Time Domain Heart Rate Variability Research Articles

Association of Novel EEG Biomarkers of Sleep Depth and Cortical Arousability with Cardiac Autonomic Modulation in Adolescents.

To examine the developmental association of the odds ratio product (ORP), an electroencephalographic measure of sleep depth, during non-rapid eye movement (NREM) sleep with 24-hour heart rate variability (HRV), an electrocardiographic measure of cardiac autonomic modulation (CAM), in the transition to adolescence. Leveraging data from the Penn State Child Cohort, we performed longitudinal analyses on 313 children (median [Md] age 9 years) followed-up after Md=7.4y and cross-sectional analyses on 344 adolescents (Md=16y). We extracted ORP during NREM sleep and in the 9 seconds following cortical arousals (ORP-9) from 9-hour, in-lab polysomnography, and frequency- and time-domain HRV indices from 24-h Holter ECG monitoring. Longitudinal and cross-sectional, multivariable-adjusted, regression models examined the association between ORP and ORP-9 with adolescent 24-h HRV indices. Longitudinally, a greater increase in ORP-9 since childhood was associated with lower daytime Log-LF, SDNN, RMSSD and higher HR in adolescence (p<0.05). A greater increase in ORP since childhood was associated with lower nighttime Log-LF and SDNN (p<0.05). Cross-sectionally, higher ORP and ORP-9 were associated with lower daytime and nighttime Log-LF, SDNN or RMSSD and higher HR within adolescence (p<0.05). A greater increase in cortical arousability since childhood is a strong developmental predictor of daytime cardiac autonomic imbalance in adolescence. Shallower sleep depth additionally arises as a proximal determinant of both daytime and nighttime cardiac autonomic imbalance within adolescence. These data suggest a coupling between fine-grained spectral measures of the sleeping brain and those of CAM, which may inform sleep-related cardiovascular risk early in life.

Circadian Misalignment Impacts Cardiac Autonomic Modulation in Adolescence.

Although heart rate variability (HRV), a marker of cardiac autonomic modulation (CAM), is known to predict cardiovascular morbidity, the circadian timing of sleep (CTS) is also involved in autonomic modulation. We examined whether circadian misalignment is associated with blunted HRV in adolescents as a function of entrainment to school or on-breaks. We evaluated 360 subjects from the Penn State Child Cohort (median 16y) who had at least 3-night at-home actigraphy (ACT), in-lab 9-h polysomnography (PSG) and 24-h Holter-monitoring heart rate variability (HRV) data. ACT-measured metrics of circadian misalignment included sleep midpoint (SM), sleep irregularity (SI), and social jetlag (SJL). Five 24-h, daytime and nighttime frequency- and time-domain HRV indices were the primary outcomes. Linear regression models adjusted for sex, race/ethnicity, age, body mass index, apnea/hypopnea index, sleep duration and its variability. These associations were also examined as a function of being in-school or on-break. While on-break, a later SM on weekends was significantly associated with all five nighttime HRV indices. While in-school, greater SI on weekdays was significantly associated with three daytime and three nighttime HRV indices. Greater SJL was not associated with any HRV index. Longitudinal analyses confirmed the association of adolescent SM, SI and SJL with change in nighttime HRV since childhood. An irregular sleep phase during days of entrainment to social demands and a delayed sleep phase during ad-libitum days are associated with blunted HRV in adolescents. Circadian misalignment contributes to increased cardiovascular risk via an altered CAM in youth.

Effect of Ramadan intermittent fasting on short-term heart rate variability among hemodialysis patients

Background In the general population, prior research has demonstrated the positive effects of fasting on the heart, where it is linked to a reduction in the risk factors for cardiovascular disease. Although hemodialysis (HD) patients are considered very high risk, some patients are highly motivated and insist on fasting. Limited data exists on the effect of Ramadan fasting on heart rate variability (HRV) a measure of cardiac autonomic function among maintenance HD patients. Patients and methods An observational longitudinal study of Ramadan fasting patients on maintenance HD. All participants underwent a 5 min Holter ECG recording at the end of the HD session during Ramadan 29 and 30, then another 5 min Holter ECG recording two months after Ramadan. Time and frequency domain HRV indices were analyzed. Results Among 95 HD patients assessed for eligibility, 53 practiced Ramadan fasting either daily or intermittently. Forty-seven patients met inclusion and exclusion criteria and underwent 5 min Holter ECG recordings twice. The mean age of participants was 47.77 years (±13.78) and 59.6% were males. Patients did not differ significantly about heart rate, frequency, and time domain measures (P&gt;0.05) during and two months after Ramadan. Conclusion Practicing Ramadan intermittent fasting does not impose a substantial risk to the cardiac autonomic nervous system function among maintenance HD patients, further research is required to confirm these findings.

Heart rate variability parameters indicate altered autonomic tone in subjects with COVID-19

COVID-19 is associated with long-term cardiovascular complications. Heart Rate Variability (HRV), a measure of sympathetic (SNS) and parasympathetic (PNS) control, has been shown to predict COVID-19 outcomes and correlate with disease progression but a comprehensive analysis that includes demographic influences has been lacking. The objective of this study was to determine the balance between SNS, PNS and heart rhythm regulation in hospitalized COVID-19 patients and compare it with similar measurements in healthy volunteers and individuals with cardiovascular diseases (CVD), while also investigating the effects of age, Body Mass Index (BMI), gender and race. Lead I ECG recordings were acquired from 50 COVID-19 patients, 31 healthy volunteers, and 51 individuals with cardiovascular diseases (CVD) without COVID-19. Fourteen HRV parameters were calculated, including time-domain, frequency-domain, nonlinear, and regularity metrics. The study population included a balanced demographic profile, with 55% of participants being under 65 years of age, 54% identifying as male, and 68% identifying as White. Among the COVID-19 patients, 52% had a BMI ≥ 30 compared to 29% of healthy volunteers and 33% of CVD patients. COVID-19 and CVD patients exhibited significantly reduced time-domain HRV parameters, including SDNN and RMSSD, compared to healthy volunteers (SDNN: 0.02 ± 0.02 s vs. 0.06 ± 0.03 s, p < 0.001; RMSSD: 0.02 ± 0.02 s vs. 0.05 ± 0.03 s, p = 0.08). In the frequency domain, both COVID-19 and CVD patients showed increased low-frequency (LF) power and lower high-frequency (HF) power compared to healthy volunteers (COVID-19 LF: 18.47 ± 18.18%, HF: 13.69 ± 25.80%; Healthy LF: 23.30 ± 11.79%, HF: 22.91 ± 21.86%, p < 0.01). The LF/HF ratio was similar in COVID-19 patients (1.038 ± 1.54) and healthy volunteers (1.03 ± 0.78). Nonlinear parameters such as SD1 were significantly lower in COVID-19 patients (0.04 ± 0.04 s vs. 0.08 ± 0.05 s, p < 0.01), indicating altered autonomic regulation. Variations in HRV were observed based on demographic factors, with younger patients, females, and non-white individuals showing more pronounced autonomic dysfunction. COVID-19 patients exhibit significant alterations in HRV, indicating autonomic dysfunction, characterized by decreased vagal tone and sympathetic dominance, similar to patients with severe cardiovascular comorbidities. Despite higher heart rates, the HRV analysis suggests COVID-19 is associated with substantial disruption in autonomic regulation, particularly in patients with specific demographic risk factors.

Immediate Effect of Uddiyana Bandha on Heart Rate Variability in Patients with Hypertension: A Randomised Controlled Study.

Hypertension, a prevalent cardiovascular condition, is linked to autonomic nervous system dysregulation, often evidenced by reduced heart rate variability (HRV). Yoga, particularly Uddiyana Bandha, may influence autonomic control and improve HRV, thus offering potential benefits for hypertension management. This study intended to assess the impact of the regular use of Uddiyana Bandha practice on HRV among hypertensive patients. This randomised controlled study included 60 hypertensive patients aged between 40 and 60. Participants were randomised into an intervention group practicing Uddiyana Bandha (n = 30) and a control group with no intervention (n = 30). The outcome measures included time and frequency domain HRV variables, specifically the standard deviation of NN intervals (SDNN), the square root of the mean squared differences of successive NN intervals (RMSSD), high-frequency (HF) and low-frequency (LF) components in normalised units (n.u), and the LF/HF ratio. These were assessed both before and immediately after the intervention. The intervention group performed three rounds of Uddiyana Bandha under supervision, while the control group rested quietly for an equivalent duration. The Uddiyana Bandha group demonstrated significant (p < .05) improvements in HRV parameters post-intervention compared to the control group. Mean RR interval, SDNN and RMSSD increased immediately after Uddiyana Bandha practice. The HF component (n.u) increased, while the LF component (n.u) and LF/HF ratio decreased (p < .05), indicating enhanced parasympathetic activity. No significant changes were observed in the control group. Uddiyana Bandha's practice immediately has notable effects on HRV in hypertensive patients, showing better autonomic balance and cardiovascular performance. These results suggest Uddiyana Bandha as a possible non-pharmacological strategy for hypertension management. Future studies with larger sample sizes and longer durations are needed to support these results and explore long-term effects.

Cardiovascular autonomic dysfunction and sleep abnormalities in children with Prader-Willi syndrome.

Prader-Willi syndrome (PWS) is a rare genetic neurodevelopmental condition characterized by cognitive disabilities, behavioral problems, hypothalamic dysfunction with obesity, and sleep disorders. A few studies have reported autonomic nervous system dysfunction. Our aim was to investigate dysautonomia by combining sleep studies and standard autonomic testing in regularly followed children with PWS. In this retrospective study, heart rate variability was analyzed during each sleep stage (polysomnography) using time and frequency domains in PWS children (N = 37) compared with age-matched controls (N = 20). Cardiovascular autonomic testing (Ewing tests) and sweating assessment (electrochemical skin conductance) were also performed in patients over 6years (N = 23). Autonomic testing: Heart rate changes with active standing and with deep breathing were impaired in 47% and 22% of the children, respectively. Asymptomatic orthostatic hypotension (OH) was found in 26%. Baroreflex sensitivity in supine position was in normal range (14.1 ± 6.7ms/mmHg). Electrochemical skin conductance was normal. Sleep study: 46% of the children with PWS had obstructive sleep apnea and 24% had central sleep apnea. None of these events were observed in the control group. Mean R-R and time domain heart rate variability parameters were significantly lower compared with controls in N2 and Rapid Eye Movement (REM) sleep stages. Narcoleptic-like phenotype was found in 47% associated with lower low-frequency (LF) power (sympathetic index) in REM sleep. Our study confirms a decreased vagal modulation during both wakefulness and sleep in children with PWS. OH in some patients suggests a sympathetic dysfunction. These changes may contribute to the increased cardiovascular risk in PWS.

Linear classification of healthy people and patients with valvular heart diseases based on heart rate variability indices derived from electrocardiograms

Abstract Heart rate variability (HRV) is an important marker in various cardiovascular and non-cardiovascular conditions. This study aimed to evaluate the effectiveness of three linear models (Logistic Regression, Ridge Regression, Support Vector Machine) in distinguishing between healthy individuals and those with valvular heart diseases (VHD) using time domain and frequency domain HRV indices derived from electrocardiographic (ECG) signals. We analyzed 59 recordings taken from two public datasets containing electrocardiographic, seismocardiographic, and gyrocardiographic signals from “Mechanocardiograms with ECG reference” and “An Open-access Database for the Evaluation of Cardio-mechanical Signals from Patients with Valvular Heart Diseases” that contain 29 and 30 recordings, respectively. HRV analysis included time and frequency domain indices and the linear models were evaluated using 5-fold stratified cross-validation. The highest sensitivity, PPV, accuracy and F1 score were observed for Logistic Regression (0.8810, 0.8819, 0.8814, 0.8812), followed by Ridge Regression (0.8805, 0.8858, 0.8814, 0.8808), and the lowest were observed for linear SVM (0.8310, 0.8318, 0.8305, 0.8305). The results showed that it is possible to distinguish healthy volunteers and patients with linear classifiers and time domain and frequency domain HRV indices obtained from ECG signals with decent performance.

Postpartum Blood Pressure Variability and Heart Rate Variability in Preeclampsia.

Preeclampsia is associated with autonomic dysregulation during pregnancy; however, less is known about autonomic function in the first week postpartum after preeclampsia. We retrospectively analyzed data from a prospective cohort of women with and without preeclampsia. Continuous blood pressure and heart rate were measured with finger plethysmography within 7 days postpartum. Frequency-domain blood pressure and heart rate variability (HRV) were calculated using spectral analysis. Time-domain HRV was calculated as the root mean square of successive R-R interval differences. We compared results between those with and without preeclampsia, as well as between those with new-onset preeclampsia, chronic hypertension with superimposed preeclampsia, and normotensive participants. A total of 70 postpartum women were enrolled: 20 normotensive, 29 new-onset preeclampsia, and 21 superimposed preeclampsia. Both low- and high-frequency blood pressure variabilities were higher in those with preeclampsia compared with controls (P=0.04 and P=0.02, respectively). This difference was driven by those with new-onset preeclampsia. The preeclampsia group had lower high-frequency HRV (P<0.005), a higher low-/high-frequency ratio of HRV (P<0.005), and lower time-domain HRV (P=0.01); this difference was seen in those with and without chronic hypertension. Postpartum patients with preeclampsia with and without chronic hypertension had lower HRV compared with normotensive postpartum controls. Higher blood pressure variability was observed only in those with nonsuperimposed preeclampsia, suggesting that the autonomic profile of preeclampsia may differ in patients with chronic hypertension.

Age-related variations in heart rate variability profiles among patients with schizophrenia and major depressive disorder.

Patients with psychiatric disorders exhibit general autonomic dysregulation and elevated cardiovascular risks, which could be indexed by heart rate variability (HRV). However, HRV is susceptible to age and other patient-specific factors. This study aimed to investigate the HRV profile and age-related variations, as well as the potential influence of sex, BMI, and HR on HRV in psychiatric populations. There were 571 consecutive patients diagnosed with schizophrenia (SZ) (N = 282) or major depressive disorder (MDD) (N = 289) recruited and classified as adolescent (11-21 years) and adult (> 21 years) groups. HRV indices were measured with 3-minute resting ECG recordings. Compared to adolescent subjects, all time-domain and nonlinear HRV indices were notably reduced in adults, while frequency-domain HRV was comparable. Between SZ and MDD groups, only HTI differed significantly. Age and psychiatric disorders exhibited complex interaction effects on HRV. Stratified by age stage, MDD patients exhibited slightly higher HRV in adolescence but slightly lower HRV in adulthood. In logistic regression analysis, HTI and SD2 were significantly distinctive between adolescents and adults in MDD group, while pNN50 was distinctive in SZ group. Moreover, female subjects demonstrated lower time-domain HRV, LF/HF and SD2 than males. HR exhibited inverse relationship with three domain HRV. No significant effect of BMI was observed. In psychiatric populations, compared to adolescents, adults decreased in time-domain and nonlinear HRV, but not in frequency-domain HRV. Age and psychotic disorders exhibited complex interaction effects on HRV. Sex and HR also emerged as important influencing factors of HRV.

The effects of Baduanjin exercise on the psychological condition and heart rate variability of sports-disadvantaged college students: A randomised trial

ObjectiveTo investigate the effects of a 16-week Baduanjin exercise programme on the psychological status and heart rate variability (HRV) of college students in a sports-disadvantaged group, offering a theoretical basis for the potential of Baduanjin exercise to improve mental health.Trial DesignThis prospective study enrolled 93 college students from Wuyi University, exempt from the National Standards for Students’ Physical Health due to illness or disability. The participants were divided into a control group (n = 47) and an experimental group (n = 46). Over 16 weeks, the experimental group engaged in the Baduanjin exercise, whereas the control group did not participate in regular physical training.MethodsWe assessed the Symptom Checklist-90-Revised (SCL-90-R, the primary outcome) scores and HRV (time domain and frequency domain indices, the secondary outcomes) of all participants both before and after the 16-week programme.Results(1) Post-16 weeks of Baduanjin exercise, a statistically significant difference was observed in the SCL-90-R scores between the control and experimental groups (P < 0.01, P < 0.05). Notably, the scores for interpersonal sensitivity, depression, anxiety, psychoticism, and other factors (predominantly relating to sleep and diet) were significantly lower in the experimental group (t = 4.234, 2.616, 3.450, 2.226, 3.980, P < 0.01, P < 0.05). (2) Following the exercise regimen, the experimental group showed a substantial decrease in heart rate, low-frequency (LF) power, and the LF/high-frequency ratio (LF/HF ratio), and a significant increase in HF compared with the control group (t = 2.358, 4.528, − 2.595, P < 0.05 P < 0.01).ConclusionSixteen weeks of Baduanjin exercise may substantially enhance HRV, potentially aiding in balancing sympathetic–vagal nerve activity and thus contributing to the regulation of mental health.

P038 Autonomic cardiovascular control is unaffected in children referred for assessment of excessive daytime sleepiness.

Abstract Introduction There is conflicting evidence for impaired autonomic control of heart rate (HR) in adults with narcolepsy and idiopathic hypersomnolence (IH). Despite these conditions primarily being diagnosed around the age of puberty, there are limited studies in children. The present study investigated cardiovascular control using heart rate variability (HRV) and the extent of nocturnal HR dipping during sleep in children and adolescents with narcolepsy and IH. Methods All children having an overnight polysomnographic study followed by a multiple sleep latency test (MSLT) for investigation of excessive daytime sleepiness (EDS) between May 2010 to December 2023 were included: 28 children diagnosed with narcolepsy, 11 with IH and 26 subjectively sleepy children who did not meet the diagnostic criteria for either narcolepsy or IH. Each clinically-referred child was matched for age and sex with a control. Time domain and frequency domain HRV were calculated from ECG recorded at 512 Hz. Results There were no differences in either time domain or spectral analysis of HRV between clinical groups or between clinical groups and their control group. The expected sleep state differences in HRV were observed in all groups. There was also no difference in HR nocturnal dipping between groups. Conclusion Despite evidence for abnormal autonomic function in adults with narcolepsy and IH, our study did not identify any abnormalities in HR, HR control or nocturnal dipping of HR in children referred for assessment of EDS. This suggests that autonomic dysfunction may be a feature of these conditions that develops in later life.

Deriving Accurate Nocturnal Heart Rate, rMSSD and Frequency HRV from the Oura Ring.

Cardiovascular diseases are a major cause of mortality worldwide. Long-term monitoring of nighttime heart rate (HR) and heart rate variability (HRV) may be useful in identifying latent cardiovascular risk. The Oura Ring has shown excellent correlation only with ECG-derived HR, but not HRV. We thus assessed if stringent data quality filters can improve the accuracy of time-domain and frequency-domain HRV measures. 92 younger (<45 years) and 22 older (≥45 years) participants from two in-lab sleep studies with concurrent overnight Oura and ECG data acquisition were analyzed. For each 5 min segment during time-in-bed, the validity proportion (percentage of interbeat intervals rated as valid) was calculated. We evaluated the accuracy of Oura-derived HR and HRV measures against ECG at different validity proportion thresholds: 80%, 50%, and 30%; and aggregated over different durations: 5 min, 30 min, and Night-level. Strong correlation and agreements were obtained for both age groups across all HR and HRV metrics and window sizes. More stringent validity proportion thresholds and averaging over longer time windows (i.e., 30 min and night) improved accuracy. Higher discrepancies were found for HRV measures, with more than half of older participants exceeding 10% Median Absolute Percentage Error. Accurate HRV measures can be obtained from Oura's PPG-derived signals with a stringent validity proportion threshold of around 80% for each 5 min segment and aggregating over time windows of at least 30 min.

Acute exercise impacts heart rate variability but not cognitive flexibility during subsequent simulated firefighter occupational tasks.

Acute exercise can transiently enhance cognitive flexibility. The cognitive demand of firefighters makes it relevant to understand if on-shift exercise could produce similar improvements in cognitive performance during subsequent occupational tasks. Metrics of heart rate variability (HRV), such as time- and frequency-domain outcomes, may shed light upon the influence exercise has on cognition, as they discern information related to cardiac autonomic (sympathetic/parasympathetic) function. We aimed to determine if acute resistance and aerobic exercise impact cognitive flexibility during occupational tasks and its relation to HRV. 32 participants completed a baseline Wisconsin Card Sorting Task (WCST) and three experimental trials: resistance exercise (RE), aerobic exercise (AE), or a rested control (CON). An occupational task assessment (OTA) including four rounds of 10 deadlifts and a 0.15-mile sandbag carry in an environmental chamber (35°C/50% humidity) was completed after each trial. The second round was followed by the WCST. Repeated measures ANOVAs were used to analyze differences by condition. For the WCST, total, perseverative, and non-perseverative errors did not differ (ps > 0.39). Time-domain HRV metrics were not different (ps > 0.05). All frequency-domain metrics, other than low-frequency power, were not different (ps > 0.24). Low-frequency power was lower based on condition (p = 0.03). Post hoc analysis showed low-frequency power was lower following AE compared to RE and CON. Results suggest an acute bout of on-shift aerobic or resistance exercise may not impact cognitive flexibility during subsequent simulated occupational tasks, despite depressed metrics of heart rate variability following aerobic exercise.

Effect of FTO Gene polymorphism on anthropometric, hemodynamic, and autonomic variables in adolescents

Objective: The study aimed to analyze the influence of physical activity levels and the rs9939609 polymorphism (FTO gene) on anthropometric, hemodynamic, and cardiac autonomic variables in public school students. Methods: A total of 288 students (aged 11 to 18, both sexes) from public schools in São Luís, Maranhão, were divided into four groups: sedentary AA+AT (AA+AT sed), active AA+AT (AA+AT activ), sedentary TT (TT sed), and active TT (TT activ). Evaluations included the International Physical Activity Questionnaire, weight, height, body mass index (BMI), buccal cells collection for DNA extraction, systolic (SBP) and diastolic (DBP) blood pressure measurements, and heart rate variability (HRV) analysis. A chi-square test for allelic associations was applied a 5% significance level. Results: No significant differences were observed in DBP or heart rate (HR). The active groups (AA+AT activ and TT activ) exhibited reductions in weight and METs/min/week compared to their respective sedentary groups (P&lt;0.05). The TT activ group also demonstrated reductions in SBP and BMI compared to the TT sed group (P&lt;0.05). The TT activ group had higher HRV in the RR time domain (ms) compared to the TT sed group (P&lt;0.05), though no significant differences were found in other HRV variables. Conclusions: The FTO gene polymorphism influences cardiac autonomic modulation, while physical activity levels affect anthropometric variables.

Relevance of high glycaemic index breakfast for heart rate variability among collegiate students with early and late chronotypes

ABSTRACT Plasma glucose spikes affect cardiac autonomic modulation resulting in a decrease of heart rate variability (HRV). We hypothesize that a later chronotype or a higher morning plasma melatonin level is associated with larger decreases of HRV following an early high glycaemic index (GI) breakfast. In persons with an early (n = 21) or a late (n = 15) chronotype who consumed a high GI breakfast at 7 a.m. glucose data were continuously monitored. Time domain HRV parameters were calculated from blood volume pulses derived by wireless wrist worn multisensor. HRV changes (values after minus values before breakfast) were associated with chronotype by multivariable linear regression adjusted for age, sex and baseline levels. Morning plasma melatonin levels were determined from samples drawn on the run-in day. Time domain parameters indicate a higher HRV before high GI breakfast in both chronotypes. A later chronotype tended to be associated with smaller decreases of mean interbeat intervals (p = 0.08) only; no associations were seen with morning melatonin levels. This exploratory analysis in a small sample provides a first indication that in young healthy adults later chronotype might be associated with reduced ANS activation following a high GI breakfast. Future studies should elucidate whether this indicates parasympathetic or sympathetic inhibition.

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.

Heart Rate Variability and Cerebral Autoregulation in Patients with Traumatic Brain Injury with Paroxysmal Sympathetic Hyperactivity Syndrome.

Severe traumatic brain injury (TBI) can lead to transient changes in autonomic nervous system (ANS) functioning and development of paroxysmal sympathetic hyperactivity (PSH) syndrome. Clinical manifestation of ANS disorders may be obscured by therapeutic interventions in TBI. This study aims to analyze ANS metrics and cerebral autoregulation in patients with PSH syndrome to determine their significance in early prognostication. This single-center retrospective study investigated the relationship between changes in ANS metrics, cerebral autoregulation, and PSH syndrome. Arterial blood pressure and intracranial pressure signals were monitored for 5 days post TBI. ANS metrics included time and frequency domain heart rate variability (HRV) metrics. Cerebral autoregulation was assessed using the pressure reactivity index. Sixty-six patients with severe TBI (median age 33 [interquartile range 26-50] years) were analyzed, and PSH was confirmed in nine cases. Impairment of cerebral autoregulation was observed in 67% of patients with PSH and 72% without the syndrome. Patients with PSH had higher HRV in the low-frequency range (LF; 253 ± 178 vs. 176 ± 227 ms2; p = 0.035) and lower heart rates (HRs; 70 ± 7 vs. 78 ± 19 bpm; p = 0.027) compared to those without PSH. A receiver operating characteristic curve analysis indicated that HR (area under the curve(AUC) = 0.73, p = 0.006) and HRV in the LF (AUC = 0.70, p = 0.009) are moderate predictors of PSH. In the multiple logistic regression model for PSH, diffuse axonal trauma (odds ratio(OR) = 10.82, 95% confidence interval(CI) = 1.70-68.98, p = 0.012) and HR (OR =0.91, 95% CI 0.84-0.98, p = 0.021) were significant factors. Elevated HRV in the LF and decreased HR may serve as early predictors of PSH syndrome development, particularly in patients with diffuse axonal trauma. Further research is needed to investigate the utility of the cerebral autoregulation-ANS relationship in PSH prognostication.

Listen to your heart: The effect of music on heart rate variability

Abstract Background Heart rate variability (HRV) is indicative of autonomic balance. High HRV during sinus rhythm is associated with reduced morbidity and mortality across a wide range of health disorders. Listening to music has been shown to induce psychological and physiological responses that increase HRV, a mechanism currently employed in music therapy to reduce anxiety and post-operative pain. However, it remains unclear which music characteristics have the most positive effect on HRV. Purpose This study aimed to assess the impact of different music genres, white noise, tempo, and personal music preferences on HRV. Methods Adults without atrial fibrillation or pacemaker dependency were included during the Netherlands largest three-day music festival. Participants were subjected to three-minute fragments of white noise, and subsequently a randomized order of classical, rock, electronic and the subject’s most-listened personal ("Spotify Wrapped 2022") music; all having an either fast (130-140 BPM) or slow tempo (70-80 BPM), which was randomized as well. Afterwards, participants ranked all music fragments in order of their preference. A tachogram was collected using the PPG sensor of an Apple Watch Series 8. Data was pre-processed to exclude non-sinus rhythm beats and measurement artefacts. HRV time-domain (SDNN, RMSSD, NN50, pNN50, triangular index) and frequency-domain (LF, LFn, HF, HFn, LF/HF) metrics were calculated from the tachograms using Python-software. HRV outcomes were corrected for age, sex, heart rate and music tempo group and analyzed using general linear mixed models in SPSS. Results In total 242 participants with a median age of 28 years (IQR 24-32) were included, of which 136 (56%) female. Classical music showed a significantly higher HRV response (RMSSD) compared to electronic (p=0.025) and the subject’s personal music (p=0.030, see figure). No other significant differences in HRV were found between the different genres and personal music. White noise showed a significantly higher HRV for all time domains, as well as LF and HF, compared to the different genres and personal music. A total of 181 (74.8%) participants ranked their personal music fragment as the most preferred. There was no difference between the fast and slow tempo group when performing an interaction analysis for tempo and the different music genres except for classical and personal music (RMSSD, p = 0.047). Conclusions This large study highlights that classical music enhances HRV more than other music, suggesting its therapeutic potential. Remarkably, white noise showed the greatest increase in HRV. Although these were bitter pills to swallow; white noise or classical music once a day might keep the doctor away.

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

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')