Refined Multiscale Fuzzy Entropy to Analyse Post-Exercise Cardiovascular Response in Older Adults With Orthostatic Intolerance.

Marcos Hortelano,Francisco Castells,Richard B Reilly,Raquel Cervigón

doi:10.3390/e20110860

Marcos Hortelano, Francisco Castells + Show 2 more

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https://doi.org/10.3390/e20110860

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Abstract

Orthostatic intolerance syndrome occurs when the autonomic nervous system is incapacitated and fails to respond to the demands associated with the upright position. Assessing this syndrome among the elderly population is important in order to prevent falls. However, this problem is still challenging. The goal of this work was to determine the relationship between orthostatic intolerance (OI) and the cardiovascular response to exercise from the analysis of heart rate and blood pressure. More specifically, the behavior of these cardiovascular variables was evaluated in terms of refined composite multiscale fuzzy entropy (RCMFE), measured at different scales. The dataset was composed by 65 older subjects, 44.6% (n = 29) were OI symptomatic and 55.4% (n = 36) were not. Insignificant differences were found in age and gender between symptomatic and asymptomatic OI participants. When heart rate was evaluated, higher differences between groups were observed during the recovery period immediately after exercise. With respect to the blood pressure and other hemodynamic parameters, most significant results were obtained in the post-exercise stage. In any case, the symptomatic OI group exhibited higher irregularity in the measured parameters, as higher RCMFE levels in all time scales were obtained. This information could be very helpful for a better understanding of cardiovascular instability, as well as to recognize risk factors for falls and impairment of functional status.

Highlights

Orthostatic intolerance (OI) is characterized by the development of symptoms such as lightheadedness, sweatiness, nausea, cold, clamminess, dizziness, fatigue, lethargy, palpitations, and blurred vision prior to the fall during standing
We propose to apply non-linear methods to analyze blood pressure (BP) and heart rate (HR) response
We tested the different parameters measures along phases in both groups, only the parameters represented in Figure 2, HR and CO, showed any statistical significant differences between both groups

Summary

Introduction

Orthostatic intolerance (OI) is characterized by the development of symptoms such as lightheadedness, sweatiness, nausea, cold, clamminess, dizziness, fatigue, lethargy, palpitations, and blurred vision prior to the fall during standing. Improved OI assessment is a challenge of clinical importance. This syndrome is a consequence of a complex multifactorial pathophysiology that involves cardiovascular instability with an unusual autonomic nervous system response or alterations in cerebral blood flow [4,5,6]. Among several causes, it is most commonly caused by orthostatic hypotension (OH)

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