Diet-Induced Metabolic Syndrome Reduced Heart Rate Variability and Increased Irregularity and Complexity of Short-Term RR Time Series in Rabbits

Metabolic syndrome (MetS) has been linked to a higher prevalence of sudden cardiac death (SCD), but the mechanisms are not well understood. One possible underlying mechanism may be an abnormal modulation of autonomic activity, which can be quantified by analyzing heart rate variability (HRV). Our aim was to investigate the modifications of short-term HRV in an experimental rabbit model during the time-course of MetS development. NZW rabbits were randomly assigned to a control (n = 10) or a MetS group (n = 13), fed 28 weeks with control or high-fat, high-sucrose diets. After anesthesia, a 15-min ECG recording was acquired before diet administration and at weeks 14 and 28. We analyzed short RR time series using time-domain, frequency-domain and nonlinear analyses. A mixed-model factorial ANOVA was used for statistical analysis. Time-domain analysis showed a 52.4% decrease in the standard deviation of heart rate in animals from the MetS group at week 28, but no changes in the rest of parameters. In the frequency domain, we found a 9.7% decrease in the very low frequency and a 380.0% increase of the low frequency bands in MetS animals at week 28, whereas high frequency remained unchanged. Nonlinear analyses showed increased complexity and irregularity of the RR time series in MetS animals.

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EFFECT OF PHYSICAL ACTIVITIES ON HEART RATE VARIABILITY AND SKIN CONDUCTANCE

Biomedical Engineering Applications Basis and Communications ◽

10.4015/s1016237221500381 ◽

2021 ◽

pp. 2150038

Author(s):

Ankita Soni ◽

Kirti Rawal

Keyword(s):

Heart Rate ◽

Heart Rate Variability ◽

Frequency Domain ◽

Skin Conductance ◽

Time Domain ◽

Low Frequency ◽

Physical Activities ◽

Rr Intervals ◽

Warm Up ◽

Frequency Domain Methods

The sympathetic and parasympathetic function of the Autonomic Nervous System[Formula: see text]ANS[Formula: see text] is the primary cause of the variations in Heart Rate and Skin Conductance[Formula: see text]SC[Formula: see text] during different physical activities. This paper aims to analyze the effect of different physical activities i.e. (a) Supine (b) Standing and (c) Warm-up, on Heart Rate Variability (HRV) and SC. The standard dataset of 18 subjects has been used to analyze the effect of physical activities on the HRV and SC. In the used dataset, the subjects are in supine, standing, and warm-up positions. The linear methods (time domain & frequency domain) of HRV are implemented on the standard dataset for analyzing the effect of physical activities. It has been observed with the analysis of the HRV that the mean value of time domain methods i.e. the NN interval’s standard deviation (SDNN), the successive RR interval’s root mean square (RMSSD), RR intervals with more than 50 ms differences in between them (NN50), percentage of successive RR intervals that have the difference of more than 50 ms (pNN50) are decreased and the value of Heart rate (HR) increased when the activity has been changed from supine to standing and standing to the warm-up positions. The value of frequency domain methods, such as low frequency (LF) and the ratio of low and high frequency (LF/HF) increased, while the value of HF decreases as activity changes from supine to standing and from supine to warm-up position. Further, the increment is also observed in the value of SC when activity is switched from supine to standing and from standing to the warm-up position. It is concluded from the results that there is a significant decrement that is observed in the value of HRV, while the increment is observed in the value of SC and HR. Decrement of HRV reflects that the sympathetic activity is increased as activity changed from supine to standing and further from standing to warm-up positions.

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Short-term Heart Rate Variability Analysis in Healthy Dogs of Different Ages

Acta Scientiae Veterinariae ◽

10.22456/1679-9216.118578 ◽

2022 ◽

Vol 50 ◽

Author(s):

Luciene Maria Martinello Romão ◽

Amanda Sarita Cruz Aleixo ◽

Felipe Gazza Romão ◽

Mayra De Castro Ferreira Lima ◽

Miriam Tsunemi ◽

...

Keyword(s):

Heart Rate ◽

Heart Rate Variability ◽

Frequency Domain ◽

Time Domain ◽

Age Groups ◽

The Other ◽

Short Term ◽

Heart Rate Monitor ◽

Rr Intervals ◽

Healthy Dogs

Background: The modulation of heart rate by autonomic nervous system may be evaluated by the heart rate variability (HRV), which illustrates the fluctuations between RR intervals. To evaluate this analysis, the intervals between 2 QRS complexes are measured. In general, high HRV values are expected in healthy individuals; otherwise, low values are indicative of organism dysfunction. Studies conducted in healthy humans show that HRV suffers reduction with ageing and that there is autonomic immaturity in neonates. The aim of this study was to describe the characteristic pattern of cardiac autonomic behavior in healthy dogs in different age groups through short-term HRV analysis.Materials, Methods & Results: A total of 87 healthy dogs were studied. HRV was analyzed in time and frequency domain, using Holter and heart rate monitor. It was observed that puppies (below one year old) presented a lower parasympathetic predominance and, consequently, lower HRV values on time domain (SDNN, PNN50% e RMSSD) compared to the other 2 groups and on frequency domain (LF, HF and LF/HF) compared to the adult animals group (between 1 and 7-year-old), which presented higher HRV values when compared to the other groups. Elderly dogs (over 8-year-old) exhibited a natural tendency to decrease cardiac parasympathetic HRV indexes.Discussion: The use of the HRV method as a prognostic index and as an arrhythmogenic marker for various canine heart diseases presents interesting perspectives. However, before it may be employed for these purposes, a better understanding should be established regarding the physiological behavior of autonomic cardiac modulation in different age groups to serve as a basis for future analyses. This study observed that puppies presented higher values for HR and, therefore, shorter RR intervals than the other groups (adult and elderly dogs), what was observed on Holter and heart rate monitor methods (HRM). There were significant differences between puppies and the other 2 groups (adults and elderly) for all time-domain variables using both methods (Holter and HRM methods). SDNN was significantly lower in puppies compared to adults and elderly dogs. In addition, both RMSSD and PNN50%, which were more reliable over shorter periods of time, also presented means and medians that were significantly lower in puppies. Regarding frequency-domain HRV parameters observed on Holter method, these indexes were decreased on the elderly group compared to adult dogs, which is a possible effect of aging. Also, puppies revealed lower frequency-domain HRV parameters on both methods when compared to adult dogs. The influence of age on HRV is possibly related to the stage of development of an individual, starting at conception up to the maturity in relation to the mechanisms that cause variations in HR. There are studies in humans that suggest a gradual increase in parasympathetic activity during childhood, followed by a steady decrease as aging occur. The present study observed the same pattern in dogs. The balance between sympathetic and parasympathetic systems is influenced by age in dogs, which alters HRV values in the short-term. The HRV method´s analysis is relatively simple and non-invasive for assessing cardiac autonomic function; also, it is widely used in human medicine as a risk measure for sudden cardiac death. The 24-hour HRV analysis is highly challenging, as it is time-consuming, expensive, delays diagnosis, and has a large number of artifacts; in this way, standards for its short-term analysis were developed. Keywords: cardiology, autonomic nervous system, heart rate monitor, Holter.

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Validity of a Smartphone Application and Chest Strap for Recording RR Intervals at Rest in Athletes

International Journal of Sports Physiology and Performance ◽

10.1123/ijspp.2019-0406 ◽

2020 ◽

Vol 15 (6) ◽

pp. 896-899

Author(s):

Reabias de A. Pereira ◽

José Luiz de B. Alves ◽

João Henrique da C. Silva ◽

Matheus da S. Costa ◽

Alexandre S. Silva

Keyword(s):

Heart Rate ◽

Heart Rate Variability ◽

Frequency Domain ◽

Time Domain ◽

High Frequency ◽

Low Frequency ◽

Smartphone Application ◽

Smartphone App ◽

Heart Rate Variability Analysis ◽

Rr Intervals

Objective: To evaluate the accuracy of the smartphone application (app) HRV Expert (CardioMood) and a chest strap (H10 Polar) for recording R-R intervals compared with electrocardiogram (ECG). Methods: A total of 31 male recreational runners (age 36.1 [6.3] y) volunteered for this study. R-R intervals were recorded simultaneously by the smartphone app and ECG for 5 minutes to analyze heart-rate variability in both the supine and sitting positions. Time-domain indexes (heart rate, mean R-R, SD of RR intervals, count of successive normal R-R intervals differing by more than 50 ms, percentage of successive normal R-R intervals differing by more than 50 ms, and root mean square of successive differences between normal R-R intervals), frequency-domain indexes (low frequency, normalized low frequency, high frequency, normalized high frequency, low-frequency to high-frequency ratio, and very low frequency), and nonlinear indexes (SD of instantaneous beat-to-beat variability and long-term SD of continuous R-R intervals) were compared by unpaired t test, Pearson correlation, simple linear regression, and Bland–Altman plot to evaluate the agreement between the devices. Results: High similarity with P value varying between .97 and 1.0 in both positions was found. The correlation coefficient of the heart-rate-variability indexes was perfect (r = 1.0; P = .00) for all variables. The constant error, standard error of estimation, and limits of agreement between ECG and the smartphone app were considered small. Conclusion: The smartphone app and chest strap provide excellent ECG compliance for all variables in the time domain, frequency domain, and nonlinear indexes, regardless of the assessed position. Therefore, the smartphone app replaces ECG for any heart-rate-variability analysis in runners.

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Daily Food Insecurity and Heart Rate Variability Among Healthy Low-Income Adults: A Longitudinal Pilot Study Over Two Seasonal Months

Current Developments in Nutrition ◽

10.1093/cdn/nzab035_026 ◽

2021 ◽

Vol 5 (Supplement_2) ◽

pp. 118-118

Author(s):

Nan Dou ◽

Muzi Na

Keyword(s):

Heart Rate ◽

Heart Rate Variability ◽

Pilot Study ◽

Food Insecurity ◽

Frequency Domain ◽

Low Income ◽

Time Domain ◽

Time Varying ◽

Short Term ◽

Stress Vulnerability

Abstract Objectives Food insecurity (FI) is prevalent among low-income adults and is related to increased stress. Heart rate variability (HRV) is associated with adverse health and a known indicator for stress vulnerability. However, the relationship between FI and HRV is unclear. Our study aims to study the associations between FI and ultra-short-term HRV (5 minutes) at daily basis. Methods A total of 22 healthy low-income adults were recruited in fall 2019 and 18 were followed up in winter 2020. Data on FI and HRV were collected over a 3-week-long wave in each surveyed month (2nd – 4th week). Daily FI was assessed using the adapted USDA adult module on the provided smartphones. Each day, a 5-minute heart rate was recorded using the Polar H7 sensor, yielding a number of HRV metrics in two domains. SDNN, Rmssd, and pNN50 are time-domain metrics quantifying the amount of variability in interbeat interval (the higher the ‘better’). LF/HF Ratio is a frequency-domain metrics estimating the distribution of power into frequency bands (the lower the ‘better’). The Time Varying Effect Models were used to estimate the association between daily FI and ultra-short-term HRV metrics as a function of study day. Results A total of 606 person-days (response rate = 72.1%) of data in FI and HRV was collected. In fall, higher FI score was significantly associated with lower lnRmssd at day 19 (b = −0.13) and 20 (b = −0.12), lower Pnn50 at day 20 (b = −0.13), and higher LF/HF ratio from day 1 to 5 (b ranges 0.29–0.88). In winter, higher FI score was related to lower lnRmssd at day 18 (b = −0.24) and 19 (b = −0.27), lower Pnn50 from day 17 to 19 (b ranges −10.99 to −7.79), and higher LF/HF ratio from day 9 to 11 (b ranges 0.78–1.22) and day 18 to 20 (b ranges 1.17–2.40). Conclusions Across the 2 months spanning two seasons, our pilot study found that daily FI was significantly and consistently associated with suboptimal time-domain HRV metrics in the last few days of the study months. Results for the frequency-domain also support a time-varying impact of FI on HRV. The preliminary results support a potential more profound impact of FI on stress vulnerability, particularly by the end of the months. Funding Sources The National Center for Advancing Translational Sciences, National Institutes of Health (UL1TR002014) and the Broadhurst Career Development Professorship for the Study of Health Promotion and Disease Prevention.

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Effects of exercise on heart rate variability by time-domain, frequency-domain and non-linear analyses in equine athletes

F1000Research ◽

10.12688/f1000research.17997.1 ◽

2019 ◽

Vol 8 ◽

pp. 147 ◽

Cited By ~ 1

Author(s):

Ka Hou Christien Li ◽

Rachel Wing Chuen Lai ◽

Yimei Du ◽

Vivian Ly ◽

David Chun Yin Li ◽

...

Keyword(s):

Heart Rate ◽

Heart Rate Variability ◽

Frequency Domain ◽

Time Domain ◽

High Frequency ◽

Low Frequency ◽

Total Power ◽

Series Data ◽

Non Linear ◽

Term Fluctuation

Background: Heart rate variability (HRV) is an intrinsic property that reflects autonomic balance and has been shown to be predictive of all-cause and cardiovascular mortality. It can be altered by physiological states such as exercise or pathological conditions. However, there are only a handful of studies on HRV in horses. The aim of this study is to compare HRV parameters before and during exercise in horses. Methods: Time-domain, frequency-domain and non-linear analyses were applied to quantify time series data on RR intervals before and during exercise in horses (n=7). Results: Exercise increased heart rate from 44±8 to 113±17 bpm (ANOVA, P<0.05) and decreased standard deviation (SD) from 7±2 to 4±2 bpm, coefficient of variation (CoV) from 16±4% to 3±2% and root mean square of successive RR interval differences (RMSSD) from 89.4±91.5 to 6.5±3.7 ms. Contrastingly, no difference in low-frequency (0.10±0.03 vs. 0.09±0.03 Hz) and high-frequency (0.19±0.03 vs. 0.18±0.03 Hz) peaks, nor in their percentage powers (2±1 vs. 4±5%; 59±9 vs. 64±20%; 39±10 vs. 32±19%) were observed but very low-frequency, low-frequency, and high-frequency powers (ms2) were reduced from 29±17 to 2±5, 1138±372 to 22±22 and 860±564 to 9±6, respectively, as was total power (in logarithms) (7.52±0.52 to 3.25±0.73). Poincaré plots of RRn+1 against RRn revealed similar ellipsoid shapes before and after exercise. The SD along the line-of-identity (SD2) and SD perpendicular to the line-of-identity (SD1) were decreased by exercise (62±17 vs. 9±5 and 63±65 vs. 5±3), corresponding to increased SD2/SD1 ratio from 1.33±0.45 to 2.19±0.72. No change in approximate and sample entropy was detected (0.97±0.23 vs. 0.82±0.22 and 1.14±0.43 vs. 1.37±0.49). Detrended fluctuation analysis revealed unaltered short-term fluctuation slopes (0.76±0.27 vs. 1.18±0.55) but increased long-term fluctuation slopes (0.16±0.11 vs. 0.50±0.16) after exercise. Conclusion: Exercise leads to a decrease in HRV but did not affect signal entropy in horses.

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Abstract P019: Insulin resistance indexes and lower heart rate variability in older adults: the Atherosclerosis Risk in Communities Study (ARIC)

Circulation ◽

10.1161/circ.137.suppl_1.p019 ◽

2018 ◽

Vol 137 (suppl_1) ◽

Author(s):

Anna K Poon ◽

Eric Whitsel ◽

Gerardo Heiss ◽

Elsayed Soliman ◽

Lynne Wagenknecht ◽

...

Keyword(s):

Insulin Resistance ◽

Heart Rate ◽

Heart Rate Variability ◽

Frequency Domain ◽

Time Domain ◽

Low Frequency ◽

Poor Quality ◽

Model Assessment ◽

Lower Heart Rate ◽

Cardiac Autonomic Dysfunction

Introduction: Lower heart rate variability (HRV) is an indicator of cardiac autonomic dysfunction which is associated with cardiovascular disease in diabetes. Whether pre-diabetes insulin resistance contributes to lower HRV is not clear; insulin resistance (IR) indexes reflect different aspects of IR, including dysregulation of glucose, insulin, and lipids. We hypothesized that IR indexes are inversely associated with HRV. Methods: We analyzed 48-hour ambulatory electrocardiograms on 759 adults in a sample of the ARIC Study, excluding diabetes, antiarrhythmic medications, and missing/poor quality recordings. Insulin resistance indexes were defined as quartiles for the homeostatic model assessment of insulin resistance (HOMA-IR), triglyceride to HDL-C ratio (TG/HDL-C), and triglyceride-glucose index (TyG). Low HRV was defined as <25 th percentile for time domain measures -- including the standard deviation of all NN intervals (SDNN) and square root of the mean squared differences of successive NN intervals (RMSSD), and frequency domain measures -- including the high-frequency (HF) and low-frequency (LF) spectral components. Logistic regression with weights for sampling and nonresponse was used to estimate odds ratios and 95% confidence intervals (OR, 95% CI). Results: Mean age was 75 years [993 (63%) women, 688 (43%) African American]. The following results are reported for TyG. For time domain measures, high IR indexes were significantly associated with low SDNN (OR 1.83, 95% CI 1.09, 3.07), but not with low RMSSD (OR 1.48, 95% CI 0.89, 2.46). For frequency domain measures, high IR indexes were not associated with low HF (OR 1.62, 95% CI 0.96, 2.74), but significantly associated with low LF (OR 1.95, 95% CI 1.15, 3.30). Although results for other indexes were in the same direction, most were not statistically significant. Conclusions: Insulin resistance indexes may be inversely associated with HRV. An understanding of this relationship informs public health strategies for prevention of cardiovascular risk.

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Algogen-induced vasosensory reflexes modulate short-term heart rate variability parameters in experimental rat models

Journal of Basic and Clinical Physiology and Pharmacology ◽

10.1515/jbcpp-2020-0361 ◽

2021 ◽

Vol 0 (0) ◽

Author(s):

Ravindran Revand ◽

Sanjeev K. Singh

Keyword(s):

Heart Rate ◽

Heart Rate Variability ◽

Frequency Domain ◽

Time Domain ◽

Inflammatory Mediators ◽

Saline Control ◽

Short Term ◽

Rat Models ◽

Reflex Responses

Abstract Objectives The present work was designed to study the modulatory effects of algogen-induced vasosensory reflex responses on short-term heart rate variability (HRV) parameters in naïve and vagotomized rat models. Methods In this study, vasosensory reflex responses were elicited by instilling algogens (bradykinin/histamine), a component of inflammatory mediators into a local segment of medium-sized peripheral blood vessel (femoral artery) while a continuous electrocardiogram (ECG) was recorded. Short-term (5 min) ECG segments obtained from original recordings were examined in detail and relevant data of HRV parameters were pooled. Time domain and frequency domain analyses were performed using dedicated software (LabChart 8, AD Instruments®, Australia) and results were analyzed. Results Bradykinin-induced vasosensory reflexes caused significant alterations in both time domain and frequency domain HRV parameters as compared to the time-matched saline control group. Instillation of bradykinin caused a transient increase in NN interval, RMSSD, TSP, HF power (HFP) along with a decrease in the standard deviation of all normal NN intervals (SDNN), SDNN/RMSSD, LF power (LFP), LFP/HFP. Histamine produced a similar pattern of responses, but HRV alterations were less pronounced compared to those with bradykinin. Further analysis revealed that algogen-induced vasosensory reflex responses caused an increase in the parasympathetic influence on the heart accompanied by a decrease in sympathetic influence. In addition, HRV modulation by algogen-induced vasosensory reflexes was significantly attenuated in vagotomized rats, illustrating the principal role of vagus in the reflex HRV modulation. Conclusions The present study proposes a novel hypothesis regarding the cardio-protective role of inflammatory mediators during acute stress, by potentiating the vagal impact and attenuating the sympathetic impact on the heart.

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HEART RATE VARIABILITY RELATED TO N95 RESPIRATOR USE IN INTERNS DURING COVID-19 PANDEMIC

10.36106/ijsr/4308359 ◽

2021 ◽

pp. 69-70

Author(s):

Pakanati Sujana ◽

Venkata Mahesh Gandhavalla ◽

K. Prabhakara Rao

Keyword(s):

Heart Rate ◽

Heart Rate Variability ◽

Low Frequency ◽

Protective Equipment ◽

Short Term ◽

Non Invasive ◽

Critical Components ◽

The Individual ◽

N95 Respirators ◽

Respiratory Droplets

Introduction: COVID19 is caused by SARS-CoV-2 which is primarily transmitted through respiratory droplets and contact routes. WHO recommended the use of personal protective equipment (PPE) for prevention and N95 respirators are critical components of PPE. Breathing through N95 respirator will impart stress in the individual and that can be assessed by heart rate variability (HRV). HRV measures the variation in time between each heartbeat controlled by autonomic nervous system (ANS), which is a non invasive reliable index to identify the ANS imbalances. Aims And Objectives: This study is aimed at assessing the HRV of Interns working in COVID19 wards using N95 respirators. Methodology: This study included 100 interns in whom short term HRV was recorded using the standard protocol. Lead II of ECG was recorded using AD instruments (ADI) 8channel polygraph and HRV was analysed using Labchart 8pro software. The recordings were taken before and 1hour after wearing N95 respirator. Results: Overall HRV (SDRR) was found to decrease signicantly after wearing N95 respirator for 1hr (p=0.000). Similarly, indices representing the parasympathetic component ( RMSSD and HF ) were also found to decrease signicantly with the use of N95 respirator. Low frequency (LF) power and LF/HF ratio increased signicantly with N95 respirator use (p=0.000). Conclusion: We conclude that using N95 respirator increased sympathetic activity reecting decreased HRV in our subjects Hence we recommend that it is better to change the duty pattern for interns.

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Heart Rate Variability and Cardiovascular Reflex Tests for Assessment of Autonomic Functions in Preeclampsia

International Journal of Hypertension ◽

10.1155/2018/8163824 ◽

2018 ◽

Vol 2018 ◽

pp. 1-7 ◽

Cited By ~ 3

Author(s):

Meenakshi Chaswal ◽

Raj Kapoor ◽

Achla Batra ◽

Savita Verma ◽

Bhupendra S. Yadav

Keyword(s):

Heart Rate ◽

Heart Rate Variability ◽

Pregnant Women ◽

Frequency Domain ◽

Low Frequency ◽

Normal Pregnancy ◽

Total Power ◽

Autonomic Functions ◽

Cardiovascular Reflex ◽

Cardiovascular Reflex Tests

Alterations in the autonomic cardiovascular control have been implicated to play an important etiologic role in preeclampsia. The present study was designed to evaluate autonomic functions in preeclamptic pregnant women and compare the values with normotensive pregnant and healthy nonpregnant controls. Assessment of autonomic functions was done by cardiovascular reflex tests and by analysis of heart rate variability (HRV). Cardiovascular reflex tests included deep breathing test (DBT) and lying to standing test (LST). HRV was analyzed in both time and frequency domain for quantifying the tone of autonomic nervous system to the heart. The time domain measures included standard deviation of normal R-R intervals (SDNN) and square root of mean squared differences of successive R-R intervals (RMSSD). In the frequency domain we measured total power (TP), high frequency (HF) power, low frequency (LF) power, and LF/HF ratio. Cardiovascular reflex tests showed a significant parasympathetic deficit in preeclamptic women. Among parameters of HRV, preeclamptic group had lower values of SDNN, RMSSD, TP, HF, and LF (ms2) and higher value of LF in normalised units along with high LF/HF ratio compared to normotensive pregnant and nonpregnant controls. Furthermore, normotensive pregnant women had lower values of SDNN, TP, and LF component in both absolute power and normalised units compared to nonpregnant females. The results confirm that normal pregnancy is associated with autonomic disturbances which get exaggerated in the state of preeclampsia.

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