Heart Rate Variability Parameters Research Articles

Heart rate variability in schizophrenia: A comparative analysis before and after electroconvulsive therapy

AbstractAimThe aim of this study was to investigate autonomic nervous system imbalance in schizophrenia by comparing heart rate variability (HRV) between patients with schizophrenia and healthy controls, and to assess changes in HRV in patients before and after electroconvulsive therapy (ECT).MethodsHRV was compared between patients with schizophrenia (n = 17) and age‐ and gender‐matched healthy controls (n = 34). Changes in HRV were also assessed in patients pre‐ and post‐ECT. Additionally, the relationship between HRV and Positive and Negative Symptom Scale (PANSS) scores in patients with schizophrenia was investigated.ResultsPatients with schizophrenia showed significantly lower high‐frequency (HF) and low‐frequency (LF) power compared with healthy controls, with a trend towards a higher LF/HF ratio. Following ECT, HF power increased significantly while the LF/HF ratio decreased significantly, resulting in no significant differences between patients and controls for these HRV parameters. The associations between HRV and symptoms observed before ECT were largely diminished after ECT, with only changes in the LF component correlating with changes in PANSS scores.ConclusionFollowing ECT, we observed a shift in autonomic balance from sympathetic dominance towards increased parasympathetic activity and a state more closely resembling that in healthy controls.

Features of Changes in Heart Rate Variability among Medical Students during the Education Process

Background: We investigated the changes of Heart Rate Variability (HRV) parameters, which reflect the state of the regulatory mechanisms of cardiovascular system, among medical students during routine academic period and examination session. Methods: The study was conducted in Jan-Feb 2024, at the IHSM in Bishkek, Kyrgyz Republic, among the healthy 70 students (mean age 19.71 ± 1.54 years) from India and Pakistan. For each student, two ECG recordings were performed: one 3 weeks before the exam and one 10-15 minutes after exam. Results: The results of study demonstrated that after the exam, students presented significantly higher HR, AMo, SI, VLF, LF and lower SDNN, TP, HF compared before the exam (P<0.05). Distribution of students showed that on a routine academic period 53% of students belonged to sympathotonic, 14% to vagotonic and 33% to normotonic. During the examination period the number of sympathotonic increased to 74%, but the number of vagotonic and normotonic decreased to 4% and 22% respectively. Conclusion: Each type revealed an individual reaction to exam stress: in the group of vagotonic there was a slight activation of the SNS; in sympathotonic students there was a tension of regulatory mechanisms, leading to depletion of adaptive mechanisms; in the group of normotonic there was a shift in the vegetative balance towards the sympathetic link of ANS.

Effect of age on clinical impact and mid-term denervation in patients undergoing cardioneuroablation.

Cardioneuroablation (CNA) represents a promising therapy for recurrent vasovagal syncope (VVS), extrinsically driven atrioventricular block (AVB) and sinus node dysfunction (SND). However, effectiveness in patients aged 50 and above is not well-established. In this prospective study of patients referred for CNA, we compared syncope and pacemaker implantation free survival, heart rate (HR) variability (HRV) and quality of life between two age groups: group A (< 50 years) and B (≥ 50 years). A total of 50 patients were included (17 Group A and 33 Group B). The etiologies comprised VVS (56%), AVB (22%), and SND (22%). After a median follow-up of 17.0 (12.5-26.0) months, there were no differences of the combined endpoint of syncope or pacemaker implantation free-survival between groups (29.4.% vs. 21.2%; p-log-rank = 0.736). 84% of the entire cohort remained free from syncope, with a better but not significant syncope free survival in the older group (23.5% vs. 12.1%; p-log rank = 0.486). There were no differences in pacemaker implantation rate (A 5.9% vs. B 17.6%; p log-rank = 0.658). Notably, older patients had lower HR values post-procedure compared to younger patients (68.9 ± 13.3 vs. 80.4 ± 16.3bpm; p = 0.012). Both groups exhibited a decrease in HRV parameters and an improvement in quality of life. In conclusion, CNA has comparable clinical benefits for patients aged 50 and above in terms of syncope or pacemaker implantation free survival and HRV reduction when compared to younger patients.

Women With Polycystic Ovary Syndrome and Excess Body Fat Exhibit Atypical Sympathetic Autonomic Modulation That is Partially Reversed by Aerobic Physical Training.

The aetiology of impairments in autonomic modulation of heart rate variability (HRV) in polycystic ovary syndrome (PCOS) remains unclear, as does the impact of aerobic physical training (APT) on controlling endocrine-metabolic disorders and HRV. This is because these women often present excess body fat. Therefore, we assessed whether the dysregulation in autonomic modulation of HRV in women with PCOS is due to endocrine-metabolic disorders and whether the combination of excess body fat with endocrine-metabolic disorders amplifies cardiovascular autonomic deficits. We also investigated whether APT positively influences autonomic modulation of HRV in PCOS. Non-randomised clinical trial. Women with and without PCOS with different percentages of body fat. Participants were divided into four groups: women without PCOS with a body fat percentage between 22% and 29% (CONTROL group; 22%-29%); CONTROL (30%-37%) group; PCOS (22%-29%) group; and PCOS (30%-37%) group. Hemodynamic, metabolic, and hormonal characteristics and HRV parameters were obtained before and after 16 weeks of APT. The PCOS (22%-29%) group exhibited lower vagal modulation than the CONTROL (22%-29%) group. In contrast, no significant differences were observed between the CONTROL (30%-37%) and PCOS (30%-37%) groups. Furthermore, the PCOS (30%-37%) group demonstrated lower sympathetic modulation than the PCOS (22%-29%) group. After APT, the PCOS (22%-29%) group increased in vagal modulation, while the PCOS (30%-37%) group increased in sympathetic modulation. PCOS affects vagal modulation; however, this effect may be masked at elevated levels of body fat. Additionally, the combination of excess body fat with endocrine-metabolic dysregulation appears to reduce sympathetic modulation, possibly due to sympathetic drive hyperactivity. APT positively affected HRV in both PCOS groups.

Changes in heart rate variability and subclinical heart failure with preserved left ventricular ejection fraction in workers of the main professions at the coal industry

Introduction. The high prevalence of diseases of the circulatory system necessitates their detection and prevention at an early stage, especially in regions with high industrial potential. The occurrence of subclinical heart failure depends on a cascade of processes that are already occurring in the body and may eventually manifest themselves in clinically pronounced diseases. One of the possible mechanisms of its development is a violation of the balance of the autonomic nervous system with a violation of adaptive capabilities to the labour process, characterized by severe physical overloads among miners. The study aims to evaluate changes in heart rate variability in workers of the main professions at the coal industry with signs of heart failure with a preserved left ventricular ejection fraction. Materials and methods. The study included 78 employees of the main professions at the coal industry. Specialists performed ultrasound examination of the heart according to generally accepted methods with the study of longitudinal deformation of the myocardium. The concentration of NT-proBNP in the blood serum was determined by solid-phase enzyme immunoassay. The authors also conducted an analysis of heart rate variability, determined temporal, spectral and linear parameters. Results. Specialists revealed a decrease in longitudinal myocardial deformation in 38.5% of the examined patients, signs of diastolic dysfunction in 41%; in these groups, a tendency to increase the concentration of NT-proBNP was revealed. In the examined miners with heart failure with preserved ejection fraction, they revealed a significant decrease in the SDNN index and an increase in IC values. The increase in DFA and LF/HF indicators reflects a vegetative imbalance towards sympathetic activation observed in all surveyed miners. Limitations. This study is limited to a sample of employees of the main professions of the coal industry undergoing periodic medical examination at the Research Institute of Complex Problems of Hygiene and Occupational Diseases. Conclusion. The revealed relationship between indicators of heart failure and heart rate variability (SDNN, LF/HF, DFA and IC) in miners allows us to identify a group of people at greatest risk of adverse outcomes. Ethics. The study was conducted in compliance with the standards of the Bioethical Committee of the Research Institute of Complex Problems of Hygiene and Occupational Diseases, established in accordance with the Helsinki Declaration of the World Medical Association "Ethical Principles of Conducting medical Research with human participation as a subject" as amended in 2013 and the "Rules of Good Clinical Practice" approved by Order No. 200n of the Ministry of Health of the Russian Federation dated 04/01/2016. The subjects signed an informed consent to participate in the study.

Inter- and intra-examiner reliability of short-term measurement of heart rate variability on rest in patients hospitalized with COVID-19

Measures reflecting cardiac sympathovagal activity, particularly those associated with heart rate variability (HRV), are widely recognized and utilized in both scientific and clinical contexts. This study aimed to assess the inter- and intra-examiner reliability of short-term HRV parameters in patients hospitalized with coronavirus disease 2019 (COVID-19). A total of 103 patients (both sexes) diagnosed with COVID-19 were included in the study. HRV was analyzed using both linear and nonlinear methods. Reliability was evaluated through intraclass correlation coefficient (ICC2.1), minimum detectable change (MDC), standard error of measurement (SEM), and coefficient of variation (CV). According to Fleiss’ criteria, excellent reliability was demonstrated, with ICC values ranging from 0.970 to 0.999 for Examiner 1, and from 0.956 to 0.999, for Examiner 2. In the inter-examiner analysis, the ICCs of HRV parameters ranged from 0.972 to 0.999. SEM values for intra-examiner reliability for Examiner 1 ranged from 0.02 to 5.64, with MDC values from 0.05 to 15.64, and CV (%) from 0.28 to 8.04. For Examiner 2, SEM values ranged from 0.02 to 8.18, MDC values from 0.05 to 22.68, and CV (%) from 0.24 to 8.14. For inter-examiner reliability, SEM values ranged from 0.02 to 6.17, MDC from 0.06 to 17.11, and CV (%) from 0.34 to 9.81. Across all analyses, CVs for HRV parameters remained below 10%. Considering different time points and different examiners, short-term resting HRV measurements in patients hospitalized with COVID-19, as evaluated using a portable heart rate device, exhibit high reliability.

Дослідження впливу фаз менструального циклу на функціональний стан кваліфікованої ветеранки спорту з дзюдо

Purpose: to investigate the influence of menstrual cycle phases on the functional status of a qualified female veteran judo athlete. Material and methods. The following methods were used in the study: analysis of scientific and methodological information and Internet sources; generalization of advanced practical experience; measurement of sensorimotor reactions and determination of heart rate variability indices; methods of mathematical statistics. A qualified veteran female judo athlete (Master of Sports of Ukraine) in the age category F2 (1983-1979) took part in the study. We performed 84 measurements of heart rate variability (n=42, HRV in the supine position; n=42, heart rate variability during the test task dedicated to measuring the choice reaction). The measurement was performed using two computer programs for mobile devices running iPadOS «Research HRV» and «HRV SR+CR» during morning hours (7-8 hours) and afternoon hours (17-18 hours). Results: analysis of the dynamics of changes in heart rate variability parameters obtained in the supine position indicates an increase in sympathetic activity in the follicular phase of the menstrual cycle. Analysis of comparisons of heart rate variability parameters in different phases of the menstrual cycle indicates that the greatest number of statistically significant (p&lt;0,05) differences is observed in the first half of the day. These changes indicate the dynamics of the decrease in the tone of the sympathetic part of the autonomic nervous system in the follicular phase when performing test tasks provided by the computer program «HRV SR+CR». Analysis of the study results indicates that the indicators of heart rate variability are also influenced by the measurement conditions. The test tasks of the computer program «HRV SR+CR» provide cognitive load and concentration of attention, especially in the second stage, where it is necessary to choose the sought-after figure. During cognitive tasks there is an increase in the activity of the parasympathetic nervous system, which leads to an increase in heart rate variability. High level of heart rate variability is associated with better cognitive functions and adaptive response to stress. Consequently, these differences in heart rate variability obtained using the «Research HRV» and «HRV SR+CR» programs may be the result of interactions between physiological changes during the menstrual cycle as well as the influence of measurement conditions. Understanding the changes in heart rate variability indices during test tasks related to the manifestation of the choice reaction provides information about the influence of cognitive load and attention concentration on the functional state of the female athlete. This will allow to plan the training process of wrestling taking into account the phases of the menstrual cycle and functional capabilities that are inherent in high-skilled female athletes. Conclusions. The parameters of heart rate variability and sensorimotor reaction time provide information about the functional state of martial artists. Understanding of metabolic and hormonal processes in different phases of the menstrual cycle of qualified wrestlers will allow to optimize their training loads and recovery measures.

Heart Rate and Its Variability Are Associated With Resting Metabolic Rate and Substrate Oxidation in Young Women but Not in Men.

This study aims to examine the relationship between resting vagal-related heart rate variability (HRV) parameters and heart rate (HR) with resting metabolic rate (RMR) and respiratory exchange ratio (RER) in young adults. A total of 74 young adults (22 ± 2 years old, 51 women) were included in this cross-sectional study. HRV was assessed using a HR monitor, whereas RMR and RER were determined by indirect calorimetry. Linear regression analyses showed a positive association between HR and RER in women (standardized β = 0.384, p = 0.008), while negative associations were observed between vagal-related HRV parameters and RER in women (β ranged from -0.262 to -0.254, all p ≤ 0.042). No significant association was found between the abovementioned physiological parameters in men. Here, we show that HR is positively associated with RER in young women but not in men, while vagal-related HRV parameters are inversely related to RMR, therefore suggesting a potential sexual dimorphism between cardiac rhythm and its relationship with markers of cardiometabolic health status. ClinicalTrials.gov identifier: NCT02365129.

Cardiovascular responses to experimental weight gain in humans: a feasibility study.

Obesity and hypertension share a well known association. However, the mechanisms underlying their relationship are not well understood. Our goal was to assess the feasibility of a longitudinal, interventional weight gain study with detailed cardiovascular measurements in humans. Sixteen healthy, normotensive, young, male volunteers (28 ± 7 years) were enrolled. Body composition, biochemical and cardiovascular data were obtained at baseline, and after an 8-week period of overfeeding (800-1000 kcal/day). Blood pressure (BP), cardiac output (CO) and peripheral vascular resistance (PVR) were determined, as were the minimum forearm vascular resistance (MFVR), forearm blood flow (FBF) response to mental stress and heart rate variability (HRV) parameters. Overfeeding resulted in a median weight gain of 5.6 kg [interquartile range (IQR) 4.6-6.4 kg; P < 0.001]. Seated systolic and diastolic BP were significantly increased by 10 ± 9 and 4 ± 6 mmHg, respectively, after weight gain ( P < 0.001 and P = 0.011, respectively). CO also increased and PVR decreased significantly as a result of weight gain ( P = 0.032 and P = 0.044, respectively). MFVR was also significantly decreased after weight gain ( P = 0.023). The FBF response to mental stress was blunted significantly ( P = 0.002), and sympathovagal balance and responsiveness to orthostatic challenge altered moderately after weight gain. Our overfeeding regimen resulted in moderate weight gain and significant increases in BP. An increase in CO is likely to be the dominant mechanism underlying the observed BP changes, with decreases in PVR partially compensating for these effects. Experimental weight gain, coupled with detailed cardiovascular phenotyping, is a feasible model to examine potential mechanisms underlying obesity-associated hypertension in young adults.

Heart rate variability in chronic ischemic stroke: analysis during the sleep-wake cycle.

Alterations of the autonomic nervous system (ANS) in the chronic stage of ischemic stroke (IS) are not well understood. Heart rate variability (HRV) provides a noninvasive approach to assess autonomic function. To compare the HRV parameters during the sleep-wake cycle between patients with IS in the chronic stage and healthy subjects. We conducted a retrospective transversal study based on clinical records and 24-hour electrocardiogram (EKG) monitoring registries of 179 patients with a confirmed IS diagnosis and 184 age- and sex-matched healthy subjects. Circadian variation was calculated according to the variation of the total autonomic activity (VTAI) and the parasympathetic activity (VPAI) indexes. Comparisons were performed using nonparametric tests. Multivariable analyses were performed with canonical discriminant analysis (CDA) and a three-way analysis of variance (ANOVA). Statistical significance was established with a confidence level of 95%. During waking hours, the healthy group exhibited higher variability in the time domain and frequency domain parameters: standard deviation of NN intervals (SDNN, p < 0.001) and of the average NN intervals (SDANN, p < 0.001), as well as low-frequency (LF) band (p < 0.001). During sleep, the difference was higher in the high-frequency (HF) band (p < 0.001), and lower in the low-/high-frequency ratio (LF/HF, p < 0.001). Both VPAI and VTAI showed less significant difference in IS patients (p < 0.001). There was diminished heart vagal activity among IS patients, as measured through HRV. During sleep, this is likely caused by an imbalance in the sympathetic and parasympathetic systems shifting through the sleep phases. These imbalances could persist over time in patients with IS, lasting months after the initial injury.

Effects of a synthetic analogue of the bovine appeasing pheromone on the overall welfare of dairy calves from birth through weaning

Environmental enrichment in the form of synthetic analogs of appeasing pheromones have shown promising results in improving the welfare of domestic animals including dogs, pigs, horses, and cattle. The main objective of this study was to determine if the use of the bovine appeasing pheromone (BAP) would improve the welfare of dairy calves; therefore, in this randomized controlled trial, 72 Holstein Friesian dairy calves were housed in individual hutches after birth and were randomly allocated to receive BAP or a placebo once every 2 weeks from birth through weaning. After weaning, calves were moved to group hutches according to treatment for 4 additional weeks. It was hypothesized that dairy calves treated with BAP would display fewer signs of stress compared with calves receiving the placebo during the weaning process. To operationalize stress, calves were fitted with triaxial accelerometers on the hind leg after birth, and activity levels were monitored throughout the experiment. Data on live weight gain (ADG) and cortisol levels in saliva and hair were also obtained. Calves were fitted with heart rate monitors every week for at least 24 h to assess heart rate variability (HRV). The use of BAP had a positive effect on ADG after weaning and during group housing and resulted in increased resting time after weaning. Moreover, BAP, was associated with a reduction in the activation of the neuroendocrine system evidenced by higher HRV parameters after weaning, including increased standard deviation of beat to beat of normal sinus beats (SDNN) and root mean squares of successive differences (RMSSD). These results suggest a potential welfare benefit of the use of BAP during the artificial rearing of dairy calves.

Heart rate variability analysis for the prediction of pre-arousal during propofol-remifentanil general anaesthesia: A feasibility study.

Accidental awareness during general anaesthesia is a major complication. Despite the routine use of continuous electroencephalographic monitoring, accidental awareness during general anaesthesia remains relatively frequent and constitutes a significant additional cost. The prediction of patients' arousal during general anaesthesia could help preventing accidental awareness and some researchers have suggested that heart rate variability (HRV) analysis contains valuable information about the patient arousal during general anaesthesia. We conducted pilot study to investigate HRV ability to detect patient arousal. RR series and the Bispectral IndexTM (BISTM) were recorded during general anaesthesia. The pre-arousal period T0 was defined as the time at which the BISTM exceeded 60 at the end of surgery. HRV parameters were computed over several time periods before and after T0 and classified as "BISTM<60" or "BISTM≥60". A multivariate logistic regression model and a classification and regression tree algorithm were used to evaluate the HRV variables' ability to detect "BISTM≥60". All the models gave high specificity but poor sensitivity. Excluding T0 from the classification increased the sensitivity for all the models and gave AUCROC>0.7. In conclusion, we found that HRV analysis provided encouraging results to predict arousal at the end of general anaesthesia.

Variabilidad de la frecuencia cardiaca en caninos saludables, adultos, y residentes en hipoxia hipobárica (Bogotá, 2600 metros sobre el nivel del mar)

Heart rate variability (HRV) refers to beat-to-beat fluctuations in heart rate and represents the neurovegetative and endocrine influence on the heart. In the present study, HRV values were obtained in healthy adult canines of both sexes, residing in the city of Bogotá (2600 meters above sea level). Time-domain and frequency-domain HRV parameters were obtained using 60-minute Holter recordings. The distribution of the data was determined using the Shapiro-Wilk test. The dogs were distributed into two subgroups to study their behaviour in relation to sex and age. ANOVA and Kruskal Wallis tests were used to determine statistical differences. In general, the mean HRV values differ from those reported by other authors in studies at sea level and at lower altitudes. The differences in HRV in relation to sex were significant in the RMSSD and pNN50 parameters. There were no differences in the relationship between HRV and age.

Machine learning model using heart rate variability for the prediction of vasovagal syncope

Abstract Background and Aims: Vasovagal syncope (VVS) is a reversible condition that can cause serious events, such as cerebral hemorrhage due to head trauma. Its occurrence is difficult to predict; therefore, this study aimed to develop machine learning (ML) models using heart rate variability (HRV) to predict the occurrence of VVS. Methods and Results We investigated 80 patients with syncope who underwent Holter monitoring during the head-up tilt test. Twenty-six ML models for the prediction of VVS using HRV parameters were examined. We randomly split the subjects into training and testing sets at a 7:3 ratio (training set: 46 positive and 9 negative subjects; testing set: 21 positive and 4 negative subjects). The XGB classifier achieved the highest performance compared with other algorithms (accuracy, 0.72; area under the curve, 0.801; sensitivity, 0.857; specificity, 0.621). When examining the time taken to predict syncope occurrence using the developed prediction model, it was found that the model could forecast approximately 3 min (equivalent to 193.2 beats) prior to the onset of symptoms. Conclusion The ML model utilizing HRV parameters was proficient in preemptively predicting VVS incidents. In practical applications, this approach can effectively enhance VVS prediction by leveraging the HRV, thereby aiding in the prevention of unforeseen accidents.

Automatic calculation of the parasympathetic, sympathetic and Baevsky stress indexes provides a more comprehensive assessment of cardiac autonomic modulation

Abstract Background Cardiac autonomic modulation (CAM) is clinically evaluated by measuring the Heart Rate Variability (HRV) parameters, related to sympathetic and parasympathetic efferences to the heart, with linear (L), nonlinear (NL), and time-varying (TV) mathematical methods. Recently, automatic calculation of the parasympathetic (PNSi), sympathetic (SNSi), and Baevsky’s stress (BSTRi) indexes [1,2], integrating some L and NL parameters, has become available for more synthetic assessment of CAM. This study aimed to evaluate in healthy subjects (HS) the normal range of PNSi, SNSi, and BSTRi and their physiological variations during daily activity (ACT) and Non-REM sleep (NREM), taking also into account aging-related changes. Methods 24-hour (H24) Holter ECG recordings of 87 HS, divided into three (Age1, Age2 and Age3) groups (16-34, 35-52, and 53-84 years old, respectively), were retrospectively analyzed with the Kubios software (version 4.0), which automatically calculates the PNSi, SNSi, and BSTRi [1], and time domain (TD), frequency domain (FD), NL and TV HRV parameters. HRV was calculated from H24 and short-term (2 minutes) intervals, selected during ACT and NREM. All HRV calculations were done after "detrending" with the "smooth priors" function (lambda=500). Statistical analysis was performed with SPSS 21. Results Average values of the three indexes and several independent L and NL parameters are summarized in Table 1. Average BSTRi values of each age group were not different between ACT and NREM, whereas significant (p&amp;lt;0.05) increments between Age3 and Age1 (during ACT) and between Age3 and both Age1 and 2 (during NREM and H24) were found. Average SNSi values were slightly above the normality range [1] during ACT, or normal (during NREM and H24). Average PNSi values were within the suggested normality range [1] with minimal aging-related variations. Significant aging-related decrement of the selected TD and FD parameters was found in all analysed conditions. Among NL parameters, the correlation dimension (D2) values showed significant aging-related decrement (H24 and NREM), while H24 and ACT sample entropy (SampEn) was lower in Age1 and Age2, compared with Age3 (p&amp;lt;0.05). An example (H24 analysis of Age3 data) of significant (p&amp;lt;0.01) correlation among the three indexes and the selected independent linear and non-linear parameters is shown in Figure 1. Conclusions In this study, a significant aging-related increment of BSTRi was found in all investigated conditions. PNSi and SNSi were always within the suggested normality range [1]. In spite of the significant changes of linear parameters consistent with the well-known aging-related decrement of HRV, the higher SampEn (and BSTRi) found in Age3 HS suggests that an "healthy elderly", is characterized by a more complex adaptation of CAM, likely mediated also by the observed moderate (healthy?) increment of physiological stress. However further investigation on a broader population is warranted.Table 1Figure 1

Analysis of ventricular repolarization parameters and heart rate variability in obesity: a comparative study

Obesity is associated with dysfunctional electrocardiographic and cardiac autonomic parameters, which may lead to increased cardiovascular morbidity. Novel electrocardiographic repolarization markers such as Tpeak-Tend (Tpe) interval have not yet been deeply studied in obese patients. We aimed to investigate the association between ventricular repolarization parameters and heart rate variability (HRV) and how they are affected by changes occurring in the cardiac autonomic nervous system. Ninety subjects categorized by Southeast Asian BMI (kg/m2) standards - normal (18-22.9), overweight (23-24.9), and obese (> 24.9), underwent assessment of ventricular repolarization parameters and HRV. Linear correlation between different parameters was also conducted. Obese subjects exhibited longer QTc and Tpe intervals compared to normal-weight subjects (p-value < 0.001, 0.026 respectively). The QTc interval showed a significant correlation (p < 0.05) with all HRV parameters by linear correlation, while the Tpe interval did not. Anthropometric parameters (BMI, WC, and WHR) were also correlated to both ventricular repolarization variables and HRV. While changes in the QTc interval may be due to obesity and/or autonomic changes occurring in the obese state, the Tpe interval does not show a relation with autonomic parameters. Thus, implicating that a change in the Tpe interval is primarily due to the direct effect of either cardiac or visceral obesity. The observed associations between ECG parameters, obesity indices, and HRV parameters suggest a role for ECG in screening for cardiovascular morbidity.

Synthetic assessment of cardiac autonomic modulation and Baevsky stress index in patients with synucleinopathies

Abstract Background The Baevsky Stress Index (BSTRi), calculated from Heart Rate Variability (HRV) data, has been proposed for quantitative assessment of physiological stress, with higher scores indicating higher levels of physical and/or psychological stress [1]. Cardiac autonomic modulation can be synthetically quantified by calculating the parasympathetic (PNSi) and the sympathetic (SNSi) indexes. The values of the BSTRi, SNSi, and PNSi in patients with synucleinopathies of different prognoses have not been reported yet. Purpose To quantify, in patients with Parkinson's disease (PD) and Multisystem Atrophy (MSA), the BSTRi, its correlation with the PNSi and the SNSi indexes, and their potential value for a synthetic assessment of cardiac autonomic modulation and early differential diagnosis between PD and MSA. Methods Holter ECG data of 66 patients with Parkinsonian syndromes were retrospectively analyzed after 10 years of follow-up. Out of them, 34 patients with a certain diagnosis of PD (17) and MSA (17) were selected for this study. HRV was analyzed with the Kubios software (version 4.0), providing automatic calculation of the BSTRi, PNSi, and SNSi [2], as well as of time domain (TD), frequency domain (FD), nonlinear (NL), and time-varying (TV) HRV parameters. HRV was calculated from selected short-term intervals (of 5 minutes), during daily activity (ACT5’), and non-REM sleep (NREM5’), and from 24-hours Holter recordings. Patients’ HRV findings were compared with those of 51 age-matched healthy subjects (HS). Results An example of individual automatic graphic summary is shown in Figure 1. Both short-term and 24-hour BSTRi and SNSi values were significantly (p &amp;lt; 0.05) higher in PD and MSA compared to those of HS, in all investigated conditions. Short-term PNSi was significantly higher in HS than in PD in all conditions, but only during NREM5’ in MSA patients (Table 1). No significant difference was found between the indexes of PD and MSA patients. As in HS (R=92), BSTRi was positively correlated with the SNSi in MSA (average R= 0.83 and 0.89 during ACT5’ and NREM5’, respectively), but less evident in PD (R=0.67). The inverse correlation between PNSi and SNSi (R=0.75 in HS) was lost in both MSA and PD. Conclusions Higher values of BSTRi in PD and MSA compared to HS suggest that patients with synucleinopathies do experience higher levels of psychophysiological stress, which may affect their quality of life negatively. However, since no significant difference was found in this study between BSTRi values of PD and MSA patients, BSTRi seems at present unreliable for early differentiation between the two diseases. Telematic assessment of BSTRi, SNSi, and PNSi could be useful for remote monitoring of PD and MSA patients’ psychophysiological stress, to provide timely intervention and adaptive treatment.Fig.1 Example of graphic summary (ACT5')

Heart rate variability to predict 1-day atrial fibrillation episode onset using machine learning

Abstract Background Studies using AI assessment of 10-second 12-lead ECG suggest that it provides incremental identification of AF risk compared with clinical scores. However, it is not clear what preventive treatment should be given as the exact time of AF onset remains unknown. The use of machine learning (ML) with 2-lead Holter ECG allows the development of predictive models for paroxysmal AF within a short time window, potentially allowing an optimised pill-in-the-pocket (PITP)-like strategy. Aim To identify patients who are still in sinus rhythm but will develop an episode of AF in the next few hours using 24-hour Holter recordings and ML. Materials and methods We created a new database of 95871 Holter recordings that were manually analysed. We identified 1319 paroxysmal AF episodes from 872 patients. A total of 835 AF episodes from 506 recordings had more than 60 minutes of normal sinus rhythm (NSR) before AF onset and more than 10 minutes of AF after onset, and a total of 964 AF episodes had 30 minutes or more of NSR before AF onset. Patients were divided into five groups: all patients, patients younger than 60 years, 60-70 years, 70-80 years, and older than 80 years. A total of 365 recordings from 347 patients without rhythm abnormalities were identified and classified in our database, from which we took two ECG windows. We used a gradient-boosted decision tree model with heart rate variability (HRV) parameters as input. Results The most significant results were obtained from recordings with more than 5 minutes of AF with an AUROC of 0.919 (95% CI: 0.879-0.958) and an AUPRC of 0.919 (0.879-0.958) 15H08 ± 13H05 hours before the onset of AF (Figures 1 - 2). Using a threshold of 0.5, the accuracy was 84.5% (81.2-87.8), the sensitivity was 83.0% (79.5-86.4), the specificity was 86.6% (79.3-93.9), the PPV was 90.2% (85.5-94.9), the NPV was 78.4% (74.7-82.1) and the F1 score was 86.2% (83.5-89.0) for all patients. Conclusion These results suggest that the most important information for short-term prediction of AF onset is contained in HRV, allowing a preventive strategy. This could be exploited by wearables in mHealth allowing the use of a PITP-like preventive strategy to reduce the burden of AF. Prospective studies are needed to confirm the encouraging potential of these findings.AUROC of the XGBoost modelPrecision-recall curves

Heart rate variability and insomnia in depressed patients with breast cancer

ObjectivesDepression is associated with unhealthy autonomic regulation. However, whether patients with breast cancer (BC) with different degrees of depression can be identified from linear and non-linear dynamics in the autonomic...

Mindfulness Exercises Reduce Acute Physiologic Stress Among Female Clinicians.

Approximately 50% of clinicians experience excessive emotional, physical, and mental stress, with repercussions across the entire medical system. Mindfulness exercises may mitigate this excessive stress. Heart rate variability (HRV) is an objective stress measure that can quantify which mindfulness exercises provide the greatest stress reduction. To define the impact of specific mindfulness exercises on HRV, a surrogate for physiologic stress, and the relationship between physiologic (HRV) and subjective stress measured by the State-Trait Anxiety Inventory during a one-day mindfulness workshop. This was a prospective observational pilot study performed at a quaternary children's hospital with diverse subspecialists of pediatric nurses, nurse practitioners, and physicians. Our primary outcome measure was change in HRV from baseline during three mindfulness exercises. The grounding, deep breathing, and body scan exercises all produced statistically significant changes in HRV among our 13 female participants. The body scan exercise produced statistically significant changes in all studied HRV parameters compared with baseline. We observed significant increases in Root Mean Square of Successive Differences between normal heartbeats (p = 0.026), high frequency (p ≤ 0.001), and the parasympathetic nervous system index (p ≤ 0.001) reflecting increased parasympathetic tone (e.g., relaxation), whereas sd 2/sd 1 ratio (p ≤ 0.001) and the stress index (p = 0.004) were decreased reflecting sympathetic withdrawal (e.g., decreased stress). Subjective stress decreased after 1-day mindfulness training (44.6 to 27.2) (p < 0.001). Individuals with the largest decrease in subjective stress also had the most improvement in HRV during the body scan exercise. Clinician stress levels (HRV) improved after participating in grounding, deep breathing, and body scan meditations, which may highlight their importance as stress reduction tools for clinicians. Monitoring of HRV during mindfulness exercises may provide deeper understanding of which specific exercises produce the greatest physiologic stress reduction for individual participants and the trend of these changes over time.