Cardiac Parasympathetic Modulation Research Articles

Association between Sleep Quality and Cardiac Autonomic Modulation in Adolescents: A Cross Sectional Study.

Objective To analyze the impact of sleep quality/duration on cardiac autonomic modulation on physically active adolescents with obesity. Materials and Methods The present cross-sectional study included 1,150 boys with a mean age of 16.6 ± 1.2 years. The assessment of cardiac functions included the frequency domain of heart rate variability (HRV; low frequency - LF; high frequency - HF; and the ratio between these bands -LF/HF -, defined as the sympathovagal balance), and each parameter was categorized as low / high . Physical activity levels and sleep quality/duration were obtained by questionnaires. Abdominal obesity was assessed and defined as waist circumference > 80 th percentile. Results Poor sleep quality resulted in lower HF (odds ratio [OR]: 1.8; 95% confidence interval [95%CI]: 1.01-3.21]) regardless of physical activity and abdominal obesity. Moreover, the study found no association between sleep duration and HRV parameters in adolescents. Conclusion Sleep quality, not sleep duration, reduces parasympathetic cardiac modulation apart from other factors such as physical activity and abdominal obesity in adolescents.

Cardiovascular autonomic regulation correlates with cognitive performance in patients with a history of traumatic brain injury

Background and objectiveTraumatic brain injury (TBI) may afflict brain areas contributing to both cardiovascular autonomic regulation and cognitive performance. To evaluate possible associations between both functions in patients with a history of TBI (post-TBI-patients), we determined correlations between cardiovascular autonomic regulation and cognitive function in post-TBI-patients.MethodsIn 86 post-TBI-patients (33.1 ± 10.8 years old, 22 women, 36.8 ± 28.9 months after injury), we monitored RR intervals (RRI), systolic and diastolic blood pressures (BPsys, BPdia), and respiration (RESP) at rest. We calculated parameters of total cardiovascular autonomic modulation (RRI-standard-deviation (RRI-SD), RRI-coefficient-of-variation (RRI-CV), RRI-total-powers), sympathetic (RRI-low-frequency-powers (RRI-LF), normalized (nu) RRI-LF-powers, BPsys-LF-powers) and parasympathetic modulation (root-mean-square-of-successive-RRI-differences (RMSSD), RRI-high-frequency-powers (RRI-HF), RRI-HFnu-powers), sympathetic-parasympathetic balance (RRI-LF/HF-ratios), and baroreflex sensitivity (BRS). We used the Mini-Mental State Examination and Clock Drawing Test (CDT) to screen the general global and visuospatial cognitive function, and applied the standardized Trail Making Test (TMT)-A assessing visuospatial abilities and TMT-B assessing executive function. We calculated correlations between autonomic and cognitive parameters (Spearman’s rank correlation test; significance: P < 0.05).ResultsCDT values positively correlated with age (P = 0.013). TMT-A values inversely correlated with RRI-HF-powers (P = 0.033) and BRS (P = 0.043), TMT-B values positively correlated with RRI-LFnu-powers (P = 0.015), RRI-LF/HF-ratios (P = 0.036), and BPsys-LF-powers (P = 0.030), but negatively with RRI-HFnu-powers (P = 0.015).ConclusionsIn patients with a history of TBI, there is an association between decreased visuospatial and executive cognitive performance and reduced parasympathetic cardiac modulation and baroreflex sensitivity with relatively increased sympathetic activity. Altered autonomic control bears an increased cardiovascular risk; cognitive impairment compromises quality of life and living conditions. Thus, both functions should be monitored in post-TBI-patients.

Increased respiratory modulation of cardiovascular control reflects improved blood pressure regulation in pregnancy.

Hypertensive pregnancy disorders put the maternal-fetal dyad at risk and are one of the leading causes of morbidity and mortality during pregnancy. Multiple efforts have been made to understand the physiological mechanisms behind changes in blood pressure. Still, to date, no study has focused on analyzing the dynamics of the interactions between the systems involved in blood pressure control. In this work, we aim to address this question by evaluating the phase coherence between different signals using wavelet phase coherence. Electrocardiogram, continuous blood pressure, electrocardiogram-derived respiration, and muscle sympathetic nerve activity signals were obtained from ten normotensive pregnant women, ten normotensive non-pregnant women, and ten pregnant women with preeclampsia during rest and cold pressor test. At rest, normotensive pregnant women showed higher phase coherence in the high-frequency band (0.15-0.4Hz) between muscle sympathetic nerve activity and the RR interval, blood pressure, and respiration compared to non-pregnant normotensive women. Although normotensive pregnant women showed no phase coherence differences with respect to hypertensive pregnant women at rest, higher phase coherence between the same pairs of variables was found during the cold pressor test. These results suggest that, in addition to the increased sympathetic tone of normotensive pregnant women widely described in the existing literature, there is an increase in cardiac parasympathetic modulation and respiratory-driven modulation of muscle sympathetic nerve activity and blood pressure that could compensate sympathetic increase and make blood pressure control more efficient to maintain it in normal ranges. Moreover, blunted modulation could prevent its buffer effect and produce an increase in blood pressure levels, as observed in the hypertensive women in this study. This initial exploration of cardiorespiratory coupling in pregnancy opens the opportunity to follow up on more in-depth analyses and determine causal influences.

Intra- and Interrater Reliability of Short-Term Measurement of Heart Rate Variability on Rest in Individuals Post-COVID-19.

Individuals affected by COVID-19 have an alteration in autonomic balance, associated with impaired cardiac parasympathetic modulation and, consequently, a decrease in heart rate variability (HRV). This study examines the inter- and intrarater reliability of HRV) parameters derived from short-term recordings in individuals post-COVID. Sixty-nine participants of both genders post-COVID were included. The RR interval, the time elapsed between two successive R-waves of the QRS signal on the electrocardiogram (RRi), were recorded during a 10 min period in a supine position using a portable heart rate monitor (Polar® V800 model). The data were transferred into Kubios® HRV standard analysis software and analyzed within the stable sessions containing 256 sequential RRi. The intraclass correlation coefficient (ICC) ranged from 0.920 to 1.000 according to the intrarater analysis by Researcher 01 and 0.959 to 0.999 according to the intrarater by Researcher 02. The interrater ICC ranged from 0.912 to 0.998. The coefficient of variation was up to 9.23 for Researcher 01 intrarater analysis, 6.96 for Researcher 02 intrarater analysis and 8.83 for interrater analysis. The measurement of HRV in post-COVID-19 individuals is reliable and presents a small amount of error inherent to the method, supporting its use in the clinical environment and in scientific research.

Royal Jelly Plus Coenzyme Q10 Supplementation Enhances High-Intensity Interval Exercise Performance via Alterations in Cardiac Autonomic Regulation and Blood Lactate Concentration in Runners.

PurposeThis study aimed to examine whether oral royal jelly (RJ) and coenzyme Q10 (CoQ10) co-supplementation could improve high-intensity interval exercise (HIIE) performance in runners, reducing exercise-induced lactic acidosis and decreasing elevated sympathetic tone following exercise.MethodsThirty regional-level runners (age: 19 ± 1 years; height: 173 ± 2 cm; body mass: 68.9 ± 2 kg; body mass index: 23.1 ± 1 kg/m2) were randomly allocated to receive either 400 mg of RJ and 60 mg of CoQ10 (RJQ) or matching placebo (PLA) once daily for 10 days. Exercise performance expressed as time taken to complete HIIE was evaluated at baseline, and then reassessed at day 10 of intervention. HIIE protocol applied to the runners included three repetitions of 100 m distance at maximum possible speed interspersed with 45 s of recovery periods. Indices of heart rate variability and blood lactate concentration were also measured before and immediately after HIIE in each group.ResultsHIIE performance significantly improved in RJQ group (p = 0.005) compared to PLA group. Blood lactate levels and sympathetic influence on the heart were significantly lower both before and after the HIIE in athletes who received RJQ (p < 0.05) compared to PLA. Regression analysis showed that oral RJQ administration for 10 days was significantly associated with reductions in HIIE-induced increases in blood lactate concentration and enhanced cardiac parasympathetic modulation following exercise compared to PLA. Principal component analysis revealed that runners treated with RJQ are grouped by the first two principal components into a separate cluster compared to PLA. Correlation analysis demonstrated that the improvements in runners’ HIIE performance were due in significant part to RJQ-induced reduction of increment in blood lactate levels in response to exercise in combination with a more rapid shift in autonomic activity toward increased parasympathetic control early at post-exercise.ConclusionThese findings suggest that RJQ supplementation for 10 days is potentially effective for enhancing HIIE performance and alleviating adverse effects of increased intramuscular acidity and prolonged sympathetic dominance following intense exercise.

Pregnancy restores altered sympathetic vasomotor modulation and parasympathetic cardiac modulation in hypertensive rats

Hypertension is associated to impaired baroreflex sensitivity (BRS). In spontaneously hypertensive rats (SHR), pregnancy reduces blood pressure, and this effect has been associated to increase nitric oxide (NO) bioavailability. Increased NO bioavailability has been linked to improve BRS in hypertensive animals. Therefore, we hypothesize that pregnancy improves the BRS in SHR. We performed experiments to evaluate the vasomotor and cardiac autonomic modulation, also to evaluate the BRS at baseline conditions (spontaneous) and after phenylephrine (PE) and sodium nitroprusside (SNP) administrations in non-pregnant (NP) and pregnant (P) Wistar rats and SHR. Beat-to-beat time series with systolic arterial pressure values were generated and processed by Fast Fourier Transform (spectral analysis). Next, spectra were integrated into low-frequency (LF) band and had their power taken as an index of sympathetic modulation on arterial pressure. Reduced mean arterial pressure was observed in P-groups when compared to NP matched rats, although we did not observe alterations in heart rate (HR). In SHR-NP, spectral analysis revealed altered cardiovascular autonomic modulation when compared to the other groups. However, in SHR-P the autonomic parameters were similar to those observed in Wistar-NP, suggesting that pregnancy changed autonomic modulation. BRS assessed by means of the sequence method was found similar in P-groups. Pregnancy reduced the BRS during hypotension in Wistar. BRS assessed with PE and SNP administration was found lower in SHR-NP as compared to Wistar-NP, and it was not altered by pregnancy. In conclusion, pregnancy did not improve the BRS in SHR, but normalized altered sympathetic vasomotor modulation in SHR.

Does obstructive sleep apnoea modulate cardiac autonomic function in paroxysmal atrial fibrillation?

PurposeThe autonomic nervous system may mediate acute apnoea–induced atrial fibrillation (AF). We compared cardiac autonomic function in paroxysmal atrial fibrillation (PAF) patients with and without obstructive sleep apnoea (OSA).MethodsCase control study of 101 patients with PAF recruited at two tertiary centres. All patients underwent in-laboratory polysomnography. ECG signal demonstrating “steady state” sinus rhythm (i.e. with arrhythmic beats and respiratory events excluded) was included in the analysis. Cardiac autonomic function was assessed via measures of heart rate variability (HRV) and reported by sleep stage (REM vs Non-REM) for patients with and without OSA.ResultsSixty-five (66.3%) of patients were male, mean age 61.5 ± 11.6 years, mean BMI 27.1 ± 4.3 kg/m2. Global measures of HRV (triangular index, total power) did not differ between PAF patients with and without OSA in either REM or non-REM sleep. Frequency-domain analysis during non-REM sleep in PAF patients with OSA showed increased cardiac parasympathetic modulation (HF-nu: 39.1 ± 15.7 vs 48.0 ± 14.6, p = 0.008) and reduced cardiac sympathetic modulation (LF-nu 54.1 ± 19.7 vs 43.7 ± 18.0, p = 0.012, LF/HF ratio: 2.1 ± 2.0 vs 1.2 ± 1.0, p = 0.007). Results remained significant after adjusting for age, sex, and BMI (adjusted p values 0.024, 0.045 and 0.018 respectively). There were no differences in HRV parameters during REM sleep.ConclusionsThis is the first study of HRV in PAF patients with and without OSA. Our results indicate limited differences in HRV between groups. However, this work suggests a chronic increase in parasympathetic nervous modulation and relative reduction in sympathetic modulation in PAF patients with OSA during steady-state non-REM sleep.

P095 Heart Rate Variability during Sleep in Paroxysmal Atrial Fibrillation patients with and without Obstructive Sleep Apnoea

Abstract Introduction Physiological studies have demonstrated the importance of the autonomic nervous system in mediating acute apnoea-induced atrial fibrillation (AF). We aimed to compare Heart Rate Variability (HRV) markers of autonomic function in paroxysmal atrial fibrillation (PAF) patients with and without obstructive sleep apnoea (OSA). A secondary aim was the analysis of ectopic beats in these groups. Methods Nocturnal ECG traces from 89 PAF patients who underwent in-laboratory polysomnography were included. After identifying ectopic beats in the ECGs, periods of arrhythmia as well as sleep apnoea events were excluded. HRV time and frequency domains were reported by sleep stage (REM vs Non-REM) for patients with and without OSA. Results Frequency domain analysis of HRV during non-REM sleep in PAF patients with OSA showed increased cardiac parasympathetic modulation (HF-nu: 39.13 ± 15.74 vs 47.98 ± 14.60, p = 0.008*) and reduced cardiac sympathetic modulation (LF/HF ratio: 2.05 ± 2.02 vs 1.17 ± 0.98, p = 0.007*). Results remained significant after adjusting for age, sex and BMI (adjusted p values 0.024 and 0.018 respectively). PAF patients with severe OSA (AHI ≥ 30/hr) had more AF beats and Ventricular Ectopic Beats than those without severe OSA (22.7 ± 42.8% vs 3.7 ± 17.9%, p = 0.006*, 1.7 ± 3.8 vs 0.3 ± 0.9%, p = 0.004* respectively). Conclusions This is the first study of HRV in AF patients with and without OSA. It suggests a chronic increase in parasympathetic nervous modulation and relative reduction in sympathetic modulation in PAF patients with OSA.

Movement analysis of upper limbs during motor task in down syndrome immediately after TDCS combined with non-immersive virtual reality

Startle is a fast response elicited by sudden acoustic, tactile or visual stimuli in a variety of animal species and in humans. The magnitude of startle response can be modulated by external and internal variables and can be a useful tool to study the sensory-motor integration in animals. Different stimuli have been used to induce startle in horses, which makes it difficult to compare the responses to these different approaches. The present study uses ultra-short-term heart rate variability (HRV) analysis to characterize the cardiac autonomic modulation, reactivity assessment and blood cortisol measurements to describe the behavioural and endocrine responses to a simple, easy to replicate, effective and safe method of startle (an umbrella is abruptly opened near the horse). The ultra-short-term (64 s) heart rate (HR) series were interpolated (4 Hz) and divided into 256 points segments then the spectra calculated (Fast Fourier Transform). The spectra were then integrated into low (LF; 0.01–0.07 Hz; Index of Cardiac Sympathetic Modulation) and high (HF; 0.07–0.50 Hz; Index of Cardiac Parasympathetic Modulation) frequency bands. Following the startle test, the HR (p = 0.0101), the power of the LF band of the cardiac interval spectrum (p = 0.0002) and the LF/HF ratio (p = 0.0066) were found to be higher, whereas the power of the HF band of the cardiac interval spectrum was found to be lower (p = 0.0002). Also, the horses showed a noticeable escape response, with latency of reaction varying from 0.28 to 1.28 s, duration of reaction ranging from 1.52 to 7.92 s and escape distance covered varying from 3.43 to 9.97 m. However, the endocrine measurements failed to reveal significant changes in the cortisol levels after the startle test. We conclude that the startle test used in the current study was effective to produce changes in behavioural parameters and cardiac autonomic modulation of the horses and can therefore be an appropriate tool for neurobiological studies. Furthermore, the use of ultra-short segments (64 s) for HRV analysis appears to be effective and promising for the detection of mental stress in horses.

Exercise Training Induces Hemodynamic and Autonomic Benefits in a Model of Aterosclerosclerosis

Considering the increase of cardiovascular risk with the progression of the atherogenic process and the effectiveness of physical training as a strategy to control/manage the cardiac dysfunction in populations exposed to elevated risks, the aim of this study was to evaluate the cardiovascular and autonomic effects of an aerobic exercise training protocol in an experimental model of atherosclerosis. Considering the cardioprotective effects already known about physical training the hypothesis of this study is that the aerobic exercise training will promote systemic benefits on hemodynamics and autonomic in a model of atherosclerosis. For this, sixteen ApoE-knockout mice, 15 months old, were divided in 2 groups (n=8, each): sedentary group (APOE 15) and moderate intensity exercise training group (APOE 15T). The exercise training lasted for 6 weeks (5 days/week, 1 hour/day, intensity 60–75% of the maximum treadmill test). At the end of the protocol, the animals were submitted to echocardiography analysis and cannulation for a direct recording of the arterial blood pressure (AP), and then, baroreflex sensitivity and cardiovascular autonomic modulation were evaluated. The aerobic exercise training improved running capacity (APOE 15: 594.90±46.95; APOE 15T: 878.6±68.54 s) and cardiac diastolic function (E/A: APOE 15: 1.10±0.05; APOE 15T: 1.70±0.24), as well as decreased diastolic blood pressure (DAP: APOE 15: 107.0±5.202; APOE 15T: 95.12±0.79 mmHg) and induced resting bradycardia (HR: APOE 15: 704±21; APOE 15T: 613±20 bpm) associated with heart rate variability increase (Var-PI: APOE 15:1.25±0.09; APOE 15T: 8.81±1.98 ms2; SD-Pl: APOE 15: 1.09±0.06; APOE 15T: 2.77±0.37 ms). In addition, greater cardiac parasympathetic modulation (RMSSD: APOE 15: 0.99±0.06; APOE 15T: 1.41±0.10 ms) and baroreflex sensitivity improvement (Alpha Index: APOE 15: 0.31±0.044; APOE 15T: 0.66±0.10 ms/mmHg) were also observed. In conclusion, aerobic exercise training may be considered an important non-pharmacological strategy for the management of cardiovascular risk induced by atherosclerosis, improving running capacity, diastolic function as well as the hemodynamic status and autonomic modulation.

Analyzing the Loss and the Recovery of Consciousness: Functional Connectivity Patterns and Changes in Heart Rate Variability During Propofol-Induced Anesthesia.

The analysis of the central and the autonomic nervous systems (CNS, ANS) activities during general anesthesia (GA) provides fundamental information for the study of neural processes that support alterations of the consciousness level. In the present pilot study, we analyzed EEG signals and the heart rate (HR) variability (HRV) in a sample of 11 patients undergoing spinal surgery to investigate their CNS and ANS activities during GA obtained with propofol administration. Data were analyzed during different stages of GA: baseline, the first period of anesthetic induction, the period before the loss of consciousness, the first period after propofol discontinuation, and the period before the recovery of consciousness (ROC). In EEG spectral analysis, we found a decrease in posterior alpha and beta power in all cortical areas observed, except the occipital ones, and an increase in delta power, mainly during the induction phase. In EEG connectivity analysis, we found a significant increase of local efficiency index in alpha and delta bands between baseline and loss of consciousness as well as between baseline and ROC in delta band only and a significant reduction of the characteristic path length in alpha band between the baseline and ROC. Moreover, connectivity results showed that in the alpha band there was mainly a progressive increase in the number and in the strength of incoming connections in the frontal region, while in the beta band the parietal region showed mainly a significant increase in the number and in the strength of outcoming connections values. The HRV analysis showed that the induction of anesthesia with propofol was associated with a progressive decrease in complexity and a consequent increase in the regularity indexes and that the anesthetic procedure determined bradycardia which was accompanied by an increase in cardiac sympathetic modulation and a decrease in cardiac parasympathetic modulation during the induction. Overall, the results of this pilot study showed as propofol-induced anesthesia caused modifications on EEG signal, leading to a “rebalance” between long and short-range cortical connections, and had a direct effect on the cardiac system. Our data suggest interesting perspectives for the interactions between the central and autonomic nervous systems for the modulation of the consciousness level.

Occipitoatlantal decompression and noninvasive vagus nerve stimulation slow conduction velocity through the atrioventricular node in healthy participants.

Management of atrial fibrillation includes either rhythm control that aims at establishing a sinus rhythm or rate control that aims at lowering the ventricular rate, usually with atrioventricular nodal blocking agents. Another potential strategy for ventricular rate control is to induce a negative dromotropic effect by augmenting cardiac vagal activity, which might be possible through noninvasive and nonpharmacologic techniques. Thus, the hypothesis of this study was that occipitoatlantal decompression (OA-D) and transcutaneous auricular vagus nerve stimulation (taVNS) not only increase cardiac parasympathetic tone as assessed by heart rate variability (HRV), but also slow atrioventricular conduction, assessed by the PQ-interval of the electrocardiogram (EKG) in generally healthy study participants without atrial fibrillation. To test whether OA-D and/or transcutaneous taVNS, which have been demonstrated to increase cardiac parasympathetic nervous system activity, would also elicit a negative dromotropic effect and prolong atrioventricular conduction. EKGs were recorded in 28 healthy volunteers on three consecutive days during a 30min baseline recording, a 15min intervention, and a 30min recovery period. Participants were randomly assigned to one of three experimental groups that differed in the 15min intervention. The first group received OA-D for 5min, followed by 10min of rest. The second group received 15min of taVNS. The intervention in the third group that served as a time control group (CTR) consisted of 15min of rest. The RR- and PQ-intervals were extracted from the EKGs and then used to assess HRV and AV-conduction, respectively. The OA-D group had nine participants (32.1%), the taVNS group had 10 participants (35.7%), and the CTR group had nine participants (32.1%). The root mean square of successive differences between normal heartbeats (RMSSD), an HRV measure of cardiac parasympathetic modulation, tended to be higher during the recovery period than during the baseline recording in the OA-D group (mean±standard error of the mean [SEM], 54.6±15.5 vs. 49.8±15.8ms; p<0.10) and increased significantly in the taVNS group (mean±SEM, 28.8±5.7 vs. 24.7±4.8ms; p<0.05), but not in the control group (mean±SEM, 31.4±4.2 vs. 28.5±3.8ms; p=0.31). This increase in RMSSD was accompanied by a lengthening of the PQ-interval in the OA-D (mean±SEM, 170.5±9.6 vs. 166.8±9.7ms; p<0.05) and taVNS (mean±SEM, 166.6±6.0 vs. 162.1±5.6ms; p<0.05) groups, but not in the control group (mean±SEM, 164.3±9.2 vs. 163.1±9.1ms; p=0.31). The PQ-intervals during the baseline recordings did not differ on the three study days in any of the three groups, suggesting that the negative dromotropic effect of OA-D and taVNS did not last into the following day. The lengthening of the PQ-interval in the OA-D and taVNS groups was accompanied by an increase in RMSSD. This implies that the negative dromotropic effects of OA-D and taVNS are mediated through an increase in cardiac parasympathetic tone. Whether these findings suggest their utility in controlling ventricular rates during persistent atrial fibrillation remains to be determined.

Post-exercise heart rate recovery and its speed are associated with cardiac autonomic responsiveness following orthostatic stress test in men

Objective: The present study sought to expand upon prior investigations of the relationship between the post-exercise heart rate recovery (HRR) and the cardiac autonomic responsiveness after orthostatic stress test. Method: HRR at the 1st, 3rd, and 5th min after maximal exercise test were correlated with relative change (Δ%) of time-domain (CV, pNN50, and rMSSD) and frequency-domain (TP, LF, HF, and LF/HF ratio) indices of heart rate variability (HRV) after active orthostatic test in 46 healthy men. Statistical analysis employed non-parametric tests with a p-value set at 5%. Results: HRR at 1st min correlated with Δ%pNN50 (rs:0.36 – p = .02). In the 3rd and 5th min, these measures correlated with Δ%pNN50, Δ%rMSSD, Δ%CV, Δ%TP, and Δ%HF indices (rs:0.33, 0.59 – p ≤ .05). Coefficient of HRR at the 1st min correlated with Δ%pNN50, Δ%rMSSD, and Δ%HF (rs:0.28, 0.45 – p ≤ .05). The 3rd and 5th min showed correlation with Δ%pNN50, Δ%rMSSD, Δ%HF, Δ%CV, and Δ%TP (rs:0.37, 0.64 – p ≤ .05). No correlation was found with indices combined sympathetic-parasympathetic modulation and HRR. After the sample was divided into high and low parasympathetic responsiveness subgroups after the orthostatic test, faster HRR was associated with the degree of parasympathetic responsiveness (reduction) following postural change (p ≤ .05). Conclusion: HRR throughout the 1st to 5th min is positively correlated with parasympathetic responsiveness and overall cardiac autonomic modulation of HRV after the orthostatic stress test, and faster HRR is positively correlated with the relative degree of parasympathetic responsiveness after the active postural change at rest in healthy men.

The effect of family history of hypertension and polymorphism of the ACE gene (rs1799752) on cardiac autonomic modulation in adolescents.

This study aims to analyze the behaviour of cardiac autonomic modulation in adolescents with a family history of hypertension along with polymorphism of the ACE gene (rs1799752). The study involved 141 adolescents, with a mean age of 14.89, divided into the following six groups: offspring of normotensive parents (ONP): DD, DI and II; and offspring of hypertensive parents (OHP): DD, DI and II. Blood pressure, body composition, family history of hypertension, sleep disorder, and sexual maturation were assessed for the groups' characterization. Afterwards, an electrocardiogram was performed, and oral mucosal cells were collected to analyze heart rate variability and genotypic research of angiotensin-converting enzyme. The main finding of this study was the decrease of vagal action in group OHP (genotype DD) relative to group ONP (genotype II): LF (%), 54.25±3.14 vs 39.33±3.80; HF (%), 45.74±3.14 vs 60.66±3.80; LF/HF, 1.48±0.23 vs 0.68±0.19. The results also showed changes in the variable diastolic blood pressure (DBP) in OHP (genotype DI) to ONP (genotype II) groups: 72.99±2.33 vs 63.27±1.72; and OHP (genotype DI) to ONP (genotype DD) groups. Adolescents with genotype DD and a family history of arterial hypertension present chances in cardiac autonomic modulation, the cardiac parasympathetic modulation is lower in these adolescents in comparison to participants of ONP + II group.

Dietary supplementation of a sulforaphane-enriched broccoli extract protects the heart from acute cardiac stress

• Sulforaphane-enriched broccoli extract (BE) prevents cardiac arrhythmogenesis. • BE supplementation shifts cardiac autonomic balance towards parasympathetic drive. • BE dietary supplementation have no detrimental cardiovascular effects. • Oral dietary supplementation with BE is safe and well tolerate. Cardiac arrythmias play a critical role in several pathological conditions. Importantly, increased arrhythmic risk is associated with systemic oxidative stress and activation of the autonomic nervous system. Thus, we hypothesized that dietary antioxidant supplementation may help in reducing cardiac stress-induced arrhythmias. Sulforaphane (SFN), an isothiocyanate present in Brassicaceaes, is recognized as a powerful health-promoting compound with known antioxidant properties. Then, we aimed to generate a broccoli extract (BE) enriched in SFN and determine whether oral BE supplementation induced cardio-protection during acute cardiac stress in rats. BE decreases cardiac sympathetic drive and increases parasympathetic cardiac modulation as evidenced by heart rate variability (HRV) shifts. In addition, isoproterenol-induced cardiac stress (a sympathomimetic agent) induced a ~ 4-fold increase in arrhythmia incidence and this effect was almost completely abolished by BE treatment. In conclusion, dietary supplementation with a BE regulates cardiac autonomic drive and protects the heart from acute cardiac stress.

Heart Rate Variability Responses to a Training Cycle in Female Youth Rowers.

Heart rate variability (HRV) is a reputable estimate of cardiac autonomic function used across multiple athletic populations to document the cardiac autonomic responses to sport demands. However, there is a knowledge gap of HRV responses in female youth rowers. Thus, the purpose of this study was to measure HRV weekly, over a 15-week training period, covering pre-season and up to competition in youth female rowers, in order to understand the physiological response to long-term training and discern how fluctuations in HRV may relate to performance in this population. Measures of heart rate and heart rate variability were recorded before training each Friday over the monitoring period in seven athletes. Analysis of heart rate variability focused on time domain indices, the standard deviation of all normal to normal R–R wave intervals, and the root mean square of successive differences as markers of cardiac parasympathetic modulation. Training load was quantified by multiplying the rating of perceived exertion of the weeks training and training duration. A decrease was identified in cardiac parasympathetic modulation as the season progressed (Effect Size (Cohen’s d) = −0.34 to −0.8, weeks 6 and 11–15), despite no significant relationship between training load and heart rate variability. Factors outside of training may further compound the reduction in heart rate variability, with further monitoring of external stressors (e.g., school) in adolescent athletes.

The effect of nitroglycerin on cardiac extrasystoles and heart rate variability in patients with ­stable angina pectoris class 1 and 2

Aim. To study the effect of nitroglycerin on the heart rate and its variability in patients with stable angina pectoris class 1 and 2.&#x0D; Methods. 85 men with stable angina pectoris class 1 and 2 pathologies were examined between 2007 and 2012 in the City Clinical Hospital No. 8 of Chelyabinsk (mean age 53.15.66 years). In addition to common methods, a rhythmocardiographic study was performed, which allows you to calculate heart rate variability. An electrocardiogram was recorded simultaneously with the rhythmocardiogram.&#x0D; Results. After sublingual nitroglycerin, the number of ventricular extrasystoles decreased in the background test and during Valsalva maneuver, increased in the Ashner's test and an exercise stress tests and did not change in the orthostatic test. An increase in supraventricular extrasystoles after nitroglycerin administration occurred in 10.6% of patients. Nitroglycerin administration resulted in a decrease in the inter-systolic intervals, an increased in the proportion of slow low-frequency waves statistically significant in the background and an exercise stress test. Spectral indicators of cardiac sympathetic modulation significantly increased in the Ashners test and decreased in the background test, while spectral indicators of cardiac parasympathetic modulation decreased in all samples except in exercise stress tests.&#x0D; Conclusion. Under the influence of nitroglycerin, supraventricular arrhythmias increased in all vegetative tests except for orthostatic, the number/severity of ventricular extrasystoles ambiguously changed: decreased in Valsalva manoeuvre the background test, did not change in orthostatic and increased in Aschner's and an exercise stress tests; after nitroglycerin, the proportions of sympathetic influence (in Ashner's test) and slow low-frequency waves in the spectrum of the vegetative modulation increased with a decrease in parasympathetic.

Poor sleep quality is associated with cardiac autonomic dysfunction in treated hypertensive men.

Hypertensives present cardiac autonomic dysfunction. Reduction in sleep quality increases blood pressure (BP) and favors hypertension development. Previous studies suggested a relationship between cardiovascular autonomic dysfunction and sleep quality, but it is unclear whether this association is present in hypertensives. Thus, this study evaluated the relationship between sleep quality and cardiac autonomic modulation in hypertensives. Forty-seven middle-aged hypertensive men under consistent anti-hypertensive treatment were assessed for sleep quality by the Pittsburgh Sleep Quality Index (PSQI-higher score means worse sleep quality). Additionally, their beat-by-beat BP and heart rate (HR) were recorded, and cardiac autonomic modulation was assessed by their variabilities. Mann-Whitney and t tests were used to compare different sleep quality groups: poor (PSQI>5, n=24) vs good (PSQI≤5, n=23), and Spearman's correlations to investigate associations between sleep quality and autonomic markers. Patients with poor sleep quality presented lower cardiac parasympathetic modulation (HR high-frequency band=26±13 vs 36±15nu, P=.03; HR total variance=951±1373 vs 1608±2272ms2 , P=.05) and cardiac baroreflex sensitivity (4.5±2.3 vs 7.1±3.7ms/mmHg, P=.01). Additionally, sleep quality score presented significant positive correlation with HR (r=+0.34, P=.02) and negative correlations with HR high-frequency band (r=-0.34, P=.03), HR total variance (r=-0.35, P=.02), and cardiac baroreflex sensitivity (r=-0.42, P=.01), showing that poor sleep quality is associated with higher HR and lower cardiac parasympathetic modulation and baroreflex sensitivity. In conclusion, in treated hypertensive men, poor sleep quality is associated with cardiac autonomic dysfunction.

A short set configuration attenuates the cardiac parasympathetic withdrawal after a whole-body resistance training session.

We aimed to analyse the acute effects of set configuration on cardiac parasympathetic modulation and blood pressure (BP) after a whole-body resistance training (RT) session. Thirty-two participants (23 men and 9 women) performed one control (CON) and two RT sessions differing in the set configuration but with the same intensity (15RM load), volume (200 repetitions) and total resting time (360s between sets for each exercise and 3min between exercises): a long set configuration (LSC: 4 sets of 10 repetitions with 2 resting minutes) and a short set configuration session (SSC, 8 sets of 5 repetitions with 51 resting seconds). Heart rate variability, baroreflex sensitivity, the low frequency of systolic blood pressure oscillations (LFSBP), BP and lactatemia were evaluated before and after the sessions and mechanical performance was evaluated during exercise. LSC induced greater reductions on cardiac parasympathetic modulation versus SSC after the session and the CON (p < 0.001 to p = 0.024). However, no LFSBP and BP significant changes were observed. Furthermore, LSC caused a higher lactate production (p < 0.001) and velocity loss (p ≤ 0.001) in comparison with SSC. These findings suggest that SSC attenuates the reduction of cardiac parasympathetic modulation after a whole-body RT, improving the mechanical performance and decreasing the glycolytic involvement, without alterations regarding vascular tone and BP.

Effect of a lactate-guided conditioning program on heart rate variability obtained using 24-Holter electrocardiography in Beagle dogs.

The dogs’ responses to training exercise are seldom monitored using physiological variables, and cardiac autonomic regulation (CAR) is a relevant determinant of endurance-training adaptation. There are studies in the literature establishing that regular exercise could interfere with CAR in dogs, measured by heart rate and vagal-derived indexes of heart-rate-variability (HRV). However, few studies were found using a prescribed training program based on the lactate threshold (LT) to determine HRV by a 24-h Holter analysis. The purpose of this study was to test whether an endurance-training program (ETP) guided individually by LT raises time-domain measures of HRV in healthy Beagle dogs. Twenty dogs were assigned to two groups: control (C) and trained (T). The dogs from group T underwent an incremental exercise test (IET) to determine their LT. Both LT and velocity corresponding to the LT (VLT) was determined by visual inspection. T group performed an eight-week endurance-training program consisting of treadmill runs set to 70–80% of the VLT. Next, dogs from the group T have submitted to IET again. The maximal velocities (Vmax) at which achieved by the trained dogs in both IETs were determined. The group S did not undergo IETs or ETP. HRV was determined by the 24-hour-Holter at rest, before and on the 2°, 4°, 6° and 8° training weeks. To examine the HR impact on HRV, standard HRV variables were normalized to prevailing HR. VLT and Vmax rose in group T, indicating an improvement of dogs’ aerobic and anaerobic capacity. The normalized standard HRV indexes were relatively attenuated since these variables had a reduction in the degree of correlation concerning an average HR. The ETP resulted in decreased resting heart rate and increased time-domain indices, highlighting the log-transformed square root of the mean sum of the squared differences between R–R intervals (Ln rMSSD). The lactate-guided endurance-training program could lead to better parasympathetic cardiac modulation in Beagle dogs.