Cardiac Autonomic Function Research Articles

Core temperature decline prior to sleep onset is associated with nocturnal heart rate variability

Impaired thermoregulation is associated with poor sleep and autonomic dysfunction. Previous studies demonstrate an association between core body temperature (CBT) dipping and an increase in heart rate variability (HRV) prior to sleep onset. However, the relationship between the rate of CBT decline prior to sleep onset and nocturnal HRV has not been established. The purpose of this study was to investigate the relationship between the rate of CBT decline prior to sleep onset and nocturnal HRV in objectively poor sleepers. We hypothesized a blunted pre-sleep CBT decline would correspond to reduced nocturnal HRV. Fifteen participants (9 males, 6 females; age, 33±4 years; BMI 27±1 kg/m 2 ) underwent an 8-hour overnight sleep opportunity with continuous polysomnography (PSG) and 2-lead electrocardiogram monitoring. A temperature monitoring pill (CoreTempTM, HQ Inc., Palmetto, FL) was ingested with a standardized dinner to record CBT every 10 seconds throughout the sleep period. Core temperature was sampled every 5 minutes from the core temperature tracing one hour prior to sleep onset until final awakening. The rate of CBT decline prior to sleep onset was measured as the slope of CBT values from 1 hour prior to lights out until PSG sleep onset. Nocturnal HRV measures including the root mean squared of successive differences (RMSSD), percentage of R-R intervals (RRI) varying by greater than 50 ms (pNN50), and the high frequency (HF) power of the RRI were determined across the night in stage 2 (N2), stage 3 (SWS), and rapid eye movement (REM) sleep stages. Bivariate correlations were performed to assess the association between CBT rate of decline and nocturnal HRV measures. An inverse correlation was observed between the rate of CBT prior to sleep onset and the RRI in N2 (R= -0.743, p=0.002), SWS (R = -0.730, P = 0.002), and REM (R = -0.708, P = 0.003). Additionally, the rate of pre-sleep CBT decline was inversely correlated with time domain HRV measures in N2 (pNN50: R= -0.598, p= 0.019; RMSSD: R = -0.557, P = 0.031) and SWS (pNN50: R = -0.542, P = 0.037; RMSSD: R = -0.591, P = 0.020). A blunted rate of CBT was further correlated to decreased HF log10 in N2 (R= -0.592, p= 0.020) and REM (R= -0.602, p= 0.018). Our results indicate an association between blunted core temperature decline prior to sleep onset and reduced nocturnal HRV. These findings suggest that adequate thermoregulation prior to sleep onset may have lasting associations with nocturnal cardiac autonomic function. Support is provided by the National Institutes of Health (AA-024892, U54GM115371; P20GM103474). This is the full abstract presented at the American Physiology Summit 2023 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.

Progressive resistance training ameliorates deteriorating cardiac autonomic dysfunction, subclinical inflammation and endothelial dysfunction in type 2 diabetes mellitus: A randomized control trial

Background and aimsTo investigate the effect of resistance training (RT) on outcomes of cardiac autonomic control, biomarkers of subclinical inflammation, endothelial dysfunction, and angiotensin II in T2DM patients with CAN. MethodsFifty six T2DM patients with CAN were recruited in the present study.After baseline assessment of all outcome variables, patients were randomly allocated into two groups – RT (n = 28) and Control (n = 28). The experimental group underwent 12 weeks of RT and the control group received usual care. RT was performed at an intensity of 65%–75% of 1 RM, 3 times/week for 12 weeks. RT program included 10 exercises of major muscle groups in the body. Cardiac autonomic control parameters, subclinical inflammation and endothelial dysfunction biomarkers, and serum angiotensin II concentration were assessed at baseline and after 12 weeks. ResultsParameters of cardiac autonomic control showed significant improvement after RT (p < 0.05). Interleukin-6, interleukin-18 were significantly reduced while endothelial nitric oxide synthase was significantly increased post-RT (p < 0.05). ConclusionsFindings of the present study suggest that RT has the potential to enhance deteriorating cardiac autonomic function in T2DM patients with CAN. RT also seems to have an anti-inflammatory role and it may also play some role in vascular remodeling in these patients. Trial registrationCTRI/2018/04/013321, Registered prospectively on 13th April 2018, Clinical Trial Registry, India.

Myocardial Infarction Signs and Symptoms: Females vs. Males.

Cardiovascular disease is the number one killer of females in the United States today, and myocardial infarction (MI) plays a role in many of these deaths. Females also present with more "atypical" symptoms than males and appear to have differences in pathophysiology underlying their MIs. Despite both differences in symptomology and pathophysiology being present in females versus males, a possible link between the two has not been studied extensively. In this systematic review, we analyzed studies examining differences in symptoms and pathophysiology of MI in females and males and evaluated possible links between the two. A search was performed for sex differences in MI in the databases PubMed, CINAHL (Cumulative Index to Nursing and Allied Health Literature) Complete, Biomedical Reference Collection: Comprehensive, Jisc Library Hub Discover, and Web of Science. Seventy-four articles were ultimately included in this systematic review. Typical symptoms for both ST-elevation myocardial infarction (STEMI) and non-STEMI (NSTEMI) such as chest, arm, or jaw pain were more common in both sexes, but females presented on average with more atypical symptoms such as nausea, vomiting, and shortness of breath. Females with MI also presented with more prodromal symptoms such as fatigue in days leading up to MI, had longer delays in presentation to the hospital after symptom onset, and were older with more comorbidities than males. Males on the other hand were more likely to have a silent or unrecognized MI, which concurs with their overall higher rate of MI. As they age, females have a decrease in antioxidative metabolites and worsened cardiac autonomic function than male. In addition, at all ages, females have less atherosclerotic burden than mles, have higher rates of MI not related to plaque rupture or erosion, and have increased microvasculature resistance when they have an MI. It has been proposed that this physiological difference is etiologic for the male-female difference in symptoms, but this has not been studied directly and is a promising area of future research. It is also possible that differences in pain tolerance between males and females may play a role in differing symptom recognition, but this has only been studied one time where females with higher pain thresholds were more likely to have unrecognized MI. Again, this is a promising area for future study for the early detection of MI. Finally, differences in symptoms for patients with different atherosclerotic burden and for patients with MI due to a cause other than plaque rupture or erosion has not been studied and are both promising avenues to improve detection and patient care in the future.

The association between bedtime and cardiac autonomic control in community-dwelling older adults – The Yilan study, Taiwan

ABSTRACT This study aimed to investigate the association between bedtime and cardiac autonomic function in older adults. This cross-sectional study included community-dwelling older adults aged ≥ 65 years. Self-reported bedtime was categorized as early (< 21:30), intermediate (21:30–22:30), and late (> 22:30). Cardiac autonomic function was evaluated by HRV. The lowest tertiles for each HRV parameter were defined as unhealthy indicators. A total of 3,729 individuals participated, with mean age of 76.3 ± 6.6 years. After controlling for various covariates, late bedtime was associated with a lower risk for unhealthy total power [Odds ratio (OR) = 0.74; 95% confidence interval (CI) = 0.59–0.93] and low frequency power (OR = 0.69, 95% CI = 0.55–0.87) than intermediate bedtime. In contrast, early bedtime was correlated with a higher risk of poor total power (OR = 1.23, 95% CI: 1.05–1.45) and high frequency power (OR = 1.18, 95% CI = 1.00–1.39). When further specifying sleep duration and physical disability into the regression models, the inverse association between late bedtime and unhealthy HRV remained; however, the association between early bedtime and HRV disappeared. Accordingly, we concluded that in terms of cardiac autonomic function, early bedtime in older adults is not necessarily beneficial for their health outcomes, whereas late bedtime may not be detrimental. Abbreviations: ADL: activity of daily living; BMI: body mass index; CI: confidence interval; GARS: the Groningen Activity Restriction Scale; HADS: The Hospital Anxiety and Depression Scale; HF: high frequency power; HRV: heart rate variability; LF: low frequency power; LF/HF: low frequency to high frequency ratio; OR: odds ratios; TP: total power.

Cardiac ischemia and reperfusion in mice: a comprehensive hemodynamic, electrocardiographic and electrophysiological characterization

Malignant ventricular arrhythmias (VA) after acute myocardial infarction remain a major threat. Aim of this study was to characterize the electrophysiological and autonomic sequelae of cardiac ischemia and reperfusion (I/R) in mice during the first week post incident. Left ventricular function was serially assessed using transthoracic echocardiography. VA were quantified by telemetric electrocardiogram (ECG) recordings and electrophysiological studies on the 2nd and 7th day after I/R. Cardiac autonomic function was evaluated by heart rate variability (HRV) and heart rate turbulence (HRT). Infarct size was quantified by planimetric measures. I/R caused significant myocardial scarring and diminished left ventricular ejection fraction. The ECG intervals QRS, QT, QTc, and JTc were prolonged in I/R mice. Both spontaneous VA scored higher and the inducibility of VA was raised in I/R mice. An analysis of HRV and HRT indicated a relative reduction in parasympathetic activity and disturbed baroreflex sensitivity up to 7 days after I/R. In summary, during the first week after I/R, the murine heart reflects essential features of the human heart after myocardial infarction, including a greater vulnerability for VA and a decreased parasympathetic tone accompanied by decelerated depolarization and repolarization parameters.

CARDIOVASCULAR AUTONOMIC DYSFUNCTION IN HIV-POSITIVE PATIENTS AND ITS CORRELATION WITH CD4 CELL COUNT

According to Global human immunodeciency virus and acquired immunodeciency disease syndrome statistics, 38.4 million(33.9 million-43.8 million) people live globally with HIV in 2021, and 1.5 million people became newly infected with HIV in 2021(1). As per India HIV estimation report 2020, national adult (15–49 years) HIV prevalence was estimated at 0.22% (0.17%–0.29%) in 2020, 0.23% (0.18%–0.31%) among males and 0.20% (0.15%– 0.26%) among females(2). HIV is a condition which can progressively affect almost all body organs and systems due to immune system failure. Infection with HIV is well known to cause peripheral neuropathy and other neurological complication thus affecting the quality of life(3). Autonomic nervous system involvement can affect heart rate, vasomotor tone, sexual function, gastrointestinal motility, urination, thermoregulation and production of tears and saliva. This can lead to diverse symptoms like postural syncope, impotence, sweating, diarrhea/constipation, dry eyes and mouth, urinary incontinence and changes in skin temperature. Abnormalities in cardiac autonomic function occur at all CD4 levels(4,5). The aim of our study is to assess autonomic dysfunction in HIV-positive patients and to show the correlation between decreasing CD4 + T cell counts with increasing severity of disease in the form of autonomic dysfunction.

Correlation between Heart rate recovery and Left Atrial phasic functions evaluated by 2D speckle-tracking Echocardiography after Acute Myocardial infarction

BackgroundHeart rate recovery (HRR) in the exercise test is the index of cardiac autonomic system function and sympathovagal balance impaired in patients with myocardial infarction (MI). An instance is left atrial (LA) phasic function, which is impaired in such patients. In this study, we investigated the role of HRR in predicting LA phasic functions in patients with MI.MethodsThe present study recruited 144 consecutive patients with ST-elevation MI. A symptom-limited exercise test was performed about 5 weeks after MI, with echocardiography conducted just before the exercise test. The patients were divided into abnormal and normal HRR at 60 s (HRR60) and again into abnormal and normal HRR at 120 s (HRR120) after the exercise test. LA phasic functions, evaluated by 2D speckle-tracking echocardiography, were compared between the 2 groups.ResultsPatients with abnormal HRR120 had lower LA strain values and strain rates during the reservoir, conduit, and contraction phases, while those with abnormal HRR60 had lower LA strain values and strain rates during the reservoir and conduit phases. The differences were lost after adjustments for possible confounders, except for LA strain and strain rate during the conduit phase, in patients with abnormal HRR120.ConclusionsAbnormal HRR120 in the exercise test can independently predict decreased LA conduit function in patients with ST-elevation MI.

The Effect of Methylphenidate Treatment on Heart Rate Variability and Cardiac Autonomic Functions in Children with Attention Deficit Hyperactivity Disorder

The Effect of Methylphenidate Treatment on Heart Rate Variability and Cardiac Autonomic Functions in Children with Attention Deficit Hyperactivity Disorder

Autonomic regulation therapy in chronic heart failure with preserved/mildly reduced ejection fraction: ANTHEM-HFpEF study results

BackgroundAutonomic regulation therapy (ART) utilizing cervical vagus nerve stimulation (VNS) appeared to be safe and to improve autonomic tone, symptoms, and cardiac mechanical function in patients with symptomatic heart failure and reduced ejection fraction in the ANTHEM-HF Study. The ANTHEM-HFpEF Study is the first investigation to evaluate the safety and feasibility of ART in patients with symptomatic heart failure and preserved or mildly reduced ejection fraction (HFpEF, HFmrEF). MethodsThis open-label interventional study enrolled 52 patients with HFpEF or HFmrEF, NYHA Class II-III, and LVEF ≥40%, who received stable guideline-directed medical therapy. All patients were successfully implanted with LivaNova VNS Therapy® system with an electrical lead surrounding the right cervical vagus nerve. ResultsAdverse event incidence was low. At 12 months, NYHA class (p <0.0001), 6-min walk distance (p <0.05), and quality of life (p <0.0001) were improved. Cardiac mechanical function measures were normal at baseline, except for left ventricular mass index in women and E/e' ratio in all patients, which were elevated at baseline, and were unchanged by ART. Autonomic tone and reflexes improved, indicated by 29% decrease in low-frequency/high-frequency heart rate variability to normal levels (p = 0.028) and by increased heart rate turbulence slope (p = 0.047). T-wave alternans (p = 0.001) and T-wave heterogeneity (p = 0.001) were reduced from abnormal to normal ranges. Nonsustained ventricular tachycardia incidence decreased (p = 0.027). ConclusionsART appeared well-tolerated and safe in patients with HFpEF or HFmrEF. Chronic ART did not alter mechanical function measures but was associated with improved heart failure symptoms, exercise tolerance, autonomic tone, and cardiac electrical stability. Clinical trial registryAutonomic Neural Regulation Therapy to Enhance Myocardial Function in Heart Failure with Preserved Ejection Fraction [ClinicalTrials.gov #NCT03163030, registered 05/22/2017].

Attenuated cardiac autonomic function in humans with high-affinity hemoglobin and compensatory polycythemia.

During hypoxic exposure, humans with high-affinity hemoglobin (and compensatory polycythemia) have blunted increases in heart rate compared with healthy humans with typical oxyhemoglobin dissociation curves. This response may be associated with altered autonomic control of heart rate. Our hypothesis-generating study aimed to investigate cardiac baroreflex sensitivity and heart rate variability among nine humans with high-affinity hemoglobin [6 females, O2 partial pressure at 50% [Formula: see text] (P50) = 16 ± 1 mmHg] compared with 12 humans with typical affinity hemoglobin (6 F, P50 = 26 ± 1 mmHg). Participants breathed normal room air for a 10-min baseline, followed by 20 min of isocapnic hypoxic exposure, designed to lower the arterial partial pressure O2 ([Formula: see text]) to ∼50 mmHg. Beat-by-beat heart rate and arterial blood pressure were recorded. Data were averaged in 5-min periods throughout the hypoxia exposure, beginning with the last 5 min of baseline in normoxia. Spontaneous cardiac baroreflex sensitivity and heart rate variability were determined using the sequence method and the time and frequency domain analyses, respectively. Cardiac baroreflex sensitivity was lower in humans with high-affinity hemoglobin than controls at baseline and during isocapnic hypoxic exposure (normoxia: 7 ± 4 vs. 16 ± 10 ms/mmHg, hypoxia minutes 15-20: 4 ± 3 vs. 14 ± 11 ms/mmHg; group effect: P = 0.02, high-affinity hemoglobin vs. control, respectively). Heart rate variability calculated in both the time (standard deviation of the N-N interval) and frequency (low frequency) domains was lower in humans with high-affinity hemoglobin than in controls (all P < 0.05). Our data suggest that humans with high-affinity hemoglobin may have attenuated cardiac autonomic function.

Effects of Therapeutic Calf Massage on Cardiac Autonomic Function in Healthy Volunteers-a Pilot Study.

Calf massage is a therapeutic intervention that improves circulation and relieves us from pain & tightness. The calf massage also improves autonomic performance by modulating the vagal tone of the cardiovascular system. Therefore, the current study was intended to determine therapeutic calf massage on cardio autonomic activity in healthy subjects. To assess the immediate effect of a single 20-min session of calf massage on cardiac autonomic modulation through heart rate variability (HRV) measurement. In this study, 26 apparent healthy female participants aged between 18 and 25 years participated. Massage over the calf muscles on both legs for 20 min was performed, and resting cardiovascular parameters and HRV parameters were measured at baseline, immediately after the massage, and during the recovery periods (10 and 30 min after the massage). Data were analyzed using one-way ANOVA followed with post hoc analysis. Immediately after the massage intervention, heart rate (HR), systolic (SBP), and diastolic (DBP) blood pressure were decreased (p < .01), and the reduction was persisted at 10 min and 30 min of the recovery period (p < .01). In HRV parameters, the root mean square of successive differences (RMSSD) and high-frequency normalized unit (HF n.u.) increased, and low frequency (LF n.u.) decreased after the massage, and at the 10 and 30 min of the recovery period. The present study reports suggest a significant reduction in heart rate and blood pressure after the massage therapy. A drop in sympathetic tone and raise in parasympathetic tone can also attribute to the therapeutic effect.

Abstract P392: Association Between Blood Pressure Variability and Subclinical Measures of Cardiovascular Disease in Desk Workers

Introduction: Previous research has demonstrated that variability in resting blood pressure (BP) across arms, measurements, or days may be associated with an increased risk for cardiovascular disease (CVD) and mortality. Yet, the extent to which BP variability increases cardiovascular risk and the mechanisms explaining this association are unclear. This study evaluated associations between BP variability with subclinical pathways of CVD development (arterial stiffness (pulse wave velocity [PWV]) and cardiac autonomic function (heart rate variability [HRV]) in desk workers. Hypothesis: Higher BP variability will be associated with higher PWV and lower (worse) HRV Methods: This secondary analysis of baseline data from the Effect of Reducing Sedentary on Blood Pressure randomized controlled trial included 265 sedentary and inactive desk workers (mean age 44.9±11.6 years; 82.0% white; 57.9% female) with elevated-to-stage 2 hypertension and who were not using antihypertensive medication. Sequential BP measurements determined the arm with the higher systolic BP by using an oscillometric device (Omron HEM-907XL). BP was then measured at least twice from the arm with the higher systolic BP at the first (visit-1) and second (visit-2) visits, occurring ≤30 days apart. Systolic BP variability metrics included inter-arm (first measurements between arms at visit-1), intra-arm (first two measurements on the arm with higher systolic BP at visit-1), and inter-visit (average BP from repeated measurements on the same arm across visits-1 and -2). Subclinical measures of CVD included resting carotid- femoral(cfPWV) and carotid-radial(crPWV) PWV (Complier Analyse) and the log transformed standard deviation of normal R-R intervals (SDNN) and the root mean square of the successive differences (RMSSD) HRV measures (Polar Electro). Adjusted linear regression estimated the associations between subclinical measures of CVD and BP variability metrics; Metrics were operationalized into three categories: differences of 0-5 mmHg, 6-10 mmHg, and 11 or more mmHg. Results: The prevalence of having 6 mmHg or more difference for the inter-arm, intra-arm, and inter-visit systolic BP was 43%, 38%, and 53%, respectively. PWV and HRV were not different across categories of inter-arm systolic BP variability or inter-visit systolic BP variability (all p&gt;0.05). However, a same-day intra-arm difference in systolic BP of 6-10 mmHg within visit-1 was associated with higher cfPWV (β=0.42 m/s, (95% CI: 0.07, 0.77) as compared to those with an intra-arm difference of 0-5 mmHg. Conclusion: These data suggest that higher systolic BP variability in the same arm within visit, but not variability across arms or between visits, may be associated with higher aortic stiffness in desk workers with untreated elevated-to-stage 2 hypertension.

Neuropsychological Performance and Cardiac Autonomic Function in Blue- and White-Collar Workers: A Psychometric and Heart Rate Variability Evaluation

The 21st century has brought a growing and significant focus on performance and health within the workforce, with the aim of improving the health and performance of the blue- and white-collar workforce. The present research investigated heart rate variability (HRV) and psychological performance between blue and white-collar workers to determine if differences were evident. A total of 101 workers (n = 48 white-collar, n = 53 blue-collar, aged 19-61 years) underwent a three lead electrocardiogram to obtain HRV data during baseline (10 min) and active (working memory and attention) phases. The Cambridge Neuropsychological Test Automated Battery, specifically the spatial working memory, attention switching task, rapid visual processing and the spatial span, were used. Differences in neurocognitive performance measures indicated that white-collar workers were better able to detect sequences and make less errors than blue-collar workers. The heart rate variability differences showed that white-collar workers exhibit lower levels of cardiac vagal control during these neuropsychological tasks. These initial findings provide some novel insights into the relationship between occupation and psychophysiological processes and further highlight the interactions between cardiac autonomic variables and neurocognitive performance in blue and white-collar workers.

Using sleep heart rate variability to investigate the sleep quality in children with obstructive sleep apnea.

Obstructive sleep apnea (OSA) is associated with impaired sleep quality and autonomic dysfunction. Adenotonsillectomy significantly improves subjective and objective sleep quality in children with OSA. However, the postoperative changes in heart rate variability (HRV) indices (indicators of cardiac autonomic function) and their importance remain inconclusive in childhood OSA. This retrospective case series aimed to investigate the association of sleep HRV indices, total OSA-18 questionnaire score (a subjective indicator of sleep quality) and polysomnographic parameters (objective indicators of sleep quality), and effects of adenotonsillectomy on HRV indices, total OSA-18 questionnaire score and polysomnographic parameters in children with OSA. Seventy-six children with OSA were included in baseline analysis, of whom 64 (84%) completed at least 3 months follow-up examinations after adenotonsillectomy and were included in outcome analysis. Associations between baseline variables, and relationships with treatment-related changes were examined. Multivariable linear regression models in the baseline analysis revealed independent relationships between tonsil size and obstructive apnea-hypopnea index (OAHI), adenoidal-nasopharyngeal ratio and very low frequency (VLF) power of HRV (an indicator of sympathetic activity), and normalized low frequency power (an indicator of sympathetic activity) and OAHI. The outcome analysis showed that adenotonsillectomy significantly improved standard deviation of all normal-to-normal intervals, and high frequency power, QoL (in terms of reduced total OSA-18 questionnaire score), OAHI and hypoxemia. Using a conceptual serial multiple mediation model, % change in OSA-18 questionnaire score and % change in VLF power serially mediated the relationships between change in tonsil size and % change in OAHI. The improvement in OAHI after adenotonsillectomy was serially mediated by reductions in total OSA-18 questionnaire score and VLF power. These preliminary findings are novel and provide a direction for future research to investigate the effects of VLF power-guided interventions on childhood OSA.

The association between cardiac autonomic system function at the entrance to rehabilitation and walking-endurance two months later among children following-ABI

ABSTRACT Background The cardiac autonomic control system function is frequently impaired after brain injury. An association exists between the cardiac autonomic control system and endurance performance. Aim To evaluate the association between cardiac autonomic control system indices at the beginning of the inpatient rehabilitation and walking endurance two months later among children and adolescents following acquired brain injury. Methods A prospective study included 28 children and adolescents following acquired brain injury in the sub-acute phase. A Polar device (RS800CX) records heart rate as a proxy measure of autonomic function at sitting and lying supine on admission and two months later. The 6-minute walk test was assessed at the second assessment in 25 participants. Non-parametric tests were used with statistical significance defined as p < 0.05. Results There were statistically significant differences in heart rate variability between lying and sitting positions, which were positively correlated with the 6-minutes walk test results two months later, mainly in the parasympathetic components (rs = 0.51 p-value <0.01). Conclusions At the beginning of the rehabilitation of children and adolescents following acquired brain injury, a simple manipulation – position change from sitting to lying, activates cardiac autonomic control system responses. These responses are positively associated with walking endurance two months later.

Cardiac autonomic and cortisol stress responses to real operations in surgeons: relationship with individual psychobiological characteristics and experience

BackgroundSurgeons are exposed to high levels of intraoperative stress, which could compromise their psychological well-being in the long term. This study aimed at exploring the effects of real operations on the activity of stress response systems (i.e., cardiac autonomic function and hypothalamic–pituitary–adrenal axis) during and in the aftermath of surgery, and the moderating role of individual psychobiological characteristics and different levels of experience (senior vs expert surgeons).MethodsHeart rate, heart rate variability, and salivary cortisol measures (as indexes of cardiac autonomic and hypothalamic–pituitary–adrenal axis activity, respectively) were assessed during real operations and in the perioperative period in a sample of surgeons (n = 16). Surgeons’ psychometric characteristics were collected using questionnaires. Results. Real operations triggered both cardiac autonomic and cortisol stress responses which were independent from surgeons’ level of experience. Intraoperative stress responses did not affect cardiac autonomic activity during the following night but were associated with a blunted cortisol awakening response. Moreover, senior surgeons reported higher levels of negative affectivity and depressive symptoms than expert surgeons prior to the surgery. Lastly, the magnitude of heart rate responses to surgery positively correlated with scores on negative affectivity, depression, perceived stress, and trait anxiety scales.ConclusionThis exploratory study allows to put forward the hypotheses that in surgeons cardiac autonomic and cortisol stress responses to real operations (i) may be associated with specific individual psychological characteristics regardless of the level of experience, (ii) and may have a longer lasting impact on hypothalamic–pituitary–adrenal axis function with potential implications for surgeons’ physical and psychological well-being.

Night-Time Heart Rate Variability during an Expedition to Mt Everest: A Case Report

Mt Everest has been gaining popularity from casual hiking athletes, climbers, and ultra-endurance marathon runners. However, living and sleeping at altitude increases the risk of injury and illness. This is because travel to high altitudes adversely affects human physiology and performance, with unfavourable changes in body composition, exercise capacity, and mental function. This is a case report of a climber who reached the summit of Mt Everest from the north side. During his 40-day expedition, we collected sleep quality data and night-time heart rate variability. During the night inside the tent, the air temperature ranged from -12.9 to 1.8 °C (-5.8 ± 4.9 °C) and the relative humidity ranged from 26.1 to 78.9% (50.7 ± 16.9%). Awake time was 17.1 ± 6.0% of every sleep-time hour and increased with altitude (r = 0.42). Sleep time (r = -0.51) and subjective quality (r = 0.89) deteriorated with altitude. Resting heart rate increased (r = 0.70) and oxygen saturation decreased (r = -0.94) with altitude. The mean NN, RMSSD, total power, LF/HF, and SD1 and SD2 were computed using the NN time series. Altitude reduced the mean ΝΝ (r = -0.73), RMSSD (r = -0.31), total power (r = -0.60), LF/HF ratio (r = -0.40), SD1 (r = -0.31), and SD2 (r = -0.70). In conclusion, this case report shows that sleeping at high altitudes above 5500 m results in progressively reduced HRV, increased awakenings, as well as deteriorated sleep duration and subjective sleep quality. These findings provide further insight into the effects of high altitude on cardiac autonomic function and sleep quality and may have implications for individuals who frequently spend time at high altitudes, such as climbers.

Screening of Cardiac Rhythm Disorders in Women Working at Information Technology Sector Using Continuous Ambulatory Wireless Cardiac Monitoring – A Community-Based Study

Objectives: The role of screening cardiac arrhythmias provides continuum of care to rediscover the causes and prevention strategies. This study was taken up to screen women working in the information and technology sector for cardiac rhythm disorders using continuous ambulatory cardiac monitoring and asses various risk factors along with work-related stress. Materials and Methods: A cross-sectional study was taken up at the workplace to screen women for cardiac rhythm disorders using wireless continuous ambulatory cardiac monitoring. Various risk factors and work-related stress were assessed using a standardized questionnaire. Differences in ECG parameters such as heart rate, heart rate variability (HRV), and frequency corrected QT (QTc) were compared on working and non-working days. Results: A total of 109 women were screened to find a proportion of 4.58% having cardiac arrhythmias. We found two cases of second-degree AV block (type 1), two cases of atrial tachycardia in the age group of 21–30 years, and one case of sinus pauses. Risk factors such as alcohol usage were statistically associated with cardiac arrhythmias. Others included a sedentary lifestyle, being underweight, a lesser number of sleep hours, no physical activity, work-related stress, and the presence of past-COVID-19 infection, but these were not statistically significant. There were significant changes in heart rate, HRV, and QTc prolongation on working day compared to non-working days. Among the domains of work-related stress, the influence at work and perceived stress due to individual demands and commitments contributed the highest mean score. Moreover, those with higher work-related stress scores were at 3.66 times the increased risk of QTc prolongation. Conclusion: The present study implies the combination of the need for the screening tool in younger age groups and lifestyle factors with more elucidation of work-related stress on autonomic cardiac function.

Alterations in heart rate variability and pro-inflammatory cytokine TNF-alpha in individuals with panic disorder

Based on the autonomic flexibility–neurovisceral integration model, panic disorder (PD) has been associated with a generalized proinflammatory state and lower cardiac vagal tone. The heart rate variability (HRV) provides an index of cardiac autonomic function and reflects the parasympathetic innervation to the heart regulated by the vagus nerve. The aim of this study was to explore the heart rate variability, pro-inflammatory cytokines and their associations in individuals with PD. Short-term HRV with time and frequency domain indices as well as pro-inflammatory cytokines Interleukin-6 (IL-6) and Tumor Necrosis Factor alpha (TNF-alpha) were assessed in seventy individuals with PD (mean age: 35.64 ± 14.21 years) and thirty-three healthy controls (mean age: 38.33 ± 14.14 years). Individuals with PD showed significantly lower HRV in the time and frequency domain parameters during a short-term resting condition. A lower TNF-alpha concentration could be observed in individuals with PD in comparison to healthy controls, but no differences in IL-6. Furthermore, the HRV parameter absolute power in the low-frequency band 0.04–0.15 Hz (LF) predicted TNF-alpha concentrations. In conclusion, a lower cardiac vagal tone, decreased adaptive autonomic nervous system (ANS), and higher pro-inflammatory cytokine state could be observed in individuals with PD compared to healthy controls.

Closing the window on COVID-19 case-control studies.

Closing the window on COVID-19 case-control studies.