Heart Rate Variability Measures Research Articles

Exploring the Influence of Fetal Sex on Heart Rate Dynamics Using Fetal Magnetocardiographic Recordings.

Fetal sex has been associated with different development trajectories that cause structural and functional differences between the sexes throughout gestation. Fetal magnetocardiography (fMCG) recordings from 123 participants (64 females and 59 males; one recording/participant) from a database consisting of low-risk pregnant women were analyzed to explore and compare fetal development trajectories of both sexes. The gestational age of the recordings ranged from 28 to 38 weeks. Linear metrics in both the time and frequency domains were applied to study fetal heart rate variability (fHRV) measures that reveal the dynamics of short- and long-term variability. Rates of linear change with GA in these metrics were analyzed using general linear model regressions with assessments for significantly different variances and GA regression slopes between the sexes. The fetal sexes were well balanced for GA and sleep state. None of the fHRV measures analyzed exhibited significant variance heterogeneity between the sexes, and none of them exhibited a significant sex-by-GA interaction. The absence of a statistically significant sex-by-GA interaction on all parameters resulted in none of the regression slope estimates being significantly different between the sexes. With high-precision fMCG recordings, we were able to explore the variation in fHRV parameters as it relates to fetal sex. The fMCG-based fHRV parameters did not show any significant difference in rates of change with gestational age between sexes. This study provides a framework for understanding normal development of the fetal autonomic nervous system, especially in the context of fetal sex.

Age and Gender Impact on Heart Rate Variability towards Noninvasive Glucose Measurement

Heart rate variability (HRV) parameters can reveal the performance of the autonomic nervous system and possibly estimate the type of its malfunction, such as that of detecting the blood glucose level. Therefore, we aim to find the impact of other factors on the proper calculation of HRV. In this paper, we research the relation between HRV and the age and gender of the patient to adjust the threshold correspondingly to the noninvasive glucose estimator that we are developing and improve its performance. While most of the literature research so far addresses healthy patients and only short- or long-term HRV, we apply a more holistic approach by including both healthy patients and patients with arrhythmia and different lengths of HRV measurements (short, middle, and long). The methods necessary to determine the correlation are (i) point biserial correlation, (ii) Pearson correlation, and (iii) Spearman rank correlation. We developed a mathematical model of a linear or monotonic dependence function and a machine learning and deep learning model, building a classification detector and level estimator. We used electrocardiogram (ECG) data from 4 different datasets consisting of 284 subjects. Age and gender influence HRV with a moderate correlation value of 0.58. This work elucidates the intricate interplay between individual input and output parameters compared with previous efforts, where correlations were found between HRV and blood glucose levels using deep learning techniques. It can successfully detect the influence of each input.

Subjective and objective measurements of nurses’ stress and recovery

Abstract Objectives High workloads and stress of healthcare workforce are global phenomena. We aimed to study work related stress and recovery of nurses with both subjective and objective methods, also aiming to examine if associations exist between subjective high work stress and need for recovery, and objectively measured stress and recovery. Methods Study sample comprised 65 nurses employed in the City of Helsinki. Heart rate variability (HRV) measurements were conducted for 3 consecutive days with ECG-based device in real-life setting, including 2 workdays and 1 day off. Objective stress and recovery were assessed from HRV and HRV-based stress and recovery variables. Participants filled out an electronic survey, where work stress was measured with Effort-reward imbalance scale and recovery after work with Need for recovery scale. Results Proportion of nurses with effort-reward ratio >1, indicating work stress, was high (84.6%), as was proportion of those with high need for recovery (64.6%). High need for recovery (score ≥54.5) was associated with lower RMSSD during sleep (p = 0.014) and higher absolute stress index (p = 0.009) on workdays. In high need for recovery group, stress balance (p = 0.040) and relaxation percentage (p = 0.033) were significantly lower on workdays than day off. In moderate work stress group, stress balance (p = 0.042), relaxation percentage (p = 0.041) and absolute relaxation index (p = 0.035) were lower on workdays than day off. No significant differences were observed within other groups. Conclusions Majority of participants suffered from work stress or high need for recovery. Based on our results, nurses’ high need for recovery is reflected in lower sleep time HRV, indicating worse physiological recovery. In those with high need for recovery, physiological recovery was also worse on workdays when compared with day off. Our findings highlight the importance of recovery, and in the future, nurses’ recovery and work stress should be increasingly monitored. Key messages • Nurses’ high need for recovery is reflected in lower sleep time heart rate variability. • Nurses’ recovery and work stress should be increasingly monitored.

P038 Characterising Pulse Wave Amplitude Drops in Patients with Acute Coronary Syndrome

Abstract Pulse wave amplitude derived from photoplethysmography signals is a surrogate measure of autonomic function and vascular response. Recent studies have demonstrated low pulse wave amplitude drop(PWAD) index to be associated with increased cardiovascular risk in obstructive sleep apnoea(OSA). The nature of PWAD in patients with cardiovascular disease remains unknown. We aimed to characterize PWAD in patients with acute coronary syndrome(ACS) diagnosed with OSA in terms of cardiovascular measures. We studied 70 patients with ACS (age:58[52,63]years, BMI:27[24,30]kg/m2). A level 2 polysomnogram was conducted to confirm OSA diagnosis within 6 months after discharge. Cardiovascular measures of heart rate variability(HRV), baroreflex sensitivity, pulse wave velocity (PWV) and endothelial function(FMD) were measured. PWAD was analysed using a validated algorithm. PWAD with an amplitude reduction of >30% from baseline and a duration >4 heartbeats were identified. PWAD frequency, duration, amplitude, area under the curve(AUC), descending and ascending slopes were calculated. There was no relationship between PWAD frequency and AHI (r=0.057, p=0.642). PWAD amplitude (rs= 0.308, p=0.031) and duration (rs= -0.319, p= 0.025) correlated with baroreflex effectiveness index. After controlling for age, gender and BMI, baroreflex effectiveness index was associated with PWAD duration (β±SE: -0.009±0.003, p=0.009). Aortic augmentation index correlated with PWAD duration (rs= 0.3565, p=0.0041). HRV parameters, FMD and PWV did not correlate with PWAD parameters (data not shown). These preliminary findings suggest PWAD duration and amplitude are not associated with OSA severity in patients with ACS. However PWAD may be appropriate markers of vascular and autonomic nervous system response in patients with cardiovascular disease.

Wearable technology metrics are associated with energy deficiency and psychological stress in elite swimmers

Energy deficiency (ED) and psychological stress affect athlete health. Given the emerging capabilities of wearable technology, the purpose of this study was to explore associations of wearable technology metrics in relation to lab-based measures of ED and psychological stress. We investigated the associations between (a) wearable-derived heart rate variability (HRV), resting heart rate (RHR), exercise strain and recovery, and (b) laboratory-derived measures of metabolism (resting metabolic rate (RMR), total triiodothyronine (TT3)) and a validated stress assessment (Recovery-Stress Questionnaire for Athletes (RESTQ)-52 items) in NCAA swimmers ( n = 23, 10 male, 13 female) during heavy training. Swimmers were grouped by degree of metabolic adaption to ED using the ratio of actual-to-predicted RMR (utilizing the validated cutoff of <0.94) and by sex. Metabolically suppressed swimmers had lower HRV (81 ± 27 ms vs.110 ± 35 ms, p = 0.04). HRV correlated positively with RMR (kcal·kg LBM−1·day−1; where LBM stands for lean body mass) ( r = 0.45; p = 0.03). HRV was negatively correlated with sport-specific ( r = −0.46; p = 0.03) and total stress ( r = −0.46; p = 0.03). In males, HRV correlated negatively with general stress ( r = −0.72; p = 0.02) and total stress ( r = −0.74, p = 0.01) (RESTQ). Additionally, in males only, the strain was correlated positively with RESTQ recovery–stress balance ( r = 0.69; p = 0.03), and negatively correlated with general stress ( r = −0.81, p = 0.01), and sport stress ( r = −0.89, p < 0.01). No correlations between HRV, RHR, strain or recovery, and stress variables were observed in females. Associations between wearable technology measures of HRV, RHR, strain, and recovery with validated measures of ED and psychological stress should continue to be explored with a focus on underlying mechanisms and moderating influences of biological sex.

Cardiac autonomic dysfunction in adult congenital heart disease

PurposeDue to recent advances in diagnosis and treatment, the number of adults with congenital heart disease (ACHD) has substantially increased. This achievement is mitigated by rhythm disorders. Here, we sought to determine alterations in heart rate variability (HRV) and their prognostic value in ACHD.MethodsNinety seven ACHD patients (39.2 ± 14.1 years, 51.5% female) and 19 controls (39.7 ± 15.0 years, 47.4% female) underwent 24-h Holter monitoring.ResultsAs compared to controls, ACHD patients offered a significantly higher burden of premature ventricular contractions (p = 0.02) and decreased HRV indices (natural logarithmic transformation of very low frequency (lnVLF): 7.46 ± 0.76 ms2 vs. 7.91 ± 0.92ms2, p = 0.03; natural logarithmic transformation of low frequency (lnLF): 6.39 ± 0.95ms2 vs. 7.01 ± 1.07ms2, p = 0.01; natural logarithmic transformation of the ratio of low to high frequency spectra (lnLF/HF): 0.81 ± 0.74 vs. 1.17 ± 0.51, p = 0.04). No differences in HRV measures were observed across ACHD lesion groups. NT-proBNP levels were significantly related to both time and frequency domain indices (natural logarithmic transformation of the standard deviation of NN intervals (lnSDNN): Spearman´s rho = -0.32, p = 0.001; natural logarithmic transformation of the standard deviation of the average NN intervals for each 5-min segment of a 24-h Holter monitoring (lnSDANN): Spearman´s rho: -0.33, p = 0.001; natural logarithmic transformation of the total power (lnTP): Spearman´s rho: -0.25, p = 0.01; lnVLF: Spearman´s rho: -0.33, p = 0.001; lnLF: Spearman´s rho: -0.35, p < 0.001; lnLF/HF: Spearman´s rho: -0.34, p = 0.001).After a mean follow-up of 3.9 ± 0.7 years, 8 patients died and 3 patients survived sudden cardiac death (SCD). Several HRV parameters were significantly higher in event-free ACHD patients than in those who died or survived SCD (natural logarithmic transformation of the average of the standard deviations of NN intervals for each 5-min segment of a 24-h Holter monitoring (lnASDNN): p = 0.04; lnPNN30: p = 0.04; lnVFL: p = 0.03; lnLF: p < 0.01). On univariate Cox regression analysis, the time domain indices lnSDNN, lnASDNN and lnPNN30, as well as the frequency domain parameters lnTP, lnVLF and lnLF were associated with death and survived cardiac arrest.ConclusionACHD is accompanied by HRV impairment that carries prognostic implications on ACHD mortality and survived SCD.

Assessment of Window Size and Layout Impact on a View Quality Perception in a Virtual Reality Environment

ABSTRACT Window views are key factors that affect buildings’ occupants psychological and physiological comfort and wellbeing. Window design should consider the holistic impacts on building energy, lighting performance, and the connection to the outdoors provided by the view which is usually overlooked. In this study, view perception, stress recovery, physiological, and psychological affect were evaluated in virtual environments of five different conditions varying the physical dimensions of a window located in the same office space with an urban view. This allowed three window-to-wall ratios (i.e. 10%, 20%, and 30%) and two different window layouts (i.e. narrow and wide) to be compared. Twenty-five participants were recruited. Subjective self-assessments on view perception (e.g. content and complexity), self-assessment and physiological measures (e.g. skin conductance and heart rate variability) stress recovery besides psychological affect were measured. Participants performed a Stroop-test to induce stress that was immediately followed by a period of recovery facilitated by exposure to one of the five window conditions. Results showed that increased window size advocated higher view perception assessments, increased stress recovery, and positive psychological affect. Measurements of skin conductance and heart rate variability also corroborated these findings. Differences in window layout were also revealed, but only for 10% WWRs. Therefore, WWR is not a reliable indicator for view perception for small window sizes, indicating that layout preference is dependent on window size. This study highlights the importance of considering view perception for occupant health and wellbeing when sizing window openings, since these may not necessarily align with other design criteria.

Effects of exercise training on heart rate variability in individuals with lower extremity arterial disease and claudication: A systematic review

PurposeTo perform a systematic review of studies assessing the effects of regular exercise on heart rate variability (HRV) in individuals with lower extremity arterial disease (LEAD) and symptoms of claudication. MethodsA systematic search in the electronic databases MEDLINE, Embase, and Scielo, was conducted and updated on January 21, 2023. Randomized clinical trials investigating patients with LEAD and IC, assessing ≥ 4 wk of exercise interventions, and reporting at least one HRV measure (e.g., time or frequency domains) at baseline and follow-up were included. Two reviewers independently screened studies for inclusion, performed data extraction, and quality assessment of included studies. ResultsData from 7 trials were included (i.e., 5 walking, 1 resistance, and 1 isometric handgrip training), totaling 327 patients (66% males; range: 61 - 68 yr; ankle brachial index: 0.4 - 0.7). Following exercise training, three studies investigating walking training reported an increase in parasympathetic modulation indices and/or a decrease in sympathetic modulation indices (n = 2) as well as an increase in non-linear indices (n = 1). ConclusionThe current evidence is weak, and larger randomized controlled trials are needed to confirm the efficacy of exercise training in improving HRV. Additionally, the high divergence in the methodology of studies indicated the need for standard tools to improve the quality of HRV measurements in exercise trials. It is recommended to use standard procedures in future trials investigating HRV.

Transcutaneous auricular vagus nerve stimulation attenuates inflammatory bowel disease in children: a proof-of-concept clinical trial

BackgroundVagus nerve stimulation is an investigational anti-inflammatory therapy targeting the nervous system to modulate immune activity. This study evaluated the efficacy and safety of transcutaneous auricular VNS (ta-VNS) in patients with pediatric-onset Crohn’s disease (CD) or ulcerative colitis (UC).MethodsParticipants were 10–21 years of age with mild/moderate CD or UC and fecal calprotectin (FC) > 200 ug/g within 4 weeks of study entry. Subjects were randomized to receive either ta-VNS targeting the cymba conchae of the external left ear, or sham stimulation, of 5 min duration once daily for a 2-week period, followed by a cross over to the alternative stimulation for an additional 2 weeks. At week 4, all subjects received ta-VNS of 5 min duration twice daily until week 16. Primary study endpoints were clinical remission, and a ≥ 50% reduction in FC level from baseline to week 16. Heart rate variability measurements and patient-reported outcome questionnaires were completed during interval and week 16 assessments.ResultsTwenty-two subjects were enrolled and analyzed (10 CD, 12 UC). Six of 10 with CD had a wPCDAI > 12.5 and 6/12 with UC had a PUCAI > 10 at baseline, correlating to mild to moderate symptom activity. Among the 12 subjects with active symptomatic disease indices at baseline, clinical remission was achieved in 3/6 (50%) with CD and 2/6 (33%) with UC at week 16. Despite all subjects having FC levels ≥ 200 within 4 weeks of enrollment, five subjects (4 UC, 1 CD) had FC levels < 200 at the baseline visit and were excluded from the FC analysis. Of the remaining 17, median baseline FC was 907 µg/g (IQR 411–2,120). At week 16, 11/17 (64.7%) of those with baseline FC ≥ 200 had a ≥ 50% reduction in FC (95% CI 38.3—85.8). In the UC subjects, there was an 81% median reduction in FC vs baseline (833 µg/g; p = 0.03) while in the CD subjects, median reduction in FC at 16 weeks was 51% (357 µg/g; p = 0.09). There were no safety concerns.ConclusionNoninvasive ta-VNS attenuated signs and symptoms in a pediatric cohort with mild to moderate inflammatory bowel disease.Trial RegistrationNCT03863704—Date of registration 3/4/2019.

Effect of Slow Breathing Exercise on Time Domain Heart Rate Variability in Transfusion Dependent Thalassemic Patients

Time domain measure of heart rate variability (HRV) is a newersystem to seek out any alteration in cardiacautonomic nerve function (CANF) in transfusion dependent thalassemic (TDT) patients. Slow breathing exercise(SBE) plays important role in improvement of HRV in health and various diseases.This research aims to observe theeffect of slow breathing exercise (SBE) on time domain measures of HRV in TDT patients. This prospectiveinterventional study was done in the Department of Physiology, Bangabandhu Sheikh Mujib Medical University(BSMMU), Dhaka in 2018 on 60 male TDT patients aged 15-30 years. Thirty patients received conventionaltreatment and 30 patients performed slow breathing exercise along with the conventional treatment for 3 months. Ageand sex matched healthy control were taken to compare. All subjects were followed up at baseline and after 3 months.Time domain HRV parameters were recorded by Power Lab 8/35. For statistical analysis paired sample 't' test andindependent sample 't' test were done. Mean RR interval, Mean SD, RMSSD and pRR50% were found significantlylower in TDT patients compared to healthy control at baseline and on the other hand mean heart rate was significantlyhigher in this group of patients. After 3 months of slow breathing exercise, significant decrement of mean heart rateand significant increment of others parameters occurred with trend of improvement in cardiac autonomic nervefunction in TDT patients. In conclusion slow breathing exercise may improve cardiac autonomic nerve function andsympathovagal balance in transfusion dependent thalassemic patients. Bangabandhu Sheikh Mujib Med. Coll. J. 2022;1(2):65-69

Heart rate variability and risk of agitation in Alzheimer's disease: the Atherosclerosis Risk in Communities Study.

Agitation in Alzheimer's disease is common and may be related to impaired emotion regulation capacity. Heart rate variability, a proposed index of autonomic and emotion regulation neural network integrity, could be associated with agitation propensity in Alzheimer's disease. We used the Atherosclerosis Risk in Communities Study cohort data, collected over seven visits spanning over two decades, to investigate whether heart rate variability (change) was associated with agitation risk in individuals clinically diagnosed with dementia due to Alzheimer's disease. Agitation (absence/presence) at Visit 5, the primary outcome, was based on the Neuropsychiatric Inventory agitation/aggression subscale, or a composite score comprising the total number of agitation/aggression, irritability, disinhibition and aberrant motor behaviour subscales present. Visit 1-5 heart rate variability measures were the log-transformed root mean square of successive differences in R-R intervals and standard deviation of normal-to-normal R-R intervals obtained from resting, supine, standard 12-lead ECGs. To aid interpretability, heart rate variability data were scaled such that model outputs were expressed for each 0.05 log-unit change in heart rate variability (which approximated to the observed difference in heart rate variability with every 5 years of age). Among 456 participants who had dementia, 120 were clinically classified to have dementia solely attributable to Alzheimer's disease. This group showed a positive relationship between heart rate variability and agitation risk in regression models, which was strongest for measures of (potentially vagally mediated) heart rate variability change over the preceding two decades. Here, a 0.05 log-unit of heart rate variability change was associated with an up to 10-fold increase in the odds of agitation and around a half-unit increase in the composite agitation score. Associations persisted after controlling for participants' cognitive status, heart rate (change), sociodemographic factors, co-morbidities and medications with autonomic effects. Further confirmatory studies, incorporating measures of emotion regulation, are needed to support heart rate variability indices as potential agitation propensity markers in Alzheimer's disease and to explore underlying mechanisms as targets for treatment development.

Cognitive function and heart rate variability in open and closed skill sports

Objectives The differences in sporting environments between open and closed skill sports impose unique demands on athletes’ cognitive and motor capabilities. Our study aims to investigate and compare cognitive function and Heart Rate Variability (HRV) among individuals involved in different sports, namely basketball, swimming, and a sedentary non-sports group. Materials and methods The study consisted of three groups, namely basketball players, swimmers, and sedentary individuals, with each group comprising twenty-six participants. HRV was assessed with the help of PowerLab. Cognition was assessed using the Ebbinghaus Memory Procedure Test (EMT), Go/No-Go Task (GNG), Color Stroop task, Trail Making Test (TMT), and Letter Cancellation test (LCT). Results The results of the Multivariate Analysis of Covariance (MANCOVA) analyses indicated that there was significance between the groups. However, no significant differences were observed between swimmers and basketball players in cognitive functions and HRV measures. Overall, the sport group outperformed the sedentary group. Specifically, basketball players and swimmers completed LCT and TMT faster than the sedentary group (p = 0.044 and p < 0.001 for basketball players, p = 0.002 and p = 0.001 for swimmers). Additionally, basketball players took fewer trials in EMT (p = 0.013) and less time (p = 0.026) compared to the sedentary group. Conclusion The results of the study indicate that sports training, regardless of sport type, positively impacts overall cognitive function. However, no significant differences were observed in cognitive task performance and HRV measures between open and closed skill sport players. These findings suggest that sports can enhance cognitive functions, regardless of the sport played.

Oscillation of Sympathetic Activity in Patients with Obstructive Sleep Apnea during the First Hour of Sleep.

(1) Background: Snoring is a cardinal symptom of obstructive sleep apnea (OSA) and has been suggested to potentially increase sympathetic activity. On the other hand, sleep itself usually leads to a decrease in sympathetic activity. Heart rate variability (HRV) analysis is a non-invasive technique used to assess autonomic nervous system function. However, there is limited research on the combined impact of sleep and snoring on sympathetic activity in individuals with OSA, particularly during the first hour of sleep (non-rapid eye movement sleep). The current study aims to investigate the net effect of sleep and snoring on sympathetic activity and explore factors that might contribute to increased sympathetic activity in individuals with OSA during the first hour of sleep. (2) Methods: The participants were referred from the outpatient department for OSA diagnosis and underwent whole-night polysomnography (PSG). Electrocardiogram (EKG) data from the PSG were downloaded for HRV analysis. HRV measurements were conducted in both the time and frequency domain, including the root mean square of successive differences between normal heartbeats (RMSSD) and the ratio of the absolute power of the low-frequency (LF) band (0.04-0.15 Hz) to the absolute power of the high-frequency (HF) band (0.15-0.4 Hz) (LF/HF ratio), respectively. (3) Results: A total of 45 participants (38 men and 7 women) were included in the analysis. The RMSSD gradually increased from 0-5 min to 50-60 min (p = 0.024), while the LF/HF ratio decreased (p < 0.001) during the first hour of sleep (non-rapid eye movement sleep). The LF/HF ratios of the "S" (snoring) episodes were compared with those of the pre-S episodes. An elevated LF/HF ratio during the S episode was associated with the first snoring episode occurring more than 20 min after lying down to sleep (Odds ratio, OR = 10.9, p = 0.004) and with patients diagnosed with severe OSA (OR = 5.01, p = 0.045), as determined by logistic regression. (4) Conclusions: The study observed an increase in the value of RMSSD and a decrease in the value of the LF/HF ratio during the first hour of sleep for patients with OSA. Higher LF/HF ratios were associated with the first occurrence of snoring while lying down for more than 20 min and with patients with severe OSA.

Psychophysiological assessment of trauma-focused Group Music and Imagery therapy for women with PTSD or CPTSD using script-driven imagery. A randomised controlled study.

BackgroundIn posttraumatic stress disorder (PTSD), physiological reactions during trauma scripts have been anchored to the diagnosis. According to the construct of research domain criteria, physiological reactions and self-rating scales could be used to evaluate treatment effects. ObjectiveIn the present study, self-rated PTSD symptoms combined with physiological reactions during trauma script were used as outcome measurements in the domain of arousal/regulatory systems in a controlled randomised study of Group Music and Imagery (GrpMI) treatment for females with PTSD or complex posttraumatic stress disorder (CPTSD) related to violence and/or sexual abuse. Methods45 traumatised women were randomised to 12 weeks of active treatment or waiting. Before and after the intervention, an assessment was done using physiological measurements during script-driven imagery (SDI) procedures. Subjective Units of Distress (SUD) were collected immediately after the trauma script (TS). Reactions during the SDI procedure were reported using the Responses to Script Driven Imagery (RSDI) scale, measuring re-experiencing, avoidance, and dissociation. Self-reported PTSD symptoms were accessed using the PTSD checklist for DSM-5 (PCL-5). Heart rate (HR), heart rate variability (HRV), and electrodermal activity were sampled during the baseline (BL) and TS conditions of the SDI procedure. As a measure of trauma-related reactivity, the difference between TS and BL was used for statistical calculations. HRV measures included high (HF; 0.15-0.4 Hz) and low (LF; 0.03-0.15 Hz) frequency band power, the LF/HF ratio, and the root mean square of successive inter-beat differences (RMSSD). Measures of electrodermal activity included skin conductance levels (SCL) and frequencies of non-specific skin conductance responses (NS-SCR). Further, correlations between self-rated PTSD symptoms and physiological reactivity measures were analysed. ResultsDuring the TS, the absolute levels of HR, LF/HF-ratio, and NS-SCR, as well as the trauma-related reactivity of HR, RMSSD, HF, LF/HF-ratio, SCL, and NS-SCR, showed significant changes indicating decreased arousal during trauma script after treatment. Compared to the waitlist control, an interaction analysis showed significant treatment effects in the BL level of HR, the absolute TS level of HR and HF, and the trauma-related reactivity of RMSSD and HF, suggesting an improvement of vagal function in the treatment group. Significant treatment-related reductions were found in symptoms of PTSD, re-experiencing and avoidance, as well as SUD. The changes pre- to post-treatment in HR reactivity and self-rated PTSD symptoms correlated significantly. Furthermore, the initial HR reactivity predicted treatment outcome as measured with PCL-5. ConclusionIn the evaluation of treatment methods for PTSD, a combination of self-report and physiological measures seems to be feasible. The physiological measures, in combination with a robust decrease in self-rated PTSD symptoms, indicate that trauma-focused GrpMI is a promising treatment for PTSD or CPTSD. More studies are needed to confirm the results, and further research comparing with other active treatments is necessary to establish the precise role of the treatment.

Evaluation of measurement accuracy of wearable devices for heart rate variability

This paper proposed a method based on heart rate variability (HRV) for evaluating the accuracy of wearable devices in measuring heart rate. HRV refers to the variation in time intervals between successive heartbeats, widely used in many fields such as clinical and sports fields. Wearable devices such as Electrocardiogram (ECG) electrode patches have gained popularity due to their portability and ease of use. However, they can be prone to measurement interference caused by environmental noise, human respiration, etc. The proposed method consists of four main components: selection of "gold standard measurement devices", identification of HRV measurement metrics, construction of an HRV evaluation framework, and quantification of measurement errors. The method is validated through simulated experiments using ECG patches. The evaluation framework and quantification model established in this method have significant implications in establishment of industry standards and diagnosis of diseases in clinical practice.

HIRA: Heart Rate Interval based Rapid Alert score to characterize autonomic dysfunction among patients with sepsis-related acute respiratory failure (ARF)

Objective. To examine whether heart rate interval based rapid alert (HIRA) score derived from a combination model of heart rate variability (HRV) and modified early warning score (MEWS) is a surrogate for the detection of acute respiratory failure (ARF) in critically ill sepsis patients. Approach. Retrospective HRV analysis of sepsis patients admitted to Emory healthcare intensive care unit (ICU) was performed between sepsis-related ARF and sepsis controls without ARF. HRV measures such as time domain, frequency domain, and nonlinear measures were analyzed up to 24 h after patient admission, 1 h before the onset of ARF, and a random event time in the sepsis controls. Statistical significance was computed by the Wilcoxon Rank Sum test. Machine learning algorithms such as eXtreme Gradient Boosting and logistic regression were developed to validate the HIRA score model. The performance of HIRA and early warning score models were evaluated using the area under the receiver operating characteristic (AUROC). Main Results. A total of 89 (ICU) patients with sepsis were included in this retrospective cohort study, of whom 31 (34%) developed sepsis-related ARF and 58 (65%) were sepsis controls without ARF. Time-domain HRV for Electrocardiogram (ECG) Beat-to-Beat RR intervals strongly distinguished ARF patients from controls. HRV measures for nonlinear and frequency domains were significantly altered (p < 0.05) among ARF compared to controls. The HIRA score AUC: 0.93; 95% confidence interval (CI): 0.88–0.98) showed a higher predictive ability to detect ARF when compared to MEWS (AUC: 0.71; 95% CI: 0.50–0.90). Significance. HRV was significantly impaired across patients who developed ARF when compared to controls. The HIRA score uses non-invasively derived HRV and may be used to inform diagnostic and therapeutic decisions regarding the severity of sepsis and earlier identification of the need for mechanical ventilation.

Heart Rate Variability in Psychiatric Disorders: A Systematic Review.

Heart rate variability (HRV) is a measure of the fluctuation in time interval between consecutive heart beats. Decreased heart rate variability has been shown to have associations with autonomic dysfunction in psychiatric conditions such as depression, substance abuse, anxiety, and schizophrenia, although its use as a prognostic tool remains highly debated. This study aims to review the current literature on heart rate variability as a diagnostic and prognostic tool in psychiatric populations. A literature search was conducted using the MEDLINE, EMBASE, Cochrane, and PsycINFO libraries to identify full-text studies involving adult psychiatric populations that reported HRV measurements. From 1647 originally identified, 31 studies were narrowed down through an abstract and full-text screen. Studies were excluded if they enrolled adolescents or children, used animal models, enrolled patients with another primary diagnosis other than psychiatric as outlined by the diagnostic and statistical manual of mental disorders (DSM) V, or if they assessed HRV in the context of treatment rather than diagnosis. Study quality assessment was conducted using a modified Downs and Blacks quality assessment tool for observational rather than interventional studies. Data were reported in four tables: 1) summarizing study characteristics, 2) methods of HRV detection, 3) key findings and statistics, and 4) quality assessment. There is significant variability between studies in their methodology of recording as well as reporting HRV, which makes it difficult to meaningfully interpret data that is clinically applicable due to the presence of significant bias in existing studies. The presence of an association between HRV and the severity of various psychiatric disorders, however, remains promising. Future studies should be done to further explore how HRV parameters may be used to enhance the diagnosis and prognosis of several psychiatric disorders.

Heart rate variability of acute ischemic stroke patients according to troponin levels

Objective: Neurogenic myocardial stunning is a type of stress-induced cardiomyopathy thought to be a result of dysregulation of the&#x0D; autonomic nervous system. Heart rate variability (HRV) analysis is a potential method for understanding the underlying mechanisms&#x0D; of autonomic dysfunction in ischemic stroke. The aim of the study was to investigate HRV in stroke patients in accordance with&#x0D; troponin levels.&#x0D; Patients and Methods: Sixty-six patients (mean age 65 ± 13 years; 39 male) presenting with acute ischemic stroke were consecutively&#x0D; included. High-sensitive cardiac troponin I (hs-cTnI) levels were accepted as elevated when&gt; 0.04 ng/mL. All patients underwent&#x0D; ambulatory electrocardiographic (ECG) monitoring within the first seven days to obtain time-domain and frequency-domain&#x0D; measures of HRV.&#x0D; Results: Twenty patients (30.3 %) had elevated hs-cTnI. Patients with high troponin levels had significantly lower left ventricular&#x0D; ejection fraction (LVEF), higher ST-segment-T wave changes, and higher N terminal pro-brain natriuretic peptide (NT-proBNP)&#x0D; levels. Low-frequency/high-frequency (LF/HF) value was significantly higher in the troponin-positive group, but other ambulatory&#x0D; ECG monitoring parameters such as SDNN, SDANN, RMSSD, and pNN50 were similar among patients.&#x0D; Conclusion: Neurogenic myocardial damage presenting with high troponin levels can be seen in ischemic stroke patients and may be&#x0D; associated with sympathetic overactivity.

The value of some indices of heart rate variability in the diagnosis of fetal growth retardation

Fetal growth retardation (FGR) is one of the most serious problems in current perinatology. This pathology leads not only to the deterioration of perinatal outcomes but also significantly increases morbidity during adult life. FGR is known to be featured by its delayed “neurological maturation”. This is manifested in a decrease in autonomic nervous regulation according to the fetal heart rate variability (HRV) scores and indices. The objective: to study HRV in fetuses with normal biometric indices compared to similar parameters of growth retarded fetuses. Materials and methods. The 47 pregnant women who had fetuses with normal biometric indices (I group) and 33 patients with fetal growth retardation (II group) were included in the study. The investigation of the fetal HRV was performed by processing the R–R intervals obtained via non-invasive electrocardiogram (ECG) and involved the following indices: STV (short term variations), LTV (long term variations), AC/DC (acceleration capacity/deceleration capacity), TP (total power), SI (stress index), SDNN (standard deviation of normal to normal intervals), EnRE (entropy of the time series), D2 (correlation dimension of the time series), Z (temporary irreversibility) і FL (measure of fuzzy logic, integrated measure of HRV). Results. The obtained data indicated that the indices of fetal HRV were reduced in the patients with FGR. These indices have utility in screening programs for the detection of fetal intrauterine nutrition and growth disturbances. The results of the study allow us to believe that the ability to accelerate heart rate patterns is partly preserved even during FGR. This may indicate a very ancient phylogenetic nature of the reaction of the heart system of the fetus to its motile activity. However, decelerations according to the DC were typical for FGR. A non-invasive fetal ECG could become a useful supplementary method in the current methods’ spectrum used in perinatal medicine. Conclusions. Therefore, the development of algorithms for the diagnosis of FGR requires the inclusion of the following HRV indices: STV, LTV, DC, TP, SI, SDNN, D2, Z, and FL. These biophysical markers of FGR can be used as a screening program in conditions of lack of access to high-quality ultrasound diagnostics or be a valuable addition to existing perinatal strategies.

Effect of mandibular advancement splint therapy on cardiac autonomic function in obstructive sleep apnoea.

This study aimed to evaluate the effect of mandibular advancement splint (MAS) therapy on cardiac autonomic function in patients with obstructive sleep apnoea (OSA) using heart rate variability (HRV) analysis. Electrocardiograms (ECG) derived from polysomnograms (PSG) of three prospective studies were used to study HRV of patients with OSA before and after MAS treatment. HRV parameters were averaged across the entire ECG signal during N2 sleep using 2-min epochs shifted by 30s. Paired t-tests were used to compare PSG and HRV measures before and after treatment, and the percent change in HRV measures was regressed on the percent change in apnoea-hypopnea index (AHI). In 101 patients with OSA, 72% were Caucasian, 54% men, the mean age was 56±11 years, BMI 29.8±5.3 kg/m2, and treatment duration was 4.0±3.2 months. After MAS therapy, there was a significant reduction in OSA severity (AHI, - 18 ± 16 events per hour, p < 0.001) and trends towards increased low-frequency to high-frequency ratio, low-frequency power, and reduced high-frequency power (LF:HF, - 0.4 ± 1.5, p = 0.01; LF, - 3 ± 16 nu, p = 0.02, HF, 3.5 ± 13.7 nu, p = 0.01). Change in NN intervals correlated with the change in AHI (β(SE) = - 2.21 (0.01), t = - 2.85, p = 0.005). No significant changes were observed in the time-domain HRV markers with MAS treatment. The study findings suggestthat successful MAS treatment correlates with changes in HRV, specifically the lengthening of NN intervals, a marker for improved cardiac autonomic adaptability.