Heart Rate Variability Indices Research Articles

SPECIAL ISSUE: Improve Client Care by Dispelling HRV Myths

Heart rate variability (HRV) indexes how efficiently we mobilize and utilize limited self-regulatory resources to maintain homeostasis. HRV plays a vital role in regulatory capacity, executive functions, health, and performance. We address common misconceptions regarding cardiovascular health, HRV measurement, and HRV biofeedback training. This review highlights the importance of context and individual differences in interpreting HRV. We debunk common misconceptions to improve HRV biofeedback training for health and performance.

Correlation of indicators of heart rate autonomic regulation and socio-economic well-being in young people 16–18 years old living in the Arctic zone of the Russian Federation

Background. The impact of natural and climatic factors on human health may change under the influence of other factors related to his socio-economic well-being. The aim of the study. To determine the correlation between indicators of heart rate variability and parameters of socio-economic well-being, quality of life of young people living in the Arctic zone of the Russian Federation (Arkhangelsk).Materials and methods. Parameters of Heart rate variability in 36 young men (16–18 years old) were determined at entry (5 minutes) and at a fixed breath rate (5 minutes). We used the World Health Organization Quality of Life Brief Version of questionnaire, Family Affluence Scale (FAS II) and a questionnaire reflecting the financial situation, composition, and large number of children in the participants’ families.Results. According to correlation analysis, a decrease in the number of family vacations per year and FAS-II scores is accompanied by an increase in sympathetic activity. Indicators of self-perceived health status, number of cars in the family, FAS-II score and family financial status are positively correlated with indicators of vagal activity. Parameters of the psychological sphere of life quality and family composition were negatively correlated with sympathetic activity; parameters of the physical sphere of life quality and the number of family vacations per year were negatively correlated with vagal activity (fixed breath rate).Conclusion. We identified specific indicators of socio-economic well-being that are most closely related to both the tension of the cardiac activity mechanisms and the decrease in vagal reserves of autonomic regulation in young men living in the Russian Arctic.

Heart rate variability-based prediction of early cardiotoxicity in breast-cancer patients treated with anthracyclines and trastuzumab

BackgroundCardiotoxicity is a recognized complication in breast cancer (BC) patients undergoing chemotherapy with anthracyclines with or without trastuzumab. However, the prognostic value of heart rate variability (HRV) indexes for early cardiotoxicity development remains unknown.MethodsFifty BC patients underwent TTE assessment before and three months after chemotherapy. HRV indexes were obtained from continuous electrocardiograms in supine position with spontaneous breathing, active standing, and supine position with controlled breathing. The magnitude of change (Δ) between supine-standing and supine-controlled breathing was calculated. Variables were compared using t-test or ANOVA. Cardiotoxicity predictive value was assessed by ROC curve analysis. A p value of < 0.05 was considered significant.ResultsTTE revealed reduced left atrial conduit strain in the cardiotoxicity group. Mean heart rate increased during all maneuvers at follow-up, with no differences in HRV indexes between patients with or without cardiotoxicity. However, a lower Δ in supine-controlled breathing of several HRV indexes predicted early cardiotoxicity identified by echocardiography (e.g. SDNN ≤ -8.44 ms: Sensitivity = 75%, Specificity = 69%).ConclusionsBC patients treated with chemotherapy maintain cardiac autonomic responses to physiological stimuli after 3 months of chemotherapy. However, a lower Δ during active standing and controlled breathing before chemotherapy may predict early cardiotoxicity.

The impact of virtual reality scenes on stress response characteristics of individuals with different personality traits

Virtual reality based physical stress (VRPS) paradigms could eliminate the influence of social factors on participants, and it may be a desirable tool to explore the impact of personality traits on stress levels. In this study, we attempt to explore the effects of VRPS on stress response among individuals with different personality traits. Forty male participants with an average age of 22.79 ± 0.41 years were divided into two groups based on Harm Avoidance (HA) scores of Tridimensional Personality Questionnaire (TPQ), referred to as the Low-HA group and the High-HA group. The stress levels of the participants were assessed using salivary α-amylase (sAA) activity and heart rate variability (HRV) indices pre- and post-stress. The influence of personality traits on stress response among different groups was analyzed. VRPS significantly affected the sAA activity and HRV indicators of both groups. During and after stress, there were significant differences in sAA activity and HRV indicators between the two groups. The sAA levels and HRV indices of the Low-HA group were lower than those of the High-HA group. Furthermore, sAA levels and HRV indices were correlated with the scores of TPQ. VRPS scenarios elicit different stress responses on individuals with different harm avoidance personality traits. Stress evaluation based on VR scenarios presents potential in personality trait assessments, particularly for distinguishing between individuals with low and high HA tendencies.

Peaks, sources, and immediate health impacts of PM2.5 and PM1 exposure in Indonesia and Taiwan with microsensors.

Microsensors have been used for the high-resolution particulate matter (PM) monitoring. This study applies PM and health microsensors with the objective of assessing the peak exposure, sources, and immediate health impacts of PM2.5 and PM1 in two Asian countries. Exposure assessment and health evaluation were carried out for 50 subjects in 2018 and 2019 in Bandung, Indonesia and for 55 subjects in 2019 and 2020 in Kaohsiung, Taiwan. Calibrated AS-LUNG sets and medical-certified RootiRx® sensors were used to assess PM and heart-rate variability (HRV), respectively. Overall, the 5-min mean exposure of PM2.5 and PM1 was 30.4 ± 20.0 and 27.0 ± 15.7 µg/m3 in Indonesia and 14.9 ± 11.2 and 13.9 ± 9.8 µg/m3 in Taiwan, respectively. The maximum 5-min peak PM2.5 and PM1 exposures were 473.6 and 154.0 µg/m3 in Indonesia and 467.4 and 217.7 µg/m3 in Taiwan, respectively. Community factories and mosquito coil burning are the two most important exposure sources, resulting in, on average, 4.73 and 5.82 µg/m3 higher PM2.5 exposure increments for Indonesian subjects and 10.1 and 9.82 µg/m3 higher PM2.5 exposure for Taiwanese subjects compared to non-exposure periods, respectively. Moreover, agricultural waste burning and incense burning were another two important exposure sources, but only in Taiwan. Furthermore, 5-min PM2.5 and PM1 exposure had statistically significantly immediate impacts on the HRV indices and heart rates of all subjects in Taiwan and the scooter subjects in Indonesia with generalized additive mixed models. The HRV change for a 10 µg/m3 increase in PM2.5 and PM1 ranged from -0.9% to -2.5% except for ratio of low-high frequency, with greater impacts associated with PM1 than PM2.5 in both countries. This work highlights the ability of microsensors to capture high peaks of PM2.5 and PM1, to identify exposure sources through the integration of activity records, and to assess immediate changes in heart rate variability for a panel of approximately 50 subjects in Indonesia and Taiwan. This study stands out as one of the few to demonstrate the immediate health impacts of peak PM, complementing to the short-term (days or weeks) or long-term effects (months or longer) assessed in most epidemiological studies. The technology/methodology employed offer great potential for researchers in the resource-limited countries with high PM2.5 and PM1 levels.

The Effects of Natural Window Views in Classrooms on College Students’ Mood and Learning Efficiency

Observing peaceful natural environments has been shown to restore cognitive abilities and reduce stress. As a result, visual access to natural environments is becoming increasingly common in educational settings. However, most current research on classroom window views has examined classroom environments in elementary and secondary schools, and only some university classrooms have been used as study sites. This study investigated the relationship between the naturalness of university classroom window views and physiological and emotional responses and standardized tests of attentional focus (learning efficiency) in university students. Thirty participants (undergraduates 21.16 ± 1.01 years old) viewed architectural window views and natural window views for 3 min each, and physiological measures of EEG, HRV index, and psychometric measures of Semantic Differences Questionnaire and Emotional State Questionnaire generated data. Measurements were generated. The results indicated that the natural window view significantly enhanced theta, alpha, and beta waves of brain activity, provided a sense of comfort, relaxation, and pleasure, and increased learning efficiency compared to the architectural window view. The findings support the beneficial associations between window views on university campuses and students’ mood and learning efficiency, emphasizing the importance of considering natural window views in the planning and designing of university classrooms.

Dynamic change, not tonic activation, of the heart rate variability predicts onset of postoperative atrial fibrillation

Abstract Background and Aims Post-operative autonomic disturbances contribute to susceptibility to post-operative atrial fibrillation (POAF) but the nature of the autonomic disturbances and whether they precede POAF and can signal POAF onset is unclear. Methods In this prospective observational study, patients undergoing cardiac surgery were consecutively enrolled. Holter monitoring was undertaken 7 days before and after surgery with continuous heart rate variability (HRV) measurement. Cox regression was used to evaluate autonomic changes, and analyzed by restricted cubic spline (RCS) to explore individual risk levels. For the first episode of POAF, HRV indexes captured an hour before the onset of POAF were divided into six 10-minute epochs and analyzed by Friedman's Two-Way Analysis of Variance by Ranks. Results A total of 2306 patients known to have been without prior AF were enrolled and completed the study; POAF occurred in 718 (31.14%) patients. Based on univariate and multivariate analysis preoperative, tonic activation and perioperative HRV change were not significantly related to new POAF. However, in the postoperative phase, a marked increase or decrease of Δ Lg (LF/HF), Δ Lg (HF) and Δ Lg (LF) were associated with increased POAF risk. Further, examination of 10-minute epochs in the 30 minutes before the onset of POAF, revealed that progressive increase of HRV indexes. Conclusions POAF susceptibility is associated with postoperative dynamic HRV changes but not tonic autonomic state. Potentially the observation that POAF was preceded by progressive rise of HRV indexes may offer a promising signal for early warning of POAF, and permit preventive intervention.

ECG screening and Sudden Cardiac Death prevention in endurance athletes

Abstract Introduction Sudden cardiac death (SCD) is the leading cause of mortality in athletes during sport activity. Identifying non-invasive and repeatable risk markers during annual athletes screening remains a crucial goal for the scientific community for the prevention of cardiovascular disease. The ECG, exercise test and spirometry are part of the annual screening program in the sport population over 40 years of age. The Heart Rate Variability (HRV) has been shown to be an independent predictor of mortality in populations with CV disease, but its relationship with SCD has been little explored in those at low risk, including athletes. This study aims to use a 5 minute ECG screening in a specific population of athletes practicing endurance sports and evaluate its clinical repercussions. Aims The primary aim of the study is to assess whether morphological and spectral ECG analysis in endurance athletes by the 5-minute 'mini Holter ECG' can add information to the annual screening for the prevention of CV diseases and SCD. Materials The study population were selected from Endurance Marathon athletes. A control group was also collected for comparison. The 5 minutes ECG was recorded at rest with the Kardia Mobile 6L™ device that use three electrodes, which allows 6 leads recording. HRV indices were obtained using the Kubios software. A morphological analysis was performed and the HRV parameters were analyzed in the time and frequency domains. Results A total of 554 subjects (220 athletes-334 controls, 325 male-229 women) were analyzed. A higher incidence of sinus arrhythmias, LAFB, 1stdegree AVB, J point/ST-segment abnormalities in athletes compared to controls was observed. Athletes had a significantly shorter QTc than the control group (394.87±30.55 ms vs. 407.01±29.09 ms), suggestive of greater protection from malignant ventricular arrhythmias. The HRV PNS (-0.73±1.25 vs -0.21±1.45) and SNS (1.71±1.91 vs 0.58 ± 1.43) indices were also higher and lower in the athlete group than in the control group, suggestive for higher vagal tone. Given the absence of a normality range of standard HRV parameters in the athlete population, values in the normal range of the 5th to 95th percentile were extrapolated in the whole population for the main HRV parameters. The project, therefore, is to evaluate patients with HRV values higher or lower than 5-95 percentile to identify those deserving further clinical investigations and closer follow-up for suspected increased risk of CV disease and SCD. Conclusions The 5-minute cardiac Holter, combining a more accurate analysis in terms of morphology and arrhythmias than the 12-lead ECG, allows a greater number of static and dynamic alterations to be detected; moreover, the analysis of HRV could provide even more information, such that it could be considered as a complementary tool during the examination and FUP of athletes. Further long-term prospective studies are needed to correlate alterations in HRV and clinical events.

ECG screening and prevention of sudden cardiac death in endurance athletes over 40

Abstract Introduction CV diseases increase with age. There are many athletes aged &amp;gt;40 years who practise in certain endurance sports (marathon, ultramarathon and cycling), that involve very high intensity physical exertion and prolonged efforts. This population, like others athletes, undergo to annual examination with a medical history, spirometry, urine test and exercise test. CVdisease and sudden cardiac death (SCD) are the main cause of mortality in athletes during sport and this specific population group are at increased CV risk due to their multiple comorbidities, so this kind of screening remains controversial. Aims The primary aim of the study is to evaluate whether a 5-minute 'mini Holter ECG', associated with the conventional examination, can have an additional role for early screening and prevention of CV diseases in older endurance sport population. Materials The population were selected as part of the larger 'Heart And Run' project, an ECG collection of endurance athletes of the main sports clubs in Rome - Italy. A control group of healty individiuals was collected for comparison. The ECG traces were recorded at rest for 5 minutes with the Kardia Mobile device 6L™. HRV indices were analysed using the software Kubios. The study group were compared for an ECG morphological analysis and HRV parameters in the time and frequency domain. Results A total of 353 subjects (182 athletes, 171 controls) were analysed. The athlets show a significantly higher incidence of sinus arrhythmias, LAFB, 1°degree AVB, Jpoint elevation and STsegment abnormalities. We found also a significantly shorter QTc in athlets compared to controls (395.95 ± 29.51 ms vs. 411.6 ± 29.01 ms), suggestive of greater protection from malignant ventricular arrhythmias. In line with the ECG findings, the HRV PNS (-0.25 ± 1.25 vs -1.05 ± 1.45) and SNS (0.69 ± 1.44 vs 2.38 ± 1.89) indices were respectively higher and lower in the athletes group than in the controls group. Differences between the two groups were also found in the time and frequency HRV domain analysis (SDNN, RMSSD, NN50 and pNN50). Due to the absence of normality range, we considered values lower of the 5th or higher of the 95th percentile range, for the main HRV parameters, as abnormals. We identified 29/182 virtually abnormal HRV individuals. Those patients could be at increased CV risk, worthy of further investigation. In total, out-of-range HRV values or morphological abnormalities were detected in 54 athletes (29%), a population that will need further attention through follow-up and additional examinations. Conclusions Despite competitive endurance sports are associated with increased vagal tone, which is virtually protective against CV diseases, even in athletes over 40, the addition of the 5-minute cardiac 'mini Holter' could increase the sensitivity in detection of CV disease, in a specific high-risk group of athletes, suggesting additional clinical and instrumental investigations in such patients.

Full-Term and Preterm Newborns Differ More Significantly in Photoplethysmographic Waveform Variability than Heart Rate Variability.

Features of cardiovascular autonomic regulation in infants are poorly studied compared with adults. However, the clinical significance of autonomic dysfunction in infants is very high. The goal of our research was to study the temporal and frequency-dependent features, as well as low-frequency synchronization in cardiovascular autonomic regulation in full-term vs. preterm newborns, based on the analysis of their heart rate variability (HRV) and photoplethysmographic waveform variability (PPGV). The study included three groups of newborns: 64 full-term newborns (with a gestational age at birth of 37-40 weeks) with a physiological course of the neonatal adaptation; 23 full-term newborns (with a gestational age at birth of 37-40 weeks) with a pathological course of the neonatal adaptation; and 17 preterm newborns (with a postconceptional age of 34 weeks or more). We conducted spectral analysis of HRV and PPGV, along with an assessment of the synchronization strength between low-frequency oscillations in HRV and in PPGV (synchronization index). We employed several options for the boundaries of the high-frequency (HF) band: 0.15-0.40 Hz, 0.2-2 Hz, 0.15-0.8 Hz, and 0.24-1.04 Hz. Preterm newborns had higher heart rate, RMSSD, and PNN50 values relative to both groups of full-term newborns. Values of SDNN index and synchronization index (S index) were similar in all groups of newborns. Differences in frequency domain indices of HRV between groups of newborns depended on the considered options of HF band boundaries. Values of frequency domain indices of PPGV demonstrated similar differences between groups, regardless of the boundaries of considered options of HF bands and the location of PPG signal recording (forehead or leg). An increase in sympathetic influences on peripheral blood flow and a decrease in respiratory influences were observed along the following gradient: healthy full-term newborns → preterm newborns → full-term newborns with pathology. Differences in frequency domain indices of autonomic regulation between the studied groups of newborns depended on the boundaries of the considered options of the HF band. Frequency domain indices of PPGV revealed significantly more pronounced differences between groups of newborns than analogous HRV indicators. An increase in sympathetic influences on peripheral blood flow and a decrease in respiratory influences were observed along the following gradient: healthy full-term newborns → preterm newborns → full-term newborns with pathology.

The Relationship between Heart Rate Variability, Pain Intensity, Pain Catastrophizing, Disability, Quality of Life and Range of Cervical Motion in Patients with Chronic Non-Specific Neck Pain: A Cross-Sectional Study.

The purpose of the present cross-sectional study was to examine the relationship between heart rate variability (HRV) and the range of cervical motion, disability, pain intensity, pain catastrophizing, and quality of life in patients with chronic, non-specific neck pain. Thirty-five patients, aged 20-48 years, with chronic non-specific neck pain, completed validated questionnaires regarding neck pain intensity, pain-associated disability, catastrophic thoughts, and quality of life. The range of cervical motion was assessed using a digital goniometer. HRV indices were recorded in three positions (supine, sitting, and standing) through a smartphone application. Several significant correlations were observed between HRV indices and neck pain disability, the helplessness factor of catastrophizing, neck rotation, and quality of life. These correlations were only observed in the standing position. Pain catastrophizing was positively correlated with disability and pain intensity during active neck movement (Pearson r = 0.544, p < 0.01; Pearson r = 0.605, p < 0.01, respectively). Quality of life was negatively correlated with pain intensity during active movement (Pearson r = -0.347, p < 0.05). HRV indices were correlated with the psychological and physical domains of neck pain. These cardiac indices have been related to neck pain variables in some previous studies. Further research is needed to confirm this relationship in different daily conditions.

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.

Exploring physiological stress response evoked by passive translational acceleration in healthy adults: a pilot study utilizing electrodermal activity and heart rate variability measurements.

Passive translational acceleration (PTA) has been demonstrated to induce the stress response and regulation of autonomic balance in healthy individuals. Electrodermal activity (EDA) and heart rate variability (HRV) measurements are reliable indicators of the autonomic nervous system (ANS) and can be used to assess stress levels. The objective of this study was to investigate the potential of combining EDA and HRV measurements in assessing the physiological stress response induced by PTA. Fourteen healthy subjects were randomly assigned to two groups of equal size. The experimental group underwent five trials of elevator rides, while the control group received a sham treatment. EDA and HRV indices were obtained via ultra-short-term analysis and compared between the two groups to track changes in the ANS. In addition, the complexity of the EDA time series was compared between the 4s before and the 2-6s after the onset of PTA to assess changes in the subjects' stress levels in the experimental group. The results revealed a significant increase in the skin conductance response (SCR) frequency and a decrease in the root mean square of successive differences (RMSSD) and high frequency (HF) components of HRV. In terms of stress assessment, the results showed an increase in the complexity of the EDA time series 2-6s after the onset of PTA. These results indicate an elevation in sympathetic tone when healthy subjects were exposed to a translational transport scenario. Furthermore, evidence was provided for the ability of EDA complexity to differentiate stress states in individual trials of translational acceleration.

Indicators of heart rhythm variability as informative markers of adaptive changes in Mixed Martial Arts

This article presents the results of a study of determining the characteristics of changes in heart rate variability indicators in athletes who have been engaged in horting, hand-to-hand combat, and Thai boxing for a long time in response to strength loads in pre-competition mesocycles. It was established that in the examined athletes, regardless of the type of mixed martial arts, the tension of all regulatory systems was fixed before the beginning of strength loads, as indicated by the parameters of the VLF indicator, which were almost twice the norm. At the same time, it was established that the HF indicator of the participants, which characterizes the parasympathetic tone, is on average only 10.3% of the total power of the spectrum, which indicates the predominance of the sympathetic system. The results revealed after the participants used power loads of a large amount of loads and medium intensity indicate a reliable decrease in the total power of the spectrum of oscillation of cardio intervals. An increase in the intensity of the autonomic regulation of the heart rhythm due to the weakening of the activation of the parasympathetic tone was revealed, primarily in athletes engaged in horting. It is in athletes from hand-to-hand combat and horting, in response to power loads with a large volume of work, the activation of the central circuit increases and the level of sympathetic regulation increases.

Analysis of Heart Rate Variability in Newborns Dogs with Different Types of Delivery during the First 35 Days of Life.

The present study aimed to evaluate the influence of the autonomic nervous system on cardiovascular function during the first 35 days of life in different types of delivery, using heart rate variability (HRV) indices. Thirty newborns were equally divided into two groups based on delivery type: eutocic delivery (EG) and emergency cesarean section (CG). Electrocardiographic evaluation was performed at birth (T0), 24 h postpartum (T1), and at 7, 14, 21, 28, and 35 days of life (T2 to T6). Physical parameters, neonatal reflexes, and Apgar scores were recorded. Over 35 days, the values of the time domain indices were higher in the GE group and increased with age. In the frequency domain, the low frequency (LF) index was higher in the CG, and the opposite occurred for the high frequency (HF) index. Since the CG presented lower HRV than the EG, it was shown that the type of delivery should be considered for the assessment of autonomic nervous system activity in neonates. Thus, as predictive factors of vitality, HRV and Apgar scores can help in the face of neonatal depression, demonstrating that delivery by emergency cesarean section can predispose newborns to delays in the autonomic influence on the heart.

Общая мощность спектра и мощность HF-волн в зависимости от этапов годичного цикла подготовки спортсменов и других факторов (обзор)

As part of the study into the nature of such heart rate variability (HRV) indicators as total spectrum power (TP), absolute power of high frequency waves (HFAP) and their relative power (as a percentage of TP (HF%)), literature data and the results of our own research on the values of these indicators in athletes are systematized. It has been established that TP, HFAP and HF% depend on the type of sports (reaching their maximum in endurance training), experience in sports (the higher the level, the higher these indicators), and phase of the training year (increasing during the preparatory phase, but decreasing slightly in the competitive phase and more significantly during the transition phase). In particular, the paper presents the results of the study of the first author of this article, elite skier D.A. Kataev, who recorded his own cardiointervalogram and the volume and intensity of daily training loads during one training year. This made it possible to evaluate TP, HFAP and HF% dynamics over the three phases and to establish that TP values are directly dependent on the volume and intensity of training loads. However, no such relationship was established for HFAP and HF%. It was shown that in 8 cross-country skiers (members of the Tatarstan national team) TP, HFAP and HF% values during the preparatory phase were higher than in the competition phase. The authors conclude that TP, HFAP and HF% values mainly reflect the influence of the parasympathetic division of the autonomic nervous system (ANS) on athletes’ cardiac activity, as well as on the activation of the sympathetic division of the ANS during the development of precompetition emotional stress in the competitive phase. An idea is postulated about the formation of the anti-apoptotic myocardial system during endurance training, which includes antioxidants, dopamine, serotonin, acetylcholine, prostaglandins, nitric oxide and other compounds.

Osteoarthritis patients exhibit an autonomic dysfunction with indirect sympathetic dominance

BackgroundOsteoarthritis (OA) is a chronic degenerative joint disease causing limited mobility and pain, with no curative treatment available. Recent in vivo studies suggested autonomic alterations during OA progression in patients, yet clinical evidence is scarce. Therefore, autonomic tone was analyzed in OA patients via heart rate variability (HRV) measurements.MethodsTime-domain (SDRR, RMSSD, pRR50) and frequency-domain (LF, HF, LF/HF) HRV indices were determined to quantify sympathetic and parasympathetic activities. In addition, perceived stress, WOMAC pain as well as serum catecholamines, cortisol and dehydroepiandrosterone-sulphate (DHEA-S) were analyzed. The impact of the grade of disease (GoD) was evaluated by linear regression analysis and correlations with clinical data were performed.ResultsGoD significantly impacted the autonomic tone in OA patients. All time-domain parameters reflected slightly decreased HRV in early OA patients and significantly reduced HRV in late OA patients. Moreover, frequency-domain analysis revealed decreased HF and LF power in all OA patients, reflecting diminished parasympathetic and sympathetic activities. However, LF/HF ratio was significantly higher in early OA patients compared to late OA patients and implied a clear sympathetic dominance. Furthermore, OA patients perceived significantly higher chronic stress and WOMAC pain levels compared to healthy controls. Serum cortisol and cortisol/DHEA-S ratio significantly increased with GoD and positively correlated with WOMAC pain. In contrast, serum catecholamines only trended to increase with GoD and pain level.ConclusionsThis prospective study provides compelling evidence of an autonomic dysfunction with indirect sympathetic dominance in early and late knee OA patients for the first time based on HRV analyses and further confirmed by serum stress hormone measurements. Increased sympathetic activity and chronic low-grade inflammation in OA as well as in its major comorbidities reinforce each other and might therefore create a vicious cycle. The observed autonomic alterations coupled with increased stress and pain levels highlight the potential of HRV as a prognostic marker. In addition, modulation of autonomic activity represents an attractive future therapeutic option.Graphical abstract

Effect of olfactory stimulation from aromatherapy on the autonomic nervous activity during aerobic exercises

Variations in the autonomic nervous system activity during exercise therapy in patients with cardiovascular diseases may lead to adverse events. Aromatherapy may reduce these adverse events by enhancing parasympathetic nervous activity (PNA). However, the effects of aromatherapy during exercise remain relatively unknown. This study aimed to evaluate the effect of aromatherapy on autonomic nervous activity during exercise and recovery. This randomized crossover study included 20 healthy men subjected to both aroma and placebo conditions which involved rest and moderate-intensity aerobic exercise on a cycle ergometer, followed by recovery. Blood pressure, heart rate variability indices, and SpO2 were measured during the rest, exercise, and recovery phases. Moreover, aroma preferences and emotional changes in response to the aroma were assessed. Under the placebo condition, high frequency (HF), root mean square of successive differences indices, and heart rate showed delayed recovery (P < 0.05). Furthermore, a moderate positive correlation was identified between aroma preference, pleasant emotions induced by aromatherapy, and the HF index (P < 0.05). These results indicate that aromatherapy facilitates the recovery of PNA after exercise. Furthermore, these effects were more pronounced among individuals who exhibited a stronger preference for and more positive emotions toward aromas.

Heart rate variability helps classify phenotype in systemic sclerosis

We aimed to develop a systemic sclerosis (SSc) subtypes classifier tool to be used at the patient’s bedside. We compared the heart rate variability (HRV) at rest (5-min) and in response to orthostatism (5-min) of patients (n = 58) having diffuse (n = 16, dcSSc) and limited (n = 38, lcSSc) cutaneous forms. The HRV was evaluated from the beat-to-beat RR intervals in time-, frequency-, and nonlinear-domains. The dcSSc group differed from the lcSSc group mainly by a higher heart rate (HR) and a lower HRV, in decubitus and orthostatism conditions. Stand-up maneuver lowered HR standard deviation (sd_HR), the major axis length of the fitted ellipse of Poincaré plot of RR intervals (SD2), and the correlation dimension (CorDim) in the dcSSc group while increased these HRV indexes in the lcSSc group (p = 0.004, p = 0.002, and p = 0.004, respectively). We identified the 5 most informative and discriminant HRV variables. We then compared 341 classifying models (1 to 5 variables combinations × 11 classifier algorithms) according to mean squared error, logloss, sensitivity, specificity, precision, accuracy, area under curve of the ROC-curves and F1-score. F1-score ranged from 0.823 for the best 1-variable model to a maximum of 0.947 for the 4-variables best model. Most specific and precise models included sd_HR, SD2, and CorDim. In conclusion, we provided high performance classifying models able to distinguish diffuse from limited cutaneous SSc subtypes easy to perform at the bedside from ECG recording. Models were based on 1 to 5 HRV indexes used as nonlinear markers of autonomic integrated influences on cardiac activity.

Intra-Individual Relationship between Heart Rate Variability and the Underlying Heart Rate in Children and Adolescents.

Background/Objective: The relationship between heart rate and heart rate variability (HRV) indices has been repeatedly studied in adults but limited data are available on the relationship in paediatric populations. Methods: Continuous 12-lead electrocardiograms were recorded in 1016 healthy children and adolescents (534 females) aged 4 to 19 years during postural manoeuvres with rapid changes between 10-min positions of supine → sitting → standing → supine → standing → sitting → supine. In each position, the averaged RR interval was measured together with four HRV indices, namely the SDNN, RMSSD, quasi-normalised high-frequency components (qnHF), and the proportions of low- and high-frequency components (LF/HF). In each subject, the slope of the linear regression between the repeated HRV measurements and the corresponding RR interval averages was calculated. Results: The intra-subject regression slopes, including their confidence intervals, were related to the age and sex of the subjects. The SDNN/RR, RMSSD/RR, and qnHF/RR slopes were significantly steeper (p < 0.001) and the (LF/HF)/RR slopes were significantly shallower (p < 0.001) in younger children compared to older children and adolescents. Conclusions: The study suggests that sympathetic and vagal influences on heart rate are present in both younger and older children. With advancing age, the sympatho-vagal balance gradually develops and allows the vagal control to suppress the sympathetic drive towards higher heart rates seen in younger age children.