Assessment Of Heart Rate Variability Research Articles

Association between heart rate variability and cardiorespiratory fitness in individuals with type 2 diabetes mellitus

Background: Type 2 Diabetes Mellitus (T2DM) is associated with cardiovascular risk, which is partly due to autonomic dysfunction and decreased cardiorespiratory fitness. This study examines the relationship between heart rate variability (HRV) and maximal oxygen uptake (VO2max) in T2DM patients to understand their interconnected impacts on autonomic and aerobic functions. Methods: In a cross-sectional study, 77 T2DM patients underwent HRV and VO2max assessments using standard protocols. HRV metrics were analysed in conjunction with VO2max, measured through direct breath-by-breath analysis. Pearson's correlation coefficient was used to investigate the relationships between HRV indices and VO2max. Results: VO2max showed strong positive correlations with RMSSD (r = 0.89, p < .001), HF (r = 0.54, p < .001), and pNN50% (r = 0.52, p < .001), indicating higher parasympathetic activity with improved cardiorespiratory fitness. Negative correlations with LF (r = -0.60, p < .001) and the LF/HF ratio (r = -0.39, p < .001) suggested that better fitness levels lead to sympathetic withdrawal and a more favourable autonomic balance. Moderate positive correlations with SDNN (r = 0.46, p < .001) and TP (r = 0.58, p < .001) further suggested that overall autonomic modulation is enhanced with increased cardiorespiratory fitness. Conclusion: This study substantiates a significant correlation between HRV and VO2max in individuals with T2DM, highlighting the intricate relationship between autonomic function and aerobic capacity. These findings suggest that enhancing cardiorespiratory fitness may improve autonomic balance, offering potential avenues for mitigating cardiovascular risk in the T2DM population.

Assessment of Heart Rate Variability in Children with Mitral Valve Prolapse.

Mitral valve prolapse (MVP) is a heart valve anomaly with specific electrocardiographic findings and arrhythmia. A predominant sympathetic tone and diminished vagal activity have been reported especially in symptomatic MVP patients. In the current study, we aim to review heart rate variability (HRV) parameters of MVP children in order to determine if there is an impaired autonomic regulation. The data of children with MVP were retrospectively analyzed. Demographic characteristics, body mass index, symptomatology, MVP type and mitral regurgitation, MVP-related electrocardiographic changes, arrhythmia, and HRV parameters in 24-h Holter monitoring were recorded. HRV parameters of the control group were obtained from children applying for sport participation. Statistical significance limit was accepted as p < 0.05. 154 of the patients (74.8%) were girls, the median age was 13.58 ± 2.99years. While MVP patients had shorter PR intervals, those who had syncope had longer PR intervals. Short PR distance may be a feature of MVP, long PR distance may be a condition associated with syncope with the underlying paroxysmal atrioventricular block. Moreover, the minimum heart rate was significantly lower in the MVP group compared to the control and there were no significant differences in terms of remaining parameters. The number of low LF values was higher in MVP patients than the control. Comparing HRV values of groups by gender, we found that overall HRV parameters were lower in girls with MVP while minimum, maximum, and average heart rate were lower in boys with MVP. Impaired HRV associated with MVP could be age, gender, and symptom related. In addition, low LF may indicate impaired baroreflex sensitivity in MVP patients.

Analysis of Heart Rate Variability in Individuals Affected by Amyotrophic Lateral Sclerosis.

Amyotrophic lateral sclerosis (ALS) produces alterations in the autonomic nervous system (ANS), which explains the cardiac manifestations observed in patients. The assessment of heart rate variability (HRV) is what best reflects the activity of the ANS on heart rate. The Polar H7 Bluetooth® device proves to be a non-invasive and much faster technology than existing alternatives for this purpose. The goal of this study is to determine HRV using Polar H7 Bluetooth technology in ALS patients, comparing the obtained measurements with values from healthy individuals. The sample consisted of 124 participants: 68 diagnosed with ALS and 56 healthy individuals. Using Polar H7 Bluetooth technology and the ELITE HRV application, various HRV measurements were determined for all participants, specifically the HRV index, RMSSD, RMSSD LN, SDNN index, PNN50, LF, HF, LF/HF ratio, HR average, and HF peak frequency. Statistically significant differences were observed between ALS patients and healthy individuals in the HRV index, RMSSD, RMSSD LN, SDNN index, PNN50, HF, and LF, where healthy individuals exhibited higher scores. For the HR average, the ALS group showed a higher value. Values were similar when comparing men and women with ALS, with only a higher HF peak frequency observed in women. The Polar H7 Bluetooth® device is effective in determining heart rate variability alterations in ALS, being a promising prognostic tool for the disease.

Continuous Long-Term Assessment of Heart Rate Variability in Adults with Cyanotic Congenital Heart Disease after Surgical Repair.

Background: Heart rate variability (HRV) is an established, non-invasive parameter for the assessment of cardiac autonomic nervous activity and the health status in general cardiology. However, there are few studies on HRV in adults with congenital heart defects (CHDs). The aim of the present study was to evaluate the use of long-term continuous HRV measurement for the assessment of global health status in adults with cyanotic CHD. Methods: This prospective study included 45 adults (40% female, mean age = 35.2 ± 9.2 [range: 19-58] years) after cardiac surgical repair. HRV parameters were calculated from continuous 24 h measurements using a Bittium Faros 180 sensor (Bittium Corp., Oulu, Finland). Results: Postoperative patients with transposition of the great arteries (TGA) (n = 18) achieved significantly higher values of standard deviation of NN intervals (SDNN) (175.4 ± 59.9 ms vs. 133.5 ± 40.6 ms; p = 0.013) compared with patients with other conotruncal anomalies (n = 22). Comparing patients with TGA after a Senning-Brom or Mustard operation (n = 13) with all other heart surgery patients (n = 32), significantly higher HRV parameters were found after atrial switch (root mean square of successive RR interval differences: 53.6 ± 20.7 ms vs. 38.4 ± 18.3 ms; p = 0.019; SDNN: 183.5 ± 58.4 ms vs. 136.3 ± 45.3 ms; p = 0.006). A higher SDNN was also measured after Senning-Brom or Mustard operations than after a Rastelli operations (n = 2) (SDNN: 183.5 ± 58.4 ms vs. 84.5 ± 5.2 ms; p = 0.037). When comparing atrial switch operations (n = 3) with Rastelli operations, the SDNN value was significantly shorter in the Rastelli group (p = 0.004). Conclusions: Our results suggest that continuous HRV monitoring may serve as a marker of cardiac autonomic dysfunction in adults with cyanotic CHD after surgical repair. Impaired cardiac autonomic nervous activity may be associated with an increased risk of adverse reactions in patients with repaired CHD. Therefore, a longitudinal assessment of HRV patterns and trends may provide a deeper insight into dynamic changes in their autonomic regulation and disease progression, lifestyle changes, or treatments. As each person has individual variability in heart rate, HRV may be useful in assessing intra-individual disease progression and may help to improve personalized medicine. Further studies are needed to better understand the underlying mechanisms and to explore the full potential of HRV analysis to optimize medical care for ACHDs.

The potential of infra-low frequency neurofeedback training in peak performance: the first double-blinded placebo-controlled longitudinal study in healthy adults

Infralow frequency neurofeedback training (ILF-NFT) has shown promise in addressing cognitive and affective distress symptoms across a range of psychiatric disorders. This study tested ILF-NFT’s effect in a double-blinded, placebo-controlled longitudinal context in healthy psychology students.Across five weeks, forty-two healthy psychology students (aged 18-35) were randomly allocated into two groups, receiving ten sessions of 30 minutes of active and sham ILF-NFT. Dependent variables were measured before, following, and two months after the intervention and were comprised of: heartrate variability assessments as a measure of stress resilience; digit span, n-back, trail making and go-no-go task measures of executive functioning performance; and SCL-90-R, WHOQOL-Bref, and peak performance measures of subjective self-report. Statistical analysis was performed using an ANCOVA and compared across groups correcting for baseline differences and multiple comparisons.ANCOVA analyses revealed no significant differences across active and placebo groups in any dependent variables, when correcting for multiple comparisons. Thus, the remaining analyses focused on questionnaire correlations. Here, significant correlations were observed between the novel peak performance questionnaire with the SCL-90-R and WHOQOL-Bref, confirming its construct and retest validity.Despite several methodological limitations, including a potential type-2 error, this study highlights limited effects of ILF-NFT in healthy volunteers. Future research should thus focus on clinically driven experimental designs to explore ILF-NFT’s potential in psychiatric contexts. Further research utilization of the novel peak performance questionnaire is recommended for measures of peak performance.

Evaluation of Cardiovascular Autonomic Nervous System in Essential Tremor and Tremor Dominant Parkinson's Disease.

(1) Background: The differential diagnosis of essential tremor (ET) and tremor-dominant Parkinson's disease (TDPD) can be challenging. Only a few studies have investigated the autonomic nervous system (ANS) in ET. However, some of these suggested that heart rate variability (HRV) might be useful in the differential diagnosis. (2) Methods: Demographic and clinical data, including medications and comorbidities, were collected from 15 TDPD patients, 19 ET patients, and 20 healthy controls. Assessment with the SCOPA-AUT questionnaire, 5 min HRV analysis in time and frequency domains, and evaluation of orthostatic hypotension (OH) with tilt test were performed. (3) Results: There were no significant differences between all groups on the SCOPA-AUT questionnaire. PD patients had OH more frequently and a larger drop in systolic blood pressure (SBP) during the tilt test than ET patients and controls. HRV was affected in PD, but not in ET and controls. Power in the low frequency band, the standard deviation of all normal RR intervals and SBP drop were potentially useful in differential diagnosis with AUCs of 0.83, 0.78, and 0.83, respectively. (4) Conclusions: Cardiovascular ANS dysfunction was present in TDPD, but not in ET and controls. HRV analysis and assessment of SBP drop may be potentially useful in the differential diagnosis of ET and TDPD.

Assessing Heart Rate Variability and Pulse Rate Variability Patterns in Cardiac Patients: Exploring the Utility of Photoplethysmography and Electrocardiography

The measure of cardiac variability (HRV) is considered an accurate diagnostic method to identify autonomic dysfunction. The heart rate influences the pulse. Therefore, pulse rate variability (PRV), like HRV, precisely indicates autonomic nervous system tone. The research investigates the correlation between HRV for the ECG signal and PRV in a cardiac patient. Method and Materials: 53 electrocardiogram (ECG) and photoplethysmogram (PPG) signals for 8 minutes from the PhysioNet BIDMC PPG and Respiration Dataset were used. Afterward, the PRV from PPG and the R-R interval calculated independently using Acqknowledge software were used to estimate the ECG and get HRV characteristics. Results: According to the results, there was a strong correlation between the R-R interval for PRV (694.49 ± 112.98ms) and HRV (695.60 ± 112.97ms) (r=0.99). For all linear parameters for both domains, frequency and time of HRV and PRV, there was a significant positive correlation: HFnu (r =0.99), HF Power (r =1), LFnu (r = 0.99), LF Power (r = 1), RMSSD (r = 0.99), SDNN (r = 0.99), NN50 (r = 0.99), and pNN50 (r =0.99). The Bland &amp; Altman plot demonstrated a high level of agreement among approaches for all parameters. Conclusion: According to the finding, which showed a high level of agreement because it provides values similar to PRV and HRV for all parameters, the idea of PRV rather than HRV can be used to assess sympathovagal regulation in a broad community-based investigation alongside HRV under various clinical circumstances.

Effects of stress management interventions on heart rate variability in adults with cardiovascular disease: a systematic review and meta-analysis.

Meta-analysis was used to investigate the potential benefits of stress management interventions (SMIs) on vagally-mediated heart rate variability (HRV) in adults with cardiovascular disease. Electronic bibliographic databases were searched through August 2022. Randomized controlled trials and quasi-experimental studies assessing effects of SMIs on HRV were included. Methodological quality was assessed with a standardized checklist. A pooled effect size was calculated for vagally-mediated HRV indices (standard deviation of normal-to-normal intervals, root mean square of the successive differences, and high frequency power) using random effects models. Fourteen studies (1202 participants, Mage: 59 ± 6.25years; 25% ± 16% women; 61% ± 22% White) were included. Ten studies (11 effects) reported short-term HRV assessment; a small between-group difference emerged for vagally-mediated HRV (d+ = .27, 95% confidence interval [CI] 0.01-0.52, k = 11). Most interventions examined biofeedback; these studies yielded a small between-group difference on vagally-mediated HRV (d+ = 0.31, 95% CI 0.09-0.53, k = 7, Q [6] = 3.82, p = .70, I2 = 11%). This is the first systematic examination of the effect of SMIs on HRV in adults with CVD. Findings suggest a small effect of SMIs on vagally-mediated HRV, with biofeedback likely driving the effect. More research is required to fully understand whether this benefit on vagally-mediated HRV applies to other SMIs.

The Post-Flight Rehabilitation Program for Astronauts in Health Resort: Case Report Series

INTRODUCTION. The prospects for studying deep space are associated with the development of methods and programs for restoring the body of astronauts after flights. In this case, an important role is given to the implementation of aspects of restoring the functions of the nervous system of astronauts at the 2nd stage of post-flight rehabilitation (PFR) in Health Resort.&#x0D; AIM. To develop a program of rehabilitation for cosmonauts in Health Resort (stage 2 of PFR), aimed at restoring the functions of the nervous system.&#x0D; MATERIALS AND METHODS. The study involved 5 cosmonauts. Diagnostics included assessment of psychological and psychophysiological parameters and properties of the nervous system, the functional state of the autonomic nervous system. The rehabilitation program included: intake of mineral water “Slavyanovsky”, carbon dioxide-hydrogen sulfide baths, baro-, halo-, inhalation and climate therapy, a course of 5 sessions of neurofeedback on the β-rhythm of the brain. The duration of PFR was 21 days, procedures were carried out every other day.&#x0D; RESULTS AND DISCUSSION. An assessment of heart rate variability revealed the predominance of the influence of the parasympathetic division. After the rehabilitation course, there was a decrease in the stiffness index. There was a positive trend towards normalization of indicators: blood saturation, reflection index, a marker of left ventricular function, cardiac output, blood pressure and oxygen absorption from the microcirculatory system. The dynamics of biofeedback training indicators based on the β-rhythm indicated the orderliness and synchronization of the electroencephalogram (EEG) rhythm signal; an increase in the efficiency of mental work was also revealed.&#x0D; CONCLUSION. The results obtained indicate the positive impact of the developed program of the 2nd stage of PFR, as a result of which a positive dynamics of indicators of autonomic regulation, central hemodynamics, improvement of mental performance, orderliness and synchronization of the EEG rhythm signal.

Investigating the Feasibility of Using a Wearable Device to Measure Physiologic Health Data in Emergency Nurses and Residents: Observational Cohort Study.

Emergency departments play a pivotal role in the US health care system, with high use rates and inherent stress placed on patients, patient care, and clinicians. The impact of the emergency department environment on the health and well-being of emergency residents and nurses can be seen in worsening rates of burnout and cardiovascular health. Research on clinician health has historically been completed outside of clinical areas and not personalized to the individual. The expansion of digital technology, specifically wearable devices, may enhance the ability to understand how health care environments impact clinicians. The primary objective of this pilot study was to assess the feasibility and acceptability of using wearable devices to measure and record physiologic data from emergency nurses and resident physicians. Understanding strategies that are accepted and used by clinicians is critical prior to launching larger investigations aimed at improving outcomes. This was a longitudinal pilot study conducted at an academic, urban, level 1 trauma center. A total of 20 participants, including emergency medicine resident physicians and nurses, were equipped with a wearable device (WHOOP band) and access to a mobile health platform for 6 weeks. Baseline surveys assessed burnout, mental health, and expectations of the device and experience. Participants provided open-ended feedback on the device and platform, contributing to the assessment of acceptance, adoption, and use of the wearable device. Secondary measures explored early signs and variations in heart rate variability, sleep, recovery, burnout, and mental health assessments. Of the 20 participants, 10 consistently used the wearable device. Feedback highlighted varying experiences with the device, with a preference for more common wearables like the Apple Watch or Fitbit. Resident physicians demonstrated higher engagement with the device and platform as compared with nurses. Baseline mental health assessments indicated mild anxiety and depressive symptoms among participants. The Professional Fulfillment Index revealed low professional fulfillment, moderate workplace exhaustion, and interpersonal disengagement. This pilot study underscores the potential of wearable devices in monitoring emergency clinicians' physiologic data but reveals challenges related to device preferences and engagement. The key takeaway is the necessity to optimize device and platform design for clinician use. Larger, randomized trials are recommended to further explore and refine strategies for leveraging wearable technology to support the well-being of the emergency workforce.

Assessment of heart rate variability among healthy 1st year medical students in a Government Medical College of Kolkata: A cross-sectional observational study

Background: Heart rate variability (HRV) means the beat-to-beat variations of cardiac rhythm which is influenced by the interplay of sympathetic and parasympathetic nerves. At present, cardiovascular morbidity and mortality have become a matter of great concern in the young population. Such complications may arise from cardiac dysautonomia. HRV analysis may be considered an efficient tool to detect this derangement as early as possible. Moreover, normative data on HRV should be established among the young population of India considering other demographic parameters such as gender, height, weight, and BMI. Aim and Objective: Our study intends to establish normative data for short-term HRV parameters among medical students of a tertiary care hospital in West Bengal. Materials and Methods: After obtaining approval from the Institutional Ethics Committee, 250 apparently healthy medical students were assessed and HRV parameters such as mean RR, mean HR, SDNN, NN50, pNN50, root mean square of successive differences (RMSSD), high frequency (HF), low frequency (LF), and LF/HF ratio were recorded. Results: In time domain parameters, values were significantly higher in males for mean HR and significantly higher in females for mean RR, NN50, and pNN50. In frequency domain parameters, significantly higher values were found for LF and LF/HF ratio in males and HF in females. Conclusion: We have established gender-based normative values of HRV parameters in the young population.

Exploring factors associated with heart rate variability in newly injured traumatic cervical spinal cord injury patients

Background: Assessment of heart rate variability (HRV) in traumatic cervical spinal cord injury (SCI) patients is widely reported, but few studies have examined the HRV in the newly injured. Further, there is paucity of data relating HRV to factors that might have a bearing on the extent of variability in them. Aim and Objectives: The current study explored the factors associated with the HRV of newly injured cervical SCI American Spinal Injury Association (ASIA) Impairment Scale (AIS) grade A/B patients. Materials and Methods: A secondary analysis of HRV data acquired from 24 newly injured tetraplegic patients in a previously published study compared the HRV between AIS grade A and B patients, and across cervical levels of lesion. In addition, the correlation of HRV indices with duration since injury and the patients’ age was examined. Results: The ratio of low to high frequency power was significantly lower in AIS B compared to AIS A patients, and significantly negatively correlated with duration since injury. Conclusion: The ratio of modulations of cardiac sympatho-vagal supply was lower in AIS B patients and reduced with increasing duration since injury. AIS grade and duration since injury need to be considered when interpreting the HRV data of newly injured tetraplegic patients.

Classification of Congestive Heart Failure Using Artificial Neural Network Based on Higher-Order Moments Detrended Fluctuation Analysis of Heart Rate Variability

Coronary heart disease or cardiovascular disease is a kind of heart disease that affects the heart and all the blood vessels in the body caused by a build-up of plaque in a person's arteries and can result in a stroke or heart attack. According to the Indonesian Ministry of Health, (Depkes RI) coronary heart disease is the main and first cause of all deaths by heart disease, which account for 26.4% among all other causes. Considering the severity of the condition, it is necessary to detect this kind of heart disease to reduce the number of deaths from heart disease. Heart disease detection can be performed by checking the Heart Rate Variability (HRV) signal. HRV assessment is carried out by analyzing short-term and long-term Electrocardiogram (ECG) records. To analyze HRV signals, a Higher-Order Moments Detrended Fluctuation Analysis feature extraction method is proposed to see the non-linear structure of HRV data. The input for Higher-Order Moments Detrended Fluctuation Analysis is an ECG signal which has been converted into an HRV signal. The output of the feature extraction shows that the value of kurtosis-based fluctuation function has a statistical significance in order to differentiate the HRV of heart disease patients and that of normal subjects. These values are then used as the input for classification using an Artificial Neural Network. The output of the classification is the classification of patients with heart disease and normal subjects. The results of the Higher-Order Moments Detrended Fluctuation Analysis feature extraction classification yield the best accuracy of 71.43% with a ROC value of 0.774 which can be categorized as a pretty good classification.

3M: Measuring Vital Signs with Markov-Gauss Model.

Measuring vital signs (VS) contained in the echoes is crucial to the analyses of breathing and heartbeat signals using medical radar. Although many advanced signal processing algorithms have been developed for radar-based VS measurement and make some improved progress, existing schemes cannot achieve a good estimation of echo phases modulated by the respiratory and cardiac activities with high accuracy or low computation, and thus resulting in serious performance degradation on the subsequent separation of breathing and heartbeat patterns as well as the assessment of breathing rate (BR), heart rate (HR), and heart rate variability (HRV). In this paper, we propose a simple yet effective method to measure VS for medical radar, named 3M method. Specifically, our method firstly introduces the Markov-Gauss model to obtain the recursive expression of the echo phases carrying VS, and secondly derive a simple observation equation(SOE) to reflect the relationship between the observed signal and VS of radar measurement. Thirdly, the aforementioned Markov-Gauss model and SOE are fused by Kalman filter to measure VS with accurate estimation. The 3M method demonstrates an elegant structure, low complexity and excellent features introduced by Kalman filter. Simulation results show the superiority of 3M over other methods. Then, we conduct extensive experiments with insightful visualizations to validate the effectiveness of the 3M method. Comparative results on different scenarios illustrate that the 3M method not only achieves state-of-the-art VS measurement performance but also expresses robust properties to HRV analysis.

Analysis of oscillatory processes in the cardiovascular system in response to local heating in patients with type 2 diabetes mellitus

A comprehensive spectral analysis was used to assess heart rate variability and skin perfusion pattern of limbs in patients with type 2 diabetes mellitus in response to local heating and to identify significant predictors of physiological and pathological changes in the cardiovascular system. An electrocardiogram and skin perfusion on the forearm and foot were measured using Laser Doppler flowmetry at rest and during local heating in both healthy volunteers and patients with type 2 diabetes. The wavelet analysis was applied to Laser Doppler signals and heart rate variability (based on electrocardiogram signals). ROC analysis was used to evaluate significant predictors. The analysis results of patients with type 2 diabetes were compared with healthy controls. The following changes were observed in patients 1) impairment of skin blood flow reserve on the foot during heating, 2) lower amplitude oscillations in heart rate at rest and during heating, 3) an increase in amplitude of oscillations in the skin blood flow from the forearm in intervals related to respiration and heart activity at rest and during heating, 4) a decrease in amplitude of oscillations in the skin blood flow on the foot in the interval related to myogenic activity at rest and in cardiointerval during heating. The parameters of cardiovascular system (energies of heart rate variability at low-frequencies recorded by laser Doppler flowmetry on forearm in intervals related to respiration activity) with high discriminative power were revealed to distinguish patients from healthy subjects in response to local heating; these parameters can be used as markers for early diagnosis of microvascular disorders.

Loneliness during the post-confinement period: The significance of social living conditions for stress biomarkers and memory

In the aftermath of the COVID-19 lockdown, concerns about the impact of loneliness and reduced social interactions on mental health have arisen. This study explored the repercussions of post-lockdown social restrictions across psychological (loneliness, perceived stress, and depressive symptoms), biological (hair cortisol and cardiovascular activity), and cognitive dimensions (subjective memory complaints and working, declarative, and prospective memory), with a specific emphasis on perceived loneliness and the living situation. The study included 45 students: 23 (mean age = 25.69 years) in the Alone Group (AG), who experienced significant family changes and international relocation, and 22 (mean age = 25.50 years) in the Not Alone Group (NAG), who maintained their nuclear family and did not move from their home country. We assessed heart rate variability (HRV) before, during, and after immediate memory evaluations using time-domain (the square root of the mean, RMSSD) measures. The analysis revealed no significant group differences in telematic contact with family and friends, perceived stress, or depression. However, the AG participants reported fewer face-to-face interactions and greater perceived loneliness compared to the NAG. Additionally, the AG group exhibited slightly higher hair cortisol levels and worse working memory (WM) and prospective memory (PM) performance. Importantly, no significant associations were observed between memory outcomes and stress biomarkers. However, a significant interaction effect of loneliness in the relationship between hair cortisol levels and PM was found. That is, hair cortisol concentrations were negatively related to PM when participants perceived high and moderate loneliness. This interaction was absent in the working and declarative memory domains. In summary, these findings underscore the intricate interplay between loneliness, cortisol, and memory, emphasizing the need for comprehensive research on the complex mechanisms governing these multifaceted relationships.

Multimodal coupling and HRV assessment characterize autonomic functional changes in congestive heart failure patients with sinus rhythm or severe arrhythmia

Autonomic nervous system (ANS) dysfunction is a significant characteristic of patients with congestive heart failure (CHF). Respiratory sinus arrhythmia (RSA) serves as an index of parasympathetic nervous system (PNS) function usually quantified by the high-frequency power of heart rate variability (HRV). However, the high breathing rate of CHF patients results in deviations when estimating RSA by HRV. Multimodal coupling analysis (MMCA) is a novel method of quantifying RSA which decomposes the R-R signal adaptively into intrinsic mode functions (IMFs) followed by identification of the RSA-related IMF. MMCA also calculates the phase synchronization between RSA-related IMF and respiratory signals to exclude the influences that are unrelated to RSA. In this study, we introduced HRV and MMCA-derived parameters to quantify ANS function for CHF patients, along with their comparisons in the clinical efficacy evaluation. Thirty-seven CHF patients were recruited, including 17 with sinus rhythm (SRHF) and 20 with severe arrhythmia (ARHF). Our results showed that all parameters for SRHF patients increased after treatment except for LF/HF. Only LF/HF, α2, and MMCA-derived RSA showed significant differences after treatment for ARHF patients, wherein the MMCA-derived RSA significantly decreased regardless of the left ventricular ejection fraction. The PNS function and ANS balance were recovered in all the CHF patients after treatment. Metrics including MeanRR, SDRR, LF, HF, TPower, SD1, SD2, and MMCA-derived RSA showed more significant improvements in SRHF patients whose New York Heart Association functional class improved after treatment. These metrics can be used to guide prognosis and therapeutic efficacy monitoring.

Heart Rate Variability as a Predictor of Daytime Sleepiness During Prolonged Isolation

The 120-day isolation experiment (SIRIUS-19 program) within the SIRIUS project (http://sirius.imbp.ru/) involved 6 volunteers aged 28 to 44 years (three men and three women). Research methods included daily ECG registration to assess heart rate variability, blood pressure measurement and self-assessment of sleep quality over the past night using a visual analogue scale. The studies were carried out in the morning after waking up. Once a week in the evening (17.00–19.00), volunteers filled out a scale of clinical daytime sleepiness self-assessment, which allows evaluate the subjective condition over the past day. During the regression analysis, the possibility of predicting the appearance of daytime sleepiness in terms of cardiac activity was assessed. It was found, that the heart rate, blood pressure and heart rate variability indicators recorded in the morning time make it possible to measure the quality of past sleep and predict the level of subsequent daytime sleepiness. We assume that the increased activity of the parasympathetic branch of the autonomic nervous system in the morning characterizes both the previous lack of sleep and the risk of developing sleep inertia and daytime sleepiness in general.

A wearable device based on the ionic liquid decorated sponge-like ultraviolet-curable resin for recognizing human mental health conditions

Developing a wearable device that can reliably and continuously detect human pulse signals and assess heart rate variability (HRV) parameters is essential for discriminating healthy subjects from patients with cardiovascular diseases and mental health disorders. Here, by combining a template-assisted ultraviolet-curing method with a subsequent ionic liquid modification, we propose a sponge-like dielectric layer and adopt it to construct a wearable device for decoding human mental health conditions. Benefiting from the coexisting sponge-like structures and an ionic liquid, the proposed wearable device presents a robust capacitance response, and could continuously monitor human pulse signals as well as analyze inter-beat intervals (IBIs) and HRV parameters of volunteers under different emotional states. Lastly, IBIs distributions and heart rates extracted from the pulse signals of the volunteers with different emotional conditions are employed as input features to train a machine-learning model, which is performed to further demonstrate the possibility of recognizing human emotions via pulse signal analysis. In conclusion, by incorporating the proposed wearable device with a machine-learning model, it is expected to achieve the emotional recognition of the volunteers with a piece of the pulse signal, showing promising potential in future human-machine interaction personalized with medical services, communications, and entertainment.

Nursing students' perceived anxiety and heart rate variability in mock skill competency assessment.

Skill competency assessments induce stress and anxiety and may affect nursing student performance. Little is known about stress and perceived anxiety levels and their relationship in the mock skill competency assessment. A cross-sectional study was conducted to examine the stress levels (as assessed by heart rate variability, HRV) and perceived anxiety before, during and after the mock skill competency assessment, and to explore their relationships to performance in a total of ninety first-year undergraduate nursing students. The HRV decreased significantly during the assessment and increased significantly 10 min after the assessment (p < 0.01). Higher performers showed significantly lower HRV during and after the assessment (p < 0.01). The assessment score was negatively correlated with HRV during and after the assessment (p < 0.05). Considering assessment-related stress and anxiety through a mock assessment prior to the actual skill assessment provides implications for future nursing education.