Autonomic Control In Patients Research Articles

Oxidative stress associated with impaired autonomic control and severity of lung function in chronic obstructive pulmonary disease patients.

Oxidative stress has been suggested to play a role in the pathogenesis of chronic obstructive pulmonary disease (COPD). This study aimed to investigate a link between malondialdehyde (MDA) levels, pulmonary function, and cardiac autonomic control in patients with COPD. Plasma levels of MDA, heart rate variability, and pulmonary function were measured in 50 clinically stable COPD patients and 50 normal male controls. COPD patients exhibited lower means of the standard deviations of all normal to normal (NN) intervals (SDNN), the square root of the mean of the sum of the squares of differences between adjacent NN intervals (RMSSD), and high frequency (HF). Nevertheless, they presented greater low frequency (LF) and low frequency/high frequency ratio (LF/HF ratio) in supine and head-up tilt positions than controls (P<0.001). More-over, a negative correlation between MDA levels with SDNN (P<0.001) and a positive correlation with LF (P<0.01) and LF/HF ratio (P<0.05) were observed in both positions. In COPD patients, plasma MDA levels were 2.3 times greater than controls (4.33±2.03 μM vs. 1.89±0.39 μM, P<0.001), and they were inversely correlated with forced vital capacity, forced expiratory volume in 1 sec, midexpiratory flow, and peak expiratory flow (P<0.001). Our findings suggest a potential role for oxidative stress in impaired cardiac autonomic control and clinical relevance of plasma MDA levels as a predictor of severity of COPD in COPD patients.

The relationship between Cardiac Autonomic Dysfunction and Glycemic Variability in Pediatric Patients with Type 1 Diabetes Mellitus

Objective: Objective: Cardiovascular autonomic neuropathy (CAN) is defined as the impairment of cardiovascular autonomic control in patients with diabetes mellitus (DM) after excluding other causes. This study aims to investigate the relationship between glycemic variability and CAN in pediatric patients with type 1 DM Material and Methods: The study population consisted of children aged 8-18 who were being followed up with the diagnosis of type 1 DM. The diagnosis of CAN was made based on the heart rate variability indices and the results of the cardiovascular reflex tests.. Results: The study included 21 pediatric patients with type 1 diabetes mellitus (DM), consisting of 6 males and 15 females, with a median age of 13.94 years. Among them, 5 (23.8%) had early involvement, and 4 (19%) had definitive cardiovascular autonomic neuropathy (CAN). Patients with definitive CAN were significantly older and had a longer disease duration than those without CAN (p&lt;0.05). Additionally, patients with definitive CAN had significantly higher hemoglobin A1c (HbA1c) levels (p&lt;0.05). The time in the target blood glucose range (TIR) was significantly lower, while the time above the target blood glucose range (TAR) was significantly higher in patients with definitive CAN than in other patients (p&lt;0.05). The standard deviation (SD) was also higher in patients with definitive CAN, but not significantly so (p&gt;0.05). Conclusion: The study's findings indicated that TIR, which is one of the glycemic variability parameters, was significantly lower and TAR was considerably higher in children with definitive CAN, and SD was higher, albeit not significantly, in children with definitive CAN. Nevertheless, large-scale, prospective cohort studies are needed to fully elucidate the relationship between CAN and glycemic variability in pediatric type 1 DM patients.

Perampanel enhances the cardiovagal tone and heart rate variability (HRV) in patients with drug-resistant temporal lobe epilepsy

ObjectiveThe temporal lobe plays a central role in the regulation of the "Central Autonomic Network" and cardiovascular functions. The blockade of glutamatergic pathways in the temporal lobe affects cardio-autonomic control. Perampanel (PER) is a non-competitive agonist of the AMPA receptor. This study evaluated PER effects on cardiac autonomic control in patients affected by drug-resistant TLE (DRTLE). MethodsWe enrolled 40 adults with DRTLE treated with PER as add-on therapy (PER group) and 32 DRTLE age, sex, and seizure-frequency matched controls treated with different additional anti-seizure medication (ASM) as add-on therapy (No-PER group). HRV analysis was performed on 5-minute EKG recording in resting state before and 6-months after the introduction of add-on ASM. Linear Mixed Models (LMM) were used to analyzed HRV variables according to time (baseline and 6-months follow-up) and groups. ResultsAt baseline no differences were detected between PER group and No-PER group according to time-domain and frequency-domain HRV parameters. At the follow-up, in PER group a multiplicative effect for the interaction between treatment and time was observed for MeanRR (ms) (p=0.03), LnRMSSD (ms) (p=0.04), LnHF (ms2) (p<0.001), HF n.u. (p=0.001), HF% (p=0.002) with increased values, and for LnLF (ms2) (p=0.001), LF n.u. (p=0.001), LF% (p=0.01), and LF/HF (p<0.001) with reduced values. The change in seizure frequency after add-on therapy was comparable between the two groups (p=0.81) ConclusionsOur data support the notion that PER increases the vagal tone in DRTLE. This activity may exert a cardioprotective effect by reducing the risk of developing cardiac arrhythmias. Furthermore, given the correlations between HRV modifications and the occurrence of SUDEP, future studies will need to test the protective effects of PER on SUDEP.

Comparison of the effects of new anti-seizure drugs (ASDS) on cardiac autonomic control in patients with temporal lobe epilepsy (TLE)

Temporal lobe epilepsy (TLE) is the most common form of focal epilepsy in adulthood. Temporal lobe plays a central role in the regulation of cardio-autonomic functions (CAF) which can be also influenced by several anti-seizure therapies. The spectral analysis of the Heart Rate Variability (HRV) represents a useful tool for the evaluation of CAF. The aim of this study is to assess, using the spectral analysis of HRV, new anti-seizure medication (ASMs) - Perampanel (PER), Lacosamide (LCS), Eslicarbazepine (ECB) and Brivaracetam (BRV) - effects on CAF in patients with TLE.

Effect of the combination of automated peripheral mechanical stimulation and physical exercise on aerobic functional capacity and cardiac autonomic control in patients with Parkinson\u2019s disease: a randomized clinical trial protocol

BackgroundAutomated peripheral mechanical stimulation (AMPS) has been proposed as a new complementary therapy with potential for improving motor and cardiovascular abnormalities in Parkinson’s disease (PD). However, AMPS long-term effects and its combination with physical exercise are unknown. Thus, this study aims to compare the effects of a program of 12 weeks of physical exercise with a 12-week intervention program combining physical exercise and AMPS on the aerobic capacity, cardiac autonomic control, and gait parameters in patients with PD.MethodsA randomized, controlled clinical trial will be conducted. Older volunteers with PD will be randomly assigned to one of the two groups studied: (1) exercise or (2) AMPS + exercise. Both groups will undergo an exercise program of 24 sessions, for 12 weeks, performed twice a week. Before exercise sessions, the group AMPS + exercise will receive a session of active AMPS, while the group exercise will receive an AMPS sham intervention. Shapiro-Wilk’s and Levene’s tests will be used to check for data normality and homogeneity, respectively. In case parametric assumptions are fulfilled, per-protocol and intention-to-treat analyses will be performed using a mixed model analysis of variance to check for group*time interaction. Significance level will be set at 5%.DiscussionSeveral non-pharmacological treatment modalities have been proposed for PD, focusing primarily on the reduction of motor and musculoskeletal disorders. Regular exercise and motor training have been shown to be effective in improving quality of life. However, treatment options in general remain limited given the high prevalence and adverse impact of these disorders. So, developing new strategies that can potentiate the improvement of motor disabilities and also improve non-motor symptoms in PD is relevant. It is expected that the participants from both groups will improve their quality of life, gait parameters, and their cardiac autonomic control, with greater improvements being observed in the group combining active AMPS and physical exercise.Trial registrationClinicalTrials.gov NCT04251728. Registered on February 05, 2020.

Regional Gray Matter Volume Changes in Parkinson's Disease with Orthostatic Hypotension.

Neurodegenerative change in the central nervous system has been suggested as one of the pathophysiological mechanisms of autonomic nervous system dysfunction in Parkinson’s disease (PD). We analyzed gray matter (GM) volume changes and clinical parameters in patients with PD to investigate any involvement in the brain structures responsible for autonomic control in patients with PD having orthostatic hypotension (OH). Voxel-based morphometry was applied to compare regional GM volumes between PD patients with and without OH. Multivariate logistic regression analysis using a hierarchical model was carried out to identify clinical factors independently contributing to the regional GM volume changes in PD patients with OH. The Sobel test was used to analyze mediation effects between the independent contributing factors to the GM volume changes. PD patients with OH had more severe autonomic dysfunction and reduction in volume in the right inferior temporal cortex than those without OH. The right inferior temporal volume was positively correlated with the Qualitative Scoring MMSE Pentagon Test (QSPT) score, reflecting visuospatial/visuoperceptual function, and negatively correlated with the Composite Autonomic Severity Score (CASS). The CASS and QSPT scores were found to be factors independently contributing to regional volume changes in the right inferior temporal cortex. The QSPT score was identified as a mediator in which regional GM volume predicts the CASS. Our findings suggest that a decrease in the visuospatial/visuoperceptual process may be involved in the presentation of autonomic nervous system dysfunction in PD patients.

Aerobic exercise and inspiratory muscle training increase functional capacity in patients with univentricular physiology after Fontan operation: A randomized controlled trial

BackgroundThe effect of exercise training and its mechanisms on the functional capacity improvement in Fontan patients (FP) are virtually unknown. This trial evaluated four-month aerobic exercise training and inspiratory muscle training on functional capacity, pulmonary function, and autonomic control in patients after Fontan operation. MethodsA randomized controlled clinical trial with 42 FP aged 12 to 30 years and, at least, five years of Fontan completion. Twenty-seven were referred to a four-months supervised and personalized aerobic exercise training (AET) or an inspiratory muscle training (IMT). A group of non-exercise (NET) was used as control. The effects of the exercise training in peak VO2; pulmonary volumes and capacities, maximal inspiratory pressure (MIP); muscle sympathetic nerve activity (MSNA); forearm blood flow (FBF); handgrip strength and cross-sectional area of the thigh were analyzed. ResultsThe AET decreased MSNA (p = 0.042), increased FBF (p = 0.012) and handgrip strength (p = 0.017). No significant changes in autonomic control were found in IMT and NET groups. Both AET and IMT increased peak VO2, but the increase was higher in the AET group compared to IMT (23% vs. 9%). No difference was found in the NET group. IMT group showed a 58% increase in MIP (p = 0.008) in forced vital capacity (p = 0.011) and forced expiratory volume in the first second (p = 0.011). No difference in pulmonary function was found in the AET group. ConclusionsBoth aerobic exercise and inspiratory muscle training improved functional capacity. The AET group developed autonomic control, and handgrip strength, and the IMT increased inspiratory muscle strength and spirometry.Clinical Trial Registration:ClinicalTrials.gov Identifier: NCT02283255

One Session of Spinal Manipulation Improves the Cardiac Autonomic Control in Patients with Musculoskeletal Pain: A Randomized Placebo-Controlled Trial.

Three-arm, parallel, randomized, placebo-controlled, assessor-blinded trial. To compare the immediate effect of manual therapy at the upper thoracic spine on the cardiovascular autonomic control of patients with musculoskeletal pain. Musculoskeletal pain increases the risk of cardiovascular events. Thus, manual therapy applied to the upper thoracic region is likely efficient to improve the cardiac autonomic control. The study included 59 patients with musculoskeletal pain enrolled at an outpatient clinic. Participants were randomly assigned to spinal manipulation (n = 19), myofascial manipulation (n = 20), or placebo (n = 20) administered to the upper thoracic region. Resting heart rate variability provided indexes of the cardiac autonomic control, and the blood pressure response to the cold pressor test as a proxy of the sympathetic responsiveness to a stressor stimulus. Groups were similar for baseline variables except for blood pressure. Two-way repeated-measures one-way analysis of covariance (ANCOVA) revealed that only spinal manipulation induced immediate increase of the square root of the mean squared differences of successive RR intervals (RMSSD), absolute (ms2), and normalized units (n.u.) of the high-frequency power (HF) as compared with pre-intervention evaluation, indicating an improvement in the parasympathetic activity to the heart. Normalized units of low-frequency power (LF) and the LF/HF ratio reduced after the spinal manipulation solely, suggesting a reduction of the sympathetic activity to the heart. There were no significant differences in the blood pressure responsiveness among the three treatments. There were no adverse events. In patients with musculoskeletal pain, spinal manipulation on the upper thoracic spine led to an immediate improvement in the resting cardiac autonomic control without an effect on the blood pressure responsiveness to a sympathoexcitatory stimulus. Myofascial manipulation or placebo did not change cardiovascular autonomic control.Level of Evidence: 2.

Immediate Effects of Rib Mobilization and Diaphragm Release Techniques on Cardiac Autonomic Control in Patients With Chronic Obstructive Pulmonary Disease: A Pilot Study

ObjectiveThe purpose of this pilot study was to evaluate the feasibility of testing an intervention protocol and measuring the immediate effects of a rib mobilization technique (RMT) and a diaphragm release technique (DRT) on the autonomic nervous system of patients with chronic obstructive pulmonary disease (COPD). MethodsThis was a pilot study of a randomized controlled trial. Fourteen individuals were evaluated. Eligibility criteria were being a sedentary person with a diagnosis of COPD, age between 50 and 72 years, and being clinically stable. Exclusion criteria were heart disease, other respiratory comorbidities, and body mass index above 30kg/m2. Participants first underwent cardiorespiratory evaluation and were then allocated into 2 groups: the RMT + DRT group and the DRT group. Clinical assessments were performed immediately before and after the intervention. Statistical analysis was carried out through a paired-sample Wilcoxon test, and the comparison between groups was performed using the Mann-Whitney test. ResultsAll randomized participants completed the assessment and intervention protocol. Sample size was estimated at 24 individuals per group. The DRT group decreased resting heart rate by 5 bpm (P = .03) and increased variance (P = .04) and mean R-R interval (P = .03). The RMT + DRT group decreased mean R-R interval (P = .02). ConclusionThe design for this study appears to be feasible for evaluating manual-therapy intervention in the nonmusculoskeletal function of patients with COPD. It was possible to determine the sample size for future studies. Preliminary data show that the diaphragm release technique may reduce mean resting heart rate and increase heart-rate variability immediately after the intervention.

Acute inspiratory muscle exercise effect on glucose levels, glucose variability and autonomic control in patients with type 2 diabetes: A crossover randomized trial.

Inspiratory muscle exercise (IME) can be an alternative to conventional exercise. We aimed to evaluate the effect of IME on glucose, glucose variability, and autonomic cardiovascular control in type 2 diabetes. Fourteen diabetic subjects were randomly assigned to IME with 2% maximal inspiratory pressure (PImax) or 60% PImax wearing a continuous glucose monitoring system for three days. Glucose variability [glucose variance (VAR), glucose coefficient of variation (CV%), glucose standard deviation (SD), and mean amplitude of glycemic excursions (MAGE)] were evaluated. Glucose reduction was observed in 5min (60% of PImax 33.2% and 2% of PImax 32.0%), 60min (60% of PImax 29.6% and 2% of PImax 31.4%) and 120min (60% of PImax 21.4% and 2% of PImax 24.0%) after IME (vs.1h before the exercise), with no difference between loads. This reduction in glucose levels was observed in all moments of the IME protocol. Glucose variability was reduced after 12h and 18h of the IME (ΔCV: P<0.001, ΔSD: P<0.001 and ΔVAR: P<0.001) for both loads. No difference was found in MAGE (P=0.594) after IME. Mean arterial pressure and heart rate rose during the exercise session with 60% of PImax. Although sufficiently strong to induce cardiovascular changes, an inspiratory muscle exercise session with 60% of PImax in subjects with type 2 diabetes has failed to induce any significant improvement in glucose, glucose variability and autonomic control, compared to the 2% Plmax exercise session.

Effects of exergames on heart rate variability of women with fibromyalgia: A randomized controlled trial

The objective of the present manuscript was to evaluate the effects of 24-weeks exergame intervention on the heart rate variability (HRV) of women with fibromyalgia. First, 56 women with fibromyalgia were assessed for eligibility. A total of 55 women fulfilled the inclusion criteria and participated in this single-blinded, randomized controlled trial. A 24-weeks of exergames were completed by the exercise group in the university facilities. It was focused on the mobility, postural control, upper and lower limbs coordination, aerobic fitness and strength. A total of 120 min per week, divided into two sessions of 60 min, was completed. A short-term 5 min record at rest was used to assess the HRV. Time (SDNN and RMSSD) and non-linear indexes (Higuchi´s Fractal Dimension, SD1, SD2, ln stress score, and SD1/SD2) of HRV were extracted. Fifty participants (achieving an 89.28% of adherence), recruited from the local fibromyalgia association completed the study. They were randomly divided into an exercise (age = 54.04[8.45]) and a control group (52.72[9.98]). Significant interaction (group*time) effects in SDNN, ln stress score, SD2, and SD1/SD2 ratio were found. The EG showed an increase of SDNN and a decreased ln stress score and SD2. The CG showed an increased ln stress score, SD1/SD2. In conclusion, 24-weeks of exergame intervention based on the tool VirtualEx-FM improved the autonomic control in patients with fibromyalgia. However, significant effects on Higuchi´s fractal dimension were not found. This is the first study using exergame as a therapy in women with fibromyalgia which has led to an improvement the autonomic balance in these patients.

Delta plot analysis of cardiovascular and cardiorespiratory interactions in young women with orthostatic intolerance

ObjectiveTemporal dynamics of cardiovascular and cardiorespiratory interactions during a head-up tilt test (HUTT) were investigated using a new method called delta plot analysis (DPA) that deals with the intrinsic nonstationarity feature of time series. MethodsTwenty-one young female patients (28 ± 7 years) with orthostatic intolerance (OI) and 13 age-matched female controls (26 ± 5 years) were investigated during a 70° HUTT. Analyses were performed on bivariate time series including beat-to-beat intervals (BBI), respiratory amplitude (RESP) at BBI onset as well as systolic (SYS) and diastolic (DIA) blood pressure at simultaneous and shifted beats. DPA was used to characterize cardiovascular interactions as SYS→BBI and BBI→DIA, as well as cardiorespiratory interactions as RESP→BBI and RESP→DIA. ResultsOccurrence of simultaneous BBI increases due to SYS increases (bradycardic baroreflex) was significantly reduced during orthostatic phase in patients (28.54 ± 6.32% versus 36.35 ± 4.77%, p < 0.01). Considering the magnitude of consecutive changes, patients revealed an increased amount of points characterized by low heart rate variability combined with high blood pressure variability for SYS→BBI at tau = 0, BBI→SYS at tau = 2 and BBI→DIA at tau = 1. Interaction analysis for SYS→BBI showed highly significant differences already in supine position (10.08±5.90% versus 4.78±2.42%, p < 0.01), during tilt-up (12.32±5.00% versus 5.51±3.07%, p < 0.0001) and during early orthostatic phase (14.55±6.00% versus 5.71±3.14%, p < 0.001). ConclusionTemporal dynamic analysis by DPA revealed impaired autonomic control in patients compared to healthy subjects during supine position, transition and orthostatic phase. SignificanceDPA is a promising graphical tool to demonstrate impaired autonomic regulation.

Influence of physical activity on cardiac autonomic control in patients with dyslipidaemia

The objective of this study was to compare the cardiac autonomic control of dyslipidaemia patients engaged in different levels of physical activity and to determine the predictive ability of physical activity for cardiac autonomic dysfunction in these patients. This study also aimed to compare the cardiac autonomic control of dyslipidaemia patients and healthy adults. 52 patients (age: 49.1±4.53 years) with dyslipidaemia were recruited along with 16 healthy adults. Physical activity levels were assessed by International Physical Activity Questionnaire, and subjects were divided into three categories – low, moderate, and high physical activity. Heart rate variability (HRV) analysis was performed for obtaining time and frequency domain parameters. Presence of cardiac autonomic dysfunction was defined as standard deviation of N-N intervals &lt;44 ms. HRV parameters were compared between 3 groups of dyslipidaemia patients and healthy controls. Predictive ability of physical activity for cardiac autonomic dysfunction in dyslipidaemia was evaluated after adjusting clinical covariates. There was a significant difference between low-frequency power (cardiac sympathetic control), and ratio of low- and high-frequency (HF) power (sympatho-vagal balance) in low versus moderate physical activity group and low versus high physical activity group (P&lt;0.001). Significant differences were also observed for HFnu power (cardiac vagal activity) and total power between the dyslipidaemia groups. Physical activity was found to be a significant (P=0.03), independent predictor of cardiac autonomic dysfunction in dyslipidaemia patients. Findings of the present study suggest that cardiac autonomic profile of dyslipidaemia patients with different physical activity levels varied significantly. Dyslipidaemia patients engaged in moderate and high physical activity demonstrated significantly less sympathetic activity and better sympatho-vagal balance than those engaged in low levels of physical activity; also, vagal cardiac control was significantly greater in high physical activity group. Lower levels of physical activity determined the presence of cardiac autonomic dysfunction in these patients at an optimal cut-off value of ≤1,558 Metabolic Equivalent of Tasks- min/week.

Effect of spinal manipulative treatment on cardiovascular autonomic control in patients with acute low back pain

BackgroundThis study aimed to quantify the effect of spinal manipulative treatment (SMT) from an analysis of baroreflex, systolic blood pressure and heart rate variability (HRV) on patients with acute back pain. It was hypothesized that SMT would increase the parasympathetic cardiovascular autonomic control.MethodsTwenty-two patients with acute back pain were randomly divided into two groups: one receiving sham treatment (Sham) and the other receiving SMT. Recordings were completed during the first day and the seventh day, immediately before and after treatment on both days. ECG and systolic blood pressure were continuously recorded to compute cardiovascular variability and baroreflex sensitivity components. The perceived level of pain was measured with the numeric pain scale (NPS) 48 h before, just before and just after each treatment. The NPS ranged from 0 to 100% (peak of pain before treatment). ECG and systolic blood pressure recordings were analyzed in time frequency domain using the Smoothed pseudo Wigner-Ville distribution.ResultsRoot mean square of the successive differences, high frequency power of the heart rate variability, and high frequency baroreflex sensitivity differences between post and pre tests were higher in the SMT group than in the Sham group (p < 0.01), whereas no differences were observed with the other heart rate variability components. Also, no differences were observed with the systolic blood pressure components. Although the estimated pain scale values decreased over time, no difference was observed between the SMT and Sham groups.ConclusionsThis seems to be the first study to assess the effect of SMT on both heart rate variability and baroreflex sensitivity in patients with acute back pain. SMT can be seen to provoke an increase in parasympathetic control known to relate to a person’s healthy state. Thus, cardiovascular variability analysis may be a useful tool for clinicians to quantify and objectify the beneficial effects of spinal manipulation treatment.

Sudarshan Kriya Yoga improves cardiac autonomic control in patients with anxiety-depression disorders

BackgroundSeveral studies have demonstrated that adjuvant therapies as exercise and breathing training are effective in improving cardiac autonomic control (CAC) in patients with affective spectrum disorders. However, the effects of Sudarshan Kriya Yoga (SKY) on autonomic function in this population is unknown. Our objective was to test the hypothesis that SKY training improves CAC and cardiorespiratory coupling in patients with anxiety and/or depression disorders. MethodsForty-six patients with a diagnosis of anxiety and/or depression disorders (DSM-IV) were consecutively enrolled and divided in two groups: 1) conventional therapy (Control) and 2) conventional therapy associated with SKY (Treatment) for 15 days. Anxiety and depression levels were determined using quantitative questionnaires. For the assessment of CAC and cardiorespiratory coupling, cardiorespiratory traces were analyzed using monovariate and bivariate autoregressive spectral analysis, respectively. ResultsAfter 15-days, we observed a reduction of anxiety and depression levels only in Treatment group. Moreover, sympathetic modulation and CAC were significantly lower while parasympathetic modulation and cardiorespiratory coupling were significantly higher in the Treatment compared to Control group. ConclusionsIntensive breathing training using SKY approach improves anxiety and/or depressive disorders as well as CAC and cardiorespiratory coupling. These finding suggest that the SKY training may be a useful non-pharmacological intervention to improve symptoms and reduce cardiovascular risk in patients with anxiety/depression disorders.

Cardiovascular autonomic control in patients with left ventricular assistance continous flow devices

Cardiovascular autonomic control in patients with left ventricular assistance continous flow devices

Inspiratory muscle training in patients with diabetic autonomic neuropathy: a randomized clinical trial.

We evaluated the effects of an 8-week inspiratory muscle training (IMT, n=5) or placebo IMT (P-IMT, n=5) on maximal respiratory pressures, pulmonary function, functional capacity, and cardiac autonomic control in patients with type 2 diabetes and diabetic autonomic neuropathy (DAN). The IMT group had a greater increase in maximum inspiratory pressure as compared to P-IMT (p<0.05). The IMT improved inspiratory muscle strength in patients with DAN.

Cardiovascular control in women with fibromyalgia syndrome: do causal methods provide nonredundant information compared with more traditional approaches?

The cardiovascular autonomic control and the baroreflex sensitivity (BRS) have been widely studied in fibromyalgia syndrome (FMS) patients through the computation of linear indices of spontaneous heart period (HP) and systolic arterial pressure (SAP) variabilities. However, there are many methodological difficulties regarding the quantification of BRS by the traditional indices especially in relation to the issue of causality. This difficulty has been directly tackled via a model-based approach describing the closed-loop HP-SAP interactions and the exogenous influences of respiration. Therefore, we aimed to assess whether the BRS assessed by the model-based causal closed-loop approach during supine and active standing in patients with FMS could provide complementary information to those obtained by traditional indices based on time and frequency domains. The findings of this study revealed that, at difference with the traditional methods to quantify BRS, the causality analysis applied to the HP, SAP, and respiratory series, through the model-based closed-loop approach, detected lower BRS in supine position, as well as a blunted response to the orthostatic stimulus in patients with FMS compared with healthy control subjects. Also, the strength of the causal relation from SAP to HP (i.e., along the cardiac baroreflex) increased during the active standing only in the control subjects. The model-based closed-loop approach proved to provide important complementary information about the cardiovascular autonomic control in patients with FMS.

Cardiovascular autonomic control in patients undergoing left ventricular assist device (LVAD) support and pharmacologic therapy

The objective of the study is to determine cardiac autonomic control in patients undergoing assessment for and/or LVAD therapy. Heart rate variability (HRV) was measured in 17 explanted LVAD, 17 implanted LVAD and 23 NYHA III-IV classified chronic heart failure (CHF) patients and ten healthy matched controls under three conditions: supine free breathing, standing and supine controlled breathing. Five measures of HRV were assessed: mean R-R interval (mR-R), high frequency (HF) and low frequency (LF) spectral power, LF in normalised units (LFnu), and LF to HF (LF:HF) ratio. Repeat measures ANOVA showed significant (p < 0.05) differences in HRV between all three conditions within groups. Lower values were observed in CHF for LF(in log natural units) compared with explanted patients (-1.4 [95% CI -2.6 to -0.7], p = 0.04) and controls (-2.1 [-3.5 to -0.7], p = 0.001) and for LF:HF compared with implanted patients under paced breathing conditions (z = -2.7, p = 0.007) and controls in standing (z = -2.9, p = 0.004) and paced breathing conditions (z = -2.3, p = 0.02). However, no significant differences were seen between explanted, implanted and control groups under any condition. Patients implanted with an LVAD and explanted from a LVAD following myocardial recovery demonstrate a more normal dynamic response to autonomic stimuli and have a lower HRV risk profile compared to CHF patients.

Symptoms of anxiety and mood disturbance alter cardiac and peripheral autonomic control in patients with metabolic syndrome

Previous investigations show that metabolic syndrome (MetSyn) causes sympathetic hyperactivation. Symptoms of anxiety and mood disturbance (AMd) provoke sympatho-vagal imbalance. We hypothesized that AMd would alter even further the autonomic function in patients with MetSyn. Twenty-six never-treated patients with MetSyn (ATP-III) were allocated to two groups, according to the levels of anxiety and mood disturbance: (1) with AMd (MetSyn + AMd, n = 15), and (2) without AMd (MetSyn, n = 11). Ten healthy control subjects were also studied (C, n = 10). AMd was determined using quantitative questionnaires. Muscle sympathetic nerve activity (MSNA, microneurography), blood pressure (oscillometric beat-to-beat basis), and heart rate (ECG) were measured during a baseline 10-min period. Spectral analysis of RR interval and systolic arterial pressure were analyzed, and the power of low (LF) and high (HF) frequency bands were determined. Sympatho-vagal balance was obtained by LF/HF ratio. Spontaneous baroreflex sensitivity (BRS) was evaluated by calculation of α-index. MSNA was greater in patients with MetSyn + AMd compared with MetSyn and C. Patients with MetSyn + AMd showed higher LF and lower HF power compared with MetSyn and C. In addition, LF/HF balance was higher in MetSyn + AMd than in MetSyn and C groups. BRS was decreased in MetSyn + AMd compared with MetSyn and C groups. Anxiety and mood disturbance alter autonomic function in patients with MetSyn. This autonomic dysfunction may contribute to the increased cardiovascular risk observed in patients with mood alterations.