Root Mean Square Of Successive RR Interval Differences Research Articles

Comparison of Heart Rate Variability in Thai Older Adults with Hypertension, Pre-Hypertension, and Normotension.

This study aims to compare HRV variables across three cohorts: normotensive (NT), prehypertensive (pre-HT), and hypertensive (HT) and to assess the relationship between the blood pressure (BP) and HRV parameters. Employing a cross-sectional design, 64 older participants were categorized based on the Joint National Committee's criteria into NT (n = 10), pre-HT (n = 33), and HT (n = 21) groups. Anthropometric data, lipid profiles, and HRV indices were evaluated. HRV data were obtained from the Polar V800 chest strap device using HRV Kubios software for data analysis of short-term recordings lasting 10 minutes. This analysis encompasses both time and frequency domain assessments. The time domain includes the standard deviation of NN intervals (SDNN), the root mean square of successive RR interval differences (RMSSD), and the percentage of successive RR intervals differing by over 50 ms (pNN50). The frequency domain includes low frequency (LF), high frequency (HF), and the ratio of LF-to-HF power (LF/HF). Data were statistically analyzed via one-way analysis of variance (ANOVA) and Pearson correlation. The HT group exhibited significantly lower values in SDNN, pNN50, LF power, and HF power in comparison to the NT group (P < 0.05). Moreover, the HT group had a significantly lower SDNN value compared to the pre-HT group (P < 0.05). Inverse associations were uncovered between systolic and diastolic blood pressure and SDNN, pNN50, and HF power (P < 0.05). Multiple regression further highlighted the significance of systolic and pulse pressure concerning HF power (P < 0.05). HRV indices are reduced in Thai older adults with HT compared with those with NT. Monitoring HRV in older adults can provide valuable insights into autonomic function and cardiovascular disease risk.

Changes in heart rate variability over time from symptom onset of transient global amnesia

Transient global amnesia (TGA) often involves precipitating events associated with changes in autonomic nervous system (ANS), and heart rate variability (HRV) reflects the ANS state. This study aimed to investigate HRV changes after TGA. A retrospective analysis of HRV included patients diagnosed with TGA between January 2015 and May 2020. The time and frequency domains of HRV were compared among three groups: early (< 1 week after TGA, n = 19), late (1–4 weeks after TGA, n = 38), and healthy control (HC, n = 19). The Pearson’s correlation between time and time-domain HRV was also examined. The standard deviation of NN intervals (SDNN) (early, 47.2; late, 35.5; HC, 41.5; p = 0.033) and root mean square of successive RR interval differences (RMSSD) (early, 38.5; late, 21.3; HC, 31.0; p = 0.006) differed significantly among the three groups. Post-hoc analysis showed statistically significant differences only in the early and late groups in both SDNN (p = 0.032) and RMSSD (p = 0.006) values. However, the frequency domain with total power, low-frequency and high-frequency powers, and low-frequency/high-frequency ratio did not differ. SDNN (Pearson correlation coefficient =− 0.396, p = 0.002) and RMSSD (Pearson correlation coefficient =− 0.406, p = 0.002) were negatively correlated with time after TGA. Changes in HRV occurred over time after the onset of TGA, with the pattern showing an increase in the first week and then a decrease within 4 weeks.

Acceptability and Perceived Utility of Virtual Reality Among People Who Are Incarcerated Who Use Drugs.

People who are incarcerated are at heightened risk of overdose upon community reentry. Virtual reality (VR) may provide an innovative tool for overdose prevention intervention in corrections facilities. This mixed methods study sought to understand incarcerated individuals' perspectives on VR for overdose prevention and explore physiological arousal associated with use of VR equipment. Study participants were 20 individuals, stratified by gender, with an opioid use disorder at a county jail. Qualitative interviews assessed acceptability and perceived utility of VR in the jail setting. Thematic analysis indicated high levels of acceptability and potential utility in the following areas: (a) mental health and substance use interventions, (b) community reentry skills training, and (c) communication and conflict resolution skills. Heart rate variability (HRV) data were collected continuously during the interview and during VR exposure to explore whether exposure to the VR environment provoked arousal. Physiological data analyses showed a significant decrease in heart rate (HR) [b = -3.14, t(18) = -3.85, p < .01] and no arousal as measured by root mean square of successive RR interval differences (RMSSD) [b = -0.06, t(18) = -1.06, p = .30] and high frequency-HRV (HF-HRV) [b = -0.21, t(18) = -1.71, p = .10]. This study demonstrated high acceptability and decreased HR response of VR among incarcerated people who use drugs.

Assessing autonomic activity and prognostic risk factors comparing multisystem inflammatory syndrome and isolated viral myocarditis/myopericarditis.

In pediatric multisystem inflammatory syndrome and isolated viral myocarditis/myopericarditis, autonomic nervous system function can be evaluated by a non-invasive method called heart rate variability. This study aims to evaluate heart rate variability in these two groups by comparing them with each other. This is the first study assessing these values in these two groups of patients. Patients who are diagnosed with multisystem inflammatory syndrome in children and isolated viral myocarditis/myopericarditis at a university hospital from September 2021 to February 2023 are screened by electrocardiography, echocardiography, and 24-hour Holter monitoring. A healthy control group, compatible in age and gender with the patient groups, was selected from healthy subjects that applied to the hospital for palpitation, murmur, and/or chest pain. Heart rate variability parameters and related laboratory markers were analyzed and compared among the three groups. There were 30 patients with multisystem inflammatory syndrome in children, 43 patients with isolated viral myocarditis/myopericarditis, and 109 participants in the healthy control group. Statistically significant differences were found in most of the heart rate variability parameters: standard deviation of normal to normal intervals (SDNN), the mean of the 5- minute RR interval standard deviations (SDNNİ), the standard deviation of 5-minute R wave to R wave(RR) interval means (SDANN), the root mean square of successive RR interval differences (RMSSD), and the percentage of the beats with a consecutive RR interval difference of more than 50 ms (pNN50%), very low frequency, high frequency, low frequency, triangular index, and low frequency/high-frequency ratio. Multisystem inflammatory syndrome in children patients had impaired and declined heart rate variability values compared to the other two groups. In patients with myocarditis/myopericarditis, we couldn't find a significant difference in these parameters with the control group. Heart rate variability can be used as an important non-invasive autonomic function parameter in determining prognosis and treatment plans, especially in patients diagnosed with multisystem inflammatory syndrome in children. This impairment of autonomic activity could be more prominent in patients with decreased left ventricular systolic functions.

Acute self-myofascial release modulates cardiac autonomic function and hemodynamic parameters at rest and reduces cardiovascular stress reaction

PurposeSelf-myofascial release (SMR) is a form of self-massage aiming to release tension, improve blood flow, and alleviate muscle soreness. This study aimed to determine whether a single session of SMR could impact cardiovascular parameters at rest and during a cold pressor test (CPT).MethodsTwenty male participants (aged 26 ± 2 years) underwent a 20-min SMR and a 20-min seated control condition (CON) on two separate test days in a randomized order. Peripheral and central blood pressure (BP), total peripheral resistance (TPR), pulse wave velocity (PWV), heart rate (HR), root mean square of successive RR interval differences (RMSSD), and the quotient of low-frequency power and high-frequency power (LF/HF) were measured both at rest and during a CPT before (t0), 2 min (t1), and 20 min (t2) after the SMR and CON.ResultsTime × condition interactions could be detected for peripheral and central diastolic BP, TPR, HR, and RMSSD. Following the SMR, peripheral diastolic BP, central diastolic BP, TPR, and RMSSD were reduced, while HR was increased compared to the CON. Regarding the CPT time × condition interactions could be detected for peripheral, and central diastolic BP, with lower values after SMR.ConclusionThe results of the present study suggest that a single bout of SMR confers favorable cardiovascular benefits in healthy normotensive individuals. Furthermore, SMR can attenuate the hemodynamic reactivity to a stress test. Future research should address whether regular SMR leads to chronic adaptations similar to regular, moderate aerobic exercise, massage therapy, and static stretching.

Autonomic nervous system function assessed by heart rate variability and the presence of symptoms affecting activities of daily living in community-dwelling residents with chronic pain: The Hisayama Study.

Autonomic nervous system dysfunction has been reported to be associated with impaired activities of daily living (ADL) among patients with chronic pain, but the association has not been fully addressed in general populations. This study cross-sectionally investigated the association between autonomic nervous system function and the presence of subjective symptoms affecting ADL in community-dwelling residents with chronic pain. A total of 888 residents with chronic pain, aged 40-79 years, who underwent a health examination in 2017-2018 were included. Based on heart rate variability measured by fingertip pulse wave, the standard deviation of normal-to-normal intervals (SDNN), root mean square of successive RR interval differences (RMSSD), low frequency (LF) power, and high frequency (HF) power were calculated. Symptoms affecting ADL were defined as those scoring ≥1 on the modified Rankin Scale. Odds ratios (ORs) and their 95% confidence intervals (CIs) for symptoms affecting ADL were estimated using a logistic regression analysis. The overall prevalence of symptoms affecting ADL was 39.4%. The ORs for symptoms affecting ADL increased significantly per 1-standard-deviation decrement in log-transformed SDNN (OR 1.23 [95% CI 1.06-1.44]), RMSSD (1.25 [1.08-1.45]), LF power (1.29 [1.11-1.52]), and HF power (1.29 [1.11-1.51]) after adjusting for age, sex, education, hypertension, diabetes, serum total cholesterol level, body mass index, past medical history, current smoking, current drinking, exercise, depressive symptoms, and pain intensity. Decreased heart rate variability was associated with the presence of symptoms affecting ADL among individuals with chronic pain in a Japanese community. Decrease in heart rate variability was associated with the presence of symptoms affecting ADL among individuals with chronic pain in a Japanese community. This article could help scientists understand the significance of autonomic nervous system dysfunction in the pathology of chronic pain. Approaches that target autonomic nervous system dysfunction may be an option to relieve or prevent symptoms affecting ADL for chronic pain sufferers.

Effects of moxibustion of "biaoben acupoint combination" on heart rate variability, atrial natriuretic peptide in the model rats of IBS-D complicated with anxiety

To compare the effects on the heart rate variability (HRV) and the expression of the atrial natriuretic peptide (ANP) in the model rats of irritable bowel syndrome with predominant diarrhea (IBS-D) rats complicated with anxiety between moxibustion of "biaoben acupoint combination" and that of "conventional acupoint combination". Of 50 healthy SPF female SD rats, aged 3 months, 8 rats were selected randomly as a blank group, and the rest rats were prepared to be the model of IBS-D complicated with anxiety. Twenty-four rats after successfully modeled were randomized into a model group, a conventional acupoint combination group (convention group) and a biaoben acupoint combination group (biaoben group), 8 rats in each one. In the convention group, moxibustion was delivered at "Tianshu" (ST 25), "Zusanli"(ST 36) and "Shangjuxu"(ST 37); and in the biaoben group, moxibustion was applied to "Neiguan" (PC 6), "Zusanli" (ST 36), and "Guanyuan" (CV 4). One session of moxibustion took 20 min, once daily, for 14 days in total. Before and after intervention, the body mass and fecal moisture content were compared in the rats of each group; using abdominal wall withdrawal reflex, the visceral hypersensitivity was evaluated; with elevated plus maze (EPM) and light-dark box (LDB), the anxiety conditions were assessed. After intervention, HRV was compared among groups, the ultrastructure of intestinal mucosa was observed under the transmission electron microscope in the rats of each group, and ANP expression in the myocardial tissue was detected using Western blot method and immunofluorescence. Before the intervention, compared with the blank group, the body mass and visceral pain threshold of rats were reduced in the model group, the convention group and the biaoben group (P<0.05), fecal moisture content and AWR scores (at the dilatation pressure of 40, 60 and 80 mm Hg, 1 mm Hg ≈ 0.133 kPa) were elevated (P<0.05); and time in the open arm, the open arm entry number and the total movement distance (EPM), the time spent in the light compartment, the number of dark to light transitions and the total transition distance (LDB) were decreased (P<0.05). After the intervention, compared with the blank group, in the model group, the body mass, visceral pain threshold, standard diviation of NN intervals (SDNN) and root mean square of successive RR interval differences (RMSSD) were dropped (P<0.05), fecal moisture content, AWR scores (the dilation pressures of 40, 60 and 80 mm Hg), LF/HF and ANP expression were increased (P<0.05), the time in open arm, the open arm entry number and the total movement distance (EPM), the time spent in the light compartment, the number of dark to light transitions and the total transition distance (LDB) were decreased (P<0.05). When compared with the model group, in the convention group and the biaoben group, the body mass, visceral pain threshold, SDNN and RMSSD were increased (P<0.05), fecal moisture content, AWR scores (the dilation pressures of 60 and 80 mm Hg), LF/HF and ANP expression were dropped (P<0.05), the time in open arm, the open arm entry number and the total movement distance (EPM), the time spent in the light compartment, the number of dark to light transitions and the total transition distance (LDB) were increased (P<0.05). In the biaoben group, compared with the convention group, the body mass, visceral pain threshold, SDNN and RMSSD were elevated (P<0.05), fecal moisture content, AWR score (the dilation pressure of 80 mm Hg), LF/HF and ANP expression were decreased (P<0.05), the time in open arm, the open arm entry number and the total movement distance (EPM), the time spent in the light compartment, the number of dark to light transitions and the total transition distance (LDB) were increased (P<0.05). The epithelial cells of the intestinal mucosa showed a normal morphology in the blank group, the tight junction of the cells was disrupted and the junction was loose in the model group; the tight junction was imperfect in the convention group, but it was intact in the biaoben group. Compared with the conventional acupoint combination, moxibustion of biaoben acupoint combination is more effective on the symptoms of IBS-D complicated with anxiety in the model rats. The effect mechanism may be related to attenuating anxiety-like negative emotions, positively regulating HRV, stabilizing IBS-D intestinal mucosal barrier and down-regulating the expression of ANP in myocardium.

Impact of subtetanic neuromuscular electrical stimulation on cardiac autonomic nervous system in young individuals.

Although subtetanic neuromuscular electrical stimulation (NMES) has been proposed as an exercise training and/or rehabilitation tool, the impact of NMES on the autonomic nervous system (ANS) is unclear. Thus, we hypothesized that NMES would alter ANS, i.e., increase sympathetic activity and decrease parasympathetic activity, in young individuals. Eighteen healthy young individuals (16 males, mean age: 22 [SD: 4] years, Body Mass Index: 21.7 [2.2] kg/m2) volunteered. Blood pressure (BP), heart rate (HR), and R-R intervals were recorded during 6-minute resting, NMES, and recovery conditions. Short-term heart rate variability analysis of R-R intervals was performed for the frequency and time domains during each condition. Time domain indices included the root mean square of successive R-R interval differences (RMSSD), and the percentage of successive R-R intervals differing by more than 50ms (pRR50%). Frequency domain indices (fast Fourier transform) of R-R intervals included total power (TP), low-frequency (LF) power (0.04-0.15 Hz), and high-frequency (HF) power (0.15-0.4 Hz). BP was not altered but HR was significantly increased during NMES (P<0.001), and it returned to the resting level at recovery. RMSSD and pRR50 decreased from resting to NMES and returned at recovery conditions (P<0.05, respectively). TP and HF decreased from resting to NMES and returned at recovery conditions (P<0.05, respectively). LF increased from NMES to recovery (P<0.05). The LF/HF ratio showed no significant differences between conditions (P=0.210). Cardiac ANS fluctuated by subtetanic NMES without BP elevation in healthy young individuals. Parasympathetic but not sympathetic activity was affected by NMES stimulation.

Linear and non‑linear indices of vagal nerve in relation to sex and inflammation in patients with Covid‑19.

Hyperinflammation is one of the most important pathophysiological risk factors for poor prognosis in patients with coronavirus disease-2019 (Covid-19). Low vagal neuro-immune modulation can lead into this kind of immune dysregulation. The association between vagal activity, sex and inflammatory markers were investigated in patients with Covid-19. A total of 19 patients with Covid-19 were included in the present study. Vagus nerve activity was indexed by heart rate variability (HRV) derived from electrocardiogram at hospital admission. Linear HRV parameters included the root mean square of successive RR interval differences (RMSSD) and high-frequency HRV (HF-HRV), while non-linear parameters included 2 UV%. Immune/inflammatory parameters included C-reactive protein (CRP), interleukin-6 (IL-6), neutrophil/lymphocyte ratio (NLR), systemic inflammatory index (SII), and procalcitonin (PCT). It has been revealed that both linear HRV indices HF-HRV and RMSSD, are significantly negatively correlated with CRP and IL-6, independent of age. The non-linear index of 2 UV% is significantly negatively correlated with NLR and SII, which reflect subtle changes in the response of immunocompetent cells. Patients that received high-flow nasal oxygen therapy had significantly higher IL-6 and CRP levels and lower levels of HF-HRV and RMSSD. These patients also had a significantly longer length of stay in hospital (LOS) than patients receiving low-flow oxygen therapy. Men had higher plasma PCT levels and longer LOS in hospital than women, and PCT statistically explained (mediated) the association between sex and LOS. The present study showed different correlations of linear and non-linear vagal indexes of HRV and inflammatory markers in patients with Covid-19. Significant sex differences in certain inflammatory markers were also observed, which may very well verify previous findings of poor prognosis in men with Covid-19. HRV reflects a continuous interaction between the sympathetic and parasympathetic autonomic nervous systems, which are affected by mental or physical stress, and certain disease states. The increased sympathetic and decreased parasympathetic vagal tone contribute to a higher risk of diseases associated with inflammation, cardiovascular disease, cancer, pulmonary diseases and other pathologies, including infectious diseases such as Covid-19. The present study showed that higher RMSSD (a marker of vagal activity) in Covid-19 patients is associated with lower levels of inflammatory biomarkers, a lower need for treatment and is negatively correlated with intensive care unit admission, leading to a shorter hospital stay. These findings support the idea that activation of vagus nerve may help certain Covid-19 patients by reducing the cytokine storm and excessive inflammation.

Fractal complexity alternations in paroxysmal atrial fibrillation patients with and without recurrence after pulmonary vein isolation.

Pulmonary vein isolation (PVI) is a cornerstone therapy for paroxysmal atrial fibrillation (PAF). The variations in nonlinear heart rate variability (HRV) between patients with and without recurrences remain unclear. We aimed to characterize the nonlinear HRV before and after PVI in patients with and without recurrence. Twenty-five drug-refractory PAF patients (56.0 ± 9.1 years old, 20 males) who received PVI were enrolled. Holter electrocardiography were performed before, 1-3, and 6-12 months after PVI. After 8.2 ± 2.5 months of follow-ups after PVI, patients were divided into two groups: the recurrence (n = 8) and non-recurrence (n = 17) groups. Linear and nonlinear HRV variables were analyzed, including the Poincaré Plot analysis and the Detrended Fluctuation Analysis (DFA). The non-recurrence group, but not the recurrence group, had decreased high-frequency component (HF), the root mean square of successive RR interval differences (RMSSD), and the Poincaré Plot index SD1 1-3 months after PVI and increased DFAslope2 6-12 months after PVI. The non-recurrence group's LF/HF ratio and DFAslope1 decreased significantly 1-3 and 6-12 months after PVI, respectively, whereas there was no significant change in the recurrence group after PVI. Significantly reduced vagal tone 1-3 months after PVI, increased long-term fractal complexity 6-12 months after PVI, and decreased sympathetic tone as well as short-term fractal complexity 1-3 and 6-12 months after PVI led to a better AF-free survival after PVI. These findings suggest that neuromodulation and heart rate dynamics play crucial roles in AF recurrence following PVI.

PO-01-078 THE ACUTE PHYSIOLOGIC EFFECTS OF OSTEOPATHIC MANIPULATIVE TREATMENT IN PATIENTS WITH CARDIAC IMPLANTABLE ELECTRONIC DEVICES: A RANDOMIZED CONTROLLED TRIAL

Osteopathic manipulative treatment (OMT) is a procedure used to improve physiologic function and maintain homeostasis. OMT modulates the autonomic nervous system (ANS) and augments heart rate variability (HRV) in healthy subjects. The acute physiologic effects of OMT have been reported in patients with heart failure, but not in those with cardiac implantable electronic devices (CIEDs). To assess the short-term physiologic effects of OMT on heart rate, respiratory rate, arterial blood pressure, and HRV in patients with CIEDs. Cardiac patients with CIEDs at an osteopathic medical center were recruited into a randomized controlled trial (ClinicalTrials.gov ID: NCT0400474) and assigned to either OMT or light touch (control) groups. Short-term physiologic data was recorded pre and post intervention (including one minute HRV via photoplethysmography). HRV was calculated using root mean square of successive RR interval differences (RMSSD). Student’s t-test was used to compare groups; p < 0.05. 20 subjects were enrolled (10 OMT/10 control). Table 1 shows physiologic measurements prior to and post intervention. Changes in HR, RR, BP, and SpO2 were no different between groups before and after intervention; OMT HRV decreased by 12.39 + 34.05 ms, whereas control HRV increased by 19.94 + 18.54 ms (p=0.022). There was a significant decrease in HRV in the OMT group, but no difference in the remaining standard physiologic variables. The difference in HRV is opposite of what would be expected, and could be due to the effects of OMT on the ANS, altered cardiac response in this population, and possibly a decrease in ectopy. Further evaluation of CIED data (arrhythmias, HRV and activity level) may be helpful in determining the long-term effects of OMT on cardiac arrhythmia patients.

Exploratory Investigation of the Effects of Tactile Stimulation Using Air Pressure at the Auricular Vagus Nerve on Heart Rate Variability.

To explore the effects of tactile stimulation using air pressure at the auricular branch of the vagus nerve on autonomic activity in healthy individuals. Three types of tactile stimulation were used in this study: continuous low-amplitude, continuous high-amplitude, and pulsed airflow. The tactile stimulations were provided to the cymba concha to investigate autonomic activity in 22 healthy participants. The mean heart rate (HR) and parameters of HR variability, including the standard deviation of R-R intervals (SDNN) and root mean square of successive R-R interval differences (RMSSD) were compared at baseline, stimulation, and recovery periods. Two-way repeated measures ANOVA indicated a significant main effect of time on HR (p=0.001), SDNN (p=0.003), and RMSSD (p<0.001). These parameters showed significant differences between baseline and stimulation periods and baseline and recovery periods in the post-hoc analyses. There were no significant differences in the changes induced by stimulation type and the interaction between time and stimulation type for all parameters. One-way repeated measures ANOVA showed that HR, SDNN, and RMSSD did not differ significantly among the three time periods during sham stimulation. Parasympathetic activity can be enhanced by auricular tactile stimulation using air pressure, targeting the cymba concha. Further studies are warranted to investigate the optimal stimulation parameters for potential clinical significance.

Quantitative cardiac autonomic outcomes of hydrotherapy in women during the first stage of labor.

Most hydrotherapy studies during childbirth report findings related to pain using a widespread set of subjective measures. In this study, ECG biomarkers as quantitative cardiac autonomic outcomes were used to assess the effects of warm shower hydrotherapy on laboring women during the first stage of labor. This was a prospective single-blind cohort study on stage I delivering women. Their cardiac autonomic function was assessed using heart rate variability (HRV) measures during a deep breathing test using point-of-care testing comprised of an HRV scanner system with wireless ECG enabling real-time data analysis and visualization. Labor pain and anxiety were assessed using the Visual Analog Scale for Pain (VASP) and the Beck Anxiety Inventory (BAI). A total of 105 pregnant women in the first stage of labor who received warm shower hydrotherapy, intravenous analgesia (scopolamine + sodium dipyrone), or spinal anesthetic (bupivacaine + morphine) were enrolled. In women during the first stage of labor, parasympathetic modulation reflected through RMSSD (root mean square of successive RR interval differences) was significantly reduced by hydrotherapy and intravenous analgesia (before vs. after mean rank diff. 35.73 and 65.93, respectively, p < 0.05). Overall HRV (SDNN, standard deviation of RR intervals) was significantly decreased only by intravenous analgesia (before vs. after mean rank diff. 65.43, p < 0.001). Mean heart rate was significantly increased by intravenous analgesia, while spinal anesthesia reduced it, and hydrotherapy did not alter it (before vs. after mean rank diff. -49.35*, 70.38*, -24.20 NS , respectively, *p < 0.05, NS not significant). This study demonstrates that warm shower therapy may impact the sympathovagal balance via parasympathetic withdrawal in women during the initial stage of labor. The findings of this study provide quantitative support for using warm shower hydrotherapy during labor via point-of-care testing. The dependability of hydrotherapy as a non-pharmacological treatment is linked to the completion of more clinical research demonstrating quantitative evidence via outcome biomarkers to support indications on stress and birth progress.

Persistent Increase of Sympathetic Activity in Post-Acute COVID-19 of Paucisymptomatic Healthcare Workers.

Healthcare workers (HCWs) represent a population with a significant burden of paucisymptomatic COVID-19, as the general population. We evaluated autonomic nervous system activity by means of heart rate variability (HRV) in HCWs during health surveillance visits. Short-term electrocardiogram (ECG) recordings were obtained 30 days (IQR 5.25-55.75) after a negative naso-pharyngeal swab for SARS-CoV-2 in 44 cases and compared with ECGs of 44 controls with similar age and sex distribution. Time and frequency domain HRV were evaluated. HCWs who used drugs, had comorbidities that affected HRV, or were hospitalized with severe COVID-19 were excluded. Frequency domain HRV analysis showed a significantly higher low/high-frequency power ratio (LF/HF) in the case study compared with controls (t = 2.84, p = 0.006). In time domain HRV analysis, mean standard deviation of normal-to-normal intervals (SDNN) and root mean square of successive RR interval differences (RMSSD) were significantly lower for cases compared with controls (t = -2.64, p = 0.01 and t = -3.27, p = 0.002, respectively). In the post-acute phase of infection, SARS-CoV-2 produces an autonomic imbalance mirrored by a reduction in HRV. These results are consistent with epidemiological data that suggest a higher risk of acute cardiovascular complications in the first 30 days after COVID-19 infection.

PS-C06-3: QUANTITATIVE CARDIAC AUTONOMIC OUTCOMES OF HYDROTHERAPY DURING CHILDBIRTH

Objective: Most hydrotherapy studies during childbirth report findings related to pain using a widespread set of subjective measures. In this study we evaluated warm shower hydrotherapy s effects during childbirth through ECG biomarkers as quantitative cardiac autonomic outcomes. Design and Methods: This was a prospective single blind cohort study. The cardiac autonomic function was assessed using heart rate variability (HRV) measures during a deep breathing test using an HRV scanner system with wireless ECG enabling real-time data analysis and visualization. Labor pain and anxiety were assessed using the Visual Analogue Scale for Pain (VASP) and the Beck Anxiety Inventory (BAI), respectively. A total of 105 pregnant women in the first stage of labor who received warm shower hydrotherapy, intravenous analgesia (scopolamine + sodium dipyrone), or spinal anesthetic (bupivacaine + morphine) were enrolled. Results: Parasympathetic modulation reflected through RMSSD (root mean square of successive RR interval differences) was significantly reduced by hydrotherapy and intravenous analgesia (before vs. after mean rank diff. 35.73 and 65.93, respectively, p &lt; 0.05). Overall HRV (SDNN, standard deviation of RR intervals) was significantly decreased only by intravenous analgesia (before vs. after mean rank diff. 65.43, p &lt; 0.001). Mean heart rate was significantly increased by intravenous analgesia, while spinal anesthesia reduced it and hydrotherapy did not alter it (before vs. after mean rank diff. -49.35∗, 70.38∗, -24.20NS, respectively, ∗ p &lt; 0.05, NS not significant). Conclusions: This study s findings give quantitative support for the use of warm shower hydrotherapy during labor. This study suggests that warm shower therapy may alter the sympathovagal balance, resulting in a shift towards sympathetic predominance as a result of parasympathetic withdrawal, as well as a better anticipation of higher levels of stress during labor. The dependability of hydrotherapy as a nonpharmacological treatment is linked to the completion of more clinical research demonstrating quantitative evidence via outcome biomarkers to support indications pertaining to stress and birth progress.

Parasympathetic Versus Sympathetic Changes in Heart Rate Variability After a Multimodal Integrative Medicine Intervention for Frontline COVID-19 Personnel.

Frontline healthcare providers (HCPs) working in COVID-19 hospital departments need to deal with considerable physical and emotional stress on a daily basis. We conducted a pilot study to examine changes in heart rate variability (HRV) in frontline COVID-19 personnel after an integrative medicine (IM) intervention. HCPs working in isolated COVID-19 inpatient departments underwent a single 30-minute individually tailored IM sessions combining various IM modalities (acupuncture, mind-body, and/or manual-movement modalities, including anthroposophic medicine). HRV parameters were compared during the first IM session at 3-minute intervals, at the beginning of treatments, and after 20 minutes. Root mean square of successive RR interval differences (RMSSD) was measured, as were domains of time (standard deviation of NN intervals, percentage of successive RR intervals that differ by more than 50 milliseconds) and frequency (low frequency/high frequency [LF/HF] ratio). Preintervention and postintervention concerns were assessed using the Measure Yourself Concerns and Well-being questionnaire, with posttreatment free-text narratives analyzed for clusters of emotional- and spiritual-related keywords (ESKs). A total of 114 HCPs underwent an IM treatment session, and their HRV values were measured, of which 75 (65.8%) expressed ESKs. The RMSSD increased only in the ESK-expressing group ( p < .001). LF/HF ratios decreased in both groups, with HF power increasing in the ESK-expressing ( p = .043) and LF power decreasing in the non-ESK-expressing groups ( p = .004). Increased parasympathetic activity was observed in all HCPs after the IM intervention, particularly among those expressing ESKs. LF/HF parameters suggest different relaxation-associated mechanisms, with increased HF (regulated predominantly by parasympathetic tone) in the ESK-expressing and decreased LF (regulated partially by sympathetic tone) in the nonexpressing group. Additional research needs to explore the relationship between subjective effects of the IM intervention and physiological mechanisms of relaxation in HCPs working in stressful environments. ClinicalTrials.gov identifier NCT05104827.

Retrospective analysis of autonomic dysfunction in epilepsy patients from neurophysiological recordings

Autonomic dysfunction is often associated with seizures in patients with epilepsy. Autonomic dysfunction during seizures can cause serious events like cardiac arrest and sudden unexplained death. Early detection of autonomic dysfunction is crucial to avoid such medical emergencies. In our study, we analyzed the heart rate variability (HRV) in physiological recording during the preictal, ictal and postictal periods. A total of 142 seizures with various semiologies recorded from 49 epilepsy patients were included. Time-domain measurements including mean hear rate (HR), RR interval (RRI), root-mean-square of successive R-R interval differences (RMSSD), The standard deviation of N-N intervals (SDNN) and percentage of successive RR intervals that differ by more than 50 ms(pNN50) were analyzed at different time points, 20 minutes before the seizure, 1 minute before the seizure, during the seizure and 20 minutes after the seizure. We observed there was a significant difference in HRV parameters during and just before the seizure onset (RMSSD with p-value&lt;0.001 and SDNN with p-value&lt;0.001). We also observed that there was a suppression of parasympathetic activity and activation of sympathetic stimulation in the ictal and peri-ictal period, which was characterized by an elevation in the mean heart rate (HR), whereas the mean RRI showed an inversely proportional trend. There was a reduction in mean RMSSD, SDNN and pNN50 prior to seizure onset and was more pronounced in generalized seizures as compared to focal seizures with preserved or impaired awareness. There was a greater sympathetic activation and parasympathetic inhibition during an epileptic seizure in females as compared to male patients. These findings suggest that autonomic dysregulation was increased during a generalized seizure when compared to a focal seizure. HRV analysis can be used as a valid method for quantifying central influences on the autonomic nervous system and its cardiac control. A major advantage of electrocardiogram (ECG)-based seizure detection is that the ECG is an essentially easier signal to obtain, with a higher signal-to-noise ratio than EEG (electroencephalogram). Based on the inferences from this study future studies could be done to build machine learning models which could form the base for the development of wearable seizure prediction devices.

Acute effects of singing on cardiovascular biomarkers.

BackgroundSinging is a physical activity involving components of the vagal nerves manifested as changes in cardiac autonomic regulation.AimsThe aim of this pilot study is to investigate the acute effects of singing on biomarkers of cardiovascular health.MethodsAdult subjects were recruited from cardiology clinics to participate in a single 90-min study visit. Vascular function was measured at the fingertips with peripheral arterial tonometry (PAT) before and after singing to a 14-min video led by a voice expert. Heart rate variability (HRV) was measured with a chest strap sensor at baseline, during, and after singing. PAT measurements were expressed as reactive hyperemia index (RHI) and Framingham reactive hyperemia index (fRHI). Measures of HRV included root mean square of successive RR interval differences (RMSSD) and standard deviation of NN (or RR) intervals (SDNN).ResultsSixty subjects completed the study (68% female, mean age 61 ±13 years, mean BMI 32 ± 8). There was a significant increase in fRHI (1.88 ± 0.14 to 2.10 ± 0.14, p = 0.02) after singing with no significant change in the RHI (1.99 ± 0.10 to 2.12 ± 0.09, p = 0.22). There was a reduction in HRV during singing (compared to baseline) (RMSSD: 42.0 ± 5 to 32.6 ± 4, p = 0.004 and SDNN: 54 ± 4 to 33.5 ± 3, p = 0.009). HRV measures trended back toward baseline after singing.ConclusionsA short duration of singing improved vascular function acutely. Improvements were more substantial in subjects with abnormal baseline endothelial function. HRV patterns were similar to that of light-intensity exercise. Future studies should confirm favorable vascular adaptation to more sustained singing interventions.Clinical trial registrationClinicalTrials.gov, identifer: NCT03805529.

Physical performance in women ́s football preseason. Body composition, heart rate and biomarkers, are they important? Rendimiento físico durante la pretemporada en fútbol femenino. Composición corporal, frecuencia cardíaca y biomarcadores, ¿son importantes?

A well-designed football pre-season is crucial for the subsequent physical performance of the players. This study aimed to analyse, in this period, the effects of body composition, heart rate variability and physiological biomar- kers on female football players’ physical performance. To this end, 22 amateur female football players (23.68 ± 3.69 years) of the same team participated in the study. Physical performance factors (acceleration capacity and jumping ability), body composition, perceived exertion load, heart rate variability and some physiological biomarkers (salivary testosterone and cortisol) were evaluated weekly during a 5-week pre-season period (from T0 to T5). Wilks’ Lambda indicated a significant F-value in all variables except the high and low heart frequency ratio (LFtoHF). Scheffe’s post-hoc identified differences between T0 and all weeks in anthropometry variables, and between T0 and T5 in all other variables. According to the regression analyses, it was revealed a negati- ve impact between percentage of body fat and physical capacities, particularly with 20-m (-13.77) and 40-m (-14.46) when the exertion is measured by the logarithm of the root mean square of successive R-R interval differences (RMSSD). Therefore, the present research suggests that amateur female football players who start the training season with a lower body fat percentage are able to achieve a better fitness level in a short period of time.

Effects of an Overnight, 8-Hour Low Oxygen Exposure on Energy Intake and Resting Energy Expenditure in Healthy, Normal Weight Adults

ObjectivesIndividuals who travel to high altitude (≥5,000 ft) are exposed to hypobaric hypoxic (HH) conditions (i.e., low pressure, low oxygen). Extended exposure to HH conditions often results in body weight loss. This body weight loss is the result of an increase in resting metabolic rate (RMR) due to alterations in the sympathetic and parasympathetic nervous system (PNS), and a decrease in energy intake due to appetite suppression. However, it is unknown if an acute bout of normobaric hypoxic (NH) exposure (i.e., normal pressure, low oxygen) at sea level induces similar changes in energy expenditure and intake. The objective of the current study was to determine the effects of a single overnight exposure to NH on RMR, heart rate variability (HRV), and energy and macronutrient intake compared to an overnight exposure to normobaric normoxia (NN) in normal-weight adults. MethodsIn this randomized crossover trial, normal-weight adults (n = 20; 22.7 ± 1.7 kg/m2, 24.5 ± 3.9 y) slept 8 h in a tent maintained at either 15% oxygen (∼8500 ft) or 20% oxygen (∼1000 ft). The following morning, HRV was measured inside the tent using electrocardiography and RMR was measured outside the tent using indirect calorimetry. Energy and macronutrient intake were assessed in the morning outside the tent with an ad-libitum breakfast buffet and a self-reported dietary record kept for the remainder of the day. ResultsOvernight oxygen saturation was lower in NH (mean ± SD: 88 ± 2%) compared to NN (96 ± 1%; P < 0.0001). Following overnight exposure to NH, RMR was elevated (1537 ± 264 kcal/d) compared to NN (1491 ± 184 kcal/d; P = 0.018. Heart rate was higher in NH (64.2 ± 10.2 bpm) compared to NN (59.7 ± 10.9 bpm; P = 0.003). PNS activity [i.e., the root mean square of successive RR interval differences (RMSSD) and high frequency activity 0.15–0.4 hz (HF)] was lower following NH (47.7 ± 19.5 ms and 524 ± 335 ms2, respectively) compared to NN (58.3 ± 22.6 ms, P = 0.034 and 748 ± 476 ms2, P = 0.052, respectively). Energy and macronutrient intake did not differ between conditions. ConclusionsOne-night exposure to NH increases RMR and reduces PNS activity without impacting energy or macronutrient intake when compared to one-night NN exposure. Future studies should evaluate whether overnight NH exposure is an effective adjunct to traditional weight loss interventions. Funding SourcesInternal funds from FSU.