Reduction In Sympathetic Activity Research Articles

The impact of exercise training on muscle sympathetic nerve activity: a systematic review and meta-analysis.

The purpose of this systematic review and meta-analysis was to examine the effects of exercise training on muscle sympathetic nerve activity (MSNA) in humans. Studies included exercise interventions [randomized controlled trials (RCTs), nonrandomized controlled trials (non-RCTs), or pre-to-post intervention] that reported on adults (≥18 yr) where MSNA was directly assessed using microneurography, and relevant outcomes were assessed [MSNA (total activity, burst frequency, burst incidence, amplitude), heart rate, blood pressure (systolic blood pressure, diastolic blood pressure, or mean blood pressure), and aerobic capacity (maximal or peak oxygen consumption)]. Forty intervention studies (n = 1,253 individuals) were included. RCTs of exercise compared with no exercise illustrated that those randomized to the exercise intervention had a significant reduction in MSNA burst frequency and incidence compared with controls. This reduction in burst frequency was not different between individuals with cardiovascular disease compared with those without. However, the reduction in burst incidence was greater in those with cardiovascular disease [9 RCTs studies, n = 234, mean difference (MD) -21.08 bursts/100 hbs; 95% confidence interval (CI) -16.51, -25.66; I2 = 63%] compared with those without (6 RCTs, n = 192, MD -10.92 bursts/100 hbs; 95% CI -4.12, -17.73; I2 = 76%). Meta-regression analyses demonstrated a dose-response relationship where individuals with higher burst frequency and incidence preintervention had a greater reduction in values post-intervention. These findings suggest that exercise training reduces muscle sympathetic nerve activity, which may be valuable for improving cardiovascular health.NEW & NOTEWORTHY This systematic review and meta-analysis suggests exercise training reduces muscle sympathetic nerve activity (MSNA), which may be valuable for improving cardiovascular health. The reduction in burst incidence was greater among individuals with cardiovascular disease when compared with those without; exercise training may be particularly beneficial for individuals with cardiovascular disease. Meta-regression analyses demonstrated a dose-response relationship, where individuals with higher sympathetic activity preintervention had greater reductions in sympathetic activity post-intervention.

Empagliflozin ameliorates ventricular arrhythmias by inhibiting sympathetic remodeling via nerve growth factor/tyrosine kinase receptor A pathway inhibition.

Sodium-glucose cotransporter 2 inhibitors (SGLT2is) can ameliorate arrhythmias; however, the mechanisms underlying their antiarrhythmic effect remain unclear. Therefore, we aimed to test the hypothesis that the SGLT2i empagliflozin (EMPA) ameliorates ventricular arrhythmias caused by myocardial infarction (MI) by inhibiting sympathetic remodeling. Male nondiabetic Sprague-Dawley rats were divided into Sham ( n = 10), MI ( n = 13), low-EMPA (10 mg/kg/day; n = 13), and high-EMPA (30 mg/kg/day; n = 13) groups. Except for the Sham group, MI models were established by ligation of the left anterior descending coronary artery. After 4 weeks, the hearts were removed. Echocardiography, electrical stimulation, hematoxylin-eosin staining and Masson's staining, Western blotting, immunohistochemistry (IHC), and ELISA were performed. Except for left ventricular posterior wall thickness (LVPWT), EMPA treatment significantly ameliorated the left ventricular anterior wall thickness (LVAWT), interventricular septum thickness (IVST), left ventricular end-diastolic diameter (LVEDD), left ventricular end-systolic diameter (LVESD), and left ventricular ejection fraction (LVEF) in MI rats; there was no statistical difference between the low-EMPA and high-EMPA groups. The threshold for ventricular fibrillation induction and myocardial fibrosis was significantly ameliorated in EMPA-treated rats, and there was no statistical difference between the high-EMPA and low-EMPA groups. EMPA decreased the expression of nerve growth factor (NGF), tyrosine kinase receptor A (TrkA), tyrosine hydroxylase, and growth-associated protein 43 (GAP43) in the left ventricular infarction margin myocardium of MI rats, especially in the high-EMPA group, with a statistically significant difference between the high-EMPA and low-EMPA groups. High-EMPA significantly decreased noradrenaline (NE) levels in the blood of MI rats; however, there was no statistical difference between the low-EMPA and MI groups. EMPA ameliorated the occurrence of ventricular arrhythmias in MI rats, which may be related to a reduction in sympathetic activity, inhibition of the NGF/TrkA pathway, inhibition of sympathetic remodeling, and improvement in cardiac function and cardiac structural remodeling.

Effect Of 12 Weeks Yoga Training And 12 Weeks Detraining on Heart Rate Variability on Subjects with Hypertension

Background: Healthy lifestyle modifications can prevent hypertension, an early predictor of cardiovascular disease. Yoga is an effective way to manage stress-induced disorders, such as hypertension. Objective: This study investigated the effects of yoga training on hypertensive individuals receiving routine treatment over a 12-week period, comparing and analyzing heart rate variability (HRV) parameters at and after the 12-week yoga training period (the 12th week) with hypertensives receiving routine treatment (the non-yoga group). Materials and methods: A total of 132 hypertensive subjects between the ages of 25 and 45 were randomly assigned to control or experimental groups (N=66), and 66 of these subjects were exposed to yoga therapy (N=66). Before, after, and during the study period, HRV parameters were obtained. Results: RM ANOVA was used to compare time domain and frequency domain parameters of HRV of the control group at pre, post, and detrain, and it was found that no significant difference existed between the groups. Test group mean values show a significant increase in time domain parameters compared with pre-training values after training. Test group post-training and detrain values significantly increased when compared to control group post-training and detrain values. Test group detrain values decreased significantly from post-training to test group detrain values. Conclusion: Yoga therapy increases the HRV values in essential hypertension at rest. An increase in vagal modulation, a reduction in sympathetic activity, and an increase in baroreflex sensitivity may be responsible for the harmonization of autonomic cardiovascular rhythms. The results of detraining from yoga did not result in an increase in HRV. As a result, the present study shows that regular yoga practice reduces hypertension, and deep rest keeps the body healthy.

Pharmacological Anti-Remodelling Effects of Disease-Modifying Drugs in Heart Failure with Reduced Ejection Fraction.

Cardiac remodelling is an adverse phenomenon linked to heart failure progression and an important contributor to heart failure severity. Cardiac remodelling could represent the real therapeutic goal in the treatment of patients with heart failure with reduced ejection fraction, being potentially reversed through different pharmacotherapies. Currently, there are well-established drugs such as angiotensin-converting enzyme inhibitors/angiotensin II receptor blockers and β-blockers with anti-remodelling effects; recently, angiotensin receptor neprilysin inhibitor effects on inhibiting cardiac remodelling (improving N-terminal pro-B-type natriuretic peptide levels, echocardiographic parameters of reverse cardiac remodelling and right ventricular function in patients with heart failure with reduced ejection fraction) were demonstrated. More recently, hemodynamic consequences of gliflozins, reduced cardiac hydrostatic pressure as a possible cause of ventricular remodelling and hypertrophy were proposed to explain potential anti-remodelling effects of gliflozins. Gliflozins exert their cardioprotective effects by attenuating myofibroblast activity and collagen-mediated remodelling. Another postulated mechanism is represented by the reduction in sympathetic activity, through the reduction in renal afferent nervous activity and the suppression of central reflex mechanisms. Benefits of gliflozins on left ventricular hypertrophy, dilation, and systolic and diastolic function were also described. In this review, we aimed to provide a wide overview on cardiac remodelling with a particular focus on possible anti-remodelling effects of angiotensin receptor neprilysin inhibitors and gliflozins.

Yoga in Arterial Stiffness: A Review

Non-communicable diseases; especially cardiovascular disease (CVD), is expected to be a leading cause of death worldwide through till 2030. Controlling this disease and its complications requires early recognition and surveillance, and as a result the accompanying health-care expenses can be kept under control. Looking back over the past, since 5 to 6 decades, studies have revealed an increase in CVD in India; ranging from 1.0% to 9.0% and 1.0% to 4.0-6.0% in both urban and rural areas, respectively. Arterial stiffness is defined as a decrease in an artery's ability to expand and contract in response to changes in pressure. Pulse Wave Velocity (PWV), which is the speed at which forward pressure is conveyed from the aorta via the vascular tree, is one of the simplest and oldest methods for determining it. Yoga, a mind-body practice that dates back to 5,000 Before Christ in India. It is regarded as a Vedic, ancient science, as a means of mental, bodily, and social existence, and has been increasingly used as a remedial measure. An comprehensive search of the electronic databases in PubMed/Medline, Web of Science, Scopus, Science Direct, Google Scholar, and Semantic Scholar for relevant publications was conducted using the keywords "Yoga and Arterial Stiffness." This current review, based on the scientific evidence, suggests yoga to pose and deliver health favourable benefits on PWV; particularly in adolescents as opposed to middle and geriatric populations. In addition, yoga is useful for young people with obesity, hypertension, and for those who lead a sedentary lifestyle. Yoga's beneficial effects on cardiovascular disease are related to a reduction in sympathetic activity as well as concomitant mental and physical relaxation.

The effects of slow deep breathing on microvascular and autonomic function and symptoms in adults with irritable bowel syndrome: A pilot study.

Irritable bowel syndrome (IBS) is linked to disruptions in sympathovagal balance, which could impair vascular homeostasis and cause IBS symptoms. Studies have shown reductions in sympathetic activity following a single slow, deep breathing (SDB) bout in healthy adults; however, no studies have investigated its chronic effects in IBS.The purpose of this study was to evaluate the feasibility and impact of a SDB intervention on microvascular and autonomic function and symptoms in adults with IBS. Fourteen participants (ages 18-65years) with IBS were randomly assigned to 4-week SDB or control conditions. The SDB group completed a 20-min video 5 times weekly while the control group maintained their normal activities. Microvascular endothelial function was measured using laser Doppler in response to thermal provocation and expressed as cutaneous vascular conductance at 39°C relative to a maximum response at 43.5°C (%CVCmax ). Heart rate variability (HRV) and post-exercise heart rate recovery (HRR) were employed as surrogate measures of autonomic function. IBS symptoms were assessed using the IBS-Severity Scale (IBS-SS). Thirteenparticipants (6 controls and 7 SDB) completed the study. Age (p = 0.541) and body mass index (p = 0.157) were similar between groups. In the SDB group, %CVCmax increased from 45% to 59% (p < 0.00001) after the 4-week intervention. HRV, HRR, and IBS-SS scores were unaltered. and Inferences. These results demonstrate the feasibility of a SDB intervention in adults with IBS and suggest improvements in microvascular function in the absence of changes in symptoms or autonomic function in this population.

Maybe angiotensin II is getting on our nerves, and the role of exercise.

Maybe angiotensin II is getting on our nerves, and the role of exercise.

Changes in the autonomic and respiratory patterns of mice submitted to short‐term sustained hypoxia

Short-term sustained hypoxia (SH) in rats induces changes in sympathetic-respiratory coupling and sympathetic overactivity, which seems to be linked to hypertension. However, there is no previous experimental data about the effects of SH on the autonomic and respiratory pattern in mice. In the present study we tested the hypothesis that mice submitted to SH present autonomic and respiratory changes similarly to rats. To reach this goal we evaluated the effects of 24-hour SH exposure on cardiovascular, respiratory and autonomic parameters in baseline conditions and upon chemoreflex activation.C57BL/6J mice (7-8 weeks old, ~25g) were deeply anesthetized for femoral artery and jugular vein catheterization. Four days later, they were submitted to SH (24h, FiO2 0.1) or normoxia. At the end of SH protocol, arterial pressure, heart rate and ventilation were recorded in vivo. Peripheral chemoreflex was activated via KCN injection (0.16 mg/Kg, i.v.). In another experimental group, we performed in situ recordings of phrenic (PN), abdominal, (AbN), cervical vagus (cVN) and thoracic sympathetic (tSN) nerves activities of SH mice using the working heart-brainstem preparation. All experimental protocols were approved by the Institutional Ethics Committee (#140/2019 and #163/2019). In the in vivo approach, although SH mice (n=13) presented a significant decrease in baseline HR (510 ± 22 vs 633 ± 16 beats min-1; P = 0.002) compared with the controls (n=17), no differences were observed in mean arterial pressure levels (109 ± 2 vs 106 ± 2 mmHg; P=0.443). SH mice (n=14) also showed significantly increased respiratory frequency [(fR) 277 ± 8 vs 203 ± 6 breaths.min-1; P <0.0001], tidal volume [(VT) 14 ± 1 vs. 12 ± 1mL.Kg1; P = 0.0019)], and ventilation [(VE) 3927 ± 164 vs 2390 ± 104 mL.Kg-1.min-1; P < 0.0001)] compared with controls (n=17). The magnitudes of bradycardic responses to chemoreflex activation were greater in SH mice (n=8) than in controls (n=11; -329 ± 36 vs -210 ± 30 beats min-1, P=0.02). In the in situ approach, baseline PN discharge (PND) frequency was significantly reduced in SH mice (n=11) in relation to controls (n=26) (0.69 ± 0.06 vs 1.13 ± 0.10 Hz, P=0.0154). The incidence of Late-E bursts in AbN activity in SH mice (n=10) was significantly increased in relation to controls (n=20) (83.3 ± 7.7 vs 24.3 ± 8.0%, P<0.0001). The duration of expiration in SH mice (n=11) was longer than in controls (n=22) (1.13 ± 0.16 vs 0.67 ± 0.07s, P= 0.0002) due to an increase in the duration of post-inspiration (0.78 ± 0.12 vs 0.35 ± 0.04s, P= 0.0032). tSNA in the SH group (n=10) was significantly reduced during late-expiration (E2) compared with the control group (n=16) (19.0 ± 4.3 vs 39.7 ± 4.2%, P= 0.0203). The data are showing that 24-h SH protocol in mice produces: a) an increase in parasympathetic tone to the heart, which seems to be related to changes in their breathing pattern; and b) prolonged expiration and active expiration associated with a reduction in sympathetic activity during E2. This autonomic imbalance favoring the parasympathetic componente may explain why mice, different of rats, do not develop hypertension after SH.

The Influence of OSA Treatment on Muscle Sympathetic Nerve Activity: A Systematic Review and Meta‐Analysis

Introduction Obstructive Sleep Apnea (OSA) is commonly treated with Continuous Positive Airway Pressure (CPAP) therapy, which reduces the number of airway obstructions while sleeping. Recently, diet and exercise interventions have been explored as a possible alternative treatment for OSA. Microneurography is a technique used to measure efferent postganglionic muscle sympathetic nerve activity (MSNA) via direct interneural recordings. CPAP therapy and diet and exercise interventions reduce disease severity, but their influence on MSNA is less clear. Purpose The present meta-analysis aims to examine the influence of type and length of treatment for OSA on MSNA. Methods A structured search of electronic databases was performed by a research librarian. Two reviewers independently assessed the titles of abstracts of articles; studies meeting eligibility criteria were selected for full-text review. Two reviewers independently extracted the data and assessed the quality of the studies using Joanna Briggs Institute Critical Appraisal of Evidence Effectiveness tool. Review Manager v5.3 was used to conduct the statistical analyses, and significance was set at P < 0.05. Results Evidence from 10 interventions (n=186) shows CPAP therapy significantly decreases MSNA burst frequency in individuals with OSA (Mean Difference, +12.6 bursts/min; 95% CI, 10.1-15.2 bursts/min; I2 = 39%). The same is shown for burst incidence in 6 studies (n=113) (MD, +21.5 bursts/100 hbs; 95% CI, 18.6-24.5 bursts/100 hbs; I2 = 0%). Reductions in MSNA (burst frequency and burst incidence) were seen for all time points of CPAP therapy: 1, 6, and 12 months. Data from 5 studies shows a significant decrease in burst frequency following diet and exercise intervention (n=68) (MD, +9.86 bursts/min; 95% CI, 5.37-14.35 bursts/min; I2 = 75%). A meta-regression analysis identified a relationship between CPAP therapy length and burst frequency (R2 = 0.329, p = 0.003). Conclusion CPAP therapy decreases MSNA in individuals with OSA, and a relationship exists between length of treatment and sympathetic activity. However, a significant reduction in sympathetic activity was also seen as a result of diet and exercise interventions; although, only burst frequency data was reported. More data is needed to determine optimal treatment type and length.

A235 EFFECTS OF SACRAL PHOTOBIOMODULATION ON THE AUTONOMIC NERVOUS SYSTEM IN PATIENTS WITH COLONIC DYSMOTILITY

BackgroundPatients with chronic refractory constipation show colon dysmotility, including impaired coordination of descending colon-sigmoid colon-rectum-anal sphincter motor functions; this may involve slow colonic transit and colo-anal dyssynergia. Impaired neuronal communication between the sacral defecation center and the distal colon may be causative. In addition, patients with lumbosacral neurological conditions (with lower back pain) may not be able to evoke an effective defecation reflex.AimsTo evaluate if a single therapeutic session of sacral low-level laser therapy (LLLT) would affect the autonomic activity in patients with chronic constipation as revealed by changes in heart rate variability, and to report a multi-session treatment case study.MethodsIn 41 patients with chronic constipation, one session of LLLT was executed, using red LED light at a wavelength of 660 nm for 10 minutes and infrared LED light at wavelength of 840 nm for 10 minutes followed by infrared laser light with wavelength of 825 nm for 20 minutes, while measuring the electrocardiogram. One patient received this treatment 8x over 3 weeks.ResultsThe lumbar-sacral light array treatment showed a significant decrease in parasympathetic activity (RSA & RMSSD) whereas pure sacral laser light treatment showed a significant increase in parasympathetic activity (RSA & RMSSD) as well as a reduction in sympathetic activity (Baevsky’s stress index: SI) (table). A single session of LLLT was also executed during HRCM in 8 patients with some but not all showing evoked colonic motility. Before COVID-19 shutdown, one patient was successfully treated. With a history of chronic constipation without ability to have spontaneous bowel movements for 5 years, symptoms improved from 13 to 8 (on a 20 scale) and quality of life improved from 1.5 to 2.5 (on a 0–4 scale) after 8 sessions. Sympathetic reactivity from supine to standing markedly reduced, from highly elevated measured as the Baevsky index from 55 to 153 s-2 it improved from 42 to 75 s-2 upon standing after 4 sessions. Parasympathetic reactivity did not change.ConclusionsA single session of sacral LLLT markedly affected autonomic nervous activity reflected in changes in HRV. The LLLT is likely affecting the sacral defecation center through peripheral nerves entering and exiting the spinal cord including the dorsal root ganglia. LLLT treatment of a patient with inability to generate spontaneous bowel movements, resulted in ability to have complete evacuations associated with marked reduction in sympathetic reactivity during the supine-standing test, after 4 LLLT sessions. Funding AgenciesCIHRFarncombe Family Digestive Health Research Institute

Caloric restriction reduces sympathetic activity similar to beta-blockers but conveys additional mitochondrio-protective effects in aged myocardium

Increased activation of sympathetic nervous system contributes to congestive heart failure (CHF) progression, and inhibition of sympathetic overactivation by beta-blockers is successful in CHF patients. Similarly, caloric restriction (CR) reduces sympathetic activity but mediates additional effects. Here, we compared the cardiac effects of CR (− 40% kcal, 3 months) with beta-blocker therapy (BB), diuretic medication (DF) or control diet in 18-months-old Wistar rats. We continuously recorded blood pressure, heart rate, body temperature and activity with telemetric devices and analysed cardiac function, activated signalling cascades and markers of apoptosis and mitochondrial biogenesis. During our study, left ventricular (LV) systolic function improved markedly (CR), mildly (BB) or even deteriorated (DF; control). Diastolic function was preserved by CR and BB but impaired by DF. CR reduced blood pressure identical to DF and BB and heart rate identical to BB. Plasma noradrenaline was decreased by CR and BB but increased by DF. Only CR reduced LV oxidative damage and apoptosis, induced AMPK and Akt phosphorylation and increased mitochondrial biogenesis. Thus, additive to the reduction of sympathetic activity, CR achieves protective effects on mitochondria and improves LV function and ROS damage in aged hearts. CR mechanisms may provide additional therapeutic targets compared to traditional CHF therapy.

Long-Term Evaluation of the Vagal Denervation by Cardioneuroablation Using Holter and Heart Rate Variability.

Several disorders present reflex or persistent increase in vagal tone that may cause refractory symptoms even in a normal heart patient. Cardioneuroablation, the vagal denervation by radiofrequency ablation of the neuromyocardial interface, was developed to treat these conditions without pacemaker implantation. A theoretical limitation could be the reinnervation, that naturally grows in the first year, that could recover the vagal hyperactivity. This study aims to verify the vagal denervation degree in the chronic phase after cardioneuroablation. Additionally, it intends to investigate the arrhythmias behavior after cardioneuroablation. Prospective longitudinal study with intrapatient comparison of 83 very symptomatic cases without significant cardiopathy, submitted to cardioneuroablation, 49 (59%) male, 47.3±17 years old, having vagal paroxysmal atrial fibrillation 58 (70%) or neurocardiogenic syncope 25 (30%), New York Heart Association class<II and absence of significant comorbidities. Cardioneuroablation was performed in both atria by interatrial septum puncture, with irrigated conventional catheter and electroanatomic reconstruction. Ablation targeted the neuromiocardial interface by fragmentation mapping (AF-Nests) using the velocity fractionation software, conventional recording, and anatomic localization of the ganglionated plexi. Heart rate variability (time and frequency domain) and arrhythmias were compared by 24h-Holter, before, and 1 year and 2 years after cardioneuroablation. In a 40 month follow-up, 80% of patients were asymptomatic. Time- and frequency-domain heart rate variability demonstrated significant decrease in all autonomic parameters, showing an important parasympathetic and sympathetic activity reduction at 2-year post-cardioneuroablation (P<0.001). There was no difference in heart rate variability between the 1-year and 2-year post-cardioneuroablation (P>0.05) suggesting that the reinnervation has halted. There was also an important reduction in all bradyarrhythmias and tachyarrhythmias pre-cardioneuroablation versus post-cardioneuroablation (P<0.01). There is an important and significant vagal and sympathetic denervation after 2 years of cardioneuroablation with a significant reduction in bradyarrhythmia and tachyarrhythmia in the whole group. There were no complications.

Acute effects of contrast bath on sympathetic skin response in patients with poststroke complex regional pain syndrome

Purpose Complex regional pain syndrome (CRPS) is one of the common complications in stroke patients. Sympathetic dysfunction is usually considered underlying pathology. The evidence for contrast bath (CB) used in the treatment of CRPS is limited. The aim of the study is to investigate the possible effects of CB on the sympathetic activity in poststroke CRPS. Materials and methods Stroke patients with CRPS (CRPS group) and without CRPS (control group) were included in the study. Age, gender, duration of stroke, aetiology, plegic side, dominant hand, spasticity level, Brunnstrom stages, and comorbidities were recorded. CB was performed for one session to the plegic side of the CRPS and control groups. Sympathetic skin responses (SSR) was recorded from the plegic and healthy hands of participants at pre-CB and post-CB. Results Each group consisted of 20 participants. No significant difference was detected in stroke duration, aetiology, and Brunnstrom stages between groups. Elbow spasticity level was significantly higher in CRPS group (p = .034). SSR amplitudes of plegic hands were significantly decreased after CB in CRPS and control groups (p = .0002, p = .013 respectively). Also, CB reduced the SSR amplitude of healty side in CRPS group (p = .003). There was no statistically significant change in SSR latency or percentage changes of SSR amplitude and latency after CB in both groups. Conclusion CB leads to a significant reduction in sympathetic activity of plegic side of stroke patients. Also, CB to the plegic side has an inhibitory effect on sympathetic activity of healty side in poststroke CRPS. ClinicalTrials.gov ID: NCT04198532

Cardiac resynchronization therapy modulates peripheral sympathetic activity

Heightened sympathetic nerve activity has been associated with poorer prognosis in patients with reduced left ventricular systolic function (ie, heart failure with reduced ejection fraction [HFrEF]). The purpose of this study was to investigate the effects of cardiac resynchronization therapy (CRT) on sympathetic nerve activity, measured by average skin sympathetic nerve activity (aSKNA). This prospective study enrolled 36 patients with HFrEF who received CRT. Ten patients who received an implantable cardioverter-defibrillator for primary prevention served as controls. Patient clinical data, echocardiographic variables, and aSKNA at baseline and 3-month follow-up were collected. CRT patients who exhibited wider QRS duration had higher aSKNA (1.52 ± 0.65 μV vs 0.97 ± 0.49 μV; P = .027) compared to the control group at baseline. In the CRT group, patients with QRS duration ≥150 ms had higher aSKNA than those with QRS duration <150 ms (1.67 ± 0.63 μV vs 1.19 ± 0.51 μV; P =.039). After CRT, left ventricular ejection fraction (LVEF) improved from 29.6% to 35.4% (P = .001). aSKNA decreased significantly (1.52 ± 0.65 μV vs 1.31 ± 0.63 μV; P = .018). Seventeen of the 36 CRT patients were CRT responders, with LVEF improvement ≥5% at 3-month follow-up. aSKNA significantly decreased from 1.47 to 1.15 μV (P = .003) in CRT responders but was unchanged in nonresponders (1.44 ± 0.69 to 1.37 ± 0.70; P = .61). After CRT, a significant reduction in aSKNA was associated with improvement in LVEF (r = 0.638; P = .001). CRT reduces elevated sympathetic activity in HFrEF patients, accompanied by improvement in systolic function at short-term follow-up. The reduction of sympathetic activity is mainly seen in CRT responders.

Feasibility and effectiveness of thoracic spine mobilization on sympathetic/parasympathetic balance in a healthy population - a randomized controlled double-blinded pilot study

BackgroundPhysiotherapists often use thoracic spine mobilization (TSM) to reduce pain in patients with back disorders via a reduction of sympathetic activity. There is a “trade-off” in the activity of the sympathetic and parasympathetic nervous system activity. A sympathetic/parasympathetic balance (SPB) is needed to guarantee body homeostasis. However, body homeostasis is seldom considered as an aim of the treatment from the perspective of most physiotherapists. Strong empirical evidence for the effects of TSM on the SPB is still lacking.Some studies showed that spinal manipulation may yield beneficial effects on SPB. Therefore, it could be hypothesized that TSM is feasible and could influence SPB reactions. The primary aim was to describe the participants’ adherence to the intervention and to the measurement protocol, to identify unexpected adverse events (UAE) after TSM, to evaluate the best method to measure SPB parameters (heart rate variability (HRV), blood pressure (BP), heart rate (HR), skin perfusion and erythema) and to estimate the investigation procedure. The secondary aim was to assess the effects of TSM on SPB parameters in a small sample of healthy participants.MethodsThis crossover pilot study investigated TSM using posterior-anterior mobilization (PAM) and anterior-posterior mobilization (APM) on segments T6 to T12 in twelve healthy participants during two consecutive days. To evaluate feasibility, the following outcomes were assessed: adherence, UAE, data collection and data analysis. To evaluate the effect of TSM on SPB, HRV, BP, HR, skin perfusion and erythema were measured.ResultsThe adherence was 100%. No UAE were reported. PAM showed larger effect sizes compared to APM in many secondary variables.ConclusionsAlthough 100% maximal adherence was reached and no UAE were observed, data recording in future studies should be done during a second time interval while the data transfer from device to the computer software should occur immediately after completion of each participant’s measurement. The results of this pilot study suggest that PAM can reduce HRV HF and HRV ratio LF/HF and increase HR.Trial registrationClinicalTrail.gov (NCT02832141).

Centrally acting adrenomedullin in the long-term potentiation of sympathetic vasoconstrictor activity induced by intermittent hypoxia in rats.

What is the central question of this study? Adrenomedullin in the rostral ventrolateral medulla (RVLM) increases sympathetic activity; given that adrenomedullin is released during hypoxia, what are the effects of its agonism and antagonism in the RVLM after chronic intermitent hypoxia (CIH) exposure? What is the main finding and its importance? CIH exposure sensitizes adrenomedullin-dependent mechanisms in the RVLM, supporting its role as a sympathoexcitatory neuromodulator. A novel mechanism was identified for the generation of sympathetic overdrive and hypertension associated with hypoxia, providing potential guidance on new therapeutic approaches for controlling sympathetic hyperactivity in diseases such as sleep apnoea and neurogenic hypertension. Adrenomedullin in the rostral ventrolateral medulla (RVLM) has been shown to increase sympathetic activity whereas the antagonism of its receptors inhibited this autonomic activity lowering blood pressure in conditions of hypertension. Given that hypoxia is a stimulant for releasing adrenomedullin, we hypothesized that the presence of this peptide in the RVLM associated with chronic intermittent hypoxia (CIH) would cause sympathetic overdrive. Juvenile male rats (50-55g) submitted to CIH (6% oxygen every 9min, 8hday-1 for 10 days) were studied in an arterially perfused in situ preparation where sympathetic activity was recorded. In control rats (n=6), exogenously applied adrenomedullin in the RVLM raised baseline sympathetic activity when combined with episodic activation of peripheral chemoreceptors (KCN 0.05%, 5 times every 5min). This sympathoexcitatory response was markedly amplified in rats previously exposed to CIH (n=6). The antagonism of adrenomedullin receptors in the RVLM caused a significant reduction in sympathetic activity in the CIH group (n=7), but not in controls (n=8). The transient reflex-evoked sympathoexcitatory response to peripheral chemoreceptor stimulation was not affected by either adrenomedullin or adrenomedullin receptor antagonism in the RVLM of control and CIH rats. Our findings indicate that CIH sensitizes the sympathoexcitatory networks within the RVLM to adrenomedullin, supporting its role as an excitatory neuromodulator when intermittent hypoxia is present. These data reveal novel state-dependent mechanistic insights into the generation of sympathetic overdrive and provide potential guidance on possible unique approaches for controlling sympathetic discharge in diseases such as sleep apnoea and neurogenic hypertension.

CLO19-048: Effects of Acupuncture on Cutaneous Microcirculation by Infrared Thermography in Cancer Patients

Objectives: The objective of this case series was to describe the experience of the use of infrared thermography to evaluate the effects of acupuncture on cutaneous microcirculation of cancer patients. Methods: The method is a cross-sectional survey, descriptive of a series of cases of a sample for convenience. The data collection procedure had a total duration of 30 minutes, being captured images at different times during the procedure: before the needling (T0); first minute (T0a); second minute (T0b); third minute (T0c); forth minute (T0d); fifth minute (T1); tenth minute (T2); and after 15 minutes (T3) of needling. Body temperature was evaluated by infrared camera, brand FLIR, series A. The FLIR Tools software version 5.9 was used to perform the calculation of the temperatures with subsequent descriptive analysis of the data. The choice of the PC6, BP10, R6, and B62 bilateral acupoints was because of the anatomic location and energetic actions on the blood circulation. The PC6 acupoint (Neiguan) is located in the meridian of the pericardium, lies on the anterior face of the forearm approximately 2 cm (0.79 inches) below the wrist and between the flexor tendons. This acupoint is responsible for sending signals to the central nervous system, which results in the reduction of sympathetic activity. Results: According to the ANOVA test, considering P value less than or equal to .05, there were statistically significant differences in the time intervals evaluated, with P value of .004. There was a 1.7% increase in the mean temperature of the interval between T3 and T0 in the sample, that is, between the time before and after 15 minutes of needling. Conclusion: This series of cases showed the viability of the method of evaluating the effects of acupuncture on cutaneous microcirculation by infrared thermography in the rehabilitation of cancer patients. The results showed statistically significant differences in the time intervals evaluated, demonstrating the importance of the evaluation at 15 minutes after needling to accurately verify the variation of cutaneous temperature by thermography in the acupoints. It was noticed that the increase of the cutaneous temperature occurred, mainly, in the first 5 minutes after the needling, with a reduction after this time interval.

Effect of Central Sympathoinhibition With Moxonidine on Sympathetic Nervous Activity in Polycystic Ovary Syndrome-A Randomized Controlled Trial.

Sympathetic nervous system (SNS) activity is increased in polycystic ovary syndrome (PCOS). Moxonidine is a centrally acting sympatholytic drug with known beneficial effects on hypertension, insulin sensitivity, dyslipidemia and inflammation. In this double-blind placebo controlled randomized clinical trial we examined the effect of moxonidine on modulating sympathetic activity and downstream metabolic abnormalities in 48 pre-menopausal women with PCOS (Rotterdam diagnostic criteria), recruited from the community (January 2013–August 2015). Participants received moxonidine (0.2 mg daily initially, up titrated to 0.4 mg daily in 2 weeks) (n = 23) or placebo (n = 25) for 12 weeks. Multiunit muscle sympathetic activity (by microneurography) and plasma noradrenaline levels were measured (primary outcomes). Fasting lipids, insulin resistance, serum androgens, and inflammatory markers were measured as secondary outcomes. Forty three women completed the trial (19 moxonidine, 24 placebo). Mean change in burst frequency (−3 ± 7 vs. −3 ± 8 per minute) and burst incidence (−3 ± 10 vs. −4 ± 12 per 100 heartbeat) did not differ significantly between moxonidine and placebo groups. Women on moxonidine had a significant reduction in hs-CRP compared to placebo group (−0.92 ± 2.3 vs. −0.04 ± 1.5) which did not persist post Bonferroni correction. There was a significant association between markers of insulin resistance at baseline and reduction in sympathetic activity with moxonidine. Moxonidine was not effective in modulating sympathetic activity in PCOS. Anti-inflammatory effects of moxonidine and a relationship between insulin resistance and sympathetic response to moxonidine are suggested which need to be further explored.Clinical Trial Registration Number: (NCT01504321)

Autonomic cardiac regulation after general anesthesia in children.

General anesthesia dramatically decreases the activity of the autonomic nervous system. Most of the hypnotic agents used to induce anesthesia inhibit sympathetic cardiovascular regulation and baroreflex control in a dose-dependent manner, lowering cardiac adaptability during the operation. The consequence of this effect in children during and after surgery has never been studied to date. The aim of this study was to follow the variations in autonomic cardiac indices in children younger than 8years old after general anesthesia (6-24hours) in programmed surgery. A prospective descriptive monocentric study of 44 children under 8years old who underwent scheduled surgery at our hospital center (Saint-Étienne University Hospital, France) was performed between June 1, 2016 and November 1, 2016. Heart rate variability was monitored for 24hours using Holter-ECG devices and the resulting data were interpreted using linear and nonlinear analyses. Compared to baseline thresholds before surgery, all heart rate variability indices decreased dramatically during general anesthesia. After awakening, a slight reduction in sympathetic activity persisted 6hours after surgery, but all measurements of sympathetic and parasympathetic activity had returned to baseline thresholds 12hours after the operation. Twenty-four hours after surgery, some parameters had increased above the corresponding baseline levels. Autonomic nervous function normalizes rapidly (within 12hours) in prepubertal children. This study indicates that general anesthesia does not seem to increase the long-term risk of autonomic dysfunction in these patients.

Effects of Transcutaneous Electrical Nerve Stimulation in Autonomic Nervous System of Hypertensive Patients: A Randomized Controlled Trial.

Patients with hypertension have altered autonomic nervous system function, which are increased sympathetic activity. Transcutaneous Electrical Nerve Stimulation (TENS) is a useful modality for pain control and has also been shown to be effective in the reduction of sympathetic activity in healthy subjects and individuals with cardiovascular diseases. The aim of this study was to verify the effects of transcutaneous electrical nerve stimulation by the evaluation of heart rate variability (HRV) in patients with essential hypertension. Twenty-eight patients received an application of low-frequency TENS(4 Hz) n=8, highfrequency TENS (100 Hz) n=10 or placebo TENS n=10 in paravertebral ganglionar region during thirty minutes. After 4 Hz TENS, there was a decrease in the low-frequency (LFn.u.) component (57.71±9.46 vs 45.58±13.51, p<0.026) and an increase in the high-frequency (HFn.u.) component (33.03±13.83 vs 45.83±20.19, p <0.05) of HRV. After 100 Hz TENS and placebo, there were no changes in the LF and HF components. No significant differences were found in systolic blood pressure with low-frequency TENS (129.37± 15.48 vs 126.69 ± 15.21, p<0.490). There was an increase, although not significant, with high-frequency TENS (131.00 ± 15.97 vs 138.75 ± 25.79, p<0.121) and placebo (133.80 ± 29.85 vs 134.80 ± 29.72, p< 0.800). No differences were found in the diastolic blood pressure with low-frequency TENS and placebo, but there was a significant increase in high-frequency TENS (81.00 ± 11.78 vs 85.65 ± 13.68, p< 0.018). Low-frequency TENS decreases sympathetic nervous system activity and increases parasympathetic nervous system activity and high-frequency TENS increases diastolic blood pressure, when applied on the paravertebral ganglionar region in the hypertensive patients.