Cardiovascular Autonomic Parameters Research Articles

Correlation between Cardiovascular Autonomic and Pulmonary Ventilation Functions in Myasthenia Gravis Patients.

This study aimed to investigate the relationship between pulmonary function and cardiac autonomic function parameters in clinically stable myasthenia gravis (MG) patients. A total of 22 MG patients and 22 healthy controls (HCs) were evaluated. Pulmonary function test parameters, heart rate variability (HRV), baroreflex sensitivity (BRS), and cardiovascular autonomic function test parameters (the Valsalva ratio, expiration/inspiration (E/I) ratio) were assessed. Compared with the HCs, the patients demonstrated a similar diffusion capacity for carbon monoxide (DLCO); a lower forced vital capacity (FVC%pred); a lower forced expiratory volume in 1 s (FEV1%pred); lower BRS and HRV, including high-frequency and total power spectral density; and a higher percentage of abnormal cardiovagal function test results (p < 0.05). A lower BRS in the patient group was associated with worse clinical disease outcomes and reduced pulmonary function (DLCO%pred, R = 0.59; TLC%pred, R = 0.48). Age, forced vital capacity, and total lung capacity predicted the E/I ratio (R2 values ranging from 0.48 to 0.49). Our study demonstrated a significant relationship between a reduced pulmonary ventilation function and respiratory mechanics with cardiovascular autonomic parameters, including the E/I ratio, BRS, and HRV measures at rest, as shown in the MG group. Future studies should focus on the interplay between respiratory and autonomic function testing, as well as pulmonary rehabilitation, to mitigate cardiovascular risk in these patients.

Altered Cardiac Autonomic Regulation in Individuals with Myasthenia Gravis-A Systematic Review and Meta-Analysis.

The aim of this systematic review with meta-analysis was to determine differences in cardiovascular autonomic parameters between patients with myasthenia gravis (MG) and healthy controls (HCs). Two reviewers searched four electronic databases, namely PubMed, Web of Science, EMBASE, and SCOPUS, from database inception to 7 July 2023 for studies investigating cardiovascular autonomic parameters in MG vs. HCs. A random-effects meta-analysis was performed to compute Hedges' g ± 95% confidence intervals (CI). Out of a total of 2200 records, 8 observational studies with a sample size of 301 patients with MG and 454 HCs were included in the systematic review. Meta-analysis revealed lower values of expiration/inspiration ratio (g = -0.45, I2 = 74.7), baroreflex sensitivity (g = -0.56, 95%CI -0.80, -0.33; I2 = 0.3), percentage of adjacent NN intervals differing by more than 50 ms (g = -1.2, I2 = 82.8), square root of the mean of squared differences between successive beat intervals (g = -1.94, I2 = 95.1), mean of the standard deviations of all NN intervals (g = -0.83, 95%CI -1.37, -0.28; I2 = 55.5), and high frequency of HRV during tilt (g = -0.75, 95%CI -0.11, -0.39; I2 = 0). MG patients vs. HCs had higher systolic blood pressure (g = 0.39; I2 = 56.1), sympathovagal balance at rest/during tilt (LF/HF-RRIsupine, g = 0.44; I2 = 0; LF/HF-RRItilt, g = 0.86; I2 = 0; LF/HFtilt, g = 0.40; I2 = 0). As a group, MG patients have altered cardiac autonomic function, including decreased parasympathetic function, lower baroreflex sensitivity, and higher sympathovagal balance at rest and during orthostatic challenges.

Cognitive and Autonomic Dysfunction in Multiple System Atrophy Type P and C: A Comparative Study.

Multiple System Atrophy (MSA) is a rare neurodegenerative disease, clinically defined by a combination of autonomic dysfunction and motor involvement, that may be predominantly extrapyramidal (MSA-P) or cerebellar (MSA-C). Although dementia is generally considered a red flag against the clinical diagnosis of MSA, in the last decade the evidence of cognitive impairment in MSA patients has been growing. Cognitive dysfunction appears to involve mainly, but not exclusively, executive functions, and may have different characteristics and progression in the two subtypes of the disease (i.e., MSA-P and MSA-C). Despite continued efforts, combining in-vivo imaging studies as well as pathological studies, the physiopathological bases of cognitive involvement in MSA are still unclear. In this view, the possible link between cardiovascular autonomic impairment and decreased cognitive performance, extensively investigated in PD, needs to be clarified as well. In the present study, we evaluated a cohort of 20 MSA patients (9 MSA-P, 11 MSA-C) by means of a neuropsychological battery, hemodynamic assessment (heart rate and arterial blood pressure) during rest and active standing and bedside autonomic function tests assessed by heart rate variability (HRV) parameters and sympathetic skin response (SSR) in the same experimental session. Overall, global cognitive functioning, as indicated by the MoCA score, was preserved in most patients. However, short- and long-term memory and attentional and frontal-executive functions were moderately impaired. When comparing MSA-P and MSA-C, the latter obtained lower scores in tests of executive functions and verbal memory. Conversely, no statistically significant difference in cardiovascular autonomic parameters was identified between MSA-P and MSA-C patients. In conclusion, moderate cognitive deficits, involving executive functions and memory, are present in MSA, particularly in MSA-C patients. In addition, our findings do not support the role of dysautonomia as a major driver of cognitive differences between MSA-P and MSA-C.

Role of aerobic physical training on cardiac autonomic and morphophysiological dysfunction in hypertensive rats subjected to ovarian hormone deprivation.

Here we investigated the effects of physical training on cardiovascular autonomic control and cardiac morphofunctional parameters in spontaneously hypertensive rats (SHRs) subjected to ovarian hormone deprivation. Forty-eight 10-week-old SHRs were divided into two groups: ovariectomized (OVX, n=24) and sham (SHAM, n=24). Half of each group (n=12) was trained by swimming for 12 weeks (OVX-T and SHAM-T). Cardiac morphology and functionality were assessed using echocardiography, and autonomic parameters were assessed using double pharmacological autonomic block, baroreflex sensitivity (BRS), and analyses of heart rate variability (HRV) and blood pressure variability (BPV). Ovariectomy did not influence the cardiac autonomic tonus balance unlike physical training, which favored greater participation of the vagal autonomic tonus. Ovariectomy and aerobic physical training did not modify HRV and BRS, unlike BPV, for which both methods reduced low-frequency oscillations, suggesting a reduction in sympathetic vascular modulation. Untrained ovariectomized animals showed a reduced relative wall thickness (RWT) and increased diastolic and systolic volumes and left ventricular diameters, resulting in increased stroke volume. Trained ovariectomized animals presented reduced posterior wall thickness and RWT as well as increased final diastolic diameter, left ventricular mass, and stroke volume. Ovarian hormone deprivation in SHRs promoted morphofunctional adaptations but did not alter the evaluation of cardiac autonomic parameters. In turn, aerobic physical training contributed to a more favorable cardiac autonomic balance to the vagal autonomic component and promoted morphological adaptations but had little effect on cardiac functionality.

Study of heart rate recovery and cardiovascular autonomic modulation in healthy participants after submaximal exercise

Heart rate variability (HRV), blood pressure variability (BPV), and baroreflex sensitivity (BRS) provide important information on cardiovascular autonomic control. However, little is known about the reorganization of HRV, BPV, and BRS after aerobic exercise. While there is a positive relationship between heart rate (HR) recovery rate and cardiorespiratory fitness, it is unclear whether there is a relationship between cardiorespiratory fitness and reorganization of cardiovascular autonomic modulation during recovery. Thus, this study aimed to investigate whether cardiorespiratory fitness influences the cardiovascular autonomic modulation recovery, after a cardiopulmonary exercise test. Sixty men were assigned into groups according to their cardiorespiratory fitness: low cardiorespiratory fitness (LCF = VO2: 22–38 mL kg−1 min−1), moderate (MCF = VO2: 38–48 mL kg−1 min−1), and high (HCF = VO2 > 48 mL kg−1 min−1). HRV (linear and non-linear analysis) and BPV (spectral analysis), and BRS (sequence method) were performed before and after a cardiopulmonary exercise test. The groups with higher cardiorespiratory fitness had lower baseline HR values and HR recovery time after the cardiopulmonary exercise test. On comparing rest and recovery periods, the spectral analysis of HRV showed a decrease in low-frequency (LF) oscillations in absolute units and high frequency (HF) in absolute and normalized units. It also showed increases in LF oscillations of blood pressure. Nonlinear analysis showed a reduction in approximate entropy (ApEn) and in Poincare Plot parameters (SD1 and SD2), accompanied by increases in detrended fluctuation analysis (DFA) parameters α1 and α2. However, we did not find differences in cardiovascular autonomic modulation parameters and BRS in relation to cardiorespiratory fitness neither before nor after the cardiopulmonary test. We concluded that cardiorespiratory fitness does not affect cardiovascular autonomic modulations after cardiopulmonary exercise test, unlike HR recovery.

Important differences between hypertensive middle-aged women and men in cardiovascular autonomic control\u2014a critical appraisal

BackgroundNormotensive premenopausal women show a vagal predominance of cardiac autonomic modulation, whereas age-matched men show a predominance of sympathetic modulation. However, some women develop systemic arterial hypertension (SAH) even with preserved ovarian function. Our hypothesis is that these women may have cardiovascular autonomic parameters similar to those of hypertensive men, even when subjected to pharmacological treatment. We aimed to investigate cardiovascular autonomic control and baroreflex sensitivity (BRS) in hypertensive premenopausal women and age-matched men.MethodsOne hundred volunteers between 18 and 45 years of age were assigned to two groups (50 participants each): a hypertensive group including patients with a history of SAH for at least 6 months (25 men and 25 women), who were under treatment with monotherapy (losartan, 25–50 mg/kg); and a normotensive group (25 men and 25 women). Anthropometric, hemodynamic, metabolic, and autonomic cardiovascular assessments were performed focusing on BRS, autonomic modulation of heart rate variability (HRV), and blood pressure variability (BPV).ResultsOn HRV analysis, women showed higher values of high-frequency (HF) oscillations in absolute and normalized units, lower values ​of low-frequency (LF) in normalized units, and lower LF/HF ratio, as compared with men. When the normotensive and hypertensive groups were compared, hypertensive groups showed lower values ​of total variance and of LF and HF bands in absolute units. On BRS, hypertensive groups showed lower values than the normotensive group.ConclusionRegardless of blood pressure control through pharmacological treatment, hypertensive patients continued to have reduced HRV compared to normotensive, and hypertensive men had more autonomic impairment than hypertensive premenopausal women.

Osteopathic Manipulative Treatment and Cardiovascular Autonomic Parameters in Rugby Players: A Randomized, Sham-Controlled Trial

ObjectiveThe purpose of this study was to investigate the effects of osteopathic manipulative treatment (OMT) on cardiovascular autonomic parameters after a rugby match. MethodsResting and reactivity (ie, response to orthostasis) measures of mean arterial pressure, heart rate, and heart rate variability were assessed in 23 male players after a single session of OMT, both 18 to 20 hours after a rugby match and in a corresponding no-match condition, in a randomized, sham-controlled, crossover design. ResultsSigns of reduced heart rate variability and elevated mean arterial pressure and heart rate were found 18 to 20 hours after a rugby match compared with the no-match condition. A significant increase in heart rate variability and a significant reduction in mean arterial pressure were observed after OMT in both the after-match and no-match conditions. Heart rate and heart rate variability responses to orthostasis were not affected by previous match competition, but were significantly larger after OMT compared with sham treatment. ConclusionThis study suggests the presence of cardiovascular autonomic alterations in rugby players after a competitive match, which may be indicative of prolonged fatigue and incomplete recovery. In these players, favorable changes in cardiovascular autonomic parameters were observed following a single session of OMT.

The Role of Electrochemical Skin Conductance as a Screening Test of Cardiovascular Autonomic Neuropathy in Patients with Parkinson's Disease.

Autonomic disorders have been recognized as an important non-motor feature in Parkinson’s disease (PD). However, there is a paucity of information on the presence and severity of cardiovascular autonomic neuropathy (CAN) among different motor phenotypes. The aims of this study were to examine the feasibility of electrochemical skin conductance (ESC) measured by Sudoscan as a screening service for CAN in patients with PD and investigate the severity of CAN among different motor phenotypes. Design: This was a cross-sectional observational study that enrolled 63 patients with PD. Patients were divided into three phenotypes, postural instability/gait difficulty (PIGD), tremor-dominant (TD), and akinetic-rigid (AR), according to their motor symptoms. Cardiovascular autonomic function was measured, and the presence and severity of CAN was determined according to the composite autonomic scoring scale (CASS). Functional scores were measured by the Hoehn and Yahr (HY) stage and the Unified Parkinson’s Disease Rating Scale (UPDRS). The median HY stage was 2.0 [1.5, 3.0]. Median UPDRS total score was 23.0 (17.5, 30.5), 10.0 (6.0, 11.0) and 14.0 (6.3, 23.8) in groups of PIGD, TD and AR, respectively (p = 0.001). Mean CASS was 1.7 ± 1.3, 0.6 ± 0.4, and 1.8 ± 1.5 in groups of PIGD, TD and AR, respectively (p = 0.204). Although the ESC was not strongly associated with the cardiovascular autonomic parameters, the CAN risk score provided by Sudoscan significantly correlated with parameters of cardiovascular autonomic function, including heart rate response to deep breathing (HR_DB), Valsalva ratio (VR), and baroreflex sensitivity (BRS). By receiver-operating characteristic (ROC) analysis, if a patient’s CAN risk score is higher than 33.5 (%), it is recommended to be aware of the presence of CAN even in PD patients who are asymptomatic. The area under ROC curve was 0.704. Based on our results, CAN risk score may be used for screening of CAN in patients with PD before resorting to the more sophisticated and specific, but ultimately more time-consuming, complete autonomic function testing.

Linking Pain Sensation to the Autonomic Nervous System: The Role of the Anterior Cingulate and Periaqueductal Gray Resting-State Networks.

There are bi-directional interactions between the autonomic nervous system (ANS) and pain. This is likely underpinned by a substantial overlap between brain areas of the central autonomic network and areas involved in pain processing and modulation. To date, however, relatively little is known about the neuronal substrates of the ANS-pain association. Here, we acquired resting state fMRI scans in 21 healthy subjects at rest and during tonic noxious cold stimulation. As indicators of autonomic function, we examined how heart rate variability (HRV) frequency measures were influenced by tonic noxious stimulation and how these variables related to participants’ pain perception and to brain functional connectivity in regions known to play a role in both ANS regulation and pain perception, namely the right dorsal anterior cingulate cortex (dACC) and periaqueductal gray (PAG). Our findings support a role of the cardiac ANS in brain connectivity during pain, linking functional connections of the dACC and PAG with measurements of low frequency (LF)-HRV. In particular, we identified a three-way relationship between the ANS, cortical brain networks known to underpin pain processing, and participants’ subjectively reported pain experiences. LF-HRV both at rest and during pain correlated with functional connectivity between the seed regions and other cortical areas including the right dorsolateral prefrontal cortex (dlPFC), left anterior insula (AI), and the precuneus. Our findings link cardiovascular autonomic parameters to brain activity changes involved in the elaboration of nociceptive information, thus beginning to elucidate underlying brain mechanisms associated with the reciprocal relationship between autonomic and pain-related systems.

Depressed baroreflex sensitivity from spontaneous oscillations of heart rate and blood pressure in SCA1 and SCA2.

To assess the time and frequency domain measures of cardiac autonomic activity/tone in patients of genetically defined spinocerebellar ataxia (SCA) types 1 and 2, as well as to decipher the probable associations among the cardiovascular autonomic parameters and genetic and clinical characteristics. Simultaneous 5-min recording of RR interval (RRI) and blood pressure (BP) for the calculation of heart rate variability (HRV), blood pressure variability (BPV) and baroreflex sensitivity (BRS) were performed in genotypically confirmed SCA1 (n=31) and SCA2 (n=40) patients and healthy controls (n=40). Additionally, the International Cooperative Ataxia Rating Scale (ICARS) was used for scoring of clinical severity in SCA patients. Time and frequency domain parameters of HRV, BPV and BRS were depressed in SCA1 and SCA2 subtypes as compared to controls, although there was no statistically significant difference in autonomic tone between the two SCA subtypes. On correlation analysis, autonomic tone parameters were found to be associated with the clinical and genetic features of the SCA subtypes. Also, ICARS was associated with the genotype (CAG repeat length) in SCA2 patents. Cardiac autonomic tone is depressed in both SCA1 and 2 as compared to healthy controls while the two SCA subtypes do not differ in terms of autonomic tone. Also, a typical association exists between disease characteristics and autonomic indices.

Plasma Levels of SDF-1 are Acutely Correlated with Adrenergic Agonists and Modulated by β-Blockers Interactions in Hypertensive Individuals

To examine the acute interference of β-blockers with plasma chemokine stromal cell-derived factor-1 (SDF-1), epinephrine and norepinephrine levels, as well as cardiovascular autonomic parameters.

Musculoskeletal pains and cardiovascular autonomic function in the general Northern Finnish population

BackgroundHeart rate variability (HRV) and baroreflex sensitivity (BRS) measurements provide means for the objective assessment of cardiovascular autonomic function. As previous studies have associated chronic pain with abnormal autonomic function, we aimed to characterize the relationship between the number of musculoskeletal pain sites (NPS), pain intensity, and cardiovascular autonomic function among the population-based Northern Finland Birth Cohort 1966.MethodsAt the age of 46, cohort members self-reported their musculoskeletal pains (enabling the determination of NPS [0–8] and pain intensity [Numerical Rating Scale, NRS, 0–10]) and underwent clinical assessments of cardiovascular autonomic function in seated and standing positions (HRV variables: heart rate [HR] and root mean square of successive differences in beat-to-beat intervals [rMSSD] for the entire cohort; BRS variables: low-frequency systolic blood pressure variability [SBPV] and cross-spectral baroreflex sensitivity [BRS] for those attending the examination in Oulu, Finland). Extensive confounder data were also collected (body mass index, physical activity, smoking, Hopkins Symptom Checklist-25, comorbidities, and medications). The full samples included 4186 and 2031 individuals (HRV and BRS samples, respectively). Three subanalyses focused on individuals with intense and frequent pain, individuals with symptoms of depression and anxiety, and the relationship between pain intensity and autonomic parameters.ResultsLinear regression models showed varying associations between NPS, pain intensity, and cardiovascular autonomic parameters. However, after all adjustments NPS was only associated with one outcome among women (BRS, standing: beta = − 0.015, p = 0.048) and two among men (HR, seated: beta = − 0.902, p = 0.003; HR, standing: beta = − 0.843, p = 0.014). Pain intensity was not associated with any outcome after full adjustments. Significant sex*pain interactions were found in the data.ConclusionsOur data suggest that musculoskeletal pain has, at most, a limited independent association with cardiovascular autonomic function. Future studies should carefully account for the potential confounders and sex interactions that this study revealed.

Low-frequency facial hemodynamic oscillations distinguish migraineurs from non-headache controls.

Surface imaging is a promising, noninvasive approach to assess regional perfusion in craniovascular disorders such as migraine. We used optical imaging to examine differences in facial blood volume at baseline and in response to ammonia inhalation (a noxious stimulus), as well as standardized measures of cardiovascular autonomic function, in healthy, non-headache controls (n = 43) and in interictal migraine subjects (n = 22). Resting facial cutaneous oscillation (FCO) frequency was significantly different in migraine compared to healthy controls. Following ammonia inhalation, healthy controls showed a significant increase in resting FCO frequency, whereas this response was not significant in the migraine group. Standardized autonomic reflex parameters did not differ significantly between study groups, and facial cutaneous activity did not correlate with standardized cardiovascular autonomic reflex parameters, suggesting potentially different regulation. This approach to the assessment of craniofacial hemodynamic function appears to exhibit differing mechanisms from previously available techniques, and represents a promising new physiological biomarker for the study of craniofacial vascular function in migraine and potentially other craniovascular disorders.

Оценка факторов риска развития сердечно-сосудистых заболеваний и показателей вегетативной нервной системы у пациентов с хронической ишемией мозга и хронической сердечной недостаточностью.

Оценка факторов риска развития сердечно-сосудистых заболеваний и показателей вегетативной нервной системы у пациентов с хронической ишемией мозга и хронической сердечной недостаточностью.

Neuromuscular taping reduces blood pressure in systemic arterial hypertension

Systemic arterial hypertension, a well-known cause of morbidity, is associated with dysfunction of the autonomic nervous system. Neuromuscular taping (also known as kinesio taping, medical taping and Vendje neuromuscular) allows movement and muscle activity to treat pain, muscle disorders and lymphoedema, in which its mode of action may involve muscular stimulation leading to increased local blood circulation or stimulating dermatological, muscular and fascial structures with a form of passive massage. We hypothesised that neuromuscular taping may reduce blood pressure in systemic arterial hypertension. This hypothesis was tested by carrying out the first pilot study of its kind to determine whether the non-invasive technique of neuromuscular taping can reduce blood pressure in patients suffering from systemic arterial hypertension. Neuromuscular taping was symmetrically applied to the back, between C1 and T2, of seven hypertensive patients for 5–7 days. Cardiovascular autonomic parameters were assessed at baseline and at the end of the study. Taping was associated with falls in mean arterial blood pressure (p = .001), mean systolic blood pressure (p < .01), mean diastolic pressure (p < .01) and cardiac vagal tone at rest (p = .063). The beneficial effects on blood pressure appeared to last for at least five days post-neuromuscular taping. There is an indication, given the reduction in cardiac vagal tone at rest, that the mechanism of action of this intervention involves modulation of the brainstem parasympathetic system during cardiovascular control. Further studies are indicated to replicate the present findings, further investigate the effects of taping on autonomic functioning, and establish the optimum time-period and taping positioning.

Effect of Nadi Shuddhi Pranayama on perceived stress and cardiovascular autonomic functions in 1st year undergraduate medical students

Background: First year medical students have reported a high level of perceived stress. Yogic breathing technique “Pranayama” is said to balance two limbs of autonomic nervous system and therefore advocated for stress reduction and prevention of related diseases. Aims and Objectives: The present study was conducted to evaluate the effects of Nadi Shuddhi Pranayama on perceived stress and cardiovascular autonomic functions in 1st year medical students. Materials and Methods: The present study was carried out in one of the tertiary care hospitals of Mumbai. A total of 60 subjects (age 18–22 years) practised Nadi Shuddhi Pranayama daily for 12 weeks under the supervision of certified yoga trainer. Following parameters were recorded before and after 12 weeks of training; perceived stress scale (PSS) score, heart rate (HR), systolic blood pressure (SBP) and diastolic BP (DBP), DBP response to isometric handgrip (IHG) test. Results: There was a significant decrease in PSS scores after intervention. A significant decrease was also seen in cardiovascular autonomic functions such as HR, SBP, DBP, and DBP response to IHG test. Conclusion: Regular practice of Nadi Shuddhi Pranayama helps in reducing stress in 1st year medical students as evidenced by the corresponding decrease in cardiovascular autonomic parameters.

Effect of Baroreceptor Sensitivity on Outcomes in Patients with Acute Spontaneous Intracerebral Hemorrhage.

Reduced baroreflex sensitivity (BRS) has been reported in patients with acute cardiovascular events. We tested the hypothesis that BRS is substantially reduced in patients with spontaneous intracerebral hemorrhage (ICH) and that BRS can predict treatment outcomes. We examined BRS and other cardiovascular autonomic parameters in 35 patients with ICH over the course of 30 days. Cardiovascular autonomic parameters also were evaluated in 30 healthy volunteer subjects during the study period. Outcome was assessed at 30 days with the modified Rankin Scale (mRS). Good outcome was defined as an mRS <1, whereas patients defined as having a poor outcome had either an mRS ≥2 or died shortly after the stroke event. Twenty patients had a poor outcome, and 15 patients had a good outcome. BRS values in the patients with poor outcome group were lower in comparison with the healthy subjects, and BRS values in patients with poor outcomes were significantly lower than that those in patients with good outcomes on day 1, day 4, and day 10. BRS was associated independently with outcome and the cut-off value of BRS on day 1 in the poor outcome group was 6.79. Based on our results, BRS value at admission is a more powerful predictor of outcome than the Glasgow Coma Scale score at admission. An assay of BRS could be added as a biomarker for outcome prediction among patients with spontaneous ICH in clinical practice.

Chronic cholinergic stimulation promotes changes in cardiovascular autonomic control in spontaneously hypertensive rats.

Hypertension is often accompanied by autonomic dysfunction, which is detrimental to cardiac regulation. On the other hand, cholinergic stimulation through inhibition of acetylcholinesterase appears to have beneficial effects on cardiac autonomic control. Thus, our objective was to investigate the effects of chronic cholinergic stimulation on hemodynamic and cardiovascular autonomic control parameters in spontaneously hypertensive rats (SHR). For this, 26-week-old SHR (N = 32) and Wistar Kyoto rats (WK; N = 32) were divided into two groups: one treated with vehicle (H2O; N = 16) and the other treated with pyridostigmine bromide (PYR; N = 16) in drinking water (25 mg/kg/day) for 2 weeks. All groups were subjected to recording of arterial pressure (AP) and heart rate (HR), quantification of ejection fraction (EF), evaluation of cardiac tonic autonomic balance by means of double autonomic blockade with methylatropine and propranolol, analysis of systolic AP (SAP) and HR variability (HRV), and evaluation of baroreflex sensitivity (BRS). AP, HR, and EF were reduced in the SHR-PYR group compared with the SHR-H2O group. Evaluation of autonomic parameters revealed an increase in vagal tone participation in cardiac tonic autonomic balance and reduced SAP variability; however, no changes were observed in HRV or BRS. These results suggest that chronic cholinergic stimulation with pyridostigmine bromide promotes reduction in the hemodynamic parameters AP, HR, and EF. Additionally, tonic autonomic balance was improved and a reduction in LF oscillations of SAP variability was observed that could not be attributed to BRS, as the latter did not change. Further studies should be conducted to identify the mechanisms involved in the observed responses.

Sex and age effects on cardiovascular autonomic function in healthy adults.

To determine the effects of sex and age on cardiovascular autonomic parameters in healthy adults as assessed by Finapres (finger arterial pressure) method and prolonged head-up tilt (HUT). We enrolled 81 healthy volunteers (41 females, 40 males, 18-74 years) for extensive cardiovascular autonomic function testing including blood pressure (BP) recordings, electrocardiography, and impedance cardiography at rest, under 60° HUT for 45 min, active standing for 5 min, Valsalva maneuver, and deep breathing (DB). Mean values and orthostatic changes, i.e., differences to baseline, of heart rate (HR), systolic and diastolic BP, stroke volume (SV), and total peripheral resistance (TPR), as well as DB ratio and Valsalva ratio were calculated. A generalized linear model (extended by generalized estimating equations) was used to assess sex- and age-related differences. Mean HR at rest was higher in women than in men (p = 0.035). In men, we observed significantly higher mean BP at rest (p < 0.001 systolic and p = 0.004 diastolic) and during HUT (p = 0.001 systolic and p < 0.001 diastolic), mean TPR at rest (p = 0.034), and mean SV during HUT (p < 0.001). We found no significant impact of sex on orthostatic changes of HR and BP. Mean TPR during HUT increased with age (p = 0.001), particularly in older women. Orthostatic changes of HR and diastolic BP, DB ratio, and Valsalva ratio became attenuated with age (p = 0.018, p = 0.006, p < 0.001, and p < 0.001, respectively). Our study suggests that aging rather than sex needs to be taken into account when interpreting HR and BP changes during prolonged HUT performance.

Improvement of baroreflex sensitivity in patients with obstructive sleep apnea following surgical treatment

ObjectiveDepressed baroreflex sensitivity (BRS) have been reported in patients with obstructive sleep apnea (OSA). This study aimed to determine if surgery can improve the clinical outcomes by investigating changes in BRS and in other cardiovascular autonomic parameters. MethodsEighty-one OSA patients were enrolled. They were classified as mild OSA if their apnea–hypopnea index (AHI) was 5–15, moderate OSA if their AHI was 15–30, and sever OSA if their AHI was >30. Twenty-three subjects with AHI<5 were recruited as controls. For patients who received surgery, polysomnography (PSG) and autonomic tests were evaluated upon enrollment and six-months after surgery. ResultsThe patient number for mild, moderate, and severe OSA was 22, 22, and 37, respectively. BRS on enrollment showed significant difference among the four groups, with the highest BRS in the control group, follow by the mild, moderate, and severe OSA groups. There were significant correlations between BRS and all PSG parameters. The depressed BRS significantly improved after surgery. ConclusionsSurgical modifications of the upper airways can improve the depressed BRS in OSA patients. SignificanceThe study offers the promise that surgical treatment for OSA not only improves the index of PSG, but also reduces the possibility of cardiovascular risk.