Predictors Of Heart Rate Variability Research Articles

Anthropometric Predictors of Heart Rate Variability in Overweight Individuals: A Comparative Study.

Introduction The autonomic nervous system is crucial in regulating cardiovascular function. Heart rate variability (HRV) analysis, a non-invasive method to assess autonomic function, reflects the beat-to-beat variations in heart rate and provides insights into the dynamic interplay between sympathetic and parasympathetic influences on the cardiovascular system. In this study, we aimed to find the HRV parameters in overweight individuals by comparing different anthropometric parameters, including body mass index (BMI), percentage body fat (%BF), waist circumference (WC), and waist-hip ratio (WHR). Method The descriptive cross-sectional study was conducted on 132 healthy first-year MBBS students (82 males and 50 females), aged between 17 and 23 years. Anthropometric parameters (BMI, %BF, WC, WHR) and HRV were recorded for the participants. The HRV parameters were analyzed for either gender. A student 't' test was used to test the difference between groups BMI <25 kg/m2 and = or >25 kg/m2,and a p-value less than 0.05 was taken to be statistically significant. The Pearson correlation coefficient was used to show the relationship between HRV parameters and BMI, %BF, WC, and WHR as the independent variables. Result A total of 132healthy individuals participated in the study, including 82 males and 50 females. The participants had a mean age of 18.72 ± 0.98 years. Our results suggest that while WC and WHR can be used alongside BMI to indicate sympathetic hyperactivity in males, BMI remains the most significant predictor in females. We found gender-specific differences in high-frequency (HF) related to various anthropometric measures, but these differences were not statistically significant. The low-frequency:high-frequency (LF/HF) ratio exhibits strong positive correlations with all measured anthropometric parameters, suggesting that increased values in BMI, %BF, WC, and WHR are associated with greater sympathetic involvement. Conclusion WC and WHR, alongside BMI, are reliable indicators of heightened sympathetic activity in both males and females. These measures should be utilized to assess healthy individuals for the early diagnosis of dysautonomia, disrupt the cycle of sympathetic overactivity, and prevent cardiovascular complications. All these anthropometric parameters are valuable for indicating sympathovagal balance, making them essential tools in the proactive management of autonomic dysfunction and associated health risks.

SPECIAL ISSUE: The Effect of Perceived Racial Discrimination in African Americans on HRV

Health disparities among African Americans have been reported for decades. This is especially true for cardiovascular disease (CVD) even when compared with other minority groups in America. Such disparities have been tied to perceived discrimination. A previous study found that perceived racism accounted for a substantial percentage of the variance in resting heart rate variability (HRV), an independent biomarker of cardiac health. The present study attempts to replicate such findings. This study includes 57 healthy African American individuals who met inclusion criteria. Participants were given the Perceived Ethnic Discrimination Questionnaire–Community Version (PEDQ-CV) and the Perceived Racism Scale (PRS) and had their resting HRV and blood pressure measured. After accounting for breathing rate and age, the lifetime score on the PRS uniquely accounted for up to 45% of the variability of HRV metrics. The PEDQ-CV was not found to be a statistically significant predictor of HRV. Within this sample, blood pressure was not significantly predicted by either scale. The findings suggest that lifetime perceived racism may directly affect HRV indices, which may indicate an increased risk for CVD. Further research should continue to investigate this association and potential avenues for related intervention.

Using heart rate variability to develop a predictive model for post-operative cardiovascular complications following major abdominal surgery: A pilot study.

Heart Rate Variability (HRV) is a dynamic reflection of heart rhythm regulation by various physiological inputs. HRV deviations have been found to correlate with clinical outcomes in patients under physiological stresses. Perioperative cardiovascular complications occur in up to 5% of adult patients undergoing abdominal surgery and are associated with significantly increased mortality. This pilot study aimed to develop a predictive model for post-operative cardiovascular complications using HRV parameters for early risk stratification and aid post-operative clinical decision-making. Adult patients admitted to High Dependency Units after elective major abdominal surgery were recruited. The primary composite outcome was defined as cardiovascular complications within 7days post-operatively. ECG monitoring for HRV parameters was conducted at three time points (pre-operative, immediately post-operative, and post-operative day 1) and analyzed based on outcome group and time interactions. Candidate HRV predictors were included in a multivariable logistic regression analysis incorporating a stepwise selection algorithm. 89 patients were included in the analysis, with 8 experiencing cardiovascular complications. Three HRV parameters, when measured immediately post-operatively and composited with patient age, provided the basis for a predictive model with AUC of 0.980 (95% CI: 0.953, 1.00). The negative predictive value was 1.00 at a statistically optimal predicted probability cut-off point of 0.16. Our model holds potential for accelerating clinical decision-making and aiding in patient triaging post-operatively, using easily acquired HRV parameters. Risk stratification with our model may enable safe early step-down care in patients assessed to have a low risk profile of post-operative cardiovascular complications.

Heart Rate Variability during Online Video Game Playing in Habitual Gamers: Effects of Internet Addiction Scale, Ranking Score and Gaming Performance.

Previous studies have demonstrated that individuals with internet gaming disorder (IGD) display abnormal autonomic activities at rest and during gameplay. Here, we examined whether and how in-game autonomic activity is modulated by human characteristics and behavioral performance of the player. We measured heart rate variability (HRV) in 42 male university student habitual gamers (HGs) when they played a round of League of Legends game online. Short-term HRV indices measured in early, middle and late phases of the game were compared between the players at high risk of developing IGD and those at low risk, as assessed by the revised Chen Internet addiction scale (CIAS-R). Multiple linear regression (MLR) was used to identify significant predictors of HRV measured over the whole gameplay period (WG), among CIAS-R, ranking score, hours of weekly playing and selected in-game performance parameters. The high-risk players showed a significantly higher low-frequency power/high-frequency power ratio (LF/HF) relative to the low-risk players, regardless of game phase. MLR analysis revealed that LF/HF measured in WG was predicted by, and only by, CIAS-R. The HRV indicators of sympathetic activity were found to be predicted only by the number of slain in WG (NSlain), and the indicators of parasympathetic activity were predicted by both CIAS-R and NSlain. Collectively, the results demonstrated that risk of developing IGD is associated with dysregulated autonomic balance during gameplay, and in-game autonomic activities are modulated by complex interactions among personal attributes and in-game behavioral performance of the player, as well as situational factors embedded in game mechanics.

Monitoring change in heart rate variability following acceptance and commitment therapy for chronic pain: Results of a randomized controlled trial for individuals with neurofibromatosis type 1

Acceptance and Commitment Therapy (ACT) is a well-evidenced therapeutic model for the treatment of chronic pain. While there is substantial data that indicates improvement in the cognitive and behavioral aspects of pain (e.g., pain acceptance, pain inflexibility, pain interference), significantly less research has explored changes in physiological variables following acceptance-based interventions. In particular, heart rate variability (HRV) is a physiological marker of pain and reflects the time elapsed between heart beats. The current study examined whether HRV changed following a randomized-controlled trial of ACT for individuals with neurofibromatosis type 1 and chronic pain (N = 62). Repeated measures analyses of covariance assessed change following ACT. In addition, hierarchical linear regression models examined pain-related predictors of HRV at follow-up. The results suggest that HRV improves following ACT, although given the small sample and limited analytical model, the findings should be considered preliminary. Further, improvements in HRV over the course of the intervention predicted improvements in pain intensity at follow-up suggesting a relationship between these two variables. Taken together, these data provide modest evidence of the relationships between ACT and HRV within a chronic pain population. Additional implications and future directions are discussed.

Low heart rate variability is associated with a negativity valence bias in interpreting ambiguous emotional expressions.

Most people tend to overstate positive aspects of their experiences, that is, a positive valence bias. However, some people tend to have attenuated attention for negative aspects of perceived information, that is, negative valence bias. This dispositional tendency in either valence is especially significant for emotion regulation as it influences the intensity of later stages of emotional experiences. Heart rate variability (HRV) is used as an index of emotion regulation and for the effect dispositional valence bias has on social cognition. The aim of the current study was to investigate whether a positivity or negativity bias in processing ambiguous facial expressions would predict high or lower HRV, respectively, in a healthy sample. The Reading the Mind in the Eyes Test was presented to a sample of 128 healthy participants (N = 86 women participants), and resting HRV was acquired. In multiple linear regression analyses, the mean accuracy scores for items with positive, negative, and neutral valences were included as predictors of HRV. As a follow-up analysis, we tested whether a general tendency to interpret negative stimulus as positive, that is, a positivity bias, predicted HRV. Higher accuracy on items with negative emotional valence predicted lower HRV. There was no association between accuracy scores on items of positive or neutral valence and HRV. Higher positivity bias predicted higher HRV. The present findings suggest that a dispositional valence bias relates to levels of HRV and, as such, is influenced by the functioning of the vagal system. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Anthropometric Determinants of Autonomic Control in Obstructive Sleep Apnea: A Large-Scale Study.

Autonomic dysfunction is an independent risk factor for cardiovascular disease (CVD). Both obesity and obstructive sleep apnea (OSA) are associated with heart rate variability (HRV) (a hall marker of sympathetic arousal) and increased risk of CVD. This study aims to investigate whether anthropometric parameters could predict reduced HRV in adult OSA during wakefulness. Cross-sectional study. Sleep center of Shanghai Jiao Tong University Affiliated Sixth Hospital from 2012 to 2017. Total of 2134 subjects (503 non-OSA and 1631 OSA) were included. Anthropometric parameters were recorded. HRV was recorded during a 5-minute wakefulness period and analyzed by using time-domain method and frequency-domain method. Multiple step-wise linear regressions were performed to determine significant predictors of HRV with and without adjustments. Multiplicative interactions between gender, OSA, and obesity on HRV were also determined and evaluated. Waist circumference (WC) was significant negative determinant of root mean square of successive NN intervals(β = -.116, p < .001) and high-frequency power (β = -.155, p < .001). Age was the strongest determining factor of HRV. Significant multiplicative interactions between obesity and OSA on HRV, gender, and obesity on cardiovascular parameters were observed. Anthropometric parameters could predict reduced HRV during wakefulness in patients with OSA, especially WC was the strongest influenceable factor. Obesity and OSA had significant multiplicative interaction on HRV. Gender and obesity had significant multiplicative interaction on cardiovascular parameters. Early intervention for obesity, especially centripetal obesity, may improve reduction of autonomic function and risk of CVD.

Predictors of Heart Rate Variability: A Systematic Review

Introduction: The heart has the ability to maintain cardiac output in accordance with the body’s momentarily changing demands by adjusting its rate of contractions and this ability is termed Heart Rate Variability (HRV), which is manifested as a fluctuation of R-R interval in milliseconds on an Electrocardiography (ECG). Maintenance of good HRV levels is significant for the patient population since they influence the prognosis and quality of life. Aim: To identify the predictors of HRV. Materials and Methods: The present study was a systematic and literature review which was based on Preferred Reporting Items for Systematic reviews and Meta-Analysis (PRISMA) guidelines 2020. Randomised Controlled Trials (RCTs) published in English from 2014 to 2021 were identified from Cochrane Library, Science Direct, PubMed, and Google Scholar databases. The keywords with Boolean operators were used as “influencing factors or determinants or predictors and HRV.” The quality assessments of the studies were performed with Cochrane risk-of-bias assessment tool. Narrative syntheses upon the selected studies were done. Results: The significant findings from the nine selected RCTs were summarised. Physical exercise, breathing exercise, diet, music, and mind-body interventions such as yoga and meditation were identified as the factors enhancing HRV or predictors of HRV. Conclusion: The findings of this systematic review strive to facilitate healthcare providers to devise the strategies to support the risk group of low HRV by the implementation of enhancing factors of HRV to achieve a better outcome.

Heart rate variability alterations in Dravet Syndrome: The role of status epilepticus and a possible association with mortality risk

PurposePreliminary data suggest that patients with Dravet Syndrome (DS) have a reduced heart rate variability (HRV). This seems particularly evident in patients who experienced sudden unexpected death in epilepsy (SUDEP). This study aims at confirming these findings in a larger cohort and at defining clinical, genetic or electroencephalographic predictors of HRV impairment in DS patients. MethodsDS patients followed at our Institution performed a 24h-ECG Holter to derive HRV parameters. We used as control population patients with epilepsy (PWEs) and healthy controls (HCs). In DS patients, we assessed the impact of different clinical, neurophysiological and genetic features on HRV alterations through multiple linear regression. After a mean follow-up of 7.4 ± 3.2 years since the HRV assessment, all DS patients were contacted to record death or life-threatening events. Results56 DS patients had a significantly reduced HRV compared to both HCs and PWEs. A recent history of status epilepticus (SE) was the only significant predictor of lower HRV in the multivariate analysis. At follow-up, only one patient died; her HRV was lower than that of all the controls and was in the low range for DS patients. ConclusionWe describe for the first time an association between SE and HRV alterations in DS. Further studies on other SCN1A-related phenotypes and other epilepsies with frequent SE will help clarify this finding. Compared to the literature, our cohort showed better HRV and lower mortality. Although limited, this observation reinforces the role of HRV as a biomarker for mortality risk in DS.

Assessment of cardiac autonomic function in patients with permanent and paroxysmal atrial fibrillation

Abstract Background Atrial fibrillation (AF) is the commonest abnormal heart rhythm with significant related morbidity and mortality. There is increasing evidence that abnormalities of the cardiac autonomic nervous system (ANS) are involved in the pathogenesis of AF. Exploring the ANS is possible through heart rate variability (HRV) evaluation. Purpose To investigate whether HRV is more abnormal in patients with permanent AF compared to paroxysmal AF. Design In a cross-sectional comparison, we studied two patient groups: permanent AF (n=30) and paroxysmal AF (n=31). Time-domain, frequency-domain and non-linear measures of HRV were determined using eMotion Faros ECG sensor. Participant's breathing was controlled with a metronome set at 12 breaths per minute. Data was analysed using SPSS software. Results Time-domain and non-linear indices of HRV were significant higher in permanent AF group compared to paroxysmal AF (table 1). Permanent AF was the only independent predictor of HRV on multivariable analysis in this cohort of patients (p=0.006) Conclusions First study investigating autonomic function in patients with permanent AF and paroxysmal AF. HRV indices were significantly higher in permanent AF compared to paroxysmal AF which may suggest pronounced cardiac autonomic influence in the pathophysiology of permanent AF. Funding Acknowledgement Type of funding sources: None.

A Novel Application of the Modified Angoff Method to Rate Case Difficulty in Simulation-Based Research.

Simulation use in research is often limited by controlling for scenario difficulty when using repeated measures. Our study assesses the feasibility of the Modified Angoff Method to reach expert consensus regarding difficulty of medical simulations. We compared scores with participant physiologic stress. Emergency medicine physicians with expertise in simulation education were asked to review 8 scenarios and estimate the percentage of resident physicians who would perform all critical actions using the modified Angoff method. A standard deviation (SD) of less than 10% of estimated percentage correct signified consensus. Twenty-five residents then performed the 6 scenarios that met consensus and heart rate variability (HRV) was measured. During round 1, experts rated 4/8 scenarios within a 10% SD for postgraduate year 3 (PGY3) and 3/8 for PGY4 residents. In round 2, 6/8 simulation scenarios were within an SD of 10% points for both years. Intraclass correlation coefficient was 0.84 for PGY3 ratings and 0.89 for PGY4 ratings. A mixed effects analysis of variance showed no significant difference in HRV change from rest to simulation between teams or scenarios. Modified Angoff Score was not a predictor of HRV (multiple R2 = 0.0176). Modified Angoff ratings demonstrated consensus in quantifying the estimated percentage of participants who would complete all critical actions for most scenarios. Although participant HRV did decrease during the scenarios, we were unable to significantly correlate this with ratings. This modified Angoff method is a feasible approach to evaluate simulation difficulty for educational and research purposes and may decrease the time and resources necessary for scenario piloting.

Heart rate variability in patients with atrial fibrillation and hypertension.

Atrial fibrillation (AF) and hypertension are independently associated with impaired autonomic function determined using heart rate variability (HRV). As these conditions frequently co-exist, we sought to determine whether AF would worsen HRV in hypertensive patients. We studied HRV in AF (and hypertension) (n=61) and hypertension control group (n=33). The AF (and hypertension) group was subdivided into permanent AF (n=30) and paroxysmal AF (n=31) and re-studied. Time-domain, frequency-domain and nonlinear measures of HRV were determined. Permanent AF group (n=30) was followed up after 8weeks following optimisation of their heart rate and blood pressure (BP). Time-domain and nonlinear indices of HRV were higher in AF (and hypertension) group compared to hypertensive controls (P≤.01). Time-domain and nonlinear indices of HRV were higher in permanent AF group compared to paroxysmal AF (P≤.001). Permanent AF was an independent predictor of HRV on multivariable analysis (P=.006). Optimisation of heart rate and BP had no significant impact on HRV in permanent AF. AF, independent of hypertension, is characterised with marked HRV and is possibly related to vagal tone. HRV is higher in permanent AF compared to paroxysmal AF suggesting evident autonomic influence in the pathophysiology of permanent AF. Modulation of autonomic influence on cardiovascular system should be explored in future studies.

Redundancy among risk predictors derived from heart rate variability and dynamics: ALLSTAR big data analysis.

BackgroundMany indices of heart rate variability (HRV) and heart rate dynamics have been proposed as cardiovascular mortality risk predictors, but the redundancy between their predictive powers is unknown.MethodsFrom the Allostatic State Mapping by Ambulatory ECG Repository project database, 24‐hr ECG data showing continuous sinus rhythm were extracted and SD of normal‐to‐normal R‐R interval (SDNN), very‐low‐frequency power (VLF), scaling exponent α1, deceleration capacity (DC), and non‐Gaussianity λ25s were calculated. The values were dichotomized into high‐risk and low‐risk values using the cutoffs reported in previous studies to predict mortality after acute myocardial infarction. The rate of multiple high‐risk predictors accumulating in the same person was examined and was compared with the rate expected under the assumption that these predictors are independent of each other.ResultsAmong 265,291 ECG data from the ALLSTAR database, the rates of subjects with high‐risk SDNN, DC, VLF, α1, and λ25s values were 2.95, 2.75, 5.89, 15.75, and 18.82%, respectively. The observed rate of subjects without any high‐risk value was 66.68%, which was 1.10 times the expected rate (60.74%). The ratios of observed rate to the expected rate at which one, two, three, four, and five high‐risk values accumulate in the same person were 0.73 times (24.10 and 32.82%), 1.10 times (6.56 and 5.99%), 4.26 times (1.87 and 0.44%), 47.66 times (0.63 and 0.013%), and 1,140.66 times (0.16 and 0.00014%), respectively.ConclusionsHigh‐risk predictors of HRV and heart rate dynamics tend to cluster in the same person, indicating a high degree of redundancy between them.

Heart rate variability and heart rate recovery in lung cancer survivors eligible for long-term cure

Lung cancer survivors are at risk for physical fitness and autonomic function impairments. In a cross-sectional study of consecutive lung cancer survivors post-curative intent therapy, we assessed and identified predictors of resting heart rate variability (HRV) and heart rate recovery (HRR), defined as standard deviation of normal-to-normal-R-to-R intervals (SDNN) and root-mean-square-of-successive-differences (rMSSD) from routine outpatient single 10-s electrocardiographs (ECGs) and difference in heart rate (HR) at 1-minute following and the end of the six-minute-walk-test (6MWT), respectively. In 69 participants, the mean (SD) HRR was -10.6 (6.7) beats. Significant independent predictors of HRR were age and HR change associated with the 6MWT. In a subset of 41 participants with available ECGs, the mean (SD) SDNN and rMSSD were 19.1 (15.6) and rMSSD 18.2 (14.6) ms, respectively. Significant independent predictors of HRV were supine HR, HRR, and total lung capacity. HRV/HRR may be useful physiological measures in studies aimed at improving physical fitness and/or autonomic function in lung cancer survivors.

Autonomic Parameter and Stress Profile Predict Secondary Ischemic Events After Transient Ischemic Attack or Minor Stroke.

Background and Purpose- Traditional risk factors for ischemic stroke are body stressors that are related to autonomic autonomic system (ANS) dysfunction. The value of ABCD2 score (age, blood pressure, clinical features, duration of symptoms, diabetes) to predict ischemic stroke after transient ischemic attack is compromised by the inclusion of a limited number of stressors. We aimed to assess whether markers of ANS function and stress could predict the occurrence of secondary ischemic events after transient ischemic attack or minor stroke. Methods- This is a prospective cohort study in which 201 patients were recruited within 48 hours after initial transient ischemic attack or minor stroke and followed for 90 days to assess the development of secondary ischemic events. ABCD2 score, heart rate variability (HRV) parameters as markers of ANS function, and psychological stress were assessed. Logistic regression and area under the curve (AUC) were used to assess the models' predictive ability. Results- Morning high frequency (HF) HRV power and changes in HF HRV from morning to afternoon (daytime HF changes) were the most useful HRV predictors for both ischemic events (AUC=0.61 and 0.70) and ischemic stroke (AUC=0.62 and 0.72). Compared with ABCD2 score, 2 HRV-based stress models showed higher predictive ability for ischemic events (AUC=0.82 versus 0.63, 0.76 versus 0.63; P<0.05) and ischemic stroke (AUC=0.87 versus 0.64, 0.82 versus 0.64; P<0.05). Conclusions- Assessing the effects of stress on the ANS may be an innovative way to stratify the risk of ischemic events after transient ischemic attack or minor stroke. New risk stratification by assessing the dynamic features of ANS dysfunction and stress may help identify high-risk sub-populations that may benefit from added management.

Recovery of Heart Rate Variability After Exercise Under Hot Conditions: The Effect of Relative Humidity

The aim of this study was to analyze changes in heart rate variability (HRV) during exercise in hot environments and recovery to baseline values depending on relative humidity. Ten recreational runners participated in this study. Each participant performed 2 trials consisting of 30 min of continuous running under hot and dry (HD) (38°C and 28% relative humidity) and hot and humid (HH) conditions (38°C and 64% relative humidity) at their common 10 km race-running rhythm. HRV and body mass were assessed pre- and post-trial; the rating of perceived exertion and HRV were assessed during the trial; and HRV measurements were repeated 2, 4, 8, and 24 h postexercise. Primary HRV outcomes were root mean square of the successive differences, high frequency power, stress score, and sympathetic/parasympathetic ratio. One-way analysis of variance testing was used to analyze differences. No significant difference in body mass occurred across the different conditions or distances covered (P>0.05). Rating of perceived exertion presented the highest correlation values with stress score (r=0.729 for HD; r=0.568 for HH) and sympathetic/parasympathetic ratio (r=0.621 for HD; r=0.519 for HH) during exercise. HRV recovered to baseline values more quickly after exercising under dry conditions (4 h) than under humid conditions (between 8 and 24 h). Stress score and sympathetic/parasympathetic ratio seem to be the best HRV predictors of internal load. Although there are no differences in HRV during recovery at the same time points in both conditions, the recovery is slower after exercise in HH than in HD.

Interoception and respiratory sinus arrhythmia in gambling disorder.

Gambling has longstanding links with excitement and physiological arousal, but prior research has not considered (a) gamblers' ability to detect internal physiological signals, or (b) markers of parasympathetic functioning. The present study measured interoception in individuals with gambling disorder, using self-report measures and a heartbeat counting task administered at rest. Resting state respiratory sinus arrhythmia (RSA), an index of heart rate variability, was measured as a proxy for parasympathetic control and emotional regulation capacity. In a case-control design, 50 individuals with gambling disorder were compared against 35 controls without gambling problems. Participants completed two self-report measures of bodily awareness and a behavioral test of heartbeat counting. A resting state electrocardiogram (5min) was used to calculate RSA. There were no significant differences on the self-report or behavioral interoception probes. The group with gambling disorder displayed significantly reduced RSA, which at face value is consistent with reduced parasympathetic control. However, the group difference in RSA did not survive controlling for age and smoking status, as established predictors of heart rate variability. Our findings do not support any changes in interoceptive processing in people with gambling disorder, at least under resting conditions. Our observation that group differences in RSA are partly explained by smoking behavior highlights the importance of controlling for nicotine use in future research characterizing physiological functioning and emotional regulation in disordered gambling.

Abstract WP197: Autonomic Nervous System Parameters to Predict the Occurrence of Ischemic Events After Transient Ischemic Attack or Minor Stroke

Background: Stress response is tightly regulated by the autonomic nervous system (ANS) which can be measured by heart rate variability (HRV). Traditional risk factors and acute triggers for ischemic stroke and transient ischemic attack (TIA) are considered as chronic and acute stressors, respectively. These risk factors all contribute to the recurrent ischemic events and are related to ANS dysfunction. The moderate predictive value of ABCD2 score may be due to assessing a limited number of stressors. Aims, Objectives and Hypotheses: We proposed to 1) assess whether HRV parameters, as markers of ANS function and stress, can predict secondary ischemic events after TIA or minor stroke, and 2) compare the HRV-based predictive tools with ABCD2 score. We expected that using HRV indicators can enhance the prediction of ischemic events. Methods: This is a prospective observational study. Patients developed TIA or minor stroke within 48 hours were eligible. The main study variables included: ABCD2 score, HRV assessment from 24-hour Holter recording, and psychological stress. HRV measurement included calculations of both absolute values and changes of HRV frequency-domain parameters: high frequency (HF), normalized HF, HF +low frequency, and total power. Patients were followed for 90 days to assess the development of outcome events. Logistic regression was employed for data analyses. Area under the curve (AUC) and diagnostic tests were used to assess models’ predictive power. Results: Final analyses include data collected from 201 patients. The most useful HRV predictors were Daytime HF changes (AUC=0.70) and Morning HF value (AUC=0.61). AUCs for the Best Stress Model and the Most Practical Model were 0.82 and 0.76, respectively, which were significantly higher than AUC of ABCD2 score (AUC=0.63), p &lt;0.05. The optimal cut-off points for Daytime HF changes and Morning HF might be increase of 12.5% and 50 ms 2 , respectively. The exploratory models that involved both values and changes of HF had AUCs ≥0.82. Conclusions: Assessing the effects of stress on ANS may be an innovative way to stratify the risk of TIA or minor stroke. Models using HRV parameters, especially HF, provide superior predictive values to ABCD2 score. Future research is needed to validate these results.

Saturated Fat Intake Is Related to Heart Rate Variability in Women with Polycystic Ovary Syndrome

Background/Aims: There is a heightened risk for cardiovascular diseases in women with polycystic ovary syndrome (PCOS). Alterations in heart rate variability (HRV) may reflect subclinical cardiovascular disease, with a putative association between HRV and dietary fat. This study evaluated HRV in PCOS and control women based on the dietary intake of saturated fatty acid (SFA). Methods: Biochemical/hormonal profile, resting metabolic rate, physical activity, HRV in response to the Stroop test, and dietary intake were assessed in 84 PCOS and 54 control women stratified by median SFA intake in the PCOS group (8.5% of daily energy intake). Results: Body mass index (p = 0.041), blood pressure (p < 0.01), and HOMA-IR (p = 0.003) were higher in PCOS vs. controls. PCOS women had higher testosterone (p = 0.001), dehydroepiandrosterone sulfate (p = 0.012), and free androgen index (p = 0.001), and lower sex hormone-binding globulin levels than controls (p = 0.001). In both groups, the clinical profile and calorie intake were similar between SFA categories. In PCOS, testosterone was lower when SFA intake <8.5%. PCOS women with SFA <8.5% consumed more beans, fruits, and vegetables and had better frequency and time domain HRV indices. No differences in HRV were detected between SFA categories in controls. In PCOS, age and SFA intake were independent predictors of HRV. Conclusions: Lower SFA intake is related to improved cardiovascular autonomic function in PCOS.

Longitudinal Associations of Leptin and Adiponectin with Heart Rate Variability in Children.

For early prevention of cardiovascular disease, early detection and risk factor insights are necessary. The autonomic balance reflects cardiovascular risk and can be measured by heart rate variability (HRV). Therefore, our purpose is to examine associations between HRV and the energy-related biomarkers leptin and adiponectin in children. Participants of this study were Belgian children recruited for the longitudinal ChiBS study (year 2010–2012). HRV was measured and fasting blood samples were taken in 249 children at baseline (4.4–11.0 y) and 223 children at follow-up (6.7–12.2 y). Cross-sectional and longitudinal linear regression analyses were separated by sex and adjusted for age, socio-economic status, body fat%, negative emotions, puberty, and mean heart rate. Leptin was a negative cross-sectional and longitudinal predictor of parasympathetic activity in boys; while leptin in girls was cross-sectionally associated with higher LF and LF/HF suggesting sympathetic predominance. Adiponectin was a negative cross-sectional and longitudinal predictor of parasympathetic activity in boys; but when adjusting for mean heart rate, this effect disappeared and adiponectin was a positive cross-sectional and longitudinal predictor of parasympathetic activity in girls. These results stress the importance of considering sex differences and adjustment for heart rate in testing HRV predictors. Leptin seemed disadvantageous for the autonomic balance, while adiponectin seemed advantageous for the autonomic balance in girls only. More research is needed to see whether leptin and adiponectin are interesting in cardiovascular screening/prevention or in determining the cardiovascular gain during weight loss follow-up.