Percentage Of Successive RR Intervals Research Articles

Comparison of Heart Rate Variability in Thai Older Adults with Hypertension, Pre-Hypertension, and Normotension.

This study aims to compare HRV variables across three cohorts: normotensive (NT), prehypertensive (pre-HT), and hypertensive (HT) and to assess the relationship between the blood pressure (BP) and HRV parameters. Employing a cross-sectional design, 64 older participants were categorized based on the Joint National Committee's criteria into NT (n = 10), pre-HT (n = 33), and HT (n = 21) groups. Anthropometric data, lipid profiles, and HRV indices were evaluated. HRV data were obtained from the Polar V800 chest strap device using HRV Kubios software for data analysis of short-term recordings lasting 10 minutes. This analysis encompasses both time and frequency domain assessments. The time domain includes the standard deviation of NN intervals (SDNN), the root mean square of successive RR interval differences (RMSSD), and the percentage of successive RR intervals differing by over 50 ms (pNN50). The frequency domain includes low frequency (LF), high frequency (HF), and the ratio of LF-to-HF power (LF/HF). Data were statistically analyzed via one-way analysis of variance (ANOVA) and Pearson correlation. The HT group exhibited significantly lower values in SDNN, pNN50, LF power, and HF power in comparison to the NT group (P < 0.05). Moreover, the HT group had a significantly lower SDNN value compared to the pre-HT group (P < 0.05). Inverse associations were uncovered between systolic and diastolic blood pressure and SDNN, pNN50, and HF power (P < 0.05). Multiple regression further highlighted the significance of systolic and pulse pressure concerning HF power (P < 0.05). HRV indices are reduced in Thai older adults with HT compared with those with NT. Monitoring HRV in older adults can provide valuable insights into autonomic function and cardiovascular disease risk.

Effect of oscillatory lower body negative pressure and isometric handgrip exercise on cardioautonomic tone of healthy individuals

Objectives: The influence of the autonomic nervous system on the heart can be quantified by assessing changes in the heart rate variability (HRV) during orthostatic challenge and exercise. However, the combination of oscillatory lower body negative pressure (oLBNP) and isometric handgrip exercise (IHE) on HRV has not been previously investigated. Therefore, the present study aimed to assess the effects of (oLBNP) at sympathetic (0.1 Hz) and parasympathetic (0.25 Hz) frequencies and IHE at 30% of maximum voluntary contraction (MVC) on HRV in normal healthy individuals. Materials and Methods: We conducted a cross-sectional study on 18 healthy male subjects. Beat-to-beat blood pressure, lead-II electrocardiogram, and oLBNP chamber pressure were recorded continuously during oLBNP at 0.1 and 0.25 Hz for 3 min each and IHE at 30% of MVC (for 4 min) along with oLBNP at 0.1 or 0.25 Hz (oLBNP was added in last 3 min) each followed by HRV analysis. Results: The oLBNP at 0.25 Hz reduced the root mean square of successive inter-beat (RR) interval differences significantly as compared to baseline values and came to normal during the recovery phase (P = 0.008). The absolute power of the high-frequency band (HF power), Poincaré plot standard deviation perpendicular to the line of identity (SD1), and percentage of successive RR intervals that differ by more than 50 ms (pNN50) were also reduced significantly during oLBNP at 0.25 Hz and when IHE at 30% of MVC (IHE) was added to oLBNP at 0.25 Hz as compared to baseline (P &lt; 0.05). Conclusion: oLBNP and IHE could be used as a non-invasive haemodynamic stressor to assess the neurocardiac axis and its mechanism of action during orthostatic stresses.

Head-to-Head Comparison of Electroacupuncture and Laser Acupuncture Effects on Autonomic Regulation and Clinical Effects in Dysmenorrhea: A Randomized Crossover Clinical Trial.

Introduction: Electroacupuncture (EA) has been applied in dysmenorrhea and has shown good efficacy. The mechanisms of EA are associated with autonomic nervous system adjustments and neuroendocrine regulation. Laser acupuncture (LA), however, has been widely investigated for its noninvasiveness. However, it remains uncertain whether LA is as effective as EA. This study aimed to compare EA and LA head to head in dysmenorrhea. Methods: A crossover, randomized clinical trial was conducted. EA or LA was applied to selected acupuncture points. Participants were randomized into two sequence treatment groups who received either EA or LA twice per week in luteal phase for 3 months followed by 2-month washout, then shifted to other groups (sequence 1: EA > LA; sequence 2: LA > EA). Outcome measures were heart rate variability (HRV), prostaglandins (PGs), pain, and quality-of-life (QoL) assessment (QoL-SF12). We also compared the effect of EA and LA in low and high LF/HF (low frequency/high frequency) status. Results: Totally, 43 participants completed all treatments. Both EA and LA significantly improved HRV activity and were effective in reducing pain (Visual Analog Scale [VAS]; EA: p < 0.001 and LA: p = 0.010) and improving QoL (SF12: EA: p < 0.001, LA, p = 0.017); although without intergroup difference. EA reduced PGs significantly (p < 0.001; δ p = 0.068). In low LF/HF, EA had stronger effects than LA in increasing parasympathetic tone in respect of percentage of successive RR intervals that differ by more than 50 ms (pNN50; p = 0.053) and very low-frequency band (VLF; p = 0.035). Conclusion: There is no significant difference between EA and LA in improving autonomic nervous system dysfunction, pain, and QoL in dysmenorrhea. EA is prominent in PGs changing and preserving vagus tone in low LF/HF; yet LA is noninvasive for those who have needle phobia. Whether LA is equivalent with EA and the mechanism warrants further study. Clinical trial identification number: NCT04178226.

Association of heart rate variability and C-reactive protein in patients with depression.

Depression has been shown to be correlated with cardiovascular (CV) morbidity and mortality. Inflammation and autonomic nervous system (ANS) dysfunction are possible causes. Numerous clinical studies have found an association between inflammatory pathways and the ANS. The aim of this study was to investigate the relationship between different heart rate variability (HRV) parameters and C-reactive protein (CRP) levels in depressed patients without concomitant diseases. Sixty-five depressed patients who were not taking medication participated in this cross-sectional study. The Tenth Revision of the International Classification of Diseases and Related Health Problems (ICD-10) categorization of mental and behavioral disorders served as the basis for the diagnosis of depression. HRV processing and analysis were performed using ADInstrument's Pro LabChart (PowerLab 8Pro) data analysis software. HRV was recorded for 5 min in an upright sitting position using a lead II electrocardiogram (ECG) (short-term HRV). CRP levels were measured using an ELISA (enzyme-linked immunosorbent assay) test. None of the measures of HRV showed a significant relationship with pulse rate, systolic blood pressure, diastolic blood pressure, or body mass index (BMI). Weight and BMI were strongly positively related (r = 0.420, P = 0.003) to pRR50 (percentage of successive RR intervals differing by more than 50 ms). Very low frequency (VLF), low frequency (LF), and the LF/HF (high frequency) ratio were all strongly positively correlated with CRP (r = 0.595, P = 0.001), whereas HF was also significantly negatively correlated (r = 0.383, P = 0.007). CRP had a significant negative correlation with the logarithm (ln) HF and a significant positive correlation with lnVLF, lnLF, and lnLF/HF. Measurement of resting HRV and CRP may be helpful in detecting CV disease in depressed patients. Low HRV and elevated serum CRP should prompt physicians to begin treatment for risk CV as soon as possible.

Atrial fibrillation organisation correlates with ventricular response regularity in patients with persistent atrial fibrillation

Abstract Background Atrial fibrillation (AF) is characterised by an irregularly irregular ventricular rhythm. However, the mechanisms by which the regularity of ventricular response is influenced by AF dynamics is yet to be understood. In AF, there is a spectrum of organisation of atrial electrical activity; from organised AF sustained by focal drivers through to disorganised AF sustained by multiple wavelet re-entry. We aimed to investigate whether the ventricular response in AF was associated with the organisation of atrial electrical activity, with the hypothesis that AF organisation correlates with ventricular response regularity. Methods We retrospectively reviewed data from 239 patients with persistent AF undergoing pulmonary vein isolation (PVI). In each patient both before and after ablation, AF organisation and measures of ventricular variability and irregularity were evaluated in 50s segments. Shannon entropy (ShEn) and Sample entropy (SampEn) derived from coronary sinus (CS) atrial electrograms were used to assess AF organisation. RR interval (RRI) metrics derived from the surface ECG were used to determine ventricular variability and irregularity. RRI variability was evaluated using the time-domain measures: normalised mean RRI difference, standard deviation of RRIs (SD RRI), normalised SD RRI, root mean square of successive RRI differences (rMSSD) and percentage of successive RR intervals that differ from each other by more than 50ms (pNN50). RRI irregularity was measured using SampEn and normalised SampEn. Results A significant decrease in atrial ShEn and SampEn was observed following PVI across all CS channels (e.g. SampEn CS 3-4: pre-ablation=0.907±0.512 vs post-ablation=0.790±0.447, p&amp;lt;0.0001). Both ShEn and SampEn from CS atrial electrograms were significantly correlated with the RRI variability and irregularity measures from surface ECG (pNN50, normalised mean RRI difference, normalised SD RRI and normalised SampEn) both pre- and post-ablation (pNN50: r=0.0771, p=0.00838, Figure 1; normalised mean RRI difference: r=0.144, p&amp;lt;0.0001; normalised SD RRI: r=0.175, p&amp;lt;0.0001; normalised SampEn: r=0.168, p&amp;lt;0.0001; correlations with SampEn CS 3-4 pre-ablation shown). Conclusion The reduction in atrial ShEn and SampEn following PVI suggests that an increase in AF organisation occurs with PVI. The significant correlations between atrial entropy and measures of RRI variability and irregularity suggest that AF organisation impacts ventricular response regularity. Therefore, interpretation of the RRI variability and irregularity from the surface ECG may give some insight, non-invasively, into the level of AF organisation.Figure 1

Effects of man-made electromagnetic fields on heart rate variability parameters of general public: a systematic review and meta-analysis of experimental studies.

The effects of man-made electromagnetic fields (EMFs) on the cardiovascular system have been investigated in many studies. In this regard, the cardiac autonomic nervous system (ANS) activity due to EMFs exposure, assessed by heart rate variability (HRV), was targeted in some studies. The studies investigating the relationship between EMFs and HRV have yielded conflicting results. We performed a systematic review and meta-analysis to assess the data's consistency and identify the association between EMFs and HRV measures. Published literature from four electronic databases, including Web of Science, PubMed, Scopus, Embase, and Cochrane, were retrieved and screened. Initially, 1601 articles were retrieved. After the screening, 15 original studies were eligible to be included in the meta-analysis. The studies evaluated the association between EMFs and SDNN (standard deviation of NN intervals), SDANN (Standard deviation of the average NN intervals for each 5 min segment of a 24 h HRV recording), and PNN50 (percentage of successive RR intervals that differ by more than 50 ms). There was a decrease in SDNN (ES=-0.227 [-0.389,-0.065], p=0.006), SDANN (ES=-0.526 [-1.001,-0.05], p=0.03) and PNN50 (ES=-0.287 [-0.549,-0.024]). However, there was no significant difference in LF (ES=0.061 (-0.267, 0.39), p=0.714) and HF (ES=-0.134 (0.581, 0.312), p=0.556). In addition, a significant difference was not observed in LF/HF (ES=0.079 (-0.191, 0.348), p=0.566). Our meta-analysis suggests that exposure to the environmental artificial EMFs could significantly correlate with SDNN, SDANN, and PNN50 indices. Therefore, lifestyle modification is essential in using the devices that emit EMs, such as cell phones, to decrease some signs and symptoms due to EMFs' effect on HRV.

0954 CORRELATION OF PULSE RATE VARIABILITY (PRV) AND HEART RATE VARIABILITY (HRV) METRICS DURING SLEEP IN SUBJECTS SUSPECTED OF OSA

Abstract Introduction Whether photoplethysmography (PPG)-derived pulse rate variability (PRV) metrics can be surrogates for ECG-derived heart rate variability (HRV) is a decade-long debate. Very few studies have assessed the performance of PRV metrics in wearables. We aimed to evaluate the performance of time- and frequency-domain PRV metrics derived from the Belun Ring (BR) in subjects suspected of sleep apnea. Methods Using Pearson’s correlation coefficient (PCC), we retrospectively analyzed the relationship between concurrent BR-PRV and PSG ECG-HRV metrics (standard deviation of NN intervals [SDNN], root mean square of successive RR interval differences [RMSSD], percentage of successive RR intervals that differ by more than 50 ms [PNN50], HF [high frequency] power, LF [low frequency] power, VLF [very low frequency] power, and LF/HF ratio) in 73 subjects suspected of OSA. Subgroup analyses were performed based on demographic information, OSA, co-morbidities, and HR-affecting medication status. Results Age (SD) 50.1 (13.4); female 68%; black 52%; BMI (SD) 36.1 (9.7); 56% OSA; mean AHI (SD) 14.7 (17.3). Nine (12%) subjects had significant arrhythmias (defined as having any arrhythmias in ≥25% of all 12-second segments.) Key findings: There was a unitary linear relationship between BR PPG-pulse rate and ECG-heart rate in the overall group. In those without significant arrhythmias (N=64), PRV-SDNN, PNN50, HF, LF, and VLF had excellent correlations (PCC ≥0.90) with corresponding HRV metrics in all subgroups. PRV-RMSSD and PRV-LF/HF also had a strong correlation (PCC ≥0.80) with ECG HRV-RMSSD and HRV-LF/HF in all subgroups except for LF/HF in the diabetes group. In those with significant arrhythmias (N=9), PRV performed less well, with most metrics having PCC &amp;lt; 0.90 or wide CI, except for PNN50. All PRV metrics had PCCs ≥0.90 in subjects on HR-affecting medications except for LF/HF. Conclusion BR-PRV metrics can serve as surrogates for ECG-HRV in patients suspected of OSA who do not have significant arrhythmias. PRV-RMSSD and LF/HF may be less robust than the rest of the PRV metrics but still showed strong correlations in most subgroups. BR-PRV can be a useful clinical and research tool in assessing autonomic nervous system function. Support (if any) This study is supported by a Grant from Belun Technology Company

A New Approach to Detecting Atrial Fibrillation Using Count Statistics of Relative Changes between Consecutive RR Intervals.

The ratio of the difference between neighboring RR intervals to the length of the preceding RR interval (x%) represents the relative change in the duration between two cardiac cycles. We investigated the diagnostic properties of the percentage of relative RR interval differences equal to or greater than x% (pRRx%) with x% in a range between 0.25% and 25% for the distinction of atrial fibrillation (AF) from sinus rhythm (SR). We used 1-min ECG segments with RR intervals with either AF (32,141 segments) or SR (32,769 segments) from the publicly available Physionet Long-Term Atrial Fibrillation Database (LTAFDB). The properties of pRRx% for different x% were analyzed using the statistical procedures and metrics commonly used to characterize diagnostic methods. The distributions of pRRx% for AF and SR differ significantly over the whole studied range of x% from 0.25% to 25%, with particularly outstanding diagnostic properties for the x% range of 1.5% to 6%. However, pRR3.25% outperformed other pRRx%. Firstly, it had one of the highest and closest to perfect areas under the curve (0.971). For pRR3.25%, the optimal threshold for distinction AF from SR was set at 75.32%. Then, the accuracy was 95.44%, sensitivity was 97.16%, specificity was 93.76%, the positive predictive value was 93.85%, the negative predictive value was 97.11%, and the diagnostic odds ratio was 514. The excellent diagnostic properties of pRR3.25% were confirmed in the publicly available MIT-BIH Atrial Fibrillation Database. In a direct comparison, pRR3.25% outperformed the diagnostic properties of pRR31 (the percentage of successive RR intervals differing by at least 31 ms), i.e., so far, the best single parameter differentiating AF from SR. A family of pRRx% parameters has excellent diagnostic properties for AF detection in a range of x% between 1.5% and 6%. However, pRR3.25% outperforms other pRRx% parameters and pRR31 (until now, probably the most robust single heart rate variability parameter for AF diagnosis). The exquisite pRRx% diagnostic properties for AF and its simple computation make it well-suited for AF detection in modern ECG technologies (mobile/wearable devices, biopatches) in long-term monitoring. The diagnostic properties of pRRx% deserve further exploration in other databases with AF.

Parasympathetic Versus Sympathetic Changes in Heart Rate Variability After a Multimodal Integrative Medicine Intervention for Frontline COVID-19 Personnel.

Frontline healthcare providers (HCPs) working in COVID-19 hospital departments need to deal with considerable physical and emotional stress on a daily basis. We conducted a pilot study to examine changes in heart rate variability (HRV) in frontline COVID-19 personnel after an integrative medicine (IM) intervention. HCPs working in isolated COVID-19 inpatient departments underwent a single 30-minute individually tailored IM sessions combining various IM modalities (acupuncture, mind-body, and/or manual-movement modalities, including anthroposophic medicine). HRV parameters were compared during the first IM session at 3-minute intervals, at the beginning of treatments, and after 20 minutes. Root mean square of successive RR interval differences (RMSSD) was measured, as were domains of time (standard deviation of NN intervals, percentage of successive RR intervals that differ by more than 50 milliseconds) and frequency (low frequency/high frequency [LF/HF] ratio). Preintervention and postintervention concerns were assessed using the Measure Yourself Concerns and Well-being questionnaire, with posttreatment free-text narratives analyzed for clusters of emotional- and spiritual-related keywords (ESKs). A total of 114 HCPs underwent an IM treatment session, and their HRV values were measured, of which 75 (65.8%) expressed ESKs. The RMSSD increased only in the ESK-expressing group ( p < .001). LF/HF ratios decreased in both groups, with HF power increasing in the ESK-expressing ( p = .043) and LF power decreasing in the non-ESK-expressing groups ( p = .004). Increased parasympathetic activity was observed in all HCPs after the IM intervention, particularly among those expressing ESKs. LF/HF parameters suggest different relaxation-associated mechanisms, with increased HF (regulated predominantly by parasympathetic tone) in the ESK-expressing and decreased LF (regulated partially by sympathetic tone) in the nonexpressing group. Additional research needs to explore the relationship between subjective effects of the IM intervention and physiological mechanisms of relaxation in HCPs working in stressful environments. ClinicalTrials.gov identifier NCT05104827.

Statistical and Diagnostic Properties of pRRx Parameters in Atrial Fibrillation Detection.

Background: We studied the diagnostic properties of the percentage of successive RR intervals differing by at least x ms (pRRx) as functions of the threshold value x in a range of 7 to 195 ms for the differentiation of atrial fibrillation (AF) from sinus rhythm (SR). Methods: RR intervals were measured in 60-s electrocardiogram (ECG) segments with either AF (32,141 segments) or SR (32,769 segments) from the publicly available Physionet Long-Term Atrial Fibrillation Database (LTAFDB). For validation, we have used ECGs from the Massachusetts Institute of Technology–Beth Israel Hospital (MIT–BIH) Atrial Fibrillation Database. The pRRx distributions in AF and SR in relation to x were studied by histograms, along with the mutual association by the nonparametric Spearman correlations for all pairs of pRRx, and separately for AF or SR. The optimal cutoff values for all pRRx were determined using the receiver operator curve characteristic. A nonparametric bootstrap with 5000 samples was used to calculate a 95% confidence interval for several classification metrics. Results: The distributions of pRRx for x in the 7–195 ms range are significantly different in AF than in SR. The sensitivity, specificity, accuracy, and diagnostic odds ratios differ for pRRx, with the highest values for x = 31 ms (pRR31) rather than x = 50 (pRR50), which is most commonly applied in studies on heart rate variability. For the optimal cutoff of pRR31 (68.79%), the sensitivity is 90.42%, specificity 95.37%, and the diagnostic odds ratio is 194.11. Validation with the ECGs from the MIT–BIH Atrial Fibrillation Database confirmed our findings. Conclusions: We demonstrate that the diagnostic properties of pRRx depend on x, and pRR31 outperforms pRR50, at least for ECGs of 60-s duration.

Retrospective analysis of autonomic dysfunction in epilepsy patients from neurophysiological recordings

Autonomic dysfunction is often associated with seizures in patients with epilepsy. Autonomic dysfunction during seizures can cause serious events like cardiac arrest and sudden unexplained death. Early detection of autonomic dysfunction is crucial to avoid such medical emergencies. In our study, we analyzed the heart rate variability (HRV) in physiological recording during the preictal, ictal and postictal periods. A total of 142 seizures with various semiologies recorded from 49 epilepsy patients were included. Time-domain measurements including mean hear rate (HR), RR interval (RRI), root-mean-square of successive R-R interval differences (RMSSD), The standard deviation of N-N intervals (SDNN) and percentage of successive RR intervals that differ by more than 50 ms(pNN50) were analyzed at different time points, 20 minutes before the seizure, 1 minute before the seizure, during the seizure and 20 minutes after the seizure. We observed there was a significant difference in HRV parameters during and just before the seizure onset (RMSSD with p-value&lt;0.001 and SDNN with p-value&lt;0.001). We also observed that there was a suppression of parasympathetic activity and activation of sympathetic stimulation in the ictal and peri-ictal period, which was characterized by an elevation in the mean heart rate (HR), whereas the mean RRI showed an inversely proportional trend. There was a reduction in mean RMSSD, SDNN and pNN50 prior to seizure onset and was more pronounced in generalized seizures as compared to focal seizures with preserved or impaired awareness. There was a greater sympathetic activation and parasympathetic inhibition during an epileptic seizure in females as compared to male patients. These findings suggest that autonomic dysregulation was increased during a generalized seizure when compared to a focal seizure. HRV analysis can be used as a valid method for quantifying central influences on the autonomic nervous system and its cardiac control. A major advantage of electrocardiogram (ECG)-based seizure detection is that the ECG is an essentially easier signal to obtain, with a higher signal-to-noise ratio than EEG (electroencephalogram). Based on the inferences from this study future studies could be done to build machine learning models which could form the base for the development of wearable seizure prediction devices.

Using Minimum Redundancy Maximum Relevance Algorithm to Select Minimal Sets of Heart Rate Variability Parameters for Atrial Fibrillation Detection.

Heart rate is quite regular during sinus (normal) rhythm (SR) originating from the sinus node. In contrast, heart rate is usually irregular during atrial fibrillation (AF). Complete atrioventricular block with an escape rhythm, ventricular pacing, or ventricular tachycardia are the most common exceptions when heart rate may be regular in AF. Heart rate variability (HRV) is the variation in the duration of consecutive cardiac cycles (RR intervals). We investigated the utility of HRV parameters for automated detection of AF with machine learning (ML) classifiers. The minimum redundancy maximum relevance (MRMR) algorithm, one of the most effective algorithms for feature selection, helped select the HRV parameters (including five original), best suited for distinguishing AF from SR in a database of over 53,000 60 s separate electrocardiogram (ECG) segments cut from longer (up to 24 h) ECG recordings. HRV parameters entered the ML-based classifiers as features. Seven different, commonly used classifiers were trained with one to six HRV-based features with the highest scores resulting from the MRMR algorithm and tested using the 5-fold cross-validation and blindfold validation. The best ML classifier in the blindfold validation achieved an accuracy of 97.2% and diagnostic odds ratio of 1566. From all studied HRV features, the top three HRV parameters distinguishing AF from SR were: the percentage of successive RR intervals differing by at least 50 ms (pRR50), the ratio of standard deviations of points along and across the identity line of the Poincare plots, respectively (SD2/SD1), and coefficient of variation—standard deviation of RR intervals divided by their mean duration (CV). The proposed methodology and the presented results of the selection of HRV parameters have the potential to develop practical solutions and devices for automatic AF detection with minimal sets of simple HRV parameters. Using straightforward ML classifiers and the extremely small sets of simple HRV features, always with pRR50 included, the differentiation of AF from sinus rhythms in the 60 s ECGs is very effective.

The effect of regular physical training on heart rate variability in healthy male volunteers

Abstract Funding Acknowledgements Type of funding sources: None. Background The autonomic nervous system's responses are reflected in heart rate variability (HRV). They have a significant role in accompanying the training process, however, assessment of long-term daily HRV indices dynamics is not widely used in sports cardiology. Purpose To determine if there are variations in long-term responses of autonomic regulation of cardiac activity to regular systematic training. Methods In this prospective study, we included 28 healthy men aged 18-19 years who had a repeated 24-hour Ambulatory ECG monitoring between February 2018 and December 2019 (Figure 1). The subjects were in similar working and living conditions. The training regimen consisted of moderate to vigorous physical activity for 270 (SD 40) minutes per week (total 100 weeks of follow-up). The subjects were divided into groups according to the median of changes in assessment results for various types of physical training (Table 1): with the maximum and minimum positive dynamics of physical fitness in endurance (3000m race), speed (100m race), strength (pull-ups on the horizontal bar). 24-hour Holter was performed using a wearable ECG device. HRV parameters at the beginning and at the end of the study in groups with the maximum positive physical fitness dynamics were compared. To assess HRV, the following daily time-domain indices were used: RMSSD (root mean square of successive RR interval differences), pNN50% (percentage of successive RR intervals that differ by more than 50 ms) and SDANN (standard deviation of the averages of the NN intervals in all 5 min segments of the entire recording). Results The initial mean heart rate in groups 1-6 did not differ significantly across repeated heart rate monitoring (Table 1). In group 1, the improvement in endurance exercise performance directly correlated with changes in RMSSD (rs = 0.297, p &amp;lt;0.05) and pNN50% (rs = 0.448, p &amp;lt;0.05). In group 3, increased fitness in short distance running was accompanied by a decrease in the values of the RMSSD (rs = –0.211, p &amp;lt;0.05) and pNN50% (rs = –0.539, p &amp;lt;0.05) and an increase in the values of the SDANN (rs = 0.352, p &amp;lt; 0.05). In group 5, increased fitness in strength exercises was accompanied by a balanced increase in pNN50% (rs = 0.371, p &amp;lt;0.05), RMSSD (rs = 0.347, p &amp;lt;0.05), as well as SDANN (rs = 0.440, p &amp;lt;0,05). In groups 2, 4, 6, there were similar but weaker associations. Conclusion Systematic training is associated with significant changes in the autonomic regulation of heart rate. An increase in fitness in sprint distance running results in a decrease in daily parasympathetic and an increase in sympathetic activity on the heart. Increased fitness in strength exercises is associated with increase in both sympathetic and parasympathetic activity. While an increase in endurance is accompanied by an increase in the activity of the parasympathetic limb of the autonomic nervous system.

Correlation between physical activity, cardiorespiratory fitness and heart rate variability among young overweight adults

ObjectiveCardiac autonomic function assessed by heart rate variability (HRV) is a non-invasive, quantitative, and reliable marker of measurement. An altered cardiac autonomic function among overweight individuals predisposes them to a greater risk of developing cardiovascular diseases. The present study aims to determine the correlation between physical activity, cardiorespiratory fitness and heart rate variability among young overweight adults. MethodsA total of 45 participants (23 men and 22 women) were enrolled in the cross-sectional study with inclusion criteria as follows: aged between 18–30 years, body mass index (kg/m2) between 25–29.9 kg/m2, and without any known or diagnosed medical condition. Physical activity level and cardiorespiratory fitness were measured using the Global Physical Activity Questionnaire and Bruce treadmill protocol test, respectively. Cardiac autonomic function was measured using a 5-min short-term heart rate variability recording. The time and frequency domain measures of HRV were used for analysis. ResultsThe mean age of study participants was 22.53 ± 1.58 years and mean body mass index was 27.38 ± 1.51 kg/m2. Among young overweight adults, cardiorespiratory fitness and physical activity were not correlated with Root mean square of successive RR interval differences, Percentage of successive RR intervals that differ by more than 50 ms, and Ratio of LF [ms2]/HF [ms2]. ConclusionThe study found no correlation between physical activity and cardiorespiratory fitness with heart rate variability among young overweight individuals.

Heart Rate Variability in Insulo-Opercular Epilepsy.

Background: We aimed to evaluate heart rate variability (HRV) changes in insulo-opercular epilepsy (IOE) and after insulo-opercular surgery. Methods: We analyzed 5-min resting HRV of IOE patients before and after surgery. Patients’ SUDEP-7 risk inventory scores were also calculated. Results were compared with age- and sex-matched patients with temporal lobe epilepsy (TLE) and healthy individuals. Results: There were no differences in HRV measurements between IOE, TLE, and healthy control groups (and within each IOE group and TLE group) in preoperative and postoperative periods. In IOE patients, the SUDEP-7 score was positively correlated with pNN50 (percentage of successive RR intervals that differ by more than 50 ms) (p = 0.008) and RMSSD (root mean square of successive RR interval differences) (p = 0.019). We stratified IOE patients into those whose preoperative RMSSD values were below (Group 1a = 7) versus above (Group 1b = 9) a cut-off threshold of 31 ms (median value of a healthy population from a previous study). In group 1a, all HRV values significantly increased after surgery. In group 1b, time-domain parameters significantly decreased postoperatively. Conclusions: Our results suggest that in IOE, HRV may be either decreased in parasympathetic tone or increased globally in both sympathetic and parasympathetic tones. We found no evidence that insulo-opercular surgeries lead to major autonomic dysfunction when a good seizure outcome is reached. The increase in parasympathetic tone observed preoperatively may be of clinical concern, as it was positively correlated with the SUDEP-7 score.

EFFECT OF PHYSICAL ACTIVITIES ON HEART RATE VARIABILITY AND SKIN CONDUCTANCE

The sympathetic and parasympathetic function of the Autonomic Nervous System (ANS) is the primary cause of the variations in Heart Rate and Skin Conductance (SC) 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 &amp; 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.

Abstract 13369: Sympathovagal Imbalance Decades After Atrial Septal Defect Repair

Introduction: Heart rate variability (HRV), a measure of the autonomic nervous system activity, is a morbidity and mortality predictor. HRV is decreased in children with atrial septal defects (ASD) indicating parasympathetic withdrawal and sympathetic predominance, and increased right atrial end-diastolic pressure is believed to influence the sympathovagal balance. Despite the belief of a benign long-term outcome after closure, ASD patients have increased mortality rates after the age of 30 yrs. This may correlate to HRV, why we study HRV in adults after closure. Hypothesis: ASD patients have impaired HRV after closure when compared with controls. Methods: Surgically closed ASD patients (n=17, mean age 32±9 yrs., mean time since closure 19±8 yrs.), percutaneously closed ASD patients (n=18, mean age 28±7 yrs., mean time since closure 15±5 yrs.) and age- and gender-matched controls (n=15, mean age 30±9 yrs.) underwent a 48-hr Holter monitoring. Inclusion criteria were an age of minimum 2 yrs. at the time of diagnosis and minimum 3 yrs. must have passed since ASD closure. The following time-domain HRV measures were analyzed: SD of NN intervals (SDNN), SD of the average NN interval for each 5-minute segment, mean of the SDs of all NN intervals for each 5-minute (SDNNi), root mean square of successive RR interval differences (RMSSD), percentage of successive RR intervals that differ by &gt;50 ms (pNN50), and triangular index. Results: Surgically closed ASD patients have an impairment of all time-domain parameters, while transcatheter closed patients have an impairment of half the parameters. Conclusion: These novel findings demonstrate a cardiac sympathovagal imbalance in adult patients several yrs. after ASD closure and may potentially explain why we observe a long-term morbidity and mortality increase in ASD patients.

Exploring the Effects of a Brief Biofeedback Breathing Session Delivered Through the BioBase App in Facilitating Employee Stress Recovery: Randomized Experimental Study.

BackgroundRecovery from stress is a predictive factor for cardiovascular health, and heart rate variability (HRV) is suggested to be an index of how well people physiologically recover from stress. Biofeedback and mindfulness interventions that include guided breathing have been shown to be effective in increasing HRV and facilitating stress recovery.ObjectiveThis study aims to assess the effectiveness of a brief app-based breathing intervention (BioBase) in enhancing physiological recovery among employees who were induced to cognitive and emotional stress.MethodsIn total, we recruited 75 full-time employees. Interbeat (RR) intervals were recorded continuously for 5 min at baseline and during cognitive and emotional stress induction. The session ended with a 5-min recovery period during which participants were randomly allocated into 3 conditions: app-based breathing (BioBase), mindfulness body scan, or control. Subjective tension was assessed at the end of each period.ResultsSubjective tension significantly increased following stress induction. HRV significantly decreased following the stress period. In the recovery phase, the root mean square of successive RR interval differences (P=.002), the percentage of successive RR intervals that differed by >50 ms (P=.008), and high frequency (P=.01) were significantly higher in the BioBase breathing condition than in the mindfulness body scan and the control groups.ConclusionsBiofeedback breathing interventions digitally delivered through a commercially available app can be effective in facilitating stress recovery among employees. These findings contribute to the mobile health literature on the beneficial effects of brief app-based breathing interventions on employees’ cardiovascular health.

Heart Rate Variability As Psychophysiological Stress Indicator In Mexican College Volleyball Players

PURPOSE: To compare the response of Heart Rate Variability (HRV) during induced stress as a psychophysiological stress indicator in Mexican college volleyball players. METHODS: We evaluated 16 male college volleyball players (18 to 26 y). Psychophysiological assessment of stress consisted of 7 stages lasting 2 min each (baseline, exposed to a physiological stressor [unpleasant sounds], 1st rest, exposed to a cognitive stressor [mathematical task], 2nd rest, exposed to stressor emotional [talk about a stressful memory] and 3rd rest). It was done by a ProCompTM Infiniti Biofeedback System. Short-term HRV was obtained by a Blood Volume Pulse (BVP) Sensor and analyzed using time-domain: SDRR (standard deviation of RR intervals) and pNN50 (percentage of successive RR intervals that differ by more than 50 ms); and frequency-domain: HRV peak frequency, Very Low Frequency (VLF) total power, Low Frequency (LF) total power, High Frequency (HF) total power, VLF % power, LF % power and HF % power measurements. Statistical analysis was performed by repeated measures ANOVA and non-parametric Friedman test. RESULTS: Significant differences in HRV were observed when we compared the seven stages of the assessment (with stress stimulus and without stress stimulus). During the COGNITIVE stage there was a difference with the BASELINE (p= .01) and EMOTIONAL (p= .004) stage in HRV peak frequency; in VLF% between PHYSIOLOGICAL and 1st REST (p= .01) stage; among the BASELINE and the EMOTIONAL (p= .04) stage on SDRR; and with pNN50 on COGNITIVE and 3rd REST (p= .02) stage. (Table 1). CONCLUSIONS: The results show significant changes in the variables associated with sympathetic activity in stages that had stressors compared to baseline and rests, which may indicate psychophysiological response to stress. These results support the idea of HRV is a useful psychophysiological stress indicator and maybe a helpful tool to identify and have better stress management in Mexican college athletes.Table 1: Heart Rate Variability indicators comparison between each stage.

Short-Term Impact of Traffic-Related Particulate Matter and Noise Exposure on Cardiac Function.

Exposure to traffic-related air pollution and noise exposure contributes to detrimental effects on cardiac function, but the underlying short-term effects related to their simultaneous personal exposure remain uncertain. The aim is to assess the impact of total inhaled dose of particulate matter and total noise exposure on the variations of electrocardiogram (ECG) parameters between pre-cycling and post-cycling periods. Mid-June 2019, we collected four participants’ personal exposure data related to traffic-related noise and particulate matter (PM2.5 and PM10) as well as ECG parameters. Several Bayesian linear models were built to examine a potential association between air pollutants and noise exposure and ECG parameters: heart rate (HR), standard deviation of the normal-to-normal intervals (SDNN), percentage of successive RR intervals that differ by more than 50 ms (pNN50), root mean square of successive RR interval differences (rMSSD), low-frequency power (LF), high-frequency power (HF), and ratio of low- to high-frequency power (LF/HF). We analyzed in total 255 5-min segments of RR intervals. We observed that per 1 µg increase in cumulative inhaled dose of PM2.5 was associated with 0.48 (95% CI: 0.22; 15.61) increase in variation of the heart rate, while one percent of total noise dose was associated with 0.49 (95% CI: 0.17; 0.83) increase in variation of heart rate between corresponding periods. Personal noise exposure was no longer significant once the PM2.5 was introduced in the whole model, whilst coefficients of the latter that were significant previously remained unchanged. Short-term exposure to traffic-related air and noise pollution did not, however, have an impact on heart rate variability.