Skin Sympathetic Nerve Activity Research Articles

Higher skin sympathetic nerve activity as a potential predictor of overactive bladder in females refractory to oral monotherapy.

This study investigates predictors of unsatisfactory outcomes in female overactive bladder (OAB) patients treated with oral monotherapy by analyzing skin sympathetic nerve activity (SKNA) using a novel "neuECG" method. The study included 55 newly diagnosed female patients with idiopathic OAB, autonomic function was evaluated using neuECG before treatment initiation, and validated OAB questionnaires and urodynamic studies were administered. Initial monotherapy was administered for the first 4 weeks, with non-responders defined as patients not achieving satisfactory symptom relief and requiring further treatment. Responders (n = 32) and non-responders (n = 23) had no significant differences in baseline characteristics or urodynamic parameters; however, non-responders exhibited significantly higher baseline average SKNA (aSKNA) (1.36 ± 0.49 vs. 0.97 ± 0.29 μV, p = 0.001), higher recovery aSKNA (1.28 ± 0.46 vs. 0.97 ± 0.35 μV, p = 0.007), and a lower stress/baseline ratio of aSKNA (1.05 ± 0.42 vs. 1.26 ± 0.26, p = 0.029). Baseline aSKNA had the highest predictive value for monotherapy refractoriness in OAB (AUROC = 0.759, p = 0.001), with an optimal cut-off point of >1.032 μV. These findings suggest that elevated pre-treatment aSKNA can predict resistance to oral monotherapy in OAB, warranting close monitoring and proactive treatment strategies for patients with high aSKNA.

Autonomic modulation by SGLT2i or DPP4i in patients with diabetes favors cardiovascular outcomes as revealed by skin sympathetic nerve activity.

Sodium-glucose cotransporter 2 inhibitors (SGLT2i) and dipeptidyl peptidase-4 inhibitors (DPP4i) are important second-line treatments for patients with type 2 diabetes mellitus (T2DM). Patients taking SGLT2i have favorable cardiovascular outcomes via various mechanisms, including autonomic nervous system (ANS) modulation. This study aimed to use neuro-electrocardiography (neuECG) to test the effects of SGLT2i or DPP4i on the ANS. Patients with T2DM, who did not reach target hemoglobin (Hb)A1C levels despite metformin treatment, were enrolled. SGLT2i or DPP4i were prescribed randomly unless a compelling indication was present. NeuECG and heart rate were recorded for 10min before and after a 3-month treatment. The patients were treated according to standard practice and the obtained data for skin sympathetic nerve activity (SKNA) and ANS entropy were analyzed offline. We enrolled 96 patients, of which 49 received SGLT2i and 47 received DPP4i. The baseline parameters were similar between the groups. No adverse event was seen during the study period. In the burst analysis of SKNA at baseline, all parameters were similar. After the 3-month treatment, the firing frequency was higher in SGLT2i group (0.104 ± 0.045 vs 0.083 ± 0.033 burst/min, p < 0.05), with increased long firing duration (7.34 ± 3.66 vs 5.906 ± 2.921, p < 0.05) in 3-s aSKNA scale; the other parameters did not show any significant change. By symbolic entropy, the most complex patterns (Rank 3) were found to be significantly higher in SGLT2i-treated patients than in DDP4i-treated group (0.084 ± 0.028 vs 0.07 ± 0.024, p = 0.01) and the direction of change in Rank 3, after SGLT2i treatment, was opposite to that observed in the DDP4i group (0.012 ± 0.036 vs. -0.005 ± 0.037, p = 0.024). Our findings demonstrated the favorable autonomic modulation by SGLTi and the detrimental effects of DPP4i on ANS. We demonstrated the autonomic modulation by SGLTi and DPP4i using SKNA in patients with DM, which might provide insights into the favorable outcomes of SGLT2i. Furthermore, we refined the analytical methods of neuECG, which uses SKNA to evaluate autonomic function.

The effects of electrical stimulation of ventromedial prefrontal cortex on skin sympathetic nerve activity.

Skin sympathetic nerve activity (SSNA) is primarily involved in thermoregulation and emotional expression; however, the brain regions involved in the generation of SSNA are not completely understood. In recent years, our laboratory has shown that blood-oxygen-level-dependent signal intensity in the ventromedial prefrontal cortex (vmPFC) and dorsolateral prefrontal cortex (dlPFC) are positively correlated with bursts of SSNA during emotional arousal and increases in signal intensity in the vmPFC occurring with increases in spontaneous bursts of SSNA even in the resting state. We have recently shown that unilateral transcranial alternating current stimulation (tACS) of the dlPFC causes modulation of SSNA but given that the current was delivered between electrodes over the dlPFC and the nasion, it is possible that the effects were due to current acting on the vmPFC. To test this, we delivered tACS to target the right vmPFC or dlPFC and nasion and recorded SSNA in 11 healthy participants by inserting a tungsten microelectrode into the right common peroneal nerve. The similarity in SSNA modulation between ipsilateral vmPFC and dlPFC suggests that the ipsilateral vmPFC, rather than the dlPFC, may be causing the modulation of SSNA during ipsilateral dlPFC stimulation.

Skin sympathetic nerve activity in symptomatic and asymptomatic paroxysmal atrial fibrillation

BackgroundThe causes of symptoms in patients with paroxysmal atrial fibrillation (AF) remains unclear. ObjectiveThe purpose of this study was to correlate the magnitudes of skin sympathetic nerve activity (SKNA) with symptoms in patients with AF. MethodsWe prospectively enrolled patients with symptomatic paroxysmal AF for ambulatory electrocardiography and SKNA recording. Heart rhythms at the time of symptoms were categorized as AF or normal sinus rhythm (NSR). Maximal and average skin sympathetic nerve activity (aSKNA) and heart rate (HR) were compared between symptomatic and asymptomatic AF and NSR episodes using mixed effects models to account for within-patient correlations. ResultsAmong the 31 enrolled patients, 16 (52%) had at least 1 episode of AF, and 24 (77%) endorsed symptoms during the monitoring period. Compared with asymptomatic AF episodes, symptomatic AF episodes had higher maximal aSKNA (1.260 [interquartile range (IQR) 1.114–1.723] μV vs 1.108 [IQR 0.974–1.312] μV; P <0.001) and higher maximal HR (152 ± 24 bpm vs 132 ± 19 bpm; P <.001). Symptomatic NSR episodes were associated with higher maximal aSKNA (1.612 [IQR 1.287–2.027] μV vs 1.332 [IQR 1.033–1.668] μV; P = .001) and higher maximal HR (152 ± 24 bpm vs 105 ± 16 bpm; P <.001) than asymptomatic NSR episodes. Of the symptomatic episodes, 66 (73%) occurred during NSR and 24 (27%) during AF. All P values were obtained from mixed effects models. ConclusionSymptomatic episodes in patients with paroxysmal AF were more frequently associated with NSR than AF. Symptomatic AF and NSR episodes were associated with higher aSKNA than asymptomatic episodes. In patients with paroxysmal AF, symptoms correlate better with SKNA than heart rhythm.

Sympathetic toggled paroxysmal atrial fibrillation and recurrent premature atrial contractions in ambulatory patients

BackgroundAutonomic nerve activity is important in the mechanisms of paroxysmal atrial fibrillation (PAF). ObjectiveThe purpose of this study was to test the hypothesis that a single burst of skin sympathetic nerve activity (SKNA) can toggle on and off PAF or premature atrial contraction (PAC) clusters. MethodsSimultaneous recording of SKNA and electrocardiogram (neuECG) recording was performed over 7 days in patients with PAF. ResultsIn study 1, 8 patients (7 men and 1 woman; age 62 ± 8 years) had 124 episodes of PAF. An SKNA burst toggled both on and off PAF in 8 episodes (6.5%) (type 1), toggled on but not off in 12 episodes (9.7%) (type 2), and toggled on a PAC cluster followed by PAF in 4 episodes (3.2%) (type 3). The duration of these PAF episodes was <10 minutes. The remaining 100 episodes (80.6%) were associated with active SKNA bursts throughout PAF (type 4) and lasted longer than type 1 (P = .0185) and type 2 (P = .0027) PAF. There were 47 PAC clusters. Among them, 24 (51.1%) were toggled on and off, and 23 (48.9%) were toggled on but not off by an SKNA burst. In study 2, 17 patients (9 men and 8 women; age 58 ± 12 years) had <10 minutes of PAF (4, 8, 0, and 31 of types 1, 2, 3, and 4, respectively). There were significant circadian variations of all types of PAF. ConclusionA single SKNA burst can toggle short-duration PAF and PAC cluster episodes on and off. The absence of continued SKNA after the onset might have affected the maintenance of these arrhythmias.

Skin sympathetic nerve activity and ST-segment depression in women

BackgroundST depression on exercise electrocardiogram (ECG) and ambulatory ECG monitoring may occur without myocardial ischemia. The mechanisms of non-ischemic ST depression remain poorly understood. ObjectiveTo test the hypothesis that the magnitudes of skin sympathetic nerve activity (SKNA) correlate negatively with the ST segment height (ST height) in ambulatory participants. MethodsWe used neuECG to measure ambulatory ST height and average SKNA (aSKNA) in 19 healthy women, 6 women with a history of Takotsubo Syndrome (TTS), and 4 women with ischemia and no obstructive coronary arteries (INOCA). ResultsBaseline average SKNA (aSKNA) was similar between healthy women, TTS, and INOCA (1.098±0.291 μV, 0.980± 0.061 μV, and 0.919 ± 0.0397 μV, respectively, p=0.22). The healthy women had only asymptomatic upsloping ST depression. All participants had a significant (p<0.05) negative correlation between ST height and aSKNA. Ischemic episodes (n=15) were identified in 2 TTS and 4 INOCA participants. The ischemic ST depression was associated with increased heart rate and elevated aSKNA compared to baseline. An analysis of SKNA burst patterns at similar heart rates revealed that SKNA total burst area was significantly higher during ischemic episodes than non-ischemic episodes (0.301±0.380 μV.s and 0.165±0.205 μV.s, p=0.023) in both the TTS and INOCA participants. ConclusionsAsymptomatic ST depression in ambulatory women is associated with elevated SKNA. Heightened aSKNA is also noted during ischemic ST depression in women with TTS and INOCA. These findings suggest that ST segment depression is a physiological response to heightened sympathetic tone but may be aggravated by myocardial ischemia.

Safety and efficacy of cardioneuroablation for vagal bradycardia in a single arm prospective study

Cardioneuroablation (CNA) is currently considered as a promising treatment option for patients with symptomatic bradycardia caused by vagotonia. This study aims to further investigate its safety and efficacy in patients suffering from vagal bradycardia. A total of 60 patients with vagal bradycardia who underwent CNA in the First Affiliated Hospital of Xinjiang Medical University from November 2019 to June 2022. Preoperative atropine tests revealed abnormal vagal tone elevation in all patients. First, the electroanatomic structures of the left atrium was mapped out by using the Carto 3 system, according to the protocol of purely anatomy-guided and local fractionated intracardiac electrogram-guided CNA methods. The upper limit of ablation power of superior left ganglion (SLGP) and right anterior ganglion (RAGP) was not more than 45W with an ablation index of 450.Postoperative transesophageal cardiac electrophysiological examination was performed 1 to 3 months after surgery. The atropine test was conducted when appropriate. Twelve-lead electrocardiogram, Holter electrocardiogram, and skin sympathetic nerve activity were reviewed at 1, 3, 6 and 12 months after operation. Adverse events such as pacemaker implantation and other complications were also recorded to analyze the safety and efficacy of CNA in the treatment of vagus bradycardia. Sixty patients were enrolled in the study (38 males, mean age 36.67 ± 9.44, ranging from 18 to 50 years old). None of the patients had a vascular injury, thromboembolism, pericardial effusion, or other surgical complications. The mean heart rate, minimum heart rate, low frequency, low/high frequency, acceleration capacity of rate, and skin sympathetic nerve activity increased significantly after CNA. Conversely, SDNN, PNN50, rMSSD, high frequency, and deceleration capacity of rate values decreased after CNA (all P < 0.05). At 3 months after ablation, the average heart rate, maximum heart rate, and acceleration capacity of heart rate remained higher than those before ablation, and the deceleration capacity of heart rate remained lower than those before ablation and the above results continued to follow up for 12 months after ablation (all P < 0.05). There was no significant difference in other indicators compared with those before ablation (all P > 0.05). The remaining 81.67% (49/60) of the patients had good clinical results, with no episodes of arrhythmia during follow-up. CNA may be a safe and effective treatment for vagal-induced bradycardia, subject to confirmation by larger multicenter trials.

Characterization of skin sympathetic nerve activity in patients undergoing ablation of ventricular tachycardia

Characterization of skin sympathetic nerve activity in patients undergoing ablation of ventricular tachycardia

Autonomic dysfunction and treatment strategies in intracerebral hemorrhage.

Autonomic dysfunction with central autonomic network (CAN) damage occurs frequently after intracerebral hemorrhage (ICH) and contributes to a series of adverse outcomes. This review aims to provide insight and convenience for future clinical practice and research on autonomic dysfunction in ICH patients. We summarize the autonomic dysfunction in ICH from the aspects of potential mechanisms, clinical significance, assessment, and treatment strategies. The CAN structures mainly include insular cortex, anterior cingulate cortex, amygdala, hypothalamus, nucleus of the solitary tract, ventrolateral medulla, dorsal motor nucleus of the vagus, nucleus ambiguus, parabrachial nucleus, and periaqueductal gray. Autonomic dysfunction after ICH is closely associated with neurological functional outcomes, cardiac complications, blood pressure fluctuation, immunosuppression and infection, thermoregulatory dysfunction, hyperglycemia, digestive dysfunction, and urogenital disturbances. Heart rate variability, baroreflex sensitivity, skin sympathetic nerve activity, sympathetic skin response, and plasma catecholamine concentration can be used to assess the autonomic functional activities after ICH. Risk stratification of patients according to autonomic functional activities, and development of intervention approaches based on the restoration of sympathetic-parasympathetic balance, would potentially improve clinical outcomes in ICH patients. The review systematically summarizes the evidence of autonomic dysfunction and its association with clinical outcomes in ICH patients, proposing that targeting autonomic dysfunction could be potentially investigated to improve the clinical outcomes.

Analysis of sympathetic responses to cognitive stress and pain through skin sympathetic nerve activity and electrodermal activity

We explored the non-invasive evaluation of the sympathetic nervous system (SNS) by employing two distinct physiological signals: skin sympathetic nerve activity (SKNA), extracted from electrocardiogram (ECG) signals, and electrodermal activity (EDA), a well-studied marker in the context of the SNS assessment. Our investigation focused on cognitive stress and pain; two conditions closely associated with the SNS. We sought to determine if the information and dynamics of EDA could be derived from the novel SKNA signal. To this end, ECG and EDA signals were recorded simultaneously during three experiments aimed at sympathetic stimulation, Valsalva maneuver (VM), Stroop test, and thermal-grill pain test. We calculated the integral area under the rectified SKNA signal (iSKNA) and decomposed the EDA signal to its phasic component (EDAphasic). An average delay of more than 4.6 s was observed in the onset of EDAphasic bursts compared to their corresponding iSKNA bursts. After shifting the EDAphasic segments by the extent of this delay and smoothing the corresponding iSKNA bursts, our results revealed a strong average correlation coefficient of 0.85±0.14 between the iSKNA and EDAphasic bursts, indicating a noteworthy similarity between the two signals. We also reconstructed the EDA signals with time-varying sympathetic (TVSymp) and modified TVSymp (MTVSymp) methods. Then we extracted the following features from iSKNA, EDAphasic, TVSymp, and MTVSymp signals: peak amplitude, average amplitude (aSKNA), standard deviation (vSKNA), and the cumulative duration during which the signals had higher amplitudes than a specified threshold (HaSKNA). A strong average correlation of 0.89±0.18 was found between vSKNA and subjects’ self-rated pain levels during the pain test. Our statistical analysis also included applying Linear Mixed-Effects Models to check if there were significant differences in features across baseline and different levels of SNS stimulation. We then assessed the discriminating power of the features using Area Under the Receiver Operating Characteristic Curve (AUROC) and Fisher’s Ratio. Finally, using all the four EDA features, a multi-layer perceptron (MLP) classifier reached the classification accuracies 95.56%, 89.29%, and 67.88% for the VM, Stroop, and thermal-grill pain control and stimulation classes. On the other hand, the highest classification accuracies based on SKNA features were achieved using K-nearest neighbors (KNN) (98.89%), KNN (89.29%), and MLP (95.11%) classifiers for the same experiments. Our comparative analysis showed the feasibility of SKNA as a novel tool for assessing the SNS with accurate classification capability, with a faster onset of amplitude increase in response to SNS activity, compared to EDA.

Assessing Skin Sympathetic Nerve Activity and Cardiac Effects in Patients with Gastric Electrical Stimulation

Background:Gastric Electrical Stimulation (GES) is a therapy for gastroparesis patients, alleviating symptoms like nausea, vomiting, and poor gastric emptying. The therapeutic impact of GES is believed to stem from changes in autonomic nerve activity, particularly parasympathetic activity via the vagal nerves. This study examines skin sympathetic nerve activity (SKNA) to assess autonomic nerve bursts, investigating the effects of GES on nerve activity and cardiac function.&#x0D; Methods:SKNA signals were recorded from 48 patients at three locations: left side of the neck (SKNA1), right side of the neck (SKNA2), and via ECG Lead 1 across the chest (SKNA3). Signals were band pass filtered (500 Hz to 1000 Hz) to eliminate ECG and muscle artifacts and highlight nerve activity. Using Labchart software, the absolute value integral (iSKNA) was calculated for each 100-millisecond sample, with resulting values exported to Excel. Data was collected during different GES conditions: GES On, GES at ½ voltage, GES Off, and GES back on. The threshold for nerve activity bursts was determined as the mean of iSKNA values + two times the standard deviation in each section.&#x0D; Results:Histograms of average aSKNA values showed reduced nerve activity with GES off. Left and vagal nerve activity on SKNA1 was significantly lower with GES fully on or off compared to GES at ½ voltage. No other significant differences were observed in variabilities or average aSKNAs in SKNA1 or SKNA2.&#x0D; Future Directions &amp; Potential Impact:Burst analysis of iSKNA data will address key questions. Variations in burst activity with different GES conditions may elucidate GES's therapeutic effects on gastroparesis. Subsequent segmentation of data into patients with resolved and unresolved symptoms could reveal the relationship between burst activity and therapeutic efficacy. Additionally, correlation of burst data with heart rate variability analysis will provide insights into the impact of GES on cardiac function. This study will advance our understanding of GES effects and safety, potentially improving patient outcomes.

Skin sympathetic nerve activity during unprovoked syncope in an ambulatory patient with postural orthostatic tachycardia syndrome

Skin sympathetic nerve activity during unprovoked syncope in an ambulatory patient with postural orthostatic tachycardia syndrome

Nomogram model based on clinical factors and autonomic nervous system activity for predicting residual renal function decline in patients undergoing peritoneal dialysis.

Several heart rate variability (HRV) parameters were reported to be associated with residual renal function (RRF) in patients undergoing continuous ambulatory peritoneal dialysis (CAPD). However, it is unclear whether using HRV or other autonomic nervous system (ANS) activity indexes can predict RRF decline in CAPD patients. Patients undergoing CAPD in 2022 from the First Affiliated Hospital of Nanjing Medical University were enrolled in this study. Their clinical characteristics, 5-min HRV parameters and average voltage of 5-min skin sympathetic nerve activity (aSKNA) were collected. According to the 12-month glomerular filtration rate (GFR) decline rate compared with the upper quartile, these patients were categorized into two groups: RRF decline (RRF-D) group and RRF stable (RRF-S) group. Clinical factors and ANS activity indexes for predicting 1-year RRF decline were analyzed using logistic regression, and a nomogram model was further established. The relationships between volume load related indexes and aSKNA were displayed by Spearman's correlation graphs. Ninety-eight patients (53 women, average age of 46.7 ± 13.0 years old) with a median dialysis vintage of 24.5 months were enrolled in this study. Seventy-three patients were categorized into the RRF-S group and 25 patients into the RRF-D group. Compared with RRF-S group, patients in the RRF-D group had higher systolic blood pressure (BP; p = 0.019), higher GFR (p = 0.016), higher serum phosphorous level (p = 0.030), lower total Kt/V (p = 0.001), and lower levels of hemoglobin (p = 0.007) and albumin (p = 0.010). The RRF-D group generally exhibited lower HRV parameters and aSKNA compared with the RRF-S group. A nomogram model included clinical factors (sex, systolic BP, hemoglobin, GFR, and total Kt/V) and aSKNA showed the largest AUC of 0.940 (95% CI: 0.890-0.990) for predicting 1-year RRF decline. The nomogram model included clinical factors (sex, systolic BP, hemoglobin, GFR and total Kt/V) and ANS activity index (aSKNA) might be a promising tool for predicting 1-year RRF decline in CAPD patients.

Effects of Postural Resonance on Skin Sympathetic Nerve Activity and Blood Pressure: A Pilot Study Evaluating Vascular Tone Baroreflex Stimulation Through Biofeedback.

Heart rate and vascular tension baroreflex exhibit resonance characteristics at approximately 0.1 and 0.03Hz. In this study, we aimed to induce postural resonance (PR) through rhythmic postural adjustments. To assess the viability of this technique, we investigated the acute impacts of postural resonance on blood pressure, sympathetic nerve activity, and mood. Fifteen healthy study participants, consisting of 8 males and 7 females, were selected for this self-controlled study. Skin sympathetic nerve activity was continuously monitored during both the intervention and stress test on the experimental day. After PR intervention, the diastolic blood pressure and mean arterial pressure in the PR group exhibited significant reductions compared to the CON group (P = 0.032, CON = 71.67 ± 2.348, PR = 64.08 ± 2.35; P = 0.041, CON = 75.00 ± 2.17, PR = 81.67 ± 2.17). After PR intervention both left brachial ankle pulse wave velocity and right brachial ankle pulse wave velocity exhibited a significant reduction compared to pre-intervention levels (from 1115.86 ± 150.08 to 1048.43 ± 127.40cm/s, p < 0.001; 1103.86 ± 144.35 to 1060.43 ± 121.35cm/s, p = 0.018). PR intervention also led to a significant decrease in burst frequency and duration (P = 0.049; CON = 8.96 ± 1.17, PR = 5.51 ± 1.17) and a noteworthy decrease in burst amplitude and burst threshold during the cold-pressor test (P = 0.002; P = 0.002). Additionally, VAS scores exhibited a substantial increase following PR (P = 0.035, CON = 28.4 ± 4.49, PR = 42.17 ± 4.10). PR can induce resonance effects within the cardiovascular system, resulting in the effective reduction of blood pressure, skin sympathetic nerve activity and pulse wave velocity, and decreased burst amplitude and burst threshold of the sympathetic nerve during the cold-pressor test.

A dataset of proteomic changes during human heat stress and heat acclimation

Hotter climates have important impacts on human health and performance. Yet, the cellular and molecular responses involved in human heat stress and acclimation remain understudied. This dataset includes physiological measurements and the plasma concentration of 2,938 proteins collected from 10 healthy adults, before and during passive heat stress that was performed both prior to and after a 7-day heat acclimation protocol. Physiological measurements included body temperatures, sweat rate, cutaneous vascular conductance, blood pressure, and skin sympathetic nerve activity. The proteomic dataset was generated using the Olink Explore 3072 assay, enabling a high-multiplex antibody-based assessment of protein changes based on proximity extension assay technology. The data need to be interpreted in the context of the moderate level of body hyperthermia attained and the specific demographic of young, healthy adults. We have made this dataset publicly available to facilitate research into the cellular and molecular mechanisms involved in human heat stress and acclimation, crucial for addressing the health and performance challenges posed by rising temperatures.

Postural orthostatic tachycardia syndrome after COVID-19 vaccination

There is an association between coronavirus disease 2019 (COVID-19) mRNA vaccination and the incidence or exacerbation of postural orthostatic tachycardia syndrome (POTS). The purpose of this study was to characterize patients reporting new or exacerbated POTS after receiving the mRNA COVID-19 vaccine. We prospectively collected data from sequential patients in a POTS clinic between July 2021 and June 2022 reporting new or exacerbated POTS symptoms after COVID-19 vaccination. Heart rate variability (HRV) and skin sympathetic nerve activity (SKNA) were compared against those of 24 healthy controls. Ten patients (6 women and 4 men; age 41.5 ± 7.9 years) met inclusion criteria. Four patients had standing norepinephrine levels > 600 pg/mL. All patients had conditions that could raise POTS risk, including previous COVID-19 infection (N = 4), hypermobile Ehlers-Danlos syndrome (N = 6), mast cell activation syndrome (N = 6), and autoimmune (N = 7), cardiac (N = 7), neurological (N = 6), or gastrointestinal conditions (N = 4). HRV analysis indicated a lower ambulatory root mean square of successive differences (46.19 ±24 ms; P = .042) vs control (72.49 ± 40.8 ms). SKNA showed a reduced mean amplitude (0.97 ± 0.052 μV; P = .011) vs control (1.2 ± 0.31 μV) and burst amplitude (1.67 ± 0.16 μV; P = .018) vs control (4. 3 ± 4.3 μV). After 417.2 ± 131.4 days of follow-up, all patients reported improvement with the usual POTS care, although 2 with COVID-19 reinfection and 1 with small fiber neuropathy did have relapses of POTS symptoms. All patients with postvaccination POTS had pre-existing conditions. There was no evidence of myocardial injuries or echocardiographic abnormalities. The decreased HRV suggests a sympathetic dominant state. Although all patients improved with guideline-directed care, there is a risk of relapse.

Transcutaneous electrical vagus nerve stimulation to suppress premature ventricular complexes (TREAT PVC): study protocol for a multi-center, double-blind, randomized controlled trial

BackgroundThe autonomic nervous system can be responsible for the initiation and maintenance of arrhythmias. Low-level tragus stimulation (LLTS), a noninvasive form of autonomic neuromodulation, has been shown to be effective in treating atrial fibrillation. We intended to treat frequent premature ventricular complexes (PVCs) with LLTS.Methods and designThe present study will be a prospective multicenter, double-blind, randomized, controlled trial to assess the antiarrhythmic effects of LLTS on frequent PVCs in patients without structured heart disease (SHD). A total of 100 patients with PVC burden > 10% will be randomly assigned to the active or sham LLTS in 1:1 fashion and receive the proposed intervention for 6 months. The primary outcome is PVC burden at 6 months as assessed by 10 days of continuous ambulatory electrocardiographic monitoring. Secondary outcomes include heart rate variability (HRV), quality of life, skin sympathetic nerve activity, and inflammatory markers. Adverse events will also be recorded.DiscussionThe present trial will be the first to evaluate the effect of LLTS on frequent PVCs on patients without SHD. LLTS may serve as a low-cost, minimal-risk, and non-invasive alternative to conventional antiarrhythmic therapy.Trial registrationClinicalTrial.gov NCT04909528. Registered on 17 June 2021. World health organization trial registration data set was shown in Supplementary Table 1.

Skin sympathetic nerve activity in different ablation settings for atrial fibrillation

BackgroundModifying the autonomic system after catheter ablation may prevent the recurrence of atrial fibrillation (AF). Evaluation of skin sympathetic nerve activity (SKNA) is a noninvasive method for the assessment of sympathetic activity. However, there are few studies on the effects of different energy settings on SKNA. ObjectiveTo investigate the changes in SKNA in different energy settings and their relationship to AF ablation outcomes. MethodsSeventy-two patients with paroxysmal and persistent AF were enrolled. Forty-three patients received AF ablation with the conventional (ConV) energy setting (low power for long duration), and 29 patients using a high-power, short-duration (HPSD) strategy. The SKNA was acquired from the right arm 1 day before and after the radiofrequency ablation. We analyzed the SKNA and ablation outcomes in the different energy settings. ResultsBoth groups had a similar baseline average SKNA (aSKNA). We found that the median aSKNA increased significantly from 446.82 μV to 805.93 μV (p = 0.003) in the ConV group but not in the HPSD group. In the ConV group, patients without AF recurrence had higher aSKNA values. However, the 1-year AF recurrence rate remained similar between both groups (35 % vs. 28 %, p = 0.52). ConclusionThe post-ablation aSKNA levels increased significantly in the ConV group but did not change significantly in the HPSD group, which may reflect different neuromodulatory effects. However, the one-year AF recurrence rates were similar for both groups. These results demonstrate that the HPSD strategy has durable lesion creation but less lesion depth, which may reduce collateral damage.

Evaluation of skin sympathetic nervous activity for classification of intracerebral hemorrhage and outcome prediction

Classification and outcome prediction of intracerebral hemorrhage (ICH) is critical for improving the survival rate of patients. Early or delayed neurological deterioration is common in ICH patients, which may lead to changes in the autonomic nervous system (ANS). Therefore, we proposed a new framework for ICH classification and outcome prediction based on skin sympathetic nervous activity (SKNA) signals. A customized measurement device presented in our previous papers was used to collect data. 117 subjects (50 healthy control subjects and 67 ICH patients) were recruited for this study to obtain their 5-min electrocardiogram (ECG) and SKNA signals. We extracted the signal's time-domain, frequency-domain, and nonlinear features and analyzed their differences between healthy control subjects and ICH patients. Subsequently, we established the ICH classification and outcome evaluation model based on the eXtreme Gradient Boosting (XGBoost). In addition, heart rate variability (HRV) as an ANS assessment method was also included as a comparison method in this study. The results showed significant differences in most features of the SKNA signal between healthy control subjects and ICH patients. The ICH patients with good outcomes have a higher change rate and complexity of SKNA signal than those with bad outcomes. In addition, the accuracy of the model for ICH classification and outcome prediction based on the SKNA signal was more than 91% and 83%, respectively. The ICH classification and outcome prediction based on the SKNA signal proved to be a feasible method in this study. Furthermore, the features of change rate and complexity, such as entropy measures, can be used to characterize the difference in SKNA signals of different groups. The method can potentially provide a new tool for rapid classification and outcome prediction of ICH patients.Index Terms—intracerebral hemorrhage (ICH), skin sympathetic nervous activity (SKNA), classification, outcome prediction, cardiovascular and cerebrovascular diseases.

The cardiovascular mononeuropathy in Hemodialysis Patients analysed by a combination with reactivity tests to noninvasively evaluate skin sympathetic nerve activity and skin microvascular function by (LDF)

Aim: Although several patients with kidney disease have simultaneous dysfunction of the parasympathetic and sympathetic nervous systems, orthostatic hypotension during a hemodialysis (HD) procedure impacts not only the form of treatment but overall comfort of life for patients with HD. Despite a number of methods that are not invasive and have already been used to assess autonomous functioning, a system for monitoring malfunction throughout filtration of blood therapy which has yet to be discovered. Methods: Regarding the purpose of monitoring the autonomous function of stable 40 regular HD patients and 35 healthy controls, we examined the clinical application of the laser-Doppler blood flow meter (LDF). By detecting the periflux blood flow decreasing velocity (PDV) while combined with the Valsalva manoeuvre, the LDF device which was used for an autonomous test. We also looked at the relationship between PDV and traditional atherosclerosis testing. Results: The baseline PDV (5.30 ± 2.93), comparative to subjects who were in excellent condition (9.65 ± 7.10), was substantially decreased in the HD populace. Furthermore, we discovered a substantial connection between PDV and established parameters like heart rate fluctuation and ankle-brachial blood pressure indexing. Conclusion: Regarding assessing autonomous functioning in hemodialysis patients, evaluation of PDV by LDF is just as effective as the standard approach. The benefit from regular and recurring assessments of autonomous dysfunction is made possible by the device's ease.