Impairment Of Autonomic Nervous System Research Articles

Association of Self-Reported Autonomic Symptoms With Sensor-Based Physiological Measures.

Autonomic regulation of organ and tissues may give rise to disruptions of typical functions. The Body Perception Questionnaire Short Form (BPQ-SF) includes items that were developed to assess autonomic symptoms in daily life. This pair of studies aimed to establish previously unexplored psychometric properties of the BPQ-SF autonomic symptoms scale, develop normative values for clinical and research use, and assess the convergence of self-reports with sensor-based measures. Study 1 reports exploratory and confirmatory factor analysis on BPQ-SF autonomic symptom items from a large US population-based online study ( n = 2048). In study 2, BPQ-SF scores were examined for associations with heart period, respiratory sinus arrhythmia, and skin conductance during seated leg lifts in a community sample ( n = 62). Study 1 results supported a two-factor supradiaphragmatic and subdiaphragmatic autonomic symptom solution (confirmatory factor analysis: root mean squared error of approximation = 0.040, Comparative Fit Index = 0.99, Tucker-Lewis Index = 0.99), although a one-factor solution also fit the data well (root mean squared error of approximation = 0.080, Comparative Fit Index = 0.99, Tucker-Lewis Index = 0.99). In study 2, heart period responses to leg lifts and rests were demonstrated at all autonomic symptom levels. However, low autonomic symptoms were associated with optimal autonomic nervous system patterns of activation and recovery to baseline levels. Moderate symptoms were associated with prolonged sympathetic activation. The highest symptom levels were associated with impaired autonomic nervous system coordination across activation and recovery. Results support the utility of self-reports of autonomic symptoms in research and clinical applications, with higher symptoms likely indicating autonomic impairment.

The autonomic and nociceptive response to acute experimental stress is impaired in people with knee osteoarthritis: A preliminary study

ObjectiveAlterations in autonomic function are evident in some chronic pain conditions but have not been thoroughly examined in people with osteoarthritis (OA). The study aimed to examine resting autonomic nervous system (ANS) function in people with knee OA, and the response of the autonomic and nociceptive systems to acute stress. MethodsA preliminary cross-sectional study was undertaken involving people with knee OA (n = 14), fibromyalgia (n = 13), and pain-free controls (n = 15). The sympathetic and parasympathetic components of the ANS were assessed through measures of pre-ejection period (PEP), skin conductance level (SCL), and high frequency heart rate variability (HF HRV). The nociceptive system was assessed through pain ratings associated with a tonic heat pain stimulus. In separate sessions, ANS and heat pain measures were assessed at rest and in response to nociceptive and mental arithmetic stressors. ResultsThe knee OA group showed reduced HF HRV at rest and reduced modulation in response to stress. Resting PEP and SCL were normal in the knee OA group but PEP modulation was impaired in both chronic pain groups during nociceptive stress. The expected reduction in tonic heat pain ratings in response to stress was lacking in the knee OA and FM groups. ConclusionPreliminary evidence shows impaired parasympathetic nervous system function at rest and in response to nociceptive and mental stress in people with knee OA, with some evidence of altered sympathetic nervous system function. Impaired ANS function could contribute to ongoing pain experienced, and interventions that target ANS function could be beneficial.

1028 Congenital Central Hypoventilation in a patient with MCEP2 duplication syndrome

Abstract Introduction Congenital central hypoventilation (CCHS) is a rare disorder due to impairment of autonomic nervous system clinically defined by a significantly reduced or abolished ventilatory response to hypercapnia and hypoxemia in the absence of pulmonary, neuromuscular, or cardiac disease. There is limited knowledge on associated respiratory manifestations and sleep-disordered breathing in children with the MECP2 duplication syndrome. Although sleep-disordered breathing and nocturnal hypoventilation are currently not well recognized in these children, we present a case of a patient with MECP2 mutation and congenital hypoventilation syndrome. Report of case(s) 24-week-old male born full-term via c-section presented with recurrent respiratory problems, laryngeal cleft, dysphagia, snoring and apneic episodes. Previous genetic work up showed chromosome 15q11.2 microdeletion. Past medical history was significant for neonatal ICU stay for respiratory distress immediately following birth. Tonsils are 1+ on exam. PSG showed profound central sleep apnea (CAI 300/h) with average apneic episodes lasted for 7 seconds and very significant periodic breathing (88%) and mild obstructive apnea. Mild hypoxemia was also seen with SpO2 in low 90s without any significant hypercapnia. Bradypnea with resp rate 10-20/m was seen. PHOX2B gene testing was negative. Genetic testing with SNP array showed MECP2 duplication syndrome. His development is delayed, currently at the age of 20 months, including cognitive, speech and motor function for which he is on therapy. Tracheostomy was recommended, however family preferred to continue with non-invasive ventilation while awaiting diaphragmatic pacing. Conclusion Respiratory manifestations in MECP2 duplication syndrome patients are common, with important impact and even a possible fatal outcome. Although sleep-disordered breathing and nocturnal hypoventilation is currently not cited as an important symptom in these children, there have been several case reports of CCHS associated with this. PSG should be considered in patients with MCEP2 duplication syndrome for timely diagnosis. Different treatment modalities (ENT surgery, CPAP and NIV) can be applied successfully to treat respiratory conditions associated with MECP2 duplication syndrome. Support (if any)  

Modulating Heart Rate Variability through Deep Breathing Exercises and Transcutaneous Auricular Vagus Nerve Stimulation: A Study in Healthy Participants and in Patients with Rheumatoid Arthritis or Systemic Lupus Erythematosus.

Rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE) are associated with an impaired autonomic nervous system and vagus nerve function. Electrical or physiological (deep breathing—DB) vagus nerve stimulation (VNS) could be a potential treatment approach, but no direct comparison has been made. In this study, the effect of transcutaneous auricular VNS (taVNS) and DB on vagal tone was compared in healthy participants and RA or SLE patients. The vagal tone was estimated using time-domain heart-rate variability (HRV) parameters. Forty-two healthy participants and 52 patients performed 30 min of DB and 30 min of taVNS on separate days. HRV was recorded before and immediately after each intervention. For the healthy participants, all HRV parameters increased after DB (SDNN + RMSSD: 21–46%), while one HRV parameter increased after taVNS (SDNN: 16%). For the patients, all HRV parameters increased after both DB (17–31%) and taVNS (18–25%), with no differences between the two types of VNS. DB was associated with the largest elevation of the HRV parameters in healthy participants, while both types of VNS led to elevated HRV parameters in the patients. The findings support a potential use of VNS as a new treatment approach, but the clinical effects need to be investigated in future studies.

Heart rate fragmentation as a marker of altered global autonomic nervous system activity: a novel predictor of atrial fibrillation occurrence in the general population

Abstract Background The dysfunction of the autonomic nervous system (ANS) plays an important role in the initiation and maintenance of atrial fibrillation (AF). However, the meaning of high heart rate variability (HRV) in predicting AF is still under debate due to conflicting results in population-based studies. Short-term HRV is conceptually attributed to vagal tone modulation. But recent data suggest that a component of short-term HRV, called heart rate fragmentation, is related to ANS breakdown. On the other hand, parasympathetic activity could be assess by a novel metric, the deceleration capacity (DC). Objective To assess predictive capacity of novel HRV-derived metrics, whether fragmentation indices or parameters of vagal tone, regarding the occurrence of AF in general population during long-term follow-up. Methods A cohort study was designed to prospectively assess the predictive value of ANS activity level among a healthy retired French population, regarding cardiovascular events and mortality. 1011 subjects aged 65 were enrolled in the study from 2000 to 2002. The enrolled population had no history of AF and a low cardiovascular risk. A median follow-up of 17.8 years (16.0–18.5) was managed. HRV data were acquired by 24-h Holter electrocardiogram (ECG) monitoring at baseline and assessed by frequency domain and time domain methods. Heart rate fragmentation using the percentage of inflection points (PIP), and assessment of specific parasympathetic activity using DC were then calculated. The study outcome was the onset of AF during follow-up, defined as a standard 12-lead ECG or Holter recording with ≥30 s of AF. Results AF was diagnosed in 123 patients along the 18-year follow-up, representing a cumulative incidence of 13.4%. Using univariate analysis (Figure 1A), a higher percentage of NN intervals that differ by more than 50 ms from the previous interval (pnn50) and root mean square differences of successive NN intervals (RMSSD) were associated with AF onset (p<0.01). A lower ratio of low-frequency and high-frequency component (LF/HF) was the only frequency-domain parameter found to predict the AF occurrence (p<0.01). The occurrence of AF was predicted by a higher PIP (p<0.01) and lower DC (p<0.01). Through multivariate analysis using clinical parameters that reached statistical significance in univariate analysis (Figure 1B), higher PIP was found as an independent predictor of AF occurrence (HR=2.1, 95% CI: 1.1–3.9, p=0.02), as well as male gender (HR=2.1, 95% CI: 1.1–3.9, p=0.02), and non-sustained supraventricular tachycardia (HR=2.1, 95% CI: 1.1–3.9, p=0.02). Conclusion (see Figure 2) Elevated PIP, a marker of heart rate fragmentation secondary to impaired ANS activity, is an independent predictor of the onset of AF in the healthy general population. Therefore, high HRV associated to AF occurrence could be the consequence of general ANS impairment rather than increased parasympathetic activity. Funding Acknowledgement Type of funding sources: None.

Pathophysiological and clinical aspects of the circadian rhythm of arterial stiffness in diabetes mellitus: A minireview.

Several cross-sectional trials have revealed increased arterial stiffness connected with the cardiac autonomic neuropathy in types 2 and 1 diabetic patients. The pathophysiological relationship between arterial stiffness and autonomic dysfunction in diabetes mellitus is still underinvestigated and the question whether the presence of cardiac autonomic neuropathy leads to arterial stiffening or increased arterial stiffness induced autonomic nervous system impairment is still open. Both arterial stiffness and dysfunction of the autonomic nervous system have common pathogenetic pathways, counting state of the chronic hyperinsulinemia and hyperglycemia, increased formation of advanced glycation end products, activation of protein kinase C, development of endothelial dysfunction, and chronic low-grade inflammation. Baroreceptor dysfunction is thought to be one of the possible reasons for the arterial wall stiffening development and progression. On the contrary, violated autonomic nervous system function can affect the vascular tone and by this way alter the large arteries walls elastic properties. Another possible mechanism of attachment and/or development of arterial stiffness is the increased heart rate and autonomic dysfunction corresponding progression. This minireview analyzes the current state of the relationship between the diabetes mellitus and the arterial stiffness. Particular attention is paid to the analysis, interpretation, and application of the results obtained in patients with type 2 diabetes mellitus and diabetic cardiac autonomic neuropathy.

Heart rate variability in congenital central hypoventilation syndrome: relationships with hypertension and sinus pauses.

Autonomic nervous system (ANS) dysregulation has been described in congenital central hypoventilation syndrome (CCHS). The objectives were to describe heart rate variability (HRV) analyses in children suffering from CCHS both while awake and asleep and their relationships with both ambulatory blood pressure (BP) and ECG monitoring results. This retrospective study enrolled children with CCHS (n = 33, median age 8.4 years, 18 girls) who had BP and ECG monitored during the same 24 h. From the latter, HRV analyses were obtained during daytime and nighttime. The prevalences of hypertension and sinus pauses were 33% (95% confidence interval [CI]: 18-52) and 18% (95% CI: 7-35), respectively. The decrease in systolic BP at night negatively correlated with an increase in very low frequency (VLF) and LF powers at night, and the longest RR interval positively correlated with daytime VLF and LF powers. Among the three groups of children (polyalanine repeat expansion mutation [PARM], moderate [20/25 and 20/26], severe [20/27 and 20/33], and non-PARMs), the prevalence of elevated BP or hypertension was different: in PARM subjects: 6/18 moderate, 7/9 severe versus 0/6 in non-PARM (p = 0.002). Modifications of cardiac ANS are associated with systemic hypertension and the occurrence of sinus pauses in CCHS. Children with congenital central hypoventilation syndrome (CCHS) exhibit an increased prevalence of hypertension and sinus pauses that are linked to cardiac autonomic nervous system dysfunction. Sinus pauses are the main manifestation of sinus nodal dysfunction in children with CCHS. The increased prevalence of hypertension, especially at nighttime, is a new finding in CCHS. Sinus nodal dysfunction can be due to the sole impairment of the cardiac autonomic nervous system. Ambulatory blood pressure and ECG monitoring are mandatory in patients with CCHS.

Reduced heart rate variability is related to the number of metabolic syndrome components and manifest diabetes in the sixth Tromsø study 2007–2008

Both diabetes mellitus (DM) and the metabolic syndrome (MetS) are associated with autonomic neuropathy, which predisposes to cardiac events and death. Measures of heart rate variability (HRV) can be used to monitor the activity of the autonomic nervous system (ANS), and there are strong indications that HRV can be used to study the progression of ANS-related diabetes complications. This study aims to investigate differences in HRV in healthy, MetS and diabetic populations. Based on 7880 participants from the sixth health survey in Tromsø (Tromsø 6, 2007–2008), we found a significant negative association between the number of MetS components and HRV as estimated from short-term pulse wave signals (PRV). This decrease in PRV did not appear to be linear, instead it leveled off after the third component, with no significant difference in PRV between the MetS and DM populations. There was a significant negative association between HbA1c and PRV, showing a decrease in PRV occurring already within the normal HbA1c range. The MetS and DM populations are different from healthy controls with respect to PRV, indicating impaired ANS in both conditions. In the future, a study with assessment of PRV measurements in relation to prospective cardiovascular events seems justified.

Evaluation of Cardiovascular Autonomic Function during Inpatient Rehabilitation following Traumatic Spinal Cord Injury.

Assessment of the degree of impaired autonomic nervous system (ANS) function is not part of routine clinical practice during inpatient rehabilitation following traumatic spinal cord injury (SCI). The goal of this investigation was to determine the utility of the International Standards for Neurologic Classification of SCI (ISNCSCI) and the recently revised International Standards to document remaining Autonomic Function after SCI (ISAFSCI) in documenting cardiovascular ANS impairment during inpatient rehabilitation following traumatic SCI. Beat-to-beat recording of supine heart rate (HR) and blood pressure (BP) were collected at the bedside for estimation of total cardiovascular ISAFSCI score, cardio-vagal modulation (i.e., high frequency HR variability [HFHRV]) and sympathetic vasomotor regulation (i.e., Mayer wave component of systolic BP [SBPmayer]). A total of 41 participants completed baseline testing, which was conducted 11 ± 5 days from the admission ISNCSCI examination. There were no differences in supine HR or BP based on the ISNCSCI or ISAFSCI assessments. The HFHRV was generally lower with more distal lesions (r2 = 0.15; p = 0.01), and SBPmayer was significantly lower in those with American Spinal Injury Association Impairment Scale (AIS) A compared with AIS B, C, D (Cohen's d = -1.4; p < 0.001). There were no significant differences in HFHRV or SBPmayer in patients with or without ISAFSCI evidence of cardiovascular ANS impairment. These preliminary data suggest that neither the ISNCSCI nor the ISAFSCI are sensitive to changes in ANS cardiovascular function following traumatic SCI. Bedside assessment of HR and BP variabilities may provide insight, but are not readily available in the clinical setting. Further research is required to evaluate methods that accurately assess the degree of ANS impairment following traumatic SCI.

Cognitive Impairment, Sleep Disturbance, and Depression in Women with Silicone Breast Implants: Association with Autoantibodies against Autonomic Nervous System Receptors.

Background: Silicone breast implants (SBIs) has been shown to be associated with an increased risk of autoimmune diseases. In the current study, we aimed to explore the potential association between circulating autoantibodies against the autonomic nervous system and cognitive impairment, memory deficit, and depressive symptoms reported by women with SBIs. Methods: ELISA assays were used to quantify anti-adrenergic receptors (α1, α2, β1, β2), anti-muscarinic receptors (M1-M5), anti-endothelin receptor type A, and anti-angiotensin II type 1 receptor titers in the sera of 93 symptomatic female subjects with SBIs and 36 age-matched healthy female controls. Results: A significant difference was detected in the level of autoantibodies against the autonomic nervous system receptors in women with SBIs who reported memory impairment, cognitive impairment, and sleep disturbance as compared with both women with SBIs who did not complain of these symptoms or with healthy individuals without SBIs. Conclusions: Clinical symptoms such as depression, cognitive impairment, and sleep disturbances were found to be associated with dysregulation of the levels of circulating autoantibodies targeting the autonomous nervous system receptors in women with SBIs. These autoantibodies may have diagnostic significance in diseases associated with breast implants.

Stress-related dysautonomias and neurocardiology-based treatment approaches.

Cardiovascular and psychiatric disorders are among the most commonly treated conditions worldwide. Research in neurocardiology, psychiatry, and epidemiology have defined bidirectional relationships between psychiatric disorders and heart disease, affirming the role of impaired autonomic nervous system, or dysautonomia in the prognosis and development in these disorders. These studies have fueled rapid clinical translation of experimental findings, with potential to complement existing pharmacological therapies. In this review, we comprehensively discuss the state-of-the-art investigations and novel treatment approaches for stress-related dysautonomias, emphasizing the effects of stress on the cardiac neuronal hierarchy. Increasing evidence suggests that autonomic modulation stands as an attractive therapeutic strategy in the treatment of dysautonomias that could complement existing therapies and possibly reduce the burden of drug-related side effects and treatment-resistant conditions. Further investigations regarding treatment optimization, selectivity, usability, and ethical concerns are required.

Frailty assessment using a novel approach based on combined motor and cardiac functions: a pilot study

BackgroundPrevious research showed association between frailty and an impaired autonomic nervous system; however, the direct effect of frailty on heart rate (HR) behavior during physical activity is unclear. The purpose of the current study was to determine the association between HR increase and decrease with frailty during a localized upper-extremity function (UEF) task to establish a multimodal frailty test.MethodsOlder adults aged 65 or older were recruited and performed the UEF task of rapid elbow flexion for 20 s with the right arm. Wearable gyroscopes were used to measure forearm and upper-arm motion, and electrocardiography were recorded using leads on the left chest. Using this setup, HR dynamics were measured, including time to peak HR, recovery time, percentage increase in HR during UEF, and percentage decrease in HR during recovery after UEF.ResultsFifty-six eligible participants were recruited, including 12 non-frail (age = 76.92 ± 7.32 years), and 40 pre-frail (age = 80.53 ± 8.12 years), and four frail individuals (age = 88.25 ± 4.43 years). Analysis of variance models showed that the percentage increase in HR during UEF and percentage decrease in HR during recovery were both 47% smaller in pre-frail/frail older adults compared to non-frails (p < 0.01, effect size = 0.70 and 0.62 for increase and decrease percentages). Using logistic models with both UEF kinematics and HR parameters as independent variables, frailty was predicted with a sensitivity of 0.82 and specificity of 0.83.ConclusionCurrent findings showed evidence of strong association between HR dynamics and frailty. It is suggested that combining kinematics and HR data in a multimodal model may provide a promising objective tool for frailty assessment.

Abstract 11335: Does Reduced Parasympathetic Heart Rate Variability Promote Obesity in Children?

Introduction: Considering the contribution of the autonomic nervous system (ANS) in regulating both energy expenditure and energy intake, assessment of heart rate variability (HRV) may elucidate the etiology and adaptive processes in the development of obesity. Variations in the cardiac ANS are associated with changes in energy balance and eating behaviours, highlighting the potential key function of the ANS in the etiology of obesity. While it is broadly accepted that obesity impacts HRV, potential impacts of HRV patterns on obesity remain unexplored. We hypothesize that certain HRV patterns increase risk of excess weight in children. Methods: Participants included 406 White youth from the QUALITY cohort (56% boys). Children were considered at risk of CVD due to confirmed parental obesity status. Time- and frequency-domain HRV indices derived from short-term ECG recordings (SDNN, RMSSD, pNN50, LF, HF, and LF/HF ratio) were analyzed at baseline (mean = 9.6 years, SD = 0.9). Adiposity at 2-year follow-up was evaluated through dual-energy X-ray absorptiometry. Total body fat (BF) and BF distribution were captured; central adiposity was estimated using the android-to-gynoid ratio. Prospective associations between HRV at baseline and adiposity at 2-year follow-up were estimated using regression models including weights for well-established confounders (difference in adiposity measures over time, sex, age, sexual maturity, and physical activity). Results: 8-10 year olds with a sympathovagal imbalance described by a sympathetic predominance (LF/HF) presented with higher BF (β = 3.32, p &lt; 0.001) and higher android-to-gynoid ratio (β =0.03, p&lt;0.001) at age 10-12 years. Furthermore, lower levels of parasympathetic indices at age 8-10 years predicted higher BF (RMSSD: β = -0.09, p &lt; 0.01; pNN50: β = -0.13, p &lt; 0.01) and higher android-to-gynoid ratio (RMSSD: β -0.001, p &lt; 0.05; pNN50: β = -0.001, p &lt; 0.01) two years later. Conclusions: Impaired cardiac ANS modulation appears associated with the occurrence of childhood obesity two years later. A sympathetic predominance paired with reduced parasympathetic indices in otherwise healthy children may foreshadow pathophysiological processes that lead to obesity and may help to identify intervention targets.

Network Analysis of Symptoms Co-Occurrence in Chronic Fatigue Syndrome.

Chronic fatigue syndrome (CFS) is a heterogenous disorder of multiple disabling symptoms with complex manifestations. Network analysis is a statistical and interrogative methodology to investigate the prevalence of symptoms (nodes) and their inter-dependent (inter-nodal) relationships. In the present study, we explored the co-occurrence of symptoms in a cohort of Polish CFS patients using network analysis. A total of 110 patients with CFS were examined (75 females). The mean age of the total sample was 37.93 (8.5) years old while the mean duration of symptoms in years was 4.4 (4). Post-exertional malaise (PEM) was present in 75.45% of patients, unrefreshing sleep was noted in 89.09% and impaired memory or concentration was observed in 87.27% of patients. The least prevalent symptom was tender cervical or axillary lymph nodes, noted in 34.55% of the total sample. Three of the most densely connected nodes were the total number of symptoms, sore throat and PEM. PEM was positively related with impairment in memory or concentration. Both PEM and impairment in memory or concentration presence are related to more severe fatigue measured by CFQ and FIS. PEM presence was positively related with the presence of multi-joint pain and negatively with tender lymph nodes and muscle pain. Sore throat was related with objective and subjective autonomic nervous system impairment. This study helps define symptom presentation of CFS with the pathophysiology of specific systems and links with multidisciplinary contemporary molecular pathology, including comparative MRI.

Aging is associated with cardiac autonomic nerve fiber depletion and reduced cardiac and circulating BDNF levels.

BackgroundAging is a multifactorial process associated with an impairment of autonomic nervous system (ANS) function. Progressive ANS remodeling includes upregulation of expression of circulating catecholamines and depletion of cardiac autonomic nerve fibers, and it is responsible, in part, for the increased susceptibility to cardiac diseases observed in elderly subjects. Neurotrophic factors, such as brain-derived neurotrophic factor (BDNF) and nerve growth factor (NGF), are involved in synaptogenesis and neurite outgrowth processes, supporting neuronal cell differentiation and maturation. However, whether and how these factors and their downstream signaling are involved in cardiac aging remains unclear. Here, we tested whether, in the aged heart, the overall extent of autonomic fibers is reduced, owing to lower production of trophic factors such as BDNF and NGF.MethodsIn vivo, we used young (age: 3 months; n = 10) and old (age: 24 months; n = 11) male Fisher rats, whereas, we used human neuroblastoma (SH-SY5Y) cells in vitro. ResultsCompared to the young rats, old rats displayed a marked reduction in the overall ANS fiber density, affecting both sympathetic and cholinergic compartments, as indicated by dopamine β-hydroxylase (dβh) and vesicular acetylcholine transporter (VaChT) immunohistochemical staining. In addition, a marked downregulation of GAP-43 and BDNF protein was observed in the left ventricular lysates of old rats compared to those of young rats. Interestingly, we did not find any significant difference in cardiac NGF levels between the young and old groups. To further explore the impact of aging on ANS fibers, we treated SH-SY5Y cells in vitro with serum obtained from young and old rats. Sera from both groups induced a remarkable increase in neuronal sprouting, as evidenced by a crystal violet assay. However, this effect was blunted in cells cultured with old rat serum and was accompanied by a marked reduction in GAP-43 and BDNF protein levels. ConclusionsOur data indicate that physiological aging is associated with an impairment of ANS structure and function and that reduced BDNF levels are responsible, at least in part, for these phenomena.

Elevated cerebral blood flow in patients with pure autonomic failure.

Pure autonomic failure (PAF) results from an impaired peripheral autonomic nervous system, and clinical symptoms present with orthostatic hypotension. While the impact on cardiovascular indices of orthostatic intolerance are well-characterized, more limited information is available regarding cerebral hemodynamic dysfunction in PAF. The objective of this study was to test the hypothesis that cerebral blood flow (CBF) is reduced in PAF, and to quantify the relationship between CBF and clinical indicators of disease severity, including peripheral supine arterial blood pressure. Participants with PAF (n = 17) and age- and sex-matched normotensive healthy controls (n = 17) were examined using established clinical rating scales, cardiovascular autonomic function tests, and 3T MRI measurements of CBF. CBF-weighted images were also used to determine the prevalence of venous hyperintensities from the major dural sinuses as evidence of abnormal capillary flow. Nonparametric tests and general linear models were used to evaluate differences and correlations between study variables. Gray matter CBF was higher in PAF (51.1 ± 13.4mL/100g/min) compared to controls (42.9 ± 6.5mL/100g/min, p = 0.007). Venous hyperintensities were more prevalent in PAF relative to controls, and the presence and degree of venous hyperintensities was associated with higher mean CBF (p = 0.027). In PAF participants, CBF and supine systolic blood pressure were inversely related (Spearman's rho = -0.545, p = 0.024). Findings suggest that PAF patients may exhibit elevated CBF and provide evidence that this condition exerts a hemodynamic impact in the central nervous system.

Modulation of heart rate variability based on sleep pattern in shift workers of automobile sector

Background: Altered circadian rhythm for sleep-wakeful cycle is seen in shift work, leading to sleep deprivation which may affect the cardiac autonomic nervous system (ANS). In the past two decades, a significant relationship has been established between impaired ANS activity and cardiovascular mortality. This effect is not addressed in workers working in both shifts. Aims and Objectives: This study aims to assess sleep quality and heart rate variability (HRV) before and after day and night shift work. Materials and Methods: A total of 140 healthy male workers aged between 24 years and 45 years working in alternate weekday and night shift at least for more than 2 years in automobile factory. Procedure: Before and after both day and night shifts sleep quality were noted by Pittsburgh Sleep Quality Index along with HRV parameters such as mean RR interval (mRRI) and low-frequency power/high-frequency power (LF/HF). Results: Global score was statistically increased with reduced mRRI and increased LF/HF after night shift. Conclusion: Reduced sleep quality and HRV may reflect sympathetic excitation and further leading to increased risk for cardiovascular diseases among the shift workers.

Effects of Cigarette Smoking on Cardiac Autonomic Responses: A Cross-Sectional Study.

It has been suggested that some of the adverse, long-term cardiovascular outcomes of smoking are mediated by impaired autonomic nervous system (ANS) activity. Yet, this association is currently inconclusive. Heart rate variability (HRV) and the deep breathing test (DBT) represent common quantitative markers of ANS activity due to their simplicity and reliability. This large cross-sectional study was designed to assess the effect of active smoking on ANS function as manifested by HRV or DBT abnormalities. Electrocardiograms were recorded at rest for 5 min and during forced metronomic breathing. HRV and DBT were calculated according to accepted standards. Participants were divided into two groups based on current smoking status. The study included 242 healthy volunteers (196 nonsmokers and 46 smokers). There were no significant differences in age, sex, and BMI between groups. Cumulative smoking exposure burden (CSEB) for the study group was 5.3 ± 1.3 pack-years. Comparative analysis of HRV and DBT parameters according to smoking status revealed no significant differences between groups. Significant (p < 0.05), yet weak or moderate correlations (r < 0.7) were found between CSEB and abnormal change in HRV parameters consistent with sympathetic overactivity and decreased parasympathetic tone. In conclusion, smoking for a relatively short period in healthy adults does not seem to lead to significant impairment in ANS function. Yet, the consequences of smoking seem to be amplified when cumulative exposure burden increases.

RELATIONSHIP BETWEEN THE CARDIOVASCULAR SYSTEM AND THE AUTONOMIC NERVOUS SYSTEM DURING THE PHYSICAL LOAD IN PERSONS WITH DIFFERENT BODY MASS

The rapid increase in the number of overweight and obese individuals poses a significant threat to the health of the world's population of all ages. Obesity is able to induce a condition of chronic low-intensity inflammation underlying the number of diseases, and, in particular, the diseases of the cardiovascular system. The aim of the study was to determine the relationship between the response of the cardiovascular system and the state of autonomic nervous system to graduated physical exercises in young adults with normal body weight and overweight. Anthropometric measurements of 84 individuals of both sexes aged 18-25 years were carried out. According to the body mass index (BMI), the following groups were defined: control group of 22 individuals (BMI 18,50-24,99 kg/m2), group with overweight individuals (n=20) of both sexes (BMI 25,00-29,99 kg/m2). The condition of the cardio-vascular system was evaluated by heart rate, systolic and diastolic blood pressure; the status of autonomic nervous system was assessed by the Kerdo index. Indicators were evaluated before and immediately after the graduated exercise test. Data obtained were processed statistically. According to the results of the study, the normotоnic type by its response to the physical exercise was found out in both study groups, but the overweight individuals of both sexes demonstrated the cardiovascular indicators were significantly higher compared to the control group. Having finished the physical exercise tests, overweight men and women showed marked sympathicotonia (≥ + 31). The Kerdo᾿s index in 29,65% of male and in 19,01% of female individuals was higher than in the individuals with normal body mass (p &lt;0.05). It can be concluded that the dominance of sympathetic influences is characteristic for overweight individuals after physical activity. Correlation between anthropometric, cardiovascular and Kerdo᾿s index immediately following the physical exertion in overweight individuals indicate impaired autonomic nervous system balance restoration.

Altered heart rate variability in angiotensin II–mediated hypertension is associated with impaired autonomic nervous system signaling and intrinsic sinoatrial node dysfunction

Hypertensive heart disease is associated with sinoatrial node (SAN) dysfunction and reductions in heart rate variability (HRV). Alterations in HRV could occur in association with changes in autonomic nervous system (ANS) activity, changes in SAN function and responsiveness to ANS agonists, or both. These relationships are unclear. The purpose of this study was to investigate the roles of ANS signaling, intrinsic SAN function, and changes in HRV in a mouse model of angiotensin II (AngII)-mediated hypertensive heart disease. Mice were treated with saline or AngII (2.5 mg/(kg⋅d)) for 3 weeks. ANS activity was assessed through HRV analysis of electrocardiograms collected invivo by telemetry as well as direct recordings of vagal nerve activity and renal sympathetic nerve activity from anesthetized mice. The effects of the ANS agonists isoproterenol and carbachol on SAN function and beating interval variability were assessed from electrogram recordings in intact isolated atrial preparations and from spontaneous action potential recordings in isolated SAN myocytes. Time and frequency domain analysis demonstrates that mice infused with AngII had reduced HRV. AngII-infused mice had elevated renal sympathetic nerve activity while resting vagal nerve activity was unchanged. AngII caused an increase in SAN beating interval variability in isolated atrial preparations and isolated SAN myocytes. Furthermore, isolated atrial preparations and SAN myocytes from AngII-infused mice had impaired responses to both isoproterenol and carbachol. Reduced HRV in hypertension occurs in association with altered sympathovagal balance as well as intrinsic SAN dysfunction and reduced responsiveness of SAN myocytes to ANS agonists.