Evaluation Of Heart Rate Variability Research Articles

A Pilot Study Using a Smartwatch to Search for Biomarkers of Heart Rate Variability in Active Ulcerative Colitis.

Autonomic imbalance has been reported to correlate with clinical remission in patients with ulcerative colitis (UC). This study evaluated heart rate variability (HRV), a potential digital biomarker, in patients with active UC using a smartwatch that is easy to handle. Patients with active UC were recruited for this prospective study. The patients' HRV was measured via the Fitbit Inspire2™ linked via Bluetooth to their smartphone. HRV during nighttime sleep was obtained from continuous data. Patients were required to input the Simple Clinical Colitis Activity Index (SCCAI) score once daily by the application on their smartphones for 3 months. Nine patients with UC were included. In clinically active disease, SCCAI scores showed a weak inverse relationship with parasympathetic activity, differences of successive R-R pulse intervals (RMSSD) (r = -0.44, p < 0.0001), high frequency (HF) (r = -0.42, p < 0.0001), and total autonomic nervous activity, low frequency (LF) (r = -0.43, p < 0.0001). Receiver operating characteristic analysis indicated that the RMSSD, HF, and LF were significantly higher in patients with active UC. Meanwhile, LF showed the most correlation with severity for bowel urgency scores. Longitudinal nighttime HRV recorded using a smartwatch is associated with disease activity in patients with active UC. In particular, RMSSD and HF, which are indices of the parasympathetic nervous system, have been suggested as potential digital biomarkers for UC.

Wearable heart rate variability analysis system based on ionic conductive hydrogels.

Developing a wearable device that can continuously and reliably detect and evaluate heart rate variability (HRV) parameters is critical for the diabetic population with cardiac autonomic neuropathy (CAN). In this work, we proposed a zwitterionic conducting hydrogel that enabled a reliable and comfortable wearable device for the evaluation and detection of the autonomic nervous system (ANS). The hydrogel can achieve a strain of 2003%, an electrical conductivity of 190mS/m, and is capable of adhering to a variety of materials, including wood, plastic, and glass. Through the excellent performance of the hydrogel, we can continuously monitor the electrocardiogram (ECG) signals of healthy people and diabetic patients in the resting state for 5min and analyze the HRV parameters in the time domain, frequency domain and nonlinear condition. The results showed that compared with healthy people, the HRV parameters of diabetic patients were decreased. Finally, the obtained state of the ANS is displayed through a self-designed mini-program on WeChat. In conclusion, by combining the proposed hydrogel with wearable devices, real-time monitoring of CAN in diabetic patients is expected to be achieved and shows great potential in personalized human-computer interaction.

Association between cardiac autonomic regulation, visceral adipose tissue, cardiorespiratory fitness and ambient air pollution: 4HAIE study (Program–4)

Background The main objective of the present cross-sectional cohort study was to determine whether there is an association between cardiac autonomic regulation, as expressed through heart rate variability (HRV), and cardiorespiratory fitness (CRF), visceral adipose tissue (VAT), and over the long-term living in areas with low or high air pollution. Methods The study sample included 1036 (487 females) healthy runners (603) and inactive participants (age 18–65 years) who had lived for at least 5 years in an area with high (Moravian-Silesian; MS) or low (South Bohemian; SB) air pollution in the Czech Republic. A multivariable regression analysis was used to evaluate the associations between multiple independent variables (CRF (peak oxygen consumption), VAT, sex, socioeconomic status (education level), and region (MS region vs. SB region) with dependent variable HRV. The root mean square of successive RR interval differences (rMSSD) was employed for the evaluation of HRV. Results The multivariable linear regression model revealed that cardiac autonomic regulation (rMSSD) was significantly associated with CRF level (p &lt; .001) and age (p &lt; .001). There were no associations between rMSSD and region (high or low air-pollution), sex, education level or VAT (p &gt; 0.050). Conclusions We showed that living in an area with low or high air pollution is not associated with cardiac autonomic modulation in healthy runners and inactive individuals. CRF and age significantly directly and inversely, respectively, associated with HRV. There were no other significant associations.

Nocturnal short-term HRV reflects impaired daytime vigilance better than overnight HRV in suspected OSA patients.

In obstructive sleep apnea (OSA), heart rate variability (HRV) decreases and performance in psychomotor vigilance task (PVT) worsens with more severe hypoxic load. Nevertheless, the association between HRV and PVT performance is poorly understood. Thus, we hypothesize that nocturnal short-term HRV is better related to daytime psychomotor vigilance compared to overnight HRV. To investigate this hypothesis, we retrospectively analyzed the electrocardiograms from polysomnographies of 546 consecutive patients with suspected OSA. We determined overnight HRV and short-term HRV in non-overlapping 5-minute segments and performed stepwise linear regression analyses to associate HRV with the median reaction time (RT) in the PVT. The short-term decrease in the median RR, root mean square of successive RRs, and normalized high-frequency band power were all significant (p < 0.001) indicators of longer median RTs. However, the overnight HRV parameters did not indicate worsening median RT. Instead, increased hypoxic load and N3 duration were associated with longer median RT in men but not women. The association of HRV and cardiorespiratory coupling with PVT performance was generally weak. Nocturnal short-term HRV evaluation reflected a state of vigilance better than the average overnight HRV. Thus, the overnight HRV analysis might not be optimal for patients with OSA. Utilizing the HRV analysis in a time-series manner and combined with the hypoxic load and sleep stages could bring new aspects to the health assessment of patients with OSA.

Evaluating heart rate variability by a novel stethoscopic approach to minimise stress in cats.

Stress associated with manipulation during electrocardiography (ECG) recording in cats potentially limits the assessment of autonomic function through heart rate variability (HRV) in the feline population. This study proposed an alternative, cat friendly, stethoscopic approach to evaluate HRV with an easily acquired vasovagal tonus index (VVTI). The aim of this prospective study was to evaluate whether VVTI derived from heart sound signals could distinguish between relaxed and stimulated states. A total of 29 cats with 56 recordings of heart sound and ECG on 31 occasions were included. In 25 cats in their home environment, a stethoscope connected to a digital recording device was used to record 2 mins of heart sounds twice - with the cats in a relaxed state and immediately after stimulation. The VVTI was calculated from 20, 60 and 120 consecutive beat-to-beat intervals on the heart sound spectrogram (stethoscopic-VVTI 20, 60 and 120), using the natural logarithm of the variance of the intervals based on previous literature. A 2-min ECG recording was obtained at home with the intention of avoiding strict restraint. To demonstrate the feasibility of the stethoscopic approach in a hospital setting, six cats (two of which were also recorded at home) underwent heart sound and ECG recordings during planned veterinary visits. Stethoscopic-VVTI 20 (5.43 to 4.79, P = 0.001), 60 (6.20 to 5.18, P <0.001) and 120 (6.24 to 5.60, P = 0.02) all significantly decreased after stimulation, indicating a reduced vasovagal tone as expected. Calculations of stethoscopic-VVTI from different sections of the recording yielded statistically similar results. Stethoscopic-VVTI showed a negative correlation with the corresponding heart rate. Bland-Altman analysis revealed a mean bias for the differences between stethoscopic-VVTI and ECG-VVTI of 0.50 and 1.07 at home and in the hospital, respectively. VVTI can be successfully detected through a stethoscopic approach, serving as a less stressful tool for HRV evaluation in cats during routine auscultation.

Evaluating the Effects of Different Cognitive Tasks on Autonomic Nervous System Responses: Implementation of a High-Precision, Low-Cost Complementary Method.

We developed a low-cost, user-friendly complementary research tool to evaluate autonomic nervous system (ANS) activity at varying levels of cognitive workload. This was achieved using visual stimuli as cognitive tasks, administered through a specially designed computer-based test battery. To assess sympathetic stress responses, skin conductance response (SCR) was measured, and electrocardiograms (ECG) were recorded to evaluate heart rate variability (HRV), an indicator of cardiac vagal tone. Twenty-five healthy adults participated in the study. SCR and ECG recordings were made during both tonic and phasic phases using a computer-based system designed for visual stimuli. Participants performed a button-pressing task upon seeing the target stimulus, and the relationship between reaction time (RT) and cognitive load was evaluated. Analysis of the data showed higher skin conductance levels (SCLs) during tasks compared to baseline, indicating successful elicitation of sympathetic responses. RTs differed significantly between simple and cognitive tasks, increasing with mental load. Additionally, significant changes in vagally mediated HRV parameters during tasks compared to baseline highlighted the impact of cognitive load on the parasympathetic branch of the ANS, thereby influencing the brain-heart connection. Our findings indicate that the developed research tool can successfully induce cognitive load, significantly affecting SCL, RTs, and HRV. This validates the tool's effectiveness in evaluating ANS responses to cognitive tasks.

Effect of sex on chronic stress induced alterations in hindbrain catecholaminergic system and autonomic dysfunction resulting in gastrointestinal dysmotility

It has been reported that the clinical symptoms of functional dyspepsia (FD) exacerbate upon stress while the gender-related factors have been incompletely understood. This study aims to investigate the role of sex in chronic heterotypic stress (CHS)-induced autonomic and gastric motor dysfunction. For CHS, the rats were exposed to the combination of different stressors for 7 consecutive days. Subsequently, electrocardiography was recorded in anesthetized rats to evaluate heart rate variability (HRV) for the determination of autonomic outflow and sympathovagal balance. Solid gastric emptying (GE) was measured in control and CHS-loaded male and female rats. The immunoreactivities of catecholaminergic cell marker tyrosine hydroxylase (TH), choline acetyltransferase (ChAT), corticotropin releasing factor (CRF), and estrogen receptor (ER-α/β) were evaluated in medullary and pontine brainstem sections by immunohistochemistry. Compared with the controls, CHS significantly delayed GE in males but not in females. There was no significant sex-related difference in parasympathetic indicator HF under either control or CHS conditions. Sympathetic indicator LF was significantly higher in control females compared to the males. The higher sympathetic output in females was found to be attenuated upon CHS; in contrast, the elevated sympathetic output was detected in CHS-loaded males. No sex- or stress-related effect was observed on ChAT immunoreactivity in the dorsal motor nucleus of N.vagus (DMV). In males, greater number of TH-ir cells was observed in the caudal locus coeruleus (LC), while they were more densely detected in the rostral LC of females. Regardless of sex, CHS elevated immunoreactivity of TH throughout the LC. Under basal conditions, greater number of TH-ir cells was detected in the rostral ventrolateral medulla (RVLM) of females. In contrast, CHS remarkably increased the number of TH-ir cells in the RVLM of males which was found to be decreased in females. There was no sex-related alteration in TH immunoreactivity in the nucleus tractus solitarius (NTS) of control rats, while CHS affected both sexes in a similar manner. Compared with females, CRF immunoreactivity was prominently observed in control males, while both of which were stimulated by CHS. ER-α/β was found to be co-expressed with TH in the NTS and LC which exhibit no alteration related to either sex or stress status. These results indicate a sexual dimorphism in the catecholaminergic and the CRF system in brainstem which might be involved in the CHS-induced autonomic and visceral dysfunction occurred in males.

(118) ORGASM AND HEART RATE VARIABILITY IN FEMALE BREAST CANCER SURVIVORS: RESULTS FROM A PSYCHOPHYSIOLOGY STUDY

Abstract Introduction Over 70 % of female breast cancer survivors suffer from sexual dysfunction. Sexual dysfunction can cause great amounts of stress and negatively impact overall health and well-being. Most studies focus on sexual arousal disorders and hypoactive sexual desire disorders. The research on orgasm in this specific group is limited. A better understanding of sexual function in breast cancer patients may yield potential targets for new treatment strategies for sexual dysfunction in this population. Low heart rate variability (HRV) has been shown to be predictive of erectile dysfunction and female sexual arousal as well as orgasm frequency. Reduced HRV and low cardiac vagal tone have previously been reported in breast cancer survivors during the first year post-treatment. If HRV is a reliable indicator of female sexual dysfunction, it could be used to assess and monitor it in a clinical setting. Objectives This study aimed to explore whether there is a link between HRV and both, sexual arousal and the ability to orgasm. We were expecting to find a difference in HRV between breast cancer survivors and healthy controls as well as orgasmic and anorgasmic women. Methods Participants were prescreened during a telephone interview. We included 40 premenopausal breast cancer survivors currently on hormonal treatment with an age range of 29 to 57 years (M = 43.5, SD = 6.4) and 20 healthy controls with an age range of 22 to 35 (M = 27.6, SD = 3.2). The vaginal pulse amplitude, heart rate variability (SDNN), subjective sexual arousal and self-reported number of orgasms were assessed in response to audiovisual sexual stimuli and vibrotactile clitoral stimulation in breast cancer survivors and healthy controls. Validated patient-reported outcome measures were used to assess sexual dysfunctions (Female Sexual Function Index, Female Sexual Distress Scale − Desire/Arousal/Orgasm), sexual self-esteem (Sexual Self-Esteem Inventory-Short Form), health-related quality of life (Patient-Reported Outcomes Measurement Information System 29 (PROMIS-29) profile questionnaire). Results Breast cancer survivors showed lower sexual function, health-related quality of life, sexual self-esteem and higher sexual distress than healthy controls. Preliminary results show a difference in baseline HRV scores between healthy controls and breast cancer survivors. However, this finding is likely due to age differences between our two groups and not cancer treatment effects. We could find no apparent differences in baseline HRV between anorgasmic and orgasmic women. Further analyses on the predictive value of HRV during sexual arousal for orgasm occurrence will be conducted. Conclusions Our data did not corroborate either of our hypotheses related to baseline HRV. For the evaluation of HRV as a predictor for orgasm occurrence, further exploratory analyses will follow. More research on the physiological parameters of sexual dysfunction is needed to reveal underlying mechanisms and find targets for future therapies.

(097) IS THERE A REDUCTION IN HEART RATE VARIABILITY IN VICTIMS OF SEXUAL VIOLENCE? A SYSTEMATIC LITERATURE REVIEW

Abstract Introduction Sexual violence has an alarming prevalence globally. Studies indicate an association between sexual violence victims (SVV) and the development of low heart rate variability, which is a predictor of negative cardiovascular outcomes. Objective The objective of this study is to conduct an initial literature review and qualitative analysis of studies to investigate the effects of sexual violence trauma on heart rate variability (HRV). Methods Three databases (PubMed, BVS and Embase) were selected for the search of studies with HRV analysis data in SVV. The chosen period was the last decade (from the year 2013 onwards). Since the R-R interval represents the interval between each heartbeat and vagal tone is the main modulator of heart rate variability, parameters representative of HRV were: SDNN (standard deviation of all RR intervals), which expresses the global sympathetic and parasympathetic activity, RMSSD (Root mean square of the successive differences), and HF (high frequency component, an indicator of parasympathetic activity on the heart). The inclusion criteria were studies involving groups of individuals who have experienced sexual violence, whether recent or past, and measuring heart rate variability using SDNN, RMSSD, and/or HF indices. The exclusion criteria stablished were those studies that did not involve sexual violence victims or the measurement of heart rate variability using SDNN, RMSSD, and/or HF to directly associate these components, studies that did not provide specific HRV evaluation results for the SVV groups, and systematic reviews. The search terms chosen were: ““Sex Offense”” OR ““Sex Offenses”” OR ““Sexual Assault”” OR ““Sexual Assaults”” OR ““Sexual Assaults”” OR ““Sexual Violence”” OR ““Sexual Violences”” OR ““Sexual Abuse”” OR ““Sexual Abuses”” AND “HRV” OR “Heart Rate Variability”, resulting in a total of 18 articles in all three databases after excluding duplicates. Based on inclusion and exclusion criteria, five studies were qualitatively analyzed regarding HRV data among sexual violence victims. In studies comparing HRV index measurements in SVV and non-SVV groups and/or measurements before and after stimulus, differences between groups were considered for the analysis. Methods for this measurement included: 24-hour Holter monitoring, Electrocardiogram, and Firstbeat Bodyguard. Studies evaluating HRV in victims of sexual abuse at baseline, over a specified period of time, or in response to a stressful/stimulating task were included. Results Among the five reviewed studies, three highlighted a significant reduction in HRV among individuals with SVV, suggesting an association between this condition and decreased HRV. While one comparative study found no statistical differences between SVV and non-SVV groups (p &amp;gt; alpha), two others indicated that the SVV group exhibited significantly lower HRV (p &amp;lt; alpha). Conclusions These findings suggest a potential link between SVV and reduced HRV, indicating a potentially elevated cardiovascular risk in this group. However, limitations such as varied methodologies, distinct objectives, and small sample sizes require further studies to investigate whether the initial findings will be replicated. Thus, a broader analysis is needed to fully understand this association and implement appropriate preventive intervention strategies against cardiovascular problems. Disclosure No.

Heart Rate Variability as a Predictor of +Gz Tolerance During the High-G Selective Test.

INTRODUCTION: Preselection of pilot candidates in the military is critical and determines the quality of subsequent selection. The Aero Medical Institute in Belgrade uses the following centrifuge endpoints: peripheral vision loss, heart rate above 180 bpm, cardiac arrhythmias, and G-induced loss of consciousness to assess relaxed +Gz tolerance. The aim of this study was to evaluate heart rate variability (HRV) associated with cardiovascular adaptability to different types of stress as a predictor of +Gz tolerance.METHODS: Thirty-six candidates were exposed to centrifuge runs, consisting of the following +Gz-acceleration phases: a 2-G plateau followed by an increase to 5.5 G, a decrease to 2 G, and ending with a plateau. Time-domain HRV indices were calculated for candidates, for a 60-s 2-G plateau, and for the entire test. The correlation was made between the groups that did (Group 1) and did not meet the criteria (Group 2).RESULTS: The results show significantly lower values in all time domain HRV indices, namely standard deviation of the normal-to-normal interval (SDNN) and root mean square of successive differences, in Group 2. Mean SDNN values were 45.98 ± 24.80 ms (2-G plateau) and 109.99 ± 39.64 ms (entire test) in Group 1, while the SDNN were 22.99 ± 12.04 ms and 69.70 ± 33.45 ms in Group 2. Root mean square of successive differences was higher in Group 1 for the 2-G plateau and for the entire test.DISCUSSION: The results suggest that HRV is positively correlated with +Gz-tolerance and can be used as an additional selection tool for military aircrew.Bacevic N, Ninkovic M, Drvendzija M, Vidakovic J, Bacevic M, Stepanic P. Heart rate variability as a predictor of +Gz tolerance during the high-G selective test. Aerosp Med Hum Perform. 2024; 95(2):93-100.

Assessing autonomic activity and prognostic risk factors comparing multisystem inflammatory syndrome and isolated viral myocarditis/myopericarditis.

In pediatric multisystem inflammatory syndrome and isolated viral myocarditis/myopericarditis, autonomic nervous system function can be evaluated by a non-invasive method called heart rate variability. This study aims to evaluate heart rate variability in these two groups by comparing them with each other. This is the first study assessing these values in these two groups of patients. Patients who are diagnosed with multisystem inflammatory syndrome in children and isolated viral myocarditis/myopericarditis at a university hospital from September 2021 to February 2023 are screened by electrocardiography, echocardiography, and 24-hour Holter monitoring. A healthy control group, compatible in age and gender with the patient groups, was selected from healthy subjects that applied to the hospital for palpitation, murmur, and/or chest pain. Heart rate variability parameters and related laboratory markers were analyzed and compared among the three groups. There were 30 patients with multisystem inflammatory syndrome in children, 43 patients with isolated viral myocarditis/myopericarditis, and 109 participants in the healthy control group. Statistically significant differences were found in most of the heart rate variability parameters: standard deviation of normal to normal intervals (SDNN), the mean of the 5- minute RR interval standard deviations (SDNNİ), the standard deviation of 5-minute R wave to R wave(RR) interval means (SDANN), the root mean square of successive RR interval differences (RMSSD), and the percentage of the beats with a consecutive RR interval difference of more than 50 ms (pNN50%), very low frequency, high frequency, low frequency, triangular index, and low frequency/high-frequency ratio. Multisystem inflammatory syndrome in children patients had impaired and declined heart rate variability values compared to the other two groups. In patients with myocarditis/myopericarditis, we couldn't find a significant difference in these parameters with the control group. Heart rate variability can be used as an important non-invasive autonomic function parameter in determining prognosis and treatment plans, especially in patients diagnosed with multisystem inflammatory syndrome in children. This impairment of autonomic activity could be more prominent in patients with decreased left ventricular systolic functions.

Changes in Heart Rate Variability Parameters Following Radiofrequency Ablation in Patients with Atrial Fibrillation: A Systematic Review and Meta-Analysis.

Radiofrequency (RF) ablation is a prevalent treatment for atrial fibrillation (AF), targeting triggers within the pulmonary vein (PV) for elimination. This study evaluated heart rate variability (HRV) parameter changes at three intervals post-RF ablation: short-term (immediately to 1 month), medium-term (1 to 6 months), and long-term (6 months to 1 year). We compared two ablation techniques: circumferential PV isolation (CPVI) and segmental PV isolation (SPVI). A thorough search of databases, including PubMed, Embase, Scopus, Web of Science, and Cochrane, in 2022 yielded 835 pertinent studies. After inclusion criteria were applied, 22 studies were analyzed. Results showed a marked decline in HRV parameters post-AF ablation, with LF/HF as an exception. These reductions persisted in short- and long-term evaluations up to a year post-procedure. Subgroup analysis revealed significant HRV declines, with distinct LF/HF values post-SPVI. This meta-analysis suggests the potential of decreased HRV as an indicator of autonomic denervation, necessitating further exploration to optimize therapeutic strategies and enhance patient outcomes.

Autonomic activity and cardiovascular system risk assessment in pediatric patients with hemolytic uremic syndrome.

In pediatric patients with hemolytic uremic syndrome (HUS), cardiac involvement and autonomic nervous system function can be evaluated by a non-invasive method called heart rate variability (HRV). This study aims to evaluate heart rate variability and electrocardiography findings in patients with HUS by comparing a healthy group. Patients who are diagnosed with HUS at a university hospital from December 2020 to June 2022 are screened by electrocardiography (ECG), echocardiography, and 24-h Holter ECG. A healthy control group, compatible in age and gender with the patient group, was selected from healthy subjects. HRV parameters, laboratory values, and ECG findings were analyzed and compared with the healthy group and each other. There were 25 patients with HUS and 51 participants in the healthy control group. Statistically significant differences were found in some HRV parameters: standard deviation of normal to normal intervals, the mean of the 5-min RR interval standard deviations, the standard deviation of 5-min RR interval means, the triangular interpolation of normal to normal interval, and very-low-frequency power. HUS patients had impaired and declined HRV values compared to the healthy group. There was a significant decrease in the PR distance, while a significant increase in the corrected QT and QT dispersion values was detected in the electrocardiographic findings of the patient group. HRV values impaired as renal failure parameters increased. Conclusion: Patients with HUS may have autonomic nervous system dysfunction. HRV measurement is a non-invasive method that can evaluate this. It can be thought that there may be an increased risk of cardiovascular events and arrhythmias in some patients with HUS. ECG should be also considered to detect arrhythmia. What is Known: • Hemolytic uremic syndrome (HUS) primarily effects the hematologic parameters and kidney. • Secondary cardiomyopathy with hypertension and renal failure could be observed in these patients. • Rhythm problems are not expected primarily in these patients. • There is very limited data in evaluating autonomic function and arrhythmia risk for these patients. What is New: • Patients with HUS may have autonomic nervous system dysfunction. • HRV measurement is a non-invasive method that can evaluate this. • Cardiovascular events and arrhythmias due to the deterioration of the balance between the sympathetic and parasympathetic systems could manifest in patients with HUS. • An ECG and screening patients for cardiac events, and monitoring them closely should be considered.

Cardiovascular autonomic nervous function in children conceived by assisted reproductive technology with frozen or fresh embryo transfer.

As a result of epigenetic changes, children conceived by assisted reproduction may be at risk of premature cardiovascular aging with notably increased blood pressures. Their cardiovascular autonomic nervous function is unknown. Therefore, this study investigated the cardiovascular autonomic nervous function in 8-12-yr-old children (51% girls) conceived naturally (n = 33) or by assisted reproduction with frozen (n = 34) or fresh (n = 38) embryo transfer by evaluating heart rate variability, during rest; from provocation maneuvers; and from baroreflex function. Heart rate and blood pressure response to provocation maneuvers and baroreflex function were comparable between children conceived naturally or by assisted reproduction. The mean RR-interval and high-frequency component of heart rate variability were lower in children conceived by assisted reproduction than in children conceived naturally. Children conceived by fresh embryo transfer had ∼17% lower heart rate-corrected standard deviation of normal-to-normal R-R intervals; ∼22% lower heart rate-corrected square root of the mean of the squared difference between successive R-R intervals; and ∼37% higher low-frequency/high-frequency ratio than naturally conceived children. Children conceived by assisted reproduction still had lower heart rate variability and vagal modulation than naturally conceived children after adjustment for confounders. Thus, these results raise the possibility of sympathetic predominance in children conceived by assisted reproduction. Therefore, it is important to reproduce these results in larger and older cohorts as sympathetic predominance relates with cardiovascular and metabolic diseases.NEW & NOTEWORTHY We observed that children conceived by assisted reproductive technology (both frozen and fresh embryo transfer) had lowered heart rate variability during rest as compared with children conceived naturally. During physiological stress maneuvers, however, the cardiovascular autonomic nervous regulation was comparable between children conceived by assisted reproductive technologies and naturally. Our findings highlight the potential that lowered heart rate variability during rest in children conceived by assisted reproductive technologies may precede premature hypertension.

Impact of long COVID on the heart rate variability at rest and during deep breathing maneuver

While the majority of individuals with coronavirus disease 2019 (COVID-19) recover completely, a significant percentage experience persistent symptom, which has been characterized as Long COVID and may be associated with cardiac and autonomic dysfunction. We evaluated heart rate variability (HRV) at rest and during deep-breathing (M-RSA) in patients with Long COVID. Case–control design involved 21 patients with Long COVID and 20 controls; the HRV was evaluated (POLAR system) at rest in the supine position and during M-RSA and expressed in time domain and non-linear analysis. In the supine position we found a reduction HRV measures in Long COVID’ patients compared to controls for: Mean_iRR (p < 0.001), STD_iRR (p < 0.001); STD_HR (p < 0.001); SD1 (p < 0.001); SD2 (p < 0.001); alpha2 (p < 0.001). In the M-RSA we found reduction Mean_iRR (p < 0.001), STD_iRR (p < 0.001), STD_HR (p < 0.001), rMSSD (p < 0.001), RR_tri-index (p < 0.001) in Long COVID’ patients except for highest Mean_HR p < 0.001. In conclusion, Long COVID reduced HRV at rest and during deep breathing. These findings may imply impairment of cardiac autonomic control when symptoms of COVID-19 persist following initial recovery.

The 24-Hour Cardiac Autonomic Activity in Patients With Allergic Rhinitis.

Definitive knowledge of the 24-hour cardiac autonomic activity in patients with allergic rhinitis (AR) is lacking. Thus, we aimed to evaluate heart rate variability (HRV), which is used to measure cardiac autonomic activity by 24-hour Holter monitoring in patients with AR. We enrolled 32 patients who visited our clinic and were diagnosed with AR. The control group was selected four-fold (n = 128) by matching (age, sex, hypertension, and diabetes) in the AR group from a Holter registry in the cardiology department. The HRV results, which were measured using 24-hour Holter monitoring, were compared between the AR and control groups. All time-domain parameters of HRV revealed no differences between the groups. However, among the frequency domain parameters of HRV, the low-frequency to high-frequency ratio and low-frequency power in normalized units were significantly lower in the AR group. Conversely, high-frequency power in normalized units was significantly higher in the AR group. In the multiple regression analysis, AR was independently associated with sympathetic withdrawal (adjusted odds ratio = 3.393, P = 0.020) after adjusting for age, sex, hypertension, diabetes mellitus, and hyperlipidemia. The present findings suggest differences in cardiac autonomic activity which are related with sympathetic withdrawal in patients with AR compared with that in the normal population over 24 hours.

Pre-operative screening of diabetic patients for heart rate variability and their hemodynamic responses during induction of general anaesthesia

: Cardiovascular autonomic neuropathy (CAN) is one of the least frequently diagnosed and the most clinically significant complications of Diabetes mellitus (DM). Impaired heart rate variability (HRV) is the earliest indicator of CAN. Peri-operative hemodynamic instability is a major concern during general anaesthesia (GA) in patients with autonomic dysfunction. Purpose of this study was to assess and compare the autonomic function using HRV in diabetic and non-diabetic patients pre-operatively and to study the haemodynamic responses of these patients during induction.: The primary objective was to assess and compare the autonomic function using HRV in diabetic and non-diabetic patients preoperatively. Secondary objective was to study hemodynamic responses of these patients during induction of GA.: We included 68 patients (34 diabetics- group D and 34 non-diabetics- group N) aged between 30 to 65 years, with American society of anaesthesiologists (ASA) physical status 1 and 2 undergoing elective surgeries under GA. All the eligible patients underwent HRV evaluation for 10 minutes on the previous day of surgery and the time &amp; frequency domain variables were evaluated. The hemodynamic parameters were recorded at pre-induction, post-induction, post-intubation and for every 3 minutes thereafter for 15 minutes and analysed.: The diabetics had a significantly lower total power (TP) with p-value 0.003. The post- induction mean arterial pressures (MAP) were comparatively lower in diabetics and the difference was significant at 12 minutes post intubation (p= 0.04). The lower trends in heart rate (HR) were comparatively more in diabetics rather than non-diabetics (p= 0.06) and the ephedrine usage was also higher in diabetics (p= 0.07). The measurement of HRV is a simple tool to evaluate the peri-operative risks in patients with suspected cardiovascular autonomic neuropathy.

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.

A Descriptive Research of Decreased Heart Rate Variability as a Risk Factor for Cardiovascular Disease in Young, Healthy Adults with Low and High BMI Indexes

Background and objectives: HRV is used to evaluate autonomic nervous system input to the heart. Several studies have examined the effect of HRV on underweight status. To assess HRV in age-matched young people with varying BMI categories. Methods: This cross-sectional study was conducted on healthy young adults between the ages of 18 and 25. Variables of anthropometrics were measured. ECG was recorded for 5 minutes in lead II setup. Kubios HRV analyzer was used to evaluate heart rate variability. Results: HRV indices were lower in the underweight, overweight, and obese BMI groups compared to the normal weight group. Both genders exhibit an inverted U-shaped association between BMI and HF log power based on second-order polynomial regression. The correlation between BMI, waist circumference, and body fat (%) and HRV indices demonstrates a substantial relationship with heart rate variability, with waist circumference (WC) exhibiting a stronger relationship than BMI. Comparing HRV parameters between men and women of different BMI groups reveals that women exhibited more heart rate variability than men across BMI groups. Conclusion: Underweight individuals share the same elevated cardiovascular risk as the obese, and abdominal obesity is a more accurate predictor of cardiovascular risk than the body mass index (BMI).

CONTRIBUTION OF RECURRENCE GRAPHS IN THE PROGNOSTIC ASSESSMENT OF INTENSIVE CARE UNIT PATIENTS

This study evaluated heart rate variability (HRV) in patients admitted to the intensive care unit with the aid of recurrence charts. This is a quantitative, qualitative, prospective and longitudinal study and the selected patients were divided into survivors group and death group. Time series of heart pulses were used with the Polar Advanced RS800CX frequency meter for 30 minutes. The analysis of the recurrence data used the following selected parameters: dimension = 2, delay = 2, radius = 70, line = 2 and as color scheme the Volcano. The classic variables of the recurrence plots were selected: ApEn, SamPEn, Alpha 1, % Recurrence, Det%, Laminarity, TT and LDmax. The continuous quantitative variables with Gaussian distribution were treated with the aid of Fischer's exact test and unpaired Student t test, and p values &lt; 0.05 were considered significant. The time series data of heart pulses were filtered and later analyzed with the software Kubios HRV Analysis.and the software Visual Recurrence Analysis. A total of 92 patients were considered, with the group of deaths consisting of 32 patients and the group of survivors by 60. indicating greater linearity (greater impairment of homeostasis). The analysis of HRV with the aid of recurrence charts allowed the differentiation of health states, and may act as a marker of severity and death.