Influence of Heart Rate in Non-linear HRV Indices as a Sampling Rate Effect Evaluated on Supine and Standing

Abstract

The purpose of this study is to characterize and attenuate the influence of mean heart rate (HR) on nonlinear heart rate variability (HRV) indices (correlation dimension, sample, and approximate entropy) as a consequence of being the HR the intrinsic sampling rate of HRV signal. This influence can notably alter nonlinear HRV indices and lead to biased information regarding autonomic nervous system (ANS) modulation. First, a simulation study was carried out to characterize the dependence of nonlinear HRV indices on HR assuming similar ANS modulation. Second, two HR-correction approaches were proposed: one based on regression formulas and another one based on interpolating RR time series. Finally, standard and HR-corrected HRV indices were studied in a body position change database. The simulation study showed the HR-dependence of non-linear indices as a sampling rate effect, as well as the ability of the proposed HR-corrections to attenuate mean HR influence. Analysis in a body position changes database shows that correlation dimension was reduced around 21% in median values in standing with respect to supine position (p < 0.05), concomitant with a 28% increase in mean HR (p < 0.05). After HR-correction, correlation dimension decreased around 18% in standing with respect to supine position, being the decrease still significant. Sample and approximate entropy showed similar trends. HR-corrected nonlinear HRV indices could represent an improvement in their applicability as markers of ANS modulation when mean HR changes.

Heart Rate Variability during Acupuncture Treatment of Lumbosacral Pain

“…This implies that a physiological correlation exists between HRV and HR. However, in a simulation study, it was demonstrated that the changes in the ANS modulation should be independent of the changes in the mean HR [7]. This is consistent with the findings of the present study.…”

Nocturnal Heart Rate Variability Spectrum Characterization in Preschool Children With Asthmatic Symptoms

“…where ∆f is twice the resolution of Hamming window, ∆f = 2.6 Fs N , being F s the sampling frequency and N the number of samples of the window (50 seg ×4 samples/seg = 200 samples). The limits of [0.15-HR/2] Hz are imposed in order to ensure that no power from the LF band or from components with uncertain origin are considered (HR/2 Hz is the highest frequency we can represent in HRV spectrum, as HR is the intrinsic sampling frequency of HRV [34]).…”

“…2, the lower frequency bound of the classical band could be inadequate when some not welldefined components (mid-frequency band [33]) are present, as power with an origin distinct from parasympathetic activity will contaminate the HF band. In addition, the upper bound of 0.4 Hz could be not enough when respiratory rate is high as some HF power will leak out of the band (young children present high respiratory rates [38]), so HR/2 was considered as it is the highest representable frequency in HRV spectrum, due to the fact that HR is the intrinsic sampling frequency of HRV [34]. Table II show statistical significant differences between LoR and HiR in ℘ IP HRV , R LF/HF and P LFn , thus suggesting a peakier component in the HF band accompanied by a reduced sympathovagal balance in HiR.…”

Pulse Rate and Transit Time Analysis to Predict Hypotension Events After Spinal Anesthesia During Programmed Cesarean Labor

“…Sympathetic and parasympathetic regulations are related to the HRV content analyzed in low (0.04-0.15 Hz) and high (0.15-0.4 Hz) frequency bands, respectively, during relax conditions in adult healthy subjects 1 . Furthermore, nonlinear HRV assessment relates changes on sympathovagal balance to regularity and complexity of ANS 8 .…”