedical Engineering
2737 Physiology (medical)
Abstract Approximate entropy (ApEn) is widely accepted as a complexity measure of the heart rate variability (HRV) signal, but selecting the criteria for the threshold value r is controversial. This paper aims to verify whether Chon's method of forecasting the r is an appropriate one for the HRV signal. The standard limb lead ECG signals of 120 subjects were recorded for 10 min in a supine position. The subjects were divided into two groups: the heart failure (22 females and 38 males, median age 62.4 ± 12.6) and healthy control group (33 females and 27 males, median age 51.5 ± 16.9). Three types of ApEn were calculated: the ApEn0.2 using the recommended constant r = 0.2, the ApEnchon using Chon's method and the ApEn using the true r. A Wilcoxon rank sum test showed that the ApEn (p = 0.267) and the ApEn (p = 0.813) had no statistical differences between the two groups, while the ApEn (p = 0.040) had. We generated a synthetic database to study the effect of two influential factors (the signal length N and the ratio of short-and long-term variability sd /sd) on the empirical formula in Chon's method (Chon et al 2009 IEEE Eng. Med. Biol. Mag. 28 18-23). The results showed that the empirical formula proposed by Chon et al is a good method for analyzing the random signal, but not an appropriate tool for analyzing nonlinear signals, such as the logistic or HRV signals.
Formatted abstract
Approximate entropy (ApEn) is widely accepted as a complexity measure of the heart rate variability (HRV) signal, but selecting the criteria for the threshold value r is controversial. This paper aims to verify whether Chon's method of forecasting the rmax is an appropriate one for the HRV signal. The standard limb lead ECG signals of 120 subjects were recorded for 10 min in a supine position. The subjects were divided into two groups: the heart failure (22 females and 38 males, median age 62.4 ± 12.6) and healthy control group (33 females and 27 males, median age 51.5 ± 16.9). Three types of ApEn were calculated: the ApEn0.2 using the recommended constant r = 0.2, the ApEnchon using Chon's method and the ApEnmax using the true rmax. A Wilcoxon rank sum test showed that the ApEn0.2 (p = 0.267) and the ApEnmax (p = 0.813) had no statistical differences between the two groups, while the ApEnchon (p = 0.040) had. We generated a synthetic database to study the effect of two influential factors (the signal length N and the ratio of short-and long-term variability sd 1/sd2) on the empirical formula in Chon's method (Chon et al 2009 IEEE Eng. Med. Biol. Mag. 28 18-23). The results showed that the empirical formula proposed by Chon et al is a good method for analyzing the random signal, but not an appropriate tool for analyzing nonlinear signals, such as the logistic or HRV signals. © 2011 Institute of Physics and Engineering in Medicine.

Language of original document
Keyword Approximate entropy
Heart rate variability
Different threshold values r for ApEn
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: Official 2011 Collection
School of Information Technology and Electrical Engineering Publications
 
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Created: Sun, 27 Feb 2011, 10:03:15 EST