HRV analysis: undependability of approximate entropy at locating optimum complexity in malnourished children

Abstract

Introduction: Approximate Entropy is an extensively enforced metric to evaluate chaotic responses and irregularities of RR intervals sourced from an eletrocardiogram. However, to estimate their responses, it has one major problem – the accurate determination of tolerances and embedding dimensions. So, we aimed to overt this potential hazard by calculating numerous alternatives to detect their optimality in malnourished children. Materials and methods: We evaluated 70 subjects split equally: malnourished children and controls. To estimate autonomic modulation, the heart rate was measured lacking any physical, sensory or pharmacologic stimuli. In the time series attained, Approximate Entropy was computed for tolerance (0.1→0.5 in intervals of 0.1) and embedding dimension (1→5 in intervals of 1) and the statistical significances between the groups by their Cohen’s ds and Hedges’s gs were totalled. Results: The uppermost value of statistical significance accomplished for the effect sizes for any of the combinations was −0.2897 (Cohen’s ds) and −0.2865 (Hedges’s gs). This was achieved with embedding dimension = 5 and tolerance = 0.3. Conclusions: Approximate Entropy was able to identify a reduction in chaotic response via malnourished children. The best values of embedding dimension and tolerance of the Approximate Entropy to identify malnourished children were, respectively, embedding dimension = 5 and embedding tolerance = 0.3. Nevertheless, Approximate Entropy is still an unreliable mathematical marker to regulate this.

Chaotic Global Metric Analysis of Heart Rate Variability Following Six Power Spectral Manipulations in Malnourished Children

“…Methods and materials were exactly as in the studies by Barreto et al [1] and Garner et al [28]. Typically, 20-25 min of RR-intervals is sufficient for chaotic global analysis [25,29,30].…”

Monitoring Blood Pressure Variability via Chaotic Global Metrics using Local Field Potential Oscillations

“…Levels of chaotic response could be assessed alternatively by the fractal dimensions of Higuchi (Garner et al 2018;Nogueira et al 2017) or Katz (Garner et al 2018). Approximate (Garner et al 2021b;Pincus 1995) and Sample (Richman and Moorman 2000) entropies could be computed. However, the latter two are excessively reliant on their embedding dimensions and tolerances.…”

“…However, the latter two are excessively reliant on their embedding dimensions and tolerances. These cannot be attained in any systematic way which maintains them undependable (Garner et al 2021b(Garner et al ,a, 2020b. Also, they are usually enforced on the inter-beat intervals rather than just the oscillating signal as with chaotic global metrics.…”