Normal Heartbeat Research Articles

Daily physical activity habits influence surgeons’ stress in the operating room: a prospective cohort study

Background: Exercise training improves heart rate variability, and evidence suggests it can mitigate the detrimental effects of stress. This study aims to evaluate the relationship between surgeons’ physical activity habits and their stress, assessed as heart rate variability, at the start of surgery. Materials and methods: This multispecialty prospective cohort study included surgeons from fourteen cardiac, endocrine, digestive, gynecologic, orthopedic, thoracic, and urologic surgical departments of four university hospitals. Surgeons wore accelerometers 24/7 from 1 November 2020 to 31 December 2021 to quantify the mean daily step counts and daily sedentary time for 7 days prior to each operation. RMSSD, the root mean square of successive differences between normal heart beats, is a heart rate variability (HRV) metric that reflects cardiac vagal tone. We evaluated RMSSD during the first 5 minutes of surgeries performed over five 15-day periods. Data were analyzed using a multivariable linear mixed model with a random effect for surgeons. Results: We analyzed 722 surgeries performed by 37 surgeons (median age = 47 (IQR 42–55); 29 (78.4%) male). On average (SD), surgeons walked 9762 (2447) steps and were sedentary 391 (102) minutes daily. The model showed a positive relationship between steps and cardiac vagal tone, with an increase in lnRMSSD (0.028, 95% CI 0.003 to 0.053, P = 0.026) for every 1000 more steps per day, but not for sedentary behavior. Senior surgeons presented lower lnRMSSD (−0.437, −0.749 to −0.126, P = 0.006), as did surgeons who spent less total time operating over the study period (−0.337, −0.646 to −0.027, P = 0.033), compared to their counterparts. Conclusions: Higher daily step counts the week before surgery were associated with increased cardiac vagal tone, indicating lower stress levels at the beginning of surgery. This relationship highlights the influence of physical activity on surgeons’ stress in the operating room.

Post-traumatic stress disorder (PTSD) symptom clusters associated with an indicator of heart rate variability: The ADVANCE cohort study.

Heart rate variability (HRV) is governed by of sympathetic and parasympathetic regulatory systems. Post-Traumatic Stress Disorder (PTSD) may influence these systems and consequently affect cardiovascular functioning. The sample consisted of 860 UK male military personnel approximately half of who had sustained physical combat injuries in Afghanistan. HRV was measured via Root-Mean Square of Successive Differences (RMSSD) in normal heart beats and PTSD using a self-report questionnaire (Posttraumatic Checklist-Civilian version (PCL)). Associations between probable PTSD status (PCL score ≥ 50) and symptom clusters (avoidance behaviours, emotional numbing, hyperarousal and intrusive thoughts) with HRV were examined. Bootstrap inclusion frequencies and model averaging were employed prior to regression modelling to identify the most important symptom clusters associated with RMSSD. Probable PTSD status was not associated with log RMSSD [-11.6 % (95 % Confidence Interval (CI) -22.2 %, 4.1 %). Increases in severity of emotional numbing were associated with reductions in RMSSD, with a - 1.1 % (95%CI -2.1 %, -0.2 %) decrease in the geometric mean of RMSSD per point increase on the emotional numbing subscale. High levels of comorbidity with depression/anxiety; possible endogeneity/bidirectionality due to PCL including both psychological and physiological symptoms. Emotional numbing, the symptom cluster including symptoms such as anhedonia, cognitive dysregulation and feeling distant from other people, was associated with HRV whilst overall PTSD status was not. These results lend support to the hypothesis that different PTSD symptom clusters may have unique effects on the cardiovascular system, and that particular symptom clusters of PTSD or combinations thereof may be associated with distinctive cardiovascular profiles.

Psychophysiological factors are not directly associated to Heart Rate Variability in Athletes: A Meta-Analysis

Objective: Although heart rate variability (HRV) has been a useful and accessible tool to monitor recovery from athletes’ training, it is not clear if it reflects changes in psychophysiological factors. The aim of these study is to identify, through a systematic review and meta-analyses, whether the psychophysiological factors are associated with alteration in heart rate variability (HRV) in sports. Methods: We searched in four databases (PubMed; Scopus; Cochrane; Web of Science) for studies assessing the association of root mean square of successive differences between normal heartbeats (RMSSD) with a variety of psychophysiological outcomes in athletes of any modality. Results: After initial search, we selected 12 studies with 27 study arms for analysis. First, we combined 19 study arms in a meta-analysis testing the correlation between HRV and the psychophysiological factors at baseline (Meta 1). Second, we combined 9 study arms in a meta-analysis testing the correlation between HRV and changes in psychophysiological factors within a training period (Meta 2). We analyzed the following psychophysiological factors: stress, sleep deprivation, fatigue, muscular soreness, mood, and hormonal changes (cortisol). summary, there was no significant association between the HRV and the psychophysiological factors in both meta-analyses (Meta 1: r = 0.084, P = 0.167; I² = 20%, P-value for heterogeneity = 0.215; and Meta 2: r = 0.268, P = 0.131, I² = 65.2%, P-value for heterogeneity = 0.003). Conclusion: We were not able to confirm the association between HRV and any psychophysiological factors by meta-analysis, but it could be due to inherent limitations of this type of analyses. To test whether this associations truly exist, future meta-analysis will need to include studies with much larger sample size and standardize the methods between studies to reduce heterogeneity. Longitudinal studies will be fundamental to understand the causal relationship between these factors to ultimately improve training monitoring tools for better recovery in athletes.

Changes and persistence in heart rate variability before and during social stress: A comparison of individuals with and without social anxiety disorder.

Individuals with social anxiety disorder (SAD) experience significant and persistent fear of social situations as they anticipate rejection, scrutiny, and embarrassment. Given that physiological reactions to social situations may shape emotional experience in SAD, understanding psychophysiological changes operating in SAD may be important to address this potentially key perpetuating factor. This study compared the patterns of change (via contrasts of estimated marginal means) and persistence (via autoregressive models) of two indices of heart rate variability (HRV; Root Mean Square of Successive Differences between normal heartbeats, and High-Frequency absolute units) as physiological measures of emotion regulation, between individuals with SAD (n = 94) and without (n = 59) using the Trier Social Stress Test phases (TSST). Results revealed that the SAD group increased their need to regulate their emotions (peak HRV) during the preparation (i.e., anticipation) phase, particularly among women, whereas HRV peaked for the non-SAD group during the social-evaluative context. The SAD group's increase in HRV in the preparation phase, relative to non-SAD group, was the opposite of the hypothesised effect. The non-SAD group demonstrated no significant persistence of HRV between some TSST phases, whereas the SAD group showed significant persistence across all phases, however no between-group differences were found. These findings provide novel evidence of similarities and differences in HRV between individuals with and without SAD while anticipating and encountering social-evaluative contexts.

Validation of an artificial intelligence system for holter ECG analysis

Abstract Introduction Holter ECG is a commonly used tool to identify heart rhythm disorders. As physician-based analysis of such Holter ECG is time consuming, various approaches using computerized interpretation have been developed. However, accuracy of these tools remains inferior to physician-based analysis. Thus, this study assesses the diagnostic performance of an artificial intelligence (AI)-powered Holter ECG service in comparison to results from reference databases as well as with physician-based evaluation. Methods 231 ECG recordings, covering 2,261 hours of ECG with annotations for 10,024,315 heartbeats from the following reference databases were used: MIT-BIH Arrhythmia (MITDB), American Heart Association ECG (AHDB), MIT-BIH Atrial Fibrillation (AFDB), Long Term Atrial Fibrillation (LTAFDB). Those recordings were originally collected from a mixed population of inpatients and outpatients between 1975 and 2008. Analysis of these recordings regarding the detection of QRS complexes, QRS classification and detection of Atrial Fibrillation (AF) was performed using a novel service for AI-based ECG analysis. Results were compared to the diagnosis stated within the database. QRS complex detection accuracy was performed on recordings from MITDB and AHADB by checking if time positions are within 150 ms to reference annotations. The QRS classification in three classes (normal, supraventricular, ventricular) was then compared for each detected heartbeat. Mismatches were adjudicated manually by three experts. Episodes of Atrial Fibrillation were detected in recordings from MITDB, AFDB and LTAFDB and compared to the reference episodes from the databases. The accuracy was evaluated based on the overlap with the reference annotations in the time-domain. Results Sensitivity and Precision of heartbeat detection compared to the reference databases exceeded 99% Figure 1 displays the results of heartbeat classification. Normal heartbeats were classified with a sensitivity of 99.6%, precision of 99.9% and specificity of 99.6%. For ventricular heartbeats, a sensitivity of 99.58 %, precision of 99.88 and specificity of 99.99% were achieved. Premature supraventricular contractions were recognized with a sensitivity of 99.58 %, precision of 100% and specificity of 100%. When comparing the 248,187 QRS complex classifications of MITDB and AHADB to the AI-powered analysis, 128 discrepancies were revealed. 43 were due to a discrepancy of convention as these beats were in sections that were also marked as AF episodes by the databases and the AI-powered analysis marks all beats in AF episodes as normal. Of the 85 remaining discrepancies, more than 87% were adjudicated in favor of the AI-powered analysis by the experts. Figure 2 shows the comparison of AF detection results showing Sensitivity and Precision above 99%. Conclusion AI-powered Holter ECG analysis compared to reference ECG stripes exceed 99% of sensitivity, specificity and precision.QRS complex detectionAF/ AFib detection

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.

Heart Rate Variability in Military Pilots During Flight: A Scoping Review.

Piloting an aircraft is a complex multitasking activity that involves managing information in a nonautomatic way and generates a high workload (psychological, cognitive, and physical) for the pilot. The excess of these demands can result in decreased performance and may impair flight safety. Heart rate variability (HRV) has been used in recent studies as a method to investigate operator's workload in complex environments. This measure can assess the stress and recovery ability of the autonomic nervous system. However, a better understanding of flight influence on the pilot's autonomic modulation is necessary. Therefore, this scoping review aims to systematically map the studies related to changes in the autonomic modulation in military pilots during flight, in order to characterize their workload at different times and flight profiles. A literature search was conducted using MEDLINE (by PubMed), SCOPUS, and LILACS databases. Recent records (2002-2022) that analyzed HRV in military pilots during flight were included. Meanwhile, studies in which piloting activity was not performed were excluded. The study was conducted in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses guideline extension for Scoping Reviews and the Updated Methodological Guidance for the Conduct of Scoping Reviews. A total of 298 records were obtained, of which 19 were included in the scoping review. The studies analyzed flights performed in high- and low-performance aircrafts, helicopters, and flight simulators, using time domain, frequency domain, and nonlinear HRV indices. Real and simulated flights produced significant autonomic changes. Some flights elicited autonomic nervous system responses that persisted up to 5 h after landing. During real flight, the most sensitive indices for identifying variations in pilot workload were root mean square of successive differences between normal heartbeats, standard deviation of interbeat interval of normal sinus beat (SDNN), ratio of low-frequency to high-frequency power, and Poincaré plot standard deviation perpendicular to the line of identity (SD1), whereas the interbeat interval (RR), SDNN, SD1, and Poincaré plot standard deviation along the line of identity (SD2) were the most sensitive indices when comparing segments of simulated flight with different levels of difficulty. This scoping review provided insight into the influence of flight on autonomic modulation in military pilots. Some key themes were highlighted: Increased sympathetic activity during flight, sensibility of different domains of HRV to flight demands, and autonomic changes during recovery time. Future research efforts may allow us to enhance the understanding of pilot's workload limits and to elucidate the optimal postflight recovery time.

Menstrual Cycle Variations in Wearable-Detected Finger Temperature and Heart Rate, But Not in Sleep Metrics, in Young and Midlife Individuals.

Most studies about the menstrual cycle are laboratory-based, in small samples, with infrequent sampling, and limited to young individuals. Here, we use wearable and diary-based data to investigate menstrual phase and age effects on finger temperature, sleep, heart rate (HR), physical activity, physical symptoms, and mood. A total of 116 healthy females, without menstrual disorders, were enrolled: 67 young (18-35 years, reproductive stage) and 53 midlife (42-55 years, late reproductive to menopause transition). Over one menstrual cycle, participants wore Oura ring Gen2 to detect finger temperature, HR, heart rate variability (root mean square of successive differences between normal heartbeats [RMSSD]), steps, and sleep. They used luteinizing hormone (LH) kits and daily rated sleep, mood, and physical symptoms. A cosinor rhythm analysis was applied to detect menstrual oscillations in temperature. The effect of menstrual cycle phase and group on all other variables was assessed using hierarchical linear models. Finger temperature followed an oscillatory trend indicative of ovulatory cycles in 96 participants. In the midlife group, the temperature rhythm's mesor was higher, but period, amplitude, and number of days between menses and acrophase were similar in both groups. In those with oscillatory temperatures, HR was lowest during menses in both groups. In the young group only, RMSSD was lower in the late-luteal phase than during menses. Overall, RMSSD was lower, and number of daily steps was higher, in the midlife group. No significant menstrual cycle changes were detected in wearable-derived or self-reported measures of sleep efficiency, duration, wake-after-sleep onset, sleep onset latency, or sleep quality. Mood positivity was higher around ovulation, and physical symptoms manifested during menses. Temperature and HR changed across the menstrual cycle; however, sleep measures remained stable in these healthy young and midlife individuals. Further work should investigate over longer periods whether individual- or cluster-specific sleep changes exist, and if a buffering mechanism protects sleep from physiological changes across the menstrual cycle.

The Impact on Autonomic Nervous System Activity during and Following Exercise in Adults: A Meta-Regression Study and Trial Sequential Analysis.

Background and Objectives: Exercise enhances cardiovascular health through various mechanisms, including the modulation of autonomic nervous system activity. This study aimed to systematically examine the impact of exercise on heart rate variability (HRV) in adults during and within one hour after exercise (WHAE). Materials and Methods: A comprehensive literature review was conducted using the MEDLINE, Embase, Cochrane Library, Scopus, and PubMed databases to identify published studies that reported the impact of exercise on autonomic nervous system activity in adults. The studies measured the absolute power of the low-frequency band (0.04-0.15 Hz) to the absolute power of the high-frequency band (0.015-0.4 Hz) (LF/HF ratio) to assess sympathetic activity and the root mean square of successive differences between normal heartbeats (RMSSD) to assess parasympathetic activity. Results: A total of 3329 studies were screened for relevance, and finally, 10 articles that utilized methods for measuring autonomic nervous system activity, such as the LF/HF ratio and RMSSD, covering 292 adult patients, were included for meta-analysis. In the current meta-analysis, we observed a significant decrease in parasympathetic activity during and after exercise, as indicated by RMSSD, compared to pre-exercise levels (mean difference [MD] = -4.96, 95% confidence interval [CI]: -8.00 to -1.91, p = 0.003). However, sympathetic activity after exercise, represented by the LF/HF ratio, showed a borderline significant increase compared to pre-exercise levels (MD = 1.06, 95% CI: -0.01 to 2.12, p = 0.052). The meta-regression model found that factors associated with RMSSD included mean age, male gender, and duration post-exercise. Additionally, the factor associated with the LF/HF ratio was the healthy condition of participants. The trial sequential analysis provided robust evidence of a decrease in RMSSD and an increase in the LF/HF ratio during and WHAE. Conclusions: Given the limitations of the current study, the findings suggest that a significant decrease in parasympathetic activity and a borderline significant increase in sympathetic activity in adults during and WHAE, as confirmed by trial sequential analysis. Meta-regression analysis indicated that parasympathetic activity was negatively associated with participant age and male gender, but positively associated with duration post-exercise. Additionally, increased sympathetic activity was linked to the healthy conditions of participants. This study suggests that exercise might differentially affect autonomic balance in individuals with chronic conditions compared to healthy individuals. This highlights the potential need for tailored exercise interventions to improve autonomic function across different populations.

The Effect of In-Ear and Behind-Ear Transcutaneous Auricular Vagus Nerve Stimulation on Autonomic Function: A Randomized, Single-Blind, Sham-Controlled Study.

Background/Objectives: Transcutaneous auricular vagus nerve stimulation (TaVNS) is a non-invasive method of electrical stimulation used to autonomic neuromodulation. Position and form of the electrodes are important for the effectiveness of autonomic modulation. This study was aimed to investigate the effect of TaVNS in-ear and behind-ear on autonomic variables. Methods: A total of 76 healthy participants (male: 40, female: 36) were randomized into four groups as in-ear TaVNS, behind-ear TaVNS, in-ear sham, and behind-ear sham. The TaVNS protocol included bilateral auricular stimulation for 20 min, 25 hertz frequency, a pulse width of 250 μs, and a suprathreshold current (0.13-50 mA). Heart rate (HR), systolic and diastolic blood pressure (SBP and DBP), and heart rate variability (HRV) were measured baseline and after stimulation. The parameters RMSSD (root mean square of consecutive differences between normal heartbeats), LF power (low-frequency), and HF power (high-frequency) were assessed in the HRV analysis. Results: HR decreased in the in-ear TaVNS after intervention (p < 0.05), but did not change in behind-ear TaVNS and sham groups compared to baseline (p > 0.05). SBP and DBP decreased and RMSSD increased in the in-ear and behind-ear TaVNS groups (p < 0.05), but did not change in sham groups compared to baseline (p > 0.05). There was no significant difference in LF and HF power after TaVNS compared to baseline in all groups (p > 0.05). SBP was lower and RMSSD was higher in-ear TaVNS than behind-ear TaVNS after intervention (p < 0.05). Conclusions: In-ear TaVNS appears to be more effective than behind-ear TaVNS in modulating SBP and RMSSD, but this needs to be studied in larger populations.

An emotional distress biomarker in pregnant women: Ultra-short-term heart rate variability

Prenatal emotional distress is common in pregnant women. Altered emotional distress can occur from the very beginning to the end of pregnancy. Heart rate variability (HRV) has recently become considered to be a potentially reliable psychophysiological stress biomarker in adults. In the current study, we evaluated ultra-short-term HRV (1-minute measurement) as a psychophysiological biomarker by examining the association between HRV parameters and self-reported prenatal emotional distress among pregnant women (N = 230) across three trimesters of pregnancy. ResultsPrenatal emotional distress was associated with a lower root mean square of successive differences between normal heartbeats (RMSSD), NN50, and SDNN Index among pregnant women who are in the second trimester. For women in the first and third trimester of pregnancy, prenatal emotional distress was not significantly correlated with any HRV indicators. LimitationsThe cross-sectional nature of our results limits the directional expression and assessment of the relationships, and longitudinal studies that target the recruitment of more pregnant women with subtypes of emotional distress issues are also needed. ConclusionsTime-domain parameters of low HRV (associated with reduced parasympathetic activity) can potentially serve as an efficient psychophysiological biomarker for prenatal emotional distress in the second trimester of pregnancy. However, the time-domain HRV indicators in pregnant women in the first and third trimesters may be affected by other physiological and psychological fluctuations, thus decreasing the HRV biomarker’s efficiency in predicting their prenatal emotional distress.

InfusedHeart: A Novel Knowledge-Infused Learning Framework for Diagnosis of Cardiovascular Events

In the undertaken study, we have used a customized dataset termed ``Cardiac-200'' and the benchmark dataset ``PhysioNet.'' which contains 1500 heartbeat acoustic event samples (without augmentation) and 1950 samples (with augmentation) heartbeat acoustic events such as normal, murmur, extrasystole, artifact, and other unlabeled heartbeat acoustic events. The primary reason for designing a customized dataset, ``cardiac-200,'' is to balance the total number of samples into categories such as normal and abnormal heartbeat acoustic events. The average duration of the recorded heartbeat acoustic events is 10-12 s. In the undertaken study, we have analyzed and evaluated various heartbeat acoustic events using audio processing libraries such as Chromagram, Chroma-cq, Chroma-short-time Fourier transform (STFT), Chroma-cqt, and Chroma-cens to extract more information from the recorded heartbeat sound signals. The noise removal process has been carried out using local binary pattern (LBP) methodology. The noise-robust heartbeat acoustic images are classified using long short-term memory (LSTM)-convolutional neural network (CNN), recurrent neural network (RNN), LSTM, Bi-LSTM, CNN, K-means Clustering, and support vector machine (SVM) methods. The obtained results have shown that the proposed InfusedHeart Framework had outclassed all the other customized machine learning and deep learning approaches such as RNN, LSTM, Bi-LSTM, CNN, K-means Clustering, and SVM-based classification methodologies. The proposed Knowledge-infused Learning Framework has achieved an accuracy of 89.36% (without augmentation), 93.38% (with augmentation), and a standard deviation of 10.64 (without augmentation), and 6.62 (with augmentation). Furthermore, the proposed framework has been tested for various signal-to-noise ratio conditions such as SignaltoNoiseRatio0, SignaltoNoiseRatio3, SignaltoNoiseRatio6, SignaltoNoiseRatio9, SignaltoNoiseRatio12, SignaltoNoiseRatio15, and SignaltoNoiseRatio18. In the end, we have shown a detailed comparison of texture and without texture approaches and have discussed future enhancements and prospective ways for future directions.

Cardiac autonomic function in young healthy Hispanic/Latino adults

The Hispanic/Latino (H/La) population in the US experiences a notably high incidence of hypertension. Recent epidemiological findings reveal that more than 50% of H/La men over the age of 20 years suffer from high blood pressure. Even among adolescents aged 8 to 17 years, H/La youth exhibit the highest prevalence of hypertension compared to other racial groups. This significantly elevates the risk of cardiovascular diseases across the lifespan of this population. H/La is the largest ethnic minority in the US, constituting 19.1% of the current population, and is projected to make up 1/3rd of the US population by 2050. As such, it is crucial to study the potential mechanism responsible for the health disparities in this population. In this study, we investigated the cardiac autonomic function by assessing the baroreflex sensitivity (BRS) and heart rate variability (HRV) in young, healthy H/La and non-Hispanic white (NHW) individuals. We hypothesized that the cardiac autonomic function (BRS and HRV) will be impaired in young healthy H/La as compared to the healthy NHW adults. Ten minutes of resting beat-to-beat blood pressure (BP; finger plethysmography) and heart rate (ECG) were measured in 14 young healthy H/La adults (11 men, 3 women) and 14 age-, sex- and weight-matched NHW adults [age (H/La: 20 ± 2yr; NHW: 22 ± 4yr; mean ± SD, p=0.32); BMI (H/La: 24 ± 2 kg/m2; NHW: 24 ± 2 kg/m2; p = 0.92); positive family history of hypertension (H/La: 21.4%; NHW: 21.4%). The resting heart rate (H/La = 59 ± 5 bpm; NHW = 55 ± 6 bpm; p = 0.12), systolic BP (H/La = 107 ± 6 mmHg; NHW = 111 ± 6 mmHg; p = 0.14) and diastolic BP (H/La = 61 ± 5 mmHg; NHW = 63 ± 6 mmHg; p = 0.46) were similar in both the groups. The respiratory rate (H/La = 14 ± 3 bpm; NHW = 14 ± 3 bpm; p = 0.41) and the sample data used (H/La = 591 ± 59 beats; NHW = 554 ± 63 beats; p = 0.12) for both the populations were similar. We found that BRS (overall gain; H/La = 24 ± 6 ms/mmHg; NHW = 27 ± 10 ms/mmHg; p = 0.39) and heart rate variability (root mean square of successive differences between normal heart beats; RMSSD, H/La = 82 ± 29 ms; NHW = 102 ± 48 ms; p = 0.101) were not significantly different between the two groups. These data suggest that baroreflex sensitivity and heart rate variability are not different between young, healthy H/La and NHW adults. Supported by Kinesiology and Health Education UT Austin Start-up Account 19-2635-91. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Sex difference in cardiac autonomic function in African American adults

African American (AA) individuals in the United States have the highest prevalence of hypertension, with an age-adjusted prevalence of 55.8% in AA men and 56.9% in women. Compared to other racial groups, the AA population also has a two- to three-fold higher mortality rate resulting from hypertension-related causes. Furthermore, AA men exhibit a higher mortality rate than AA women. Previous studies have demonstrated sex differences in some biological mechanisms linked to the increased cardiovascular disease risk in the AA population —such as impaired vascular function and elevated oxidative stress. However, it is unknown whether sex differences are present in baroreflex sensitivity (BRS) and heart rate variability (HRV), which are key mechanisms that may contribute to the pathogenesis and clinical outcomes of hypertension. Herein, we tested the hypothesis that young AA men exhibit impaired cardiac autonomic function (spontaneous BRS and HRV) compared to AA women. We studied 26 young normotensive AA adults (13 women) [Age (men: 22 ± 3; and women: 19 ± 1yr; mean ± SD, p = 0.03); BMI (men: 24 ± 3; and women: 24 ± 2 kg/m2; p = 0.92)]. Heart rate (HR; ECG) and beat-to-beat blood pressure (BP; finger plethysmography) were continuously recorded during 10 min of rest to assess HRV and cardiac BRS. Resting HR (men, 61 ± 8; and women: 65 ± 9 bpm; p = 0.18), diastolic BP (men, 66 ± 6; and women: 65 ± 5 mmHg; p = 0.48) and respiratory rate (men, 17 ± 3; and women, 17 ± 3 bpm; p = 0.97) were similar between the groups. Mean BP and systolic BP were higher in AA men, though within the normotensive range for both groups [mean BP (men: 84 ± 5; and women: 76 ± 5 mmHg; p = 0.001); SBP (men: 119 ± 4; and women: 103 ± 7 mmHg; p &lt; 0.001)]. HRV [root mean square of successive differences between normal heartbeats (RMSSD); men, 113 ± 78; and women, 79 ± 43 ms; p = 0.18] and cardiac BRS (overall gain; men, 25 ± 13; and women, 28 ± 12 ms/mmHg; p = 0.66) were not different between groups. These results indicate that BRS and HRV, which are markers of cardiac autonomic regulation, do not differ based on sex among young normotensive African American individuals. Supported by: Kinesiology and Health Education UT Austin Start-up Account 19-2635-91; and TACSM 2023 Student Research Development Award. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Examination of Cardiac Activity with ECG Monitoring Using Heart Rate Variability Methods.

The paper presents a system for analyzing cardiac activity with the possibility of continuous and remote monitoring. The created sensor mobile device monitors heart activity by means of the convenient and imperceptible registration of cardiac signals. At the same time, the behavior of the human body is also monitored through the accelerometer and gyroscope built into the device, thanks to which it is possible to signal in the event of loss of consciousness or fall (in patients with syncope). Conducting real-time cardio monitoring and the analysis of recordings using various mathematical methods (linear, non-linear, and graphical) enables the research, accurate diagnosis, timely assistance, and correct treatment of cardiovascular diseases. The paper examines the recordings of patients diagnosed with arrhythmia and syncope recorded by electrocardiography (ECG) sensors in real conditions. The obtained results are subjected to statistical analysis to determine the accuracy and significance of the obtained results. The studies show significant deviations in the patients with arrhythmia and syncope regarding the obtained values of the studied parameters of heart rate variability (HRV) from the accepted normal values (for example, the root mean square of successive differences between normal heartbeats (RMSSD) in healthy individuals is 24.02 ms, while, in patients with arrhythmia (6.09 ms) and syncope (5.21 ms), it is much lower). The obtained quantitative and graphic results identify some possible abnormalities and demonstrate disorders regarding the activity of the autonomic nervous system, which is directly related to the work of the heart.

The Impact of Prenatal Alcohol Exposure on the Autonomic Nervous System and Cardiovascular System in Rats in a Sex-Specific Manner.

Fetal Alcohol Spectrum Disorder (FASD) is a consequence of prenatal alcohol exposure (PAE) associated with a range of effects, including dysmorphic features, prenatal and/or postnatal growth problems, and neurodevelopmental difficulties. Despite advances in treatment methods, there are still gaps in knowledge that highlight the need for further research. The study investigates the effect of PAE on the autonomic system, including sex differences that may aid in early FASD diagnosis, which is essential for effective interventions. During gestational days 5 to 20, five pregnant female Wistar rats were orally administered either glucose or ethanol. After 22 days, 26 offspring were born and kept with their mothers for 21 days before being isolated. Electrocardiographic recordings were taken on the 29th and 64th day. Heart rate variability (HRV) parameters were collected, including heart rate (HR), standard deviation (SD), standard deviation of normal-to-normal intervals (SDNN), and the root mean square of successive differences between normal heartbeats (RMSSD). Additionally, a biochemical analysis of basic serum parameters was performed on day 68 of the study. The study found that PAE had a significant impact on HRV. While electrolyte homeostasis remained mostly unaffected, sex differences were observed across various parameters in both control and PAE groups, highlighting the sex-specific effects of PAE. Specifically, the PAE group had lower mean heart rates, particularly among females, and higher SDNN and RMSSD values. Additionally, there was a shift towards parasympathetic activity and a reduction in heart rate entropy in the PAE group. Biochemical changes induced by PAE were also observed, including elevated levels of alanine transaminase (ALT) and aspartate aminotransferase (AST), especially in males, increased creatinine concentration in females, and alterations in lipid metabolism. PAE negatively affects the development of the autonomic nervous system, resulting in decreased heart rate and altered sympathetic activity. PAE also induces cardiovascular abnormalities with sex-specific effects, highlighting a relationship between PAE consequences and sex. Elevated liver enzymes in the PAE group may indicate direct toxic effects, while increased creatinine levels, particularly in females, may suggest an influence on nephrogenesis and vascular function. The reduced potassium content may be linked to hypothalamus-pituitary-adrenal axis overactivity.

Heartbeats and high scores: esports triggers cardiovascular and autonomic stress response.

Gaming is often labeled as sedentary behavior. However, competitive gaming, also known as esports, involves significant cognitive demands and may induce stress. This study aims to investigate whether the psychophysical demands during esports elicit a physiological stress response. Fourteen FIFA 21 and thirteen League of Legends players (23.3 ± 2.8 years) were recruited for the study. Heart rate (HR), root mean square of successive differences between normal heartbeats (RMSSD), peripheral and central blood pressure (BP), pulse wave velocity (PWV), and energy expenditure (EE) were assessed during supine rest, seated rest, and competitive FIFA or League of Legends matches. No significant group × condition interactions were observed for any of the outcomes. However, there were significant increases in mean HR (p < 0.001, = 0.383), RMSSD (p = 0.019, = 0.226), peripheral systolic BP (p < 0.001, = 0.588), peripheral diastolic BP (p = 0.005, = 0.272), central systolic BP (p = 0.005; = 0.369), central diastolic BP (p = 0.016, = 0.313), PWV (p = 0.004, = 0.333), and EE (p < 0.001, = 0.721) during both games compared to the seated rest condition. Despite the sedentary nature of esports, the psychophysical demands appear to elicit physiological responses. Interestingly, no significant differences were found between the different game genres.

Cardiac Rhythm Aberrations in Subacute Sclerosing Panencephalitis: Insights From Heart Rate Variability Analysis.

Subacute sclerosing panencephalitis (SSPE) is a fatal neurological disorder resulting from persistent measles virus infection within the brain. Although neurological manifestations have been well-documented, the impact of SSPE on cardiac autonomic function, assessed through heart rate variability (HRV), remains understudied. In this prospective single-center study conducted from January 2022 to March 2023 in Southern India, 30 consecutive SSPE patients and age- and sex-matched controls underwent electrocardiogram recordings for HRV analysis. Various HRV parameters were assessed, including time-domain metrics (SD of normal-to-normal intervals, root mean square of successive differences between normal heartbeats, percentage of successive normal interbeat intervals greater than 50 msec), SD1 and SD2 for Poincaré plot analysis, and frequency-domain metrics (low frequency %, high frequency %, low frequency:high frequency ratio). In the study, SSPE patients exhibited markedly reduced HRV. Specifically, SD of normal-to-normal intervals (P = 0.003), percentage of successive normal interbeat intervals greater than 50 msec (P = 0.03), and SD2 (P = 0.0016) were significantly lower compared with controls. Frequency-domain analysis did not reveal significant distinctions. Correlation analysis demonstrated a negative relationship between percentage of successive normal interbeat intervals greater than 50 msec and SSPE severity (r = -0.37, P = 0.042). Heart rate variability did not significantly differ between SSPE stages or with clinical variables. The interbeat interval range showed a narrower distribution in SSPE subjects. Our study highlights the clinical relevance of HRV analysis in SSPE and autonomic dysfunction throughout the disease course underscoring its importance in SSPE. This investigation provides valuable insights into cardiac autonomic dysfunction probably because of affliction of the central autonomic networks caused by the disease process and may be a contributing factor to mortality in SSPE.

Dynamics of heart rhythm disorders in combatants with acute myocarditis during a 6-month follow-up

The main factors of an unfavorable prognosis, are life-threatening heart rhythm disorders which determine the severity of the clinical course of myocarditis, in addition to impaired contractility and dilatation of the left ventricle (LV). The aim of the study was to assess the frequency and nature of arrhythmias and establish predictors of their long-term persistence, assess the severity of anxiety and depression, changes in heart rate variability in combatants on the background of changes in the structural and functional state of the left ventricle during a 6-month follow-up. The study included 52 male servicemen (combatants) with acute myocarditis (AM) with an average age of 33.4±2.5 years. All patients were assessed by Questionnaire according to the Hospital Anxiety and Depression Scale (HADS) and underwent 24 hour ECG monitoring, transthoracic echocardiography and cardiac magnetic resonance (CMR) with late enhancement using gadovist. At the onset of AM frequent supraventricular (30.7% of cases) and frequent ventricular (42.3% of cases) extrasystolic arrhythmia, as well as paroxysms of non-sustained ventricular tachycardia (26.9% of cases) on the background of heart rhythm variability disorders were recorded. After 6 months, there was an improvement in the structural and functional state of the heart, which was characterized by a decrease in dilatation and an improvement of LV systolic function, a decrease in the volume of the inflammatory lesion and the total number of affected LV segments revealed on cardiac MRI, which was associated with a decrease in the number of ventricular rhythm disorders and reduction of clinical manifestations of anxiety according to the HADS scale. The obtained data indicate that the persistence of supraventricular rhythm disorders is associated with the long-term presence of anxiety and low values of standard deviation of RR intervals (SDNN) and root mean square of successive differences between normal heartbeats (RMSSD). Also predictors of persistence of non-sustained ventricular tachycardia paroxysms were established – SDNN value ≤80.0 ms, LV end-diastolic volume index ≥95 ml/m2, total number of affected LV segments ≥6 segments, presence of delayed contrasting in ≥3 LV segments, pre­sence of ≥12 points on the HADS scale and predictors of atrial fibrillation – SDNN value ≤80.0 ms, RMSSD value ≤12.0 ms, total number of affected segments of LV≥6 seg. and ≥12 points on the HADS anxiety scale, determined at the onset of AM.

Anesthesia in A Patient with Pulmonary Atresia with Intact Ventricular Septum (PA IVS) Underwent Bidirectional Cavo-Pulmonary Shunt (BCPS)

Background: Pulmonary atresia with intact ventricular septum (PA-IVS) is a rare condition, encompassing approximately 1%–3% of congenital heart diseases. Patients with PA-IVS have functional single-ventricle physiology. The ultimate possible outcomes for patients with PA-IVS are biventricular circulation, 1.5-ventricle or single-ventricle palliation, or cardiac transplantation. The bidirectional cavopulmonary shunt (BCPS) procedure directs flow from the superior vena cava into both the right and left pulmonary arteries, permitting flow to both lungs. The shunt is considered to be the second stage of palliation and is generally preparative for the third-stage Fontan procedure. The BCPS improves systemic arterial oxygen saturation without increasing ventricular work or pulmonary vascular resistance.Case: A 10-month-old, 25-day-old boy, weight 9.93 kg, body length 72 cm, diagnosed with PA-IVS, restricted persistent foramen ovale (PFO), right ventricle hypoplastic, and turtuous patent ductus arteriosus (PDA), underwent BCPS, atrial septectomy, and PDA stent evacuation surgery. The patient underwent a PDA stenting and ballooning atrial septectomy (BAS) at 17 days of age at the cathlab. The patient was cyanotic with stable hemodynamics and a saturation of 72% preoperatively.Discussion: Preoperative fasting must be observed to maintain the patient's hydration state. Pulmonary blood flow and systemic blood flow must be balanced. An adequate analgetic can prevent pain stimuli that increase pulmonary vascular resistance. Drugs to reduce the afterload, such as milrinone, are needed. Mechanical ventilation was set to get PaCO2 between 40 and 45 mmHg. Maintain the normal heart beat, preload, and contractility to maintain cardiac output (CO) with saturation 80–85%. Wean from mechanical ventilation as soon as possible.Conclusion: Anesthetic management for BCPS in patients with single ventricles from the preoperative period, intraoperative period, and postoperative period. Understanding single ventricle phsiology is important in order to treat the patient.