Stating asymmetry in neural pathways: methodological trends in autonomic neuroscience.

PubMed

Xavier, Carlos Henrique; Mendonça, Michelle Mendanha; Marins, Fernanda Ribeiro; da Silva, Elder Sales; Ianzer, Danielle; Colugnati, Diego Basile; Pedrino, Gustavo Rodrigues; Fontes, Marco Antonio Peliky

2018-05-22

Many particularities concerning interhemispheric differences still need to be explored and unveiled. Functional and anatomical differential features found between left and right brain sides are best known as asymmetries and are consequence of the unilateral neuronal recruitment or predominance that is set to organize some function. The outflow from different neural pathways involved in the autonomic control of the cardiovascular system may route through asymmetrically relayed efferences (ipsilateral/lateralized and/or contralateral). In spite of this, the literature reporting on the role of central nuclei involved in the autonomic control is not always dedicated on these interhemispheric comparisons. Considering the recent reports demonstrating that asymmetries may set differential functional responses, it is worth checking differences between right and left sides of central regions. This review aims to inspire neuroscientists with the idea that studying the interhemispheric differences may deepen the understanding on several centrally controlled responses, with special regard to the autonomic functions underlying the cardiovascular regulation. Thus, an avenue of knowledge may unfold from a field of research that requires further exploration.

High Intensity Aerobic Exercise Training Improves Deficits of Cardiovascular Autonomic Function in a Rat Model of Type 1 Diabetes Mellitus with Moderate Hyperglycemia

PubMed Central

Grisé, Kenneth N.; Olver, T. Dylan; McDonald, Matthew W.; Dey, Adwitia; Jiang, Mao; Lacefield, James C.; Shoemaker, J. Kevin; Noble, Earl G.; Melling, C. W. James

2016-01-01

Indices of cardiovascular autonomic neuropathy (CAN) in experimental models of Type 1 diabetes mellitus (T1DM) are often contrary to clinical data. Here, we investigated whether a relatable insulin-treated model of T1DM would induce deficits in cardiovascular (CV) autonomic function more reflective of clinical results and if exercise training could prevent those deficits. Sixty-four rats were divided into four groups: sedentary control (C), sedentary T1DM (D), control exercise (CX), or T1DM exercise (DX). Diabetes was induced via multiple low-dose injections of streptozotocin and blood glucose was maintained at moderate hyperglycemia (9–17 mM) through insulin supplementation. Exercise training consisted of daily treadmill running for 10 weeks. Compared to C, D had blunted baroreflex sensitivity, increased vascular sympathetic tone, increased serum neuropeptide Y (NPY), and decreased intrinsic heart rate. In contrast, DX differed from D in all measures of CAN (except NPY), including heart rate variability. These findings demonstrate that this T1DM model elicits deficits and exercise-mediated improvements to CV autonomic function which are reflective of clinical T1DM. PMID:26885531

Understanding the physiology of mindfulness: aortic hemodynamics and heart rate variability.

PubMed

May, Ross W; Bamber, Mandy; Seibert, Gregory S; Sanchez-Gonzalez, Marcos A; Leonard, Joseph T; Salsbury, Rebecca A; Fincham, Frank D

2016-01-01

Data were collected to examine autonomic and hemodynamic cardiovascular modulation underlying mindfulness from two independent samples. An initial sample (N = 185) underwent laboratory assessments of central aortic blood pressure and myocardial functioning to investigated the association between mindfulness and cardiac functioning. Controlling for religiosity, mindfulness demonstrated a strong negative relationship with myocardial oxygen consumption and left ventricular work but not heart rate or blood pressure. A second sample (N = 124) underwent a brief (15 min) mindfulness inducing intervention to examine the influence of mindfulness on cardiovascular autonomic modulation via blood pressure variability and heart rate variability. The intervention had a strong positive effect on cardiovascular modulation by decreasing cardiac sympathovagal tone, vasomotor tone, vascular resistance and ventricular workload. This research establishes a link between mindfulness and cardiovascular functioning via correlational and experimental methodologies in samples of mostly female undergraduates. Future directions for research are outlined.

Effect of Pranayama on stress and cardiovascular autonomic function.

PubMed

Bhimani, N T; Kulkarni, N B; Kowale, A; Salvi, S

2011-01-01

The stress either physical or mental, leads to cardiovascular morbidity. Newly admitted medical students are likely to be exposed to various stresses like change of environment, demanding medical education and different teaching protocol in a medical college. Pranayama is known since ancient times to relieve stress and stabilize autonomic function of the body. Therefore it was decided to study effect of Pranayama on stress and cardiovascular autonomic function. The subjects were first M.B.B.S students and the sample size was 59 consisting of 27 males and 32 females. The group of students thus selected was briefed about the study. After the orientation session, informed written consent was taken, stress questionnaire was put and the autonomic function tests were done. This was followed by practice of Pranayama for 2 months, 1 hour/day for 5 days/week and again stress questionnaire was put and the autonomic function tests were performed on the study group. The above tests were done before and after the practice of Pranayama. The results obtained were analyzed using SPSS software. The stress level has reduced after 2 months of practicing various pranayama as evident by decrease in total stress score which is highly significant. VLF and LF in n.u have reduced significantly after practice of pranayama signifying reduction in sympathetic drive to heart. HF in n.u has increased significantly after practice of pranayama for 2 months showing the increase in parasympathetic output to the heart. LF/ HF ratio reduced significantly after 2 months of practice of pranayama indicating a better sympatho vagal balance with resting balance tilting toward better parasympathetic control.

Cardiovascular autonomic dysfunction in Ehlers-Danlos syndrome-Hypermobile type.

PubMed

Hakim, Alan; O'Callaghan, Chris; De Wandele, Inge; Stiles, Lauren; Pocinki, Alan; Rowe, Peter

2017-03-01

Autonomic dysfunction contributes to health-related impairment of quality of life in the hypermobile type of Ehlers-Danlos syndrome (hEDS). Typical signs and symptoms include tachycardia, hypotension, gastrointestinal dysmotility, and disturbed bladder function and sweating regulation. Cardiovascular autonomic dysfunction may present as Orthostatic Intolerance, Orthostatic Hypotension, Postural Orthostatic Tachycardia Syndrome, or Neurally Mediated Hypotension. The incidence, prevalence, and natural history of these conditions remain unquantified, but observations from specialist clinics suggest they are frequently seen in hEDS. There is growing understanding of how hEDS-related physical and physiological pathology contributes to the development of these conditions. Evaluation of cardiovascular symptoms in hEDS should include a careful history and clinical examination. Tests of cardiovascular function range from clinic room observation to tilt-table assessment to other laboratory investigations such as supine and standing catecholamine levels. Non-pharmacologic treatments include education, managing the environment to reduce exposure to triggers, improving cardiovascular fitness, and maintaining hydration. Although there are limited clinical trials, the response to drug treatments in hEDS is supported by evidence from case and cohort observational data, and short-term physiological studies. Pharmacologic therapy is indicated for patients with moderate-severe impairment of daily function and who have inadequate response or tolerance to conservative treatment. Treatment in hEDS often requires a focus on functional maintenance. Also, the negative impact of cardiovascular symptoms on physical and psycho-social well-being may generate a need for a more general evaluation and on-going management and support. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Role of training and detraining on inflammatory and metabolic profile in infarcted rats: influences of cardiovascular autonomic nervous system.

PubMed

Rodrigues, Bruno; Santana, Aline Alves; Santamarina, Aline Boveto; Oyama, Lila Missae; Caperuto, Érico Chagas; de Souza, Cláudio Teodoro; Barboza, Catarina de Andrade; Rocha, Leandro Yanase; Figueroa, Diego; Mostarda, Cristiano; Irigoyen, Maria Cláudia; Lira, Fábio Santos

2014-01-01

The aim of this study was to evaluate the effects of exercise training (ET, 50-70% of VO2 max, 5 days/week) and detraining (DT) on inflammatory and metabolic profile after myocardial infarction (MI) in rats. Male Wistar rats were divided into control (C, n = 8), sedentary infarcted (SI, n = 9), trained infarcted (TI, n = 10; 3 months of ET), and detrained infarcted (DI, n = 11; 2 months of ET + 1 month of DT). After ET and DT protocols, ventricular function and inflammation, cardiovascular autonomic modulation (spectral analysis), and adipose tissue inflammation and lipolytic pathway were evaluated. ET after MI improved cardiac and vascular autonomic modulation, and these benefits were correlated with reduced inflammatory cytokines on the heart and adipose tissue. These positive changes were sustained even after 1 month of detraining. No expressive changes were observed in oxidative stress and lipolytic pathway in experimental groups. In conclusion, our results strongly suggest that the autonomic improvement promoted by ET, and maintained even after the detraining period, was associated with reduced inflammatory profile in the left ventricle and adipose tissue of rats subjected to MI. These data encourage enhancing cardiovascular autonomic function as a therapeutic strategy for the treatment of inflammatory process triggered by MI.

Role of Training and Detraining on Inflammatory and Metabolic Profile in Infarcted Rats: Influences of Cardiovascular Autonomic Nervous System

PubMed Central

Santana, Aline Alves; Santamarina, Aline Boveto; Oyama, Lila Missae; Caperuto, Érico Chagas; de Souza, Cláudio Teodoro; Barboza, Catarina de Andrade; Rocha, Leandro Yanase; Figueroa, Diego; Mostarda, Cristiano; Irigoyen, Maria Cláudia; Lira, Fábio Santos

2014-01-01

The aim of this study was to evaluate the effects of exercise training (ET, 50–70% of VO2 max, 5 days/week) and detraining (DT) on inflammatory and metabolic profile after myocardial infarction (MI) in rats. Male Wistar rats were divided into control (C, n = 8), sedentary infarcted (SI, n = 9), trained infarcted (TI, n = 10; 3 months of ET), and detrained infarcted (DI, n = 11; 2 months of ET + 1 month of DT). After ET and DT protocols, ventricular function and inflammation, cardiovascular autonomic modulation (spectral analysis), and adipose tissue inflammation and lipolytic pathway were evaluated. ET after MI improved cardiac and vascular autonomic modulation, and these benefits were correlated with reduced inflammatory cytokines on the heart and adipose tissue. These positive changes were sustained even after 1 month of detraining. No expressive changes were observed in oxidative stress and lipolytic pathway in experimental groups. In conclusion, our results strongly suggest that the autonomic improvement promoted by ET, and maintained even after the detraining period, was associated with reduced inflammatory profile in the left ventricle and adipose tissue of rats subjected to MI. These data encourage enhancing cardiovascular autonomic function as a therapeutic strategy for the treatment of inflammatory process triggered by MI. PMID:25045207

Effects of aerobic or resistance exercise training on cardiovascular autonomic function of subjects with type 2 diabetes: A pilot study.

PubMed

Bellavere, F; Cacciatori, V; Bacchi, E; Gemma, M L; Raimondo, D; Negri, C; Thomaseth, K; Muggeo, M; Bonora, E; Moghetti, P

2018-03-01

Both aerobic (AER) and resistance (RES) training improve metabolic control in patients with type 2 diabetes (T2DM). However, information on the effects of these training modalities on cardiovascular autonomic control is limited. Our aim was to compare the effects of AER and RES training on cardiovascular autonomic function in these subjects. Cardiovascular autonomic control was assessed by Power Spectral Analysis (PSA) of Heart Rate Variability (HRV) and baroreceptors function indexes in 30 subjects with T2DM, randomly assigned to aerobic or resistance training for 4 months. In particular, PSA of HRV measured the Low Frequency (LF) and High Frequency (HF) bands of RR variations, expression of prevalent sympathetic and parasympathetic drive, respectively. Furthermore, we measured the correlation occurring between systolic blood pressure and heart rate during a standardized Valsalva maneuver using two indexes, b2 and b4, considered an expression of baroreceptor sensitivity and peripheral vasoactive adaptations during predominant sympathetic and parasympathetic drive, respectively. After training, the LF/HF ratio, which summarizes the sympatho-vagal balance in HRV control, was similarly decreased in the AER and RES groups. After AER, b2 and b4 significantly improved. After RES, changes of b2 were of borderline significance, whereas changes of b4 did not reach statistical significance. However, comparison of changes in baroreceptor sensitivity indexes between groups did not show statistically significant differences. Both aerobic and resistance training improve several indices of the autonomic control of the cardiovascular system in patients with T2DM. Although these improvements seem to occur to a similar extent in both training modalities, some differences cannot be ruled out. NCT01182948, clinicaltrials.gov. Copyright © 2017 The Italian Society of Diabetology, the Italian Society for the Study of Atherosclerosis, the Italian Society of Human Nutrition, and the Department of Clinical Medicine and Surgery, Federico II University. Published by Elsevier B.V. All rights reserved.

Role of Autonomic Reflex Arcs in Cardiovascular Responses to Air Pollution Exposure

EPA Science Inventory

The body responds to environmental stressors by triggering autonomic reflexes in the pulmonary receptors, baroreceptors, and chemoreceptors to maintain homeostasis. Numerous studies have shown that exposure to various gases and airborne particles can alter the functional outcome ...

Cardiopulmonary and Metabolic Effects of Yoga in Healthy Volunteers

PubMed Central

Divya, T Satheesh; Vijayalakshmi, MT; Mini, K; Asish, K; Pushpalatha, M; Suresh, Varun

2017-01-01

Background: Yoga the spiritual union of mind with the divine intelligence of the universe aims to liberate a human being from conflicts of body–mind duality. Beneficial cardiovascular and pulmonary effects of yoga are in par with aerobic exercise, even amounting to replace the exercise model. We conducted an interventional study in healthy volunteers, to analyze the impact of short-term yoga training on cardiovascular, pulmonary, autonomic function tests, lipid profile, and thyroid function tests. Materials and Methods: A sample of fifty new recruits attending the district yoga center was subject to 75 min yoga practice a day for 41 days. Basal values of cardiovascular, pulmonary, autonomic function tests, lipid profile, and thyroid function tests were recorded before yoga training and were reassessed for postyoga changes after 41 days. Results: After yoga practice there was a significant reduction in the resting heart rate, systolic blood pressure, diastolic blood pressure, and mean blood pressure of the participants. Effects on autonomic function tests were variable and inconclusive. There was a significant increase in forced vital capacity, forced expiratory volume in 1 s, and peak expiratory flow rate after yoga. A significant reduction in body mass index was observed. Effects on metabolic parameters were promising with a significant reduction in fasting blood sugar level, serum total cholesterol, serum triglycerides serum low-density lipoprotein levels, and significant increase in high-density lipoprotein. There was no significant change in thyroid function tests after yoga. Conclusion: Short-term yoga practice has no effect on thyroid functions. Yoga practice was found beneficial in maintaining physiological milieu pertaining to cardiovascular and other metabolic parameters. PMID:29422741

Cardiopulmonary and Metabolic Effects of Yoga in Healthy Volunteers.

PubMed

Divya, T Satheesh; Vijayalakshmi, M T; Mini, K; Asish, K; Pushpalatha, M; Suresh, Varun

2017-01-01

Yoga the spiritual union of mind with the divine intelligence of the universe aims to liberate a human being from conflicts of body-mind duality. Beneficial cardiovascular and pulmonary effects of yoga are in par with aerobic exercise, even amounting to replace the exercise model. We conducted an interventional study in healthy volunteers, to analyze the impact of short-term yoga training on cardiovascular, pulmonary, autonomic function tests, lipid profile, and thyroid function tests. A sample of fifty new recruits attending the district yoga center was subject to 75 min yoga practice a day for 41 days. Basal values of cardiovascular, pulmonary, autonomic function tests, lipid profile, and thyroid function tests were recorded before yoga training and were reassessed for postyoga changes after 41 days. After yoga practice there was a significant reduction in the resting heart rate, systolic blood pressure, diastolic blood pressure, and mean blood pressure of the participants. Effects on autonomic function tests were variable and inconclusive. There was a significant increase in forced vital capacity, forced expiratory volume in 1 s, and peak expiratory flow rate after yoga. A significant reduction in body mass index was observed. Effects on metabolic parameters were promising with a significant reduction in fasting blood sugar level, serum total cholesterol, serum triglycerides serum low-density lipoprotein levels, and significant increase in high-density lipoprotein. There was no significant change in thyroid function tests after yoga. Short-term yoga practice has no effect on thyroid functions. Yoga practice was found beneficial in maintaining physiological milieu pertaining to cardiovascular and other metabolic parameters.

Plastics and cardiovascular health: phthalates may disrupt heart rate variability and cardiovascular reactivity.

PubMed

Jaimes, Rafael; Swiercz, Adam; Sherman, Meredith; Muselimyan, Narine; Marvar, Paul J; Posnack, Nikki Gillum

2017-11-01

Plastics have revolutionized medical device technology, transformed hematological care, and facilitated modern cardiology procedures. Despite these advances, studies have shown that phthalate chemicals migrate out of plastic products and that these chemicals are bioactive. Recent epidemiological and research studies have suggested that phthalate exposure adversely affects cardiovascular function. Our objective was to assess the safety and biocompatibility of phthalate chemicals and resolve the impact on cardiovascular and autonomic physiology. Adult mice were implanted with radiofrequency transmitters to monitor heart rate variability, blood pressure, and autonomic regulation in response to di-2-ethylhexyl-phthalate (DEHP) exposure. DEHP-treated animals displayed a decrease in heart rate variability (-17% SD of normal beat-to-beat intervals and -36% high-frequency power) and an exaggerated mean arterial pressure response to ganglionic blockade (31.5% via chlorisondamine). In response to a conditioned stressor, DEHP-treated animals displayed enhanced cardiovascular reactivity (-56% SD major axis Poincarè plot) and prolonged blood pressure recovery. Alterations in cardiac gene expression of endothelin-1, angiotensin-converting enzyme, and nitric oxide synthase may partly explain these cardiovascular alterations. This is the first study to show an association between phthalate chemicals that are used in medical devices with alterations in autonomic regulation, heart rate variability, and cardiovascular reactivity. Because changes in autonomic balance often precede clinical manifestations of hypertension, atherosclerosis, and conduction abnormalities, future studies are warranted to assess the downstream impact of plastic chemical exposure on end-organ function in sensitive patient populations. This study also highlights the importance of adopting safer biomaterials, chemicals, and/or surface coatings for use in medical devices. NEW & NOTEWORTHY Phthalates are widely used in the manufacturing of consumer and medical products. In the present study, di-2-ethylhexyl-phthalate exposure was associated with alterations in heart rate variability and cardiovascular reactivity. This highlights the importance of investigating the impact of phthalates on health and identifying suitable alternatives for medical device manufacturing. Copyright © 2017 the American Physiological Society.

Autonomic and metabolic effects of OSA in childhood obesity.

PubMed

Oliveira, F M; Tran, W H; Lesser, D; Bhatia, R; Ortega, R; Mittelman, S D; Keens, T G; Davidson Ward, S L; Khoo, M C

2010-01-01

This study investigates the effects of exposure to intermittent hypoxia on cardiovascular autonomic control and metabolic function in obese children with obstructive sleep apnea (OSA). Each subject underwent: (1) a polysomnography; (2) morning fasting blood samples and a subsequent FSIVGTT; (3) noninvasive measurement of respiration, arterial blood pressure, and heart rate during supine and standing postures. Assessment of adiposity was performed using a DEXA scan. From these measurements, we deduced the pertinent sleep parameters, Bergman minimal model parameters and the parameters characterizing a minimal model of cardiovascular variability. Results suggest that intermittent hypoxia in OSA contributes independently to insulin resistance and autonomic dysfunction in overweight children.

Association between aerobic fitness and indices of autonomic regulation: cardiovascular risk implications.

PubMed

Sala, Roberto; Malacarne, Mara; Pagani, Massimo; Lucini, Daniela

2016-06-01

In the general population higher levels of exercise capacity seem to protect the cardiovascular system with effects well beyond traditional risk factors. We hypothesize that this phenomenon, called "risk factor gap", could be ascribed to functional components, such as autonomic adaptation to aerobic training. In 257 subjects (age 36.2±0.8 years) we measured VO2peak (incremental cycling exercise), together with arterial pressure and autonomic proxies (baroreflex gain, R-R variance and standing induced increase in marker of excitatory oscillatory regulation of the SA node, ∆LFRRnu). Autonomic proxies appeared significantly correlated with indicators of aerobic fitness (age and gender corrected correlation between VO2peak, baroreflex gain: r=0.277, P<0.001, and DAP r=-0.228, P<0.001). Subsequently, subjects were subdivided in three age and gender adjusted categories of VO2peak (poor, medium and good). Autonomic indices and arterial pressure appeared significantly ordered with categories of VO2peak (P<0.006). In addition, within these categories the proportion of subjects with a desirable autonomic and pressure profile becomes significantly greater with better fitness levels. The strong ordered relationship between categories of aerobic fitness and autonomic proxies speaks in favor of a complementary role of the autonomic nervous system in the management of cardiovascular risk factor gap at a population level.

Executive Cognitive Functioning and Cardiovascular Autonomic Regulation in a Population-Based Sample of Working Adults.

PubMed

Stenfors, Cecilia U D; Hanson, Linda M; Theorell, Töres; Osika, Walter S

2016-01-01

Objective: Executive cognitive functioning is essential in private and working life and is sensitive to stress and aging. Cardiovascular (CV) health factors are related to cognitive decline and dementia, but there is relatively few studies of the role of CV autonomic regulation, a key component in stress responses and risk factor for cardiovascular disease (CVD), and executive processes. An emerging pattern of results from previous studies suggest that different executive processes may be differentially associated with CV autonomic regulation. The aim was thus to study the associations between multiple measures of CV autonomic regulation and measures of different executive cognitive processes. Method: Participants were 119 healthy working adults (79% women), from the Swedish Longitudinal Occupational Survey of Health. Electrocardiogram was sampled for analysis of heart rate variability (HRV) measures, including the Standard Deviation of NN, here heart beats (SDNN), root of the mean squares of successive differences (RMSSD), high frequency (HF) power band from spectral analyses, and QT variability index (QTVI), a measure of myocardial repolarization patterns. Executive cognitive functioning was measured by seven neuropsychological tests. The relationships between CV autonomic regulation measures and executive cognitive measures were tested with bivariate and partial correlational analyses, controlling for demographic variables, and mental health symptoms. Results: Higher SDNN and RMSSD and lower QTVI were significantly associated with better performance on cognitive tests tapping inhibition, updating, shifting, and psychomotor speed. After adjustments for demographic factors however (age being the greatest confounder), only QTVI was clearly associated with these executive tests. No such associations were seen for working memory capacity . Conclusion: Poorer CV autonomic regulation in terms of lower SDNN and RMSSD and higher QTVI was associated with poorer executive cognitive functioning in terms of inhibition, shifting, updating, and speed in healthy working adults. Age could largely explain the associations between the executive measures and SDNN and RMSSD, while associations with QTVI remained. QTVI may be a useful measure of autonomic regulation and promising as an early indicator of risk among otherwise healthy adults, compared to traditional HRV measures, as associations between QTVI and executive functioning was not affected by age.

Executive Cognitive Functioning and Cardiovascular Autonomic Regulation in a Population-Based Sample of Working Adults

PubMed Central

Stenfors, Cecilia U. D.; Hanson, Linda M.; Theorell, Töres; Osika, Walter S.

2016-01-01

Objective: Executive cognitive functioning is essential in private and working life and is sensitive to stress and aging. Cardiovascular (CV) health factors are related to cognitive decline and dementia, but there is relatively few studies of the role of CV autonomic regulation, a key component in stress responses and risk factor for cardiovascular disease (CVD), and executive processes. An emerging pattern of results from previous studies suggest that different executive processes may be differentially associated with CV autonomic regulation. The aim was thus to study the associations between multiple measures of CV autonomic regulation and measures of different executive cognitive processes. Method: Participants were 119 healthy working adults (79% women), from the Swedish Longitudinal Occupational Survey of Health. Electrocardiogram was sampled for analysis of heart rate variability (HRV) measures, including the Standard Deviation of NN, here heart beats (SDNN), root of the mean squares of successive differences (RMSSD), high frequency (HF) power band from spectral analyses, and QT variability index (QTVI), a measure of myocardial repolarization patterns. Executive cognitive functioning was measured by seven neuropsychological tests. The relationships between CV autonomic regulation measures and executive cognitive measures were tested with bivariate and partial correlational analyses, controlling for demographic variables, and mental health symptoms. Results: Higher SDNN and RMSSD and lower QTVI were significantly associated with better performance on cognitive tests tapping inhibition, updating, shifting, and psychomotor speed. After adjustments for demographic factors however (age being the greatest confounder), only QTVI was clearly associated with these executive tests. No such associations were seen for working memory capacity. Conclusion: Poorer CV autonomic regulation in terms of lower SDNN and RMSSD and higher QTVI was associated with poorer executive cognitive functioning in terms of inhibition, shifting, updating, and speed in healthy working adults. Age could largely explain the associations between the executive measures and SDNN and RMSSD, while associations with QTVI remained. QTVI may be a useful measure of autonomic regulation and promising as an early indicator of risk among otherwise healthy adults, compared to traditional HRV measures, as associations between QTVI and executive functioning was not affected by age. PMID:27761124

Orthostatic Intolerance and Motion Sickness After Parabolic Flight

NASA Technical Reports Server (NTRS)

Schlegel, Todd T.; Brown, Troy E.; Wood, Scott J.; Benavides, Edgar W.; Bondar, Roberta L.; Stein, Flo; Moradshahi, Peyman; Harm, Deborah L.; Low, Phillip A.

1999-01-01

Orthostatic intolerance is common in astronauts after prolonged space flight. However, the "push-pull effect" in military aviators suggests that brief exposures to transitions between hypo- and hypergravity are sufficient to induce untoward autonomic cardiovascular physiology in susceptible individuals. We therefore investigated orthostatic tolerance and autonomic cardiovascular function in 16 healthy test subjects before and after a seated 2-hr parabolic flight. At the same time, we also investigated relationships between parabolic flight-induced vomiting and changes in orthostatic and autonomic cardiovascular function. After parabolic flight, 8 of 16 subjects could not tolerate a 30-min upright tilt test, compared to 2 of 16 before flight. Whereas new intolerance in non-Vomiters resembled the clinical postural tachycardia syndrome (POTS), new intolerance in Vomiters was characterized by comparatively isolated upright hypocapnia and cerebral vasoconstriction. As a group, Vomiters also had evidence for increased postflight fluctuations in efferent vagal-cardiac nerve traffic occurring independently of any superimposed change in respiration. Results suggest that syndromes of orthostatic intolerance resembling those occurring after space flight can occur after a brief (i.e., 2-hr) parabolic flight.

Effect of 48 h Fasting on Autonomic Function, Brain Activity, Cognition, and Mood in Amateur Weight Lifters.

PubMed

Solianik, Rima; Sujeta, Artūras; Terentjevienė, Asta; Skurvydas, Albertas

2016-01-01

Objectives. The acute fasting-induced cardiovascular autonomic response and its effect on cognition and mood remain debatable. Thus, the main purpose of this study was to estimate the effect of a 48 h, zero-calorie diet on autonomic function, brain activity, cognition, and mood in amateur weight lifters. Methods. Nine participants completed a 48 h, zero-calorie diet program. Cardiovascular autonomic function, resting frontal brain activity, cognitive performance, and mood were evaluated before and after fasting. Results. Fasting decreased ( p < 0.05) weight, heart rate, and systolic blood pressure, whereas no changes were evident regarding any of the measured heart rate variability indices. Fasting decreased ( p < 0.05) the concentration of oxygenated hemoglobin and improved ( p < 0.05) mental flexibility and shifting set, whereas no changes were observed in working memory, visuospatial discrimination, and spatial orientation ability. Fasting also increased ( p < 0.05) anger, whereas other mood states were not affected by it. Conclusions. 48 h fasting resulted in higher parasympathetic activity and decreased resting frontal brain activity, increased anger, and improved prefrontal-cortex-related cognitive functions, such as mental flexibility and set shifting, in amateur weight lifters. In contrast, hippocampus-related cognitive functions were not affected by it.

Effect of 48 h Fasting on Autonomic Function, Brain Activity, Cognition, and Mood in Amateur Weight Lifters

PubMed Central

Skurvydas, Albertas

2016-01-01

Objectives. The acute fasting-induced cardiovascular autonomic response and its effect on cognition and mood remain debatable. Thus, the main purpose of this study was to estimate the effect of a 48 h, zero-calorie diet on autonomic function, brain activity, cognition, and mood in amateur weight lifters. Methods. Nine participants completed a 48 h, zero-calorie diet program. Cardiovascular autonomic function, resting frontal brain activity, cognitive performance, and mood were evaluated before and after fasting. Results. Fasting decreased (p < 0.05) weight, heart rate, and systolic blood pressure, whereas no changes were evident regarding any of the measured heart rate variability indices. Fasting decreased (p < 0.05) the concentration of oxygenated hemoglobin and improved (p < 0.05) mental flexibility and shifting set, whereas no changes were observed in working memory, visuospatial discrimination, and spatial orientation ability. Fasting also increased (p < 0.05) anger, whereas other mood states were not affected by it. Conclusions. 48 h fasting resulted in higher parasympathetic activity and decreased resting frontal brain activity, increased anger, and improved prefrontal-cortex-related cognitive functions, such as mental flexibility and set shifting, in amateur weight lifters. In contrast, hippocampus-related cognitive functions were not affected by it. PMID:28025637

Cardiovascular Autonomic Dysfunction in Patients with Morbid Obesity

PubMed Central

de Sant Anna Junior, Maurício; Carneiro, João Regis Ivar; Carvalhal, Renata Ferreira; Torres, Diego de Faria Magalhães; da Cruz, Gustavo Gavina; Quaresma, José Carlos do Vale; Lugon, Jocemir Ronaldo; Guimarães, Fernando Silva

2015-01-01

Background Morbid obesity is directly related to deterioration in cardiorespiratory capacity, including changes in cardiovascular autonomic modulation. Objective This study aimed to assess the cardiovascular autonomic function in morbidly obese individuals. Methods Cross-sectional study, including two groups of participants: Group I, composed by 50 morbidly obese subjects, and Group II, composed by 30 nonobese subjects. The autonomic function was assessed by heart rate variability in the time domain (standard deviation of all normal RR intervals [SDNN]; standard deviation of the normal R-R intervals [SDNN]; square root of the mean squared differences of successive R-R intervals [RMSSD]; and the percentage of interval differences of successive R-R intervals greater than 50 milliseconds [pNN50] than the adjacent interval), and in the frequency domain (high frequency [HF]; low frequency [LF]: integration of power spectral density function in high frequency and low frequency ranges respectively). Between-group comparisons were performed by the Student’s t-test, with a level of significance of 5%. Results Obese subjects had lower values of SDNN (40.0 ± 18.0 ms vs. 70.0 ± 27.8 ms; p = 0.0004), RMSSD (23.7 ± 13.0 ms vs. 40.3 ± 22.4 ms; p = 0.0030), pNN50 (14.8 ± 10.4 % vs. 25.9 ± 7.2%; p = 0.0061) and HF (30.0 ± 17.5 Hz vs. 51.7 ± 25.5 Hz; p = 0.0023) than controls. Mean LF/HF ratio was higher in Group I (5.0 ± 2.8 vs. 1.0 ± 0.9; p = 0.0189), indicating changes in the sympathovagal balance. No statistical difference in LF was observed between Group I and Group II (50.1 ± 30.2 Hz vs. 40.9 ± 23.9 Hz; p = 0.9013). Conclusion morbidly obese individuals have increased sympathetic activity and reduced parasympathetic activity, featuring cardiovascular autonomic dysfunction. PMID:26536979

Spaceflight-induced cardiovascular changes and recovery during NASA's Functional Task Test

NASA Astrophysics Data System (ADS)

Arzeno, Natalia M.; Stenger, Michael B.; Bloomberg, Jacob J.; Platts, Steven H.

2013-11-01

Microgravity-induced physiologic changes could impair a crewmember's performance upon return to a gravity environment. The Functional Task Test aims to correlate these physiologic alterations with changes in performance during mission-critical tasks. In this study, we evaluated spaceflight-induced cardiovascular changes during 11 functional tasks in 7 Shuttle astronauts before spaceflight, on landing day, and 1, 6, and 30 days after landing. Mean heart rate was examined during each task and autonomic activity was approximated by heart rate variability during the Recovery from Fall/Stand Test, a 2-min prone rest followed by a 3-min stand. Heart rate was increased on landing day during all of the tasks, and remained elevated 6 days after landing during 6 of the 11 tasks. Parasympathetic modulation was diminished and sympathovagal balance was increased on landing day. Additionally, during the stand test 6 days after landing, parasympathetic modulation remained suppressed and heart rate remained elevated compared to preflight levels. Heart rate and autonomic activity were not different from preflight levels 30 days after landing. We detected changes in heart rate and autonomic activity during a 3-min stand and a variety of functional tasks, where cardiovascular deconditioning was still evident 6 days after returning from short-duration spaceflight. The delayed recovery times for heart rate and parasympathetic modulation indicate the necessity of assessing functional performance after long-duration spaceflight to ensure crew health and safety.

Acupuncture's Cardiovascular Actions: A Mechanistic Perspective.

PubMed

Longhurst, John

2013-04-01

Over the last several decades, there has been an explosion of articles on acupuncture, including studies that have begun to explore mechanisms underlying its analgesic and cardiovascular actions. Modulation of cardiovascular function is most effective during manual and low-frequency, low-intensity electroacupuncture (EA) at a select set of acupoints situated along meridians located over deep somatic nerves on the upper and lower extremities. Stimulation at these acupoints activates underlying sensory neural pathways that project to a number of regions in the central nervous system (CNS) that ultimately regulate autonomic outflow and hence cardiovascular function. A long-loop pathway involving the hypothalamus, midbrain, and medulla underlies EA modulation of reflex increases in blood pressure (BP). Actions of excitatory and inhibitory neurotransmitters in the supraspinal CNS underlie processing of the somatic input and adjustment of autonomic outflow during EA. Acupuncture also decreases elevated blood pressure through actions in the thoracic spinal cord. Reflexes that lower BP likewise are modulated by EA through its actions on sympathetic and parasympathetic nuclei in the medulla. The autonomic influence of acupuncture is slow in onset but prolonged in duration, typically lasting beyond the period of stimulation. Clinical studies suggest that acupuncture can be used to treat cardiac diseases, such as myocardial ischemia and hypertension, associated with overactivity of the sympathetic nervous system.

Acupuncture's Cardiovascular Actions: A Mechanistic Perspective

PubMed Central

2013-01-01

Abstract Over the last several decades, there has been an explosion of articles on acupuncture, including studies that have begun to explore mechanisms underlying its analgesic and cardiovascular actions. Modulation of cardiovascular function is most effective during manual and low-frequency, low-intensity electroacupuncture (EA) at a select set of acupoints situated along meridians located over deep somatic nerves on the upper and lower extremities. Stimulation at these acupoints activates underlying sensory neural pathways that project to a number of regions in the central nervous system (CNS) that ultimately regulate autonomic outflow and hence cardiovascular function. A long-loop pathway involving the hypothalamus, midbrain, and medulla underlies EA modulation of reflex increases in blood pressure (BP). Actions of excitatory and inhibitory neurotransmitters in the supraspinal CNS underlie processing of the somatic input and adjustment of autonomic outflow during EA. Acupuncture also decreases elevated blood pressure through actions in the thoracic spinal cord. Reflexes that lower BP likewise are modulated by EA through its actions on sympathetic and parasympathetic nuclei in the medulla. The autonomic influence of acupuncture is slow in onset but prolonged in duration, typically lasting beyond the period of stimulation. Clinical studies suggest that acupuncture can be used to treat cardiac diseases, such as myocardial ischemia and hypertension, associated with overactivity of the sympathetic nervous system. PMID:24761168

Early life persistent vitamin D deficiency exacerbates arrhythmias and autonomic imbalance following acrolein exposure in mice.

EPA Science Inventory

Epidemiological and animal data have conclusively linked adverse cardiovascular outcomes to air pollution exposure. As such, cardiovascular function is maintained by adequate levels of certain essential micronutrients like vitamin D. Unfortunately, vitamin D deficiency (VDD) has ...

Override of spontaneous respiratory pattern generator reduces cardiovascular parasympathetic influence

NASA Technical Reports Server (NTRS)

Patwardhan, A. R.; Vallurupalli, S.; Evans, J. M.; Bruce, E. N.; Knapp, C. F.

1995-01-01

We investigated the effects of voluntary control of breathing on autonomic function in cardiovascular regulation. Variability in heart rate was compared between 5 min of spontaneous and controlled breathing. During controlled breathing, for 5 min, subjects voluntarily reproduced their own spontaneous breathing pattern (both rate and volume on a breath-by-breath basis). With the use of this experimental design, we could unmask the effects of voluntary override of the spontaneous respiratory pattern generator on autonomic function in cardiovascular regulation without the confounding effects of altered respiratory pattern. Results from 10 subjects showed that during voluntary control of breathing, mean values of heart rate and blood pressure increased, whereas fractal and spectral powers in heart rate in the respiratory frequency region decreased. End-tidal PCO2 was similar during spontaneous and controlled breathing. These results indicate that the act of voluntary control of breathing decreases the influence of the vagal component, which is the principal parasympathetic influence in cardiovascular regulation.

Cardiopulmonary functional capacity and the role of exercise in improving maximal oxygen consumption in women with PCOS.

PubMed

Lenarcik, Agnieszka; Bidzińska-Speichert, Bozena

2010-01-01

Polycystic ovary syndrome (PCOS) is one of the most common reproductive disorder in premenopausal women and is frequently accompanied by the presence of cardiovascular risk factors. It has also been recognized that PCOS women are characterized by cardiopulmonary impairment. Reduced cardiopulmonary functional capacity and the autonomic dysfunction associated with abnormal heart rate recovery might be responsible for the increased cardiovascular risk in patients with PCOS. Exercise training has beneficial effects on cardiopulmonary functional capacity and reduces the risk of cardiovascular disease in PCOS women.

Insights into the background of autonomic medicine.

PubMed

Laranjo, Sérgio; Geraldes, Vera; Oliveira, Mário; Rocha, Isabel

2017-10-01

Knowledge of the physiology underlying the autonomic nervous system is pivotal for understanding autonomic dysfunction in clinical practice. Autonomic dysfunction may result from primary modifications of the autonomic nervous system or be secondary to a wide range of diseases that cause severe morbidity and mortality. Together with a detailed history and physical examination, laboratory assessment of autonomic function is essential for the analysis of various clinical conditions and the establishment of effective, personalized and precise therapeutic schemes. This review summarizes the main aspects of autonomic medicine that constitute the background of cardiovascular autonomic dysfunction. Copyright © 2017 Sociedade Portuguesa de Cardiologia. Publicado por Elsevier España, S.L.U. All rights reserved.

Is There an Association Between Markers of Cardiovascular Autonomic Dysfunction at Discharge From Rehabilitation and Participation 1 and 5 Years Later in Individuals With Spinal Cord Injury?

PubMed

Rianne Ravensbergen, H J; de Groot, Sonja; Post, Marcel W; Bongers-Janssen, Helma M; van der Woude, Lucas H; Claydon, Victoria E

2016-09-01

To determine whether physical activity and participation 1 and 5 years after discharge are associated with measures of cardiovascular autonomic function: prevalence of hypotension and reduced peak heart rate at discharge from initial inpatient spinal cord injury (SCI) rehabilitation. Prospective cohort study. Rehabilitation centers. Individuals with SCI (N=146). Not applicable. We recorded markers of cardiovascular autonomic dysfunction (resting blood pressure and peak heart rate) and personal and lesion characteristics at the time of discharge from rehabilitation. Parameters for participation (social health status dimension of the Sickness Impact Profile) and physical activity (Physical Activity Scale for Individuals with Physical Disabilities [PASIPD]) were measured 1 and 5 years after discharge. Effects of prevalence of cardiovascular autonomic dysfunction were analyzed using linear regression analysis while correcting for possible confounders. We found no significant association between hypotension and social health status dimension of the Sickness Impact Profile or PASIPD, either at 1 or at 5 years after discharge. A significant association between peak heart rate and social health status dimension of the Sickness Impact Profile was found at 1 year after discharge, showing poorer participation in individuals with low peak heart rate (ie, cardiovascular autonomic dysfunction). The unadjusted relation between peak heart rate and the social health status dimension of the Sickness Impact Profile was significant at 5 years, but not when adjusted for confounders. We found associations between peak heart rate and PASIPD for both 1 and 5 years after discharge; however, these were not significant after correction for potential confounding factors. Autonomic dysfunction after SCI is a crucial factor influencing quality of life. We found that cardiovascular autonomic impairment, assessed from low peak heart rate, was associated with reduced participation after 1 year. The results suggest that peak heart rate at discharge from rehabilitation after SCI should be used to identify those needing additional support to facilitate physical activity and participation after discharge. Copyright © 2016 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

Cardiovascular autonomic function in Cushing's syndrome.

PubMed

Fallo, F; Maffei, P; Dalla Pozza, A; Carli, M; Della Mea, P; Lupia, M; Rabbia, F; Sonino, N

2009-01-01

Cardiac autonomic dysfunction is associated with increased cardiovascular mortality. No data on sympathovagal balance are available in patients with Cushing's syndrome, in whom cardiovascular risk is high. We studied 10 patients with newly diagnosed Cushing's syndrome (1 male/9 females; age mean+/-SD, 47+/-10 yr) and 10 control subjects matched for age, sex, body mass index, and cardiovascular risk factors. In both groups there were 7 patients with arterial hypertension, 3 with diabetes mellitus, and 2 with obesity. Cardiac autonomic function was evaluated by analysis of short time heart rate variability (HRV) measures in frequency domain over 24-h, daytime, and nighttime. The 24-h ambulatory blood pressure monitoring and echocardiography were also performed. In comparison with controls, patients with Cushing's syndrome had lower 24-h (1.3+/-0.6 vs 3.7+/-1.5, mean+/-SD, p<0.01), daytime (2.0+/-1.4 vs 4.5+/-1.6, p<0.01), and night-time (1.0+/-0.4 vs 3.5+/-2.3, p<0.01) low-frequency/ high frequency (LF/HF) power ratio. In the presence of similar LF power, the difference was due to elevation in HF power in Cushing's syndrome compared to controls: 24-h, 12.7+/-6.7 vs 5.8+/-2.8, p<0.01; daytime, 10.2+/-7.3 vs 4.5+/-2.1, p<0.05; nighttime, 14.2+/-7.0 vs 7.8+/-4.7, p<0.05. Eight Cushing patients vs 4 controls had a non-dipping blood pressure profile. At echocardiography, Cushing patients had a greater left ventricular mass index and/or relative wall thickness, and impaired diastolic function, compared with controls. Compared to controls, patients with Cushing's syndrome showed a sympathovagal imbalance, characterized by a relatively increased parasympathetic activity. Whether this autonomic alteration is meant to counterbalance cortisol-induced effects on blood pressure and cardiac structure/function or has a different pathophysiological significance is still unknown.

Multi-organ autonomic dysfunction in Parkinson disease

PubMed Central

2010-01-01

Both pathologic and clinical studies of autonomic pathways have expanded the concept of Parkinson disease (PD) from a movement disorder to a multi-level widespread neurodegenerative process with non-motor features spanning several organ systems. This review integrates neuropathologic findings and autonomic physiology in PD as it relates to end organ autonomic function. Symptoms, pathology and physiology of the cardiovascular, skin/sweat gland, urinary, gastrointestinal, pupillary and neuroendocrine systems can be probed by autopsy, biopsy and non-invasive electrophysiological techniques in vivo which assess autonomic anatomy and function. There is mounting evidence that PD affects a chain of neurons in autonomic pathways. Consequently, autonomic physiology may serve as a window into non-motor PD progression and allow the development of mechanistically based treatment strategies for several non-motor features of PD. End-organ physiologic markers may be used to inform a model of PD pathophysiology and non-motor progression. PMID:20851033

Effects of 2-day calorie restriction on cardiovascular autonomic response, mood, and cognitive and motor functions in obese young adult women.

PubMed

Solianik, Rima; Sujeta, Artūras; Čekanauskaitė, Agnė

2018-06-02

Although long-term energy restriction has been widely investigated and has consistently induced improvements in health and cognitive and motor functions, the responses to short-duration calorie restriction are not completely understood. The purpose of this study was to investigate the effects of a 2-day very low-calorie diet on evoked stress, mood, and cognitive and motor functions in obese women. Nine obese women (body fatness > 32%) aged 22-31 years were tested under two randomly allocated conditions: 2-day very low-calorie diet (511 kcal) and 2-day usual diet. The perceived stressfulness of the diet, cardiovascular autonomic response, and cognitive and motor performances were evaluated before and after each diet. The subjective stress rating of the calorie-restricted diet was 41.5 ± 23.3. Calorie restriction had no detectable effects on the heart rate variability indices, mood, grip strength, or psychomotor functions. By contrast, calorie restriction increased (p < 0.05) spatial processing and visuospatial working memory accuracy, and decreased (p < 0.05) accuracy of cognitive flexibility. In conclusion, our results demonstrate that although a 2-day calorie restriction evoked moderate stress in obese women, cardiovascular autonomic function was not affected. Calorie restriction had complex effects on cognition: it declined cognitive flexibility, and improved spatial processing and visuospatial working memory, but did not affect mood or motor behavior.

Effects of antipsychotic drugs on cardiovascular variability in participants with bipolar disorder

PubMed Central

Linder, Jonathan R.; Sodhi, Simrit K.; Haynes, William G.; Fiedorowicz, Jess G.

2014-01-01

Objective The risk for cardiovascular diseases is elevated in persons with bipolar disorder. However, it remains unknown how much of this excess risk is secondary to pharmacologic treatment. We tested the hypothesis that current and cumulative antipsychotic drug exposure is associated with increased cardiovascular risk as indicated by lower heart rate variability (HRV) and increased blood pressure variability (BPV). Methods 55 individuals with bipolar disorder (33±7 years; 67% female) underwent non-invasive electrocardiogram assessment of time- and frequency-domain HRV, as well as BPV analysis. Medication histories were obtained through systematic review of pharmacy records for the past five years. Results Current antipsychotic exposure was associated with lower SDNN. Second generation antipsychotics were associated with lower SDNN and RMSSD. There was no significant relationship between five-year antipsychotic exposure and HRV in subjects with bipolar disorder. Exploratory analysis revealed a possible link between SSRI exposure and increased low frequency spectral HRV. Conclusions Current antipsychotic use (particularly second generation antipsychotics with high affinities for the D2S receptor) is associated with reduced autonomic-mediated variability of heart rate. The absence of an association with cumulative exposure suggests that the effects are acute in onset, and may therefore relate more to altered autonomic function than structural cardiovascular abnormalities. Future studies should prospectively examine effects of these antipsychotics on autonomic function. PMID:24590543

Promethazine affects autonomic cardiovascular mechanisms minimally

NASA Technical Reports Server (NTRS)

Brown, T. E.; Eckberg, D. L.

1997-01-01

Promethazine hydrochloride, Phenergan, is a phenothiazine derivative with antihistaminic (H1), sedative, antiemetic, anticholinergic, and antimotion sickness properties. These properties have made promethazine a candidate for use in environments such as microgravity, which provoke emesis and motion sickness. Recently, we evaluated carotid baroreceptor-cardiac reflex responses during two Space Shuttle missions 18 to 20 hr after the 50 mg intramuscular administration of promethazine. Because the effects of promethazine on autonomic cardiovascular mechanisms in general and baroreflex function in particular were not known, we were unable to exclude a possible influence of promethazine on our results. Our purpose was to determine the ground-based effects of promethazine on autonomic cardiovascular control. Because of promethazine's antihistaminic and anticholinergic properties, we expected that a 50-mg intramuscular injection of promethazine would affect sympathetically and vagally mediated cardiovascular mechanisms. Eight healthy young subjects, five men and three women, were studied at rest in recumbency. All reported drowsiness as a result of the promethazine injection; most also reported nervous excitation, dry mouth, and fatigue. Three subjects had significant reactions: two reported excessive anxiety and one reported dizziness. Measurements were performed immediately prior to injection and 3.1 +/- 0.1 and 19.5 +/- 0.4 hr postinjection. We found no significant effect of promethazine on resting mean R-R interval, arterial pressure, R-R interval power spectra, carotid baroreflex function, and venous plasma catecholamine levels.

Takotsubo-like Myocardial Dysfunction in a Patient with Botulism.

PubMed

Tonomura, Shuichi; Kakehi, Yoshiaki; Sato, Masatoshi; Naito, Yuki; Shimizu, Hisao; Goto, Yasunobu; Takahashi, Nobuyuki

2017-11-01

Botulinum toxin A (BTXA) can disrupt the neuromuscular and autonomic functions. We herein report a case of autonomic system dysfunction that manifested as Takotsubo-like myocardial dysfunction in a patient with botulism. Takotsubo syndrome results in acute cardiac insufficiency, another fatal complication of botulism in addition to respiratory muscle paralysis, particularly in patients with cardiovascular disease.

Takotsubo-like Myocardial Dysfunction in a Patient with Botulism

PubMed Central

Tonomura, Shuichi; Kakehi, Yoshiaki; Sato, Masatoshi; Naito, Yuki; Shimizu, Hisao; Goto, Yasunobu; Takahashi, Nobuyuki

2017-01-01

Botulinum toxin A (BTXA) can disrupt the neuromuscular and autonomic functions. We herein report a case of autonomic system dysfunction that manifested as Takotsubo-like myocardial dysfunction in a patient with botulism. Takotsubo syndrome results in acute cardiac insufficiency, another fatal complication of botulism in addition to respiratory muscle paralysis, particularly in patients with cardiovascular disease. PMID:28924131

CARDIOMETABOLIC, AUTONOMIC, AND AIRWAY TOXICITY OF ACUTE EXPOSURES TO PM2.5 FROM MULTIPOLLUTANT ATMOSPHERES IN THE GREAT LAKES REGION

EPA Science Inventory

Our research has the potential to identify potentially harmful effects of exposures to specific PM_2.5 components, emission sources, and O₃ to cardiovascular function. It will also provide mechanistic evidence for the dysregulation of normal cardiovascular...

Metabolic Syndrome and Short-Term Heart Rate Variability in Adults with Intellectual Disabilities

ERIC Educational Resources Information Center

Chang, Yaw-Wen; Lin, Jin-Ding; Chen, Wei-Liang; Yen, Chia-Feng; Loh, Ching-Hui; Fang, Wen-Hui; Wu, Li-Wei

2012-01-01

Metabolic syndrome (MetS) increases the risk of cardiovascular events. Heart rate variability (HRV) represents autonomic functioning, and reduced HRV significantly increases cardiovascular mortality. The aims of the present paper are to assess the prevalence of MetS in adults with intellectual disabilities (ID), the difference in short-term HRV…

Cardiac autonomic function in children with type 1 diabetes.

PubMed

Metwalley, Kotb Abbass; Hamed, Sherifa Ahmed; Farghaly, Hekma Saad

2018-06-01

Cardiovascular autonomic neuropathy (CAN) is a major complication of type 1 diabetes (T1D). This study aimed to evaluate cardiac autonomic nervous system (ANS) function in children with T1D and its relation to different demographic, clinical and laboratory variable. This cross-sectional study included 60 children with T1D (mean age = 15.1 ± 3.3 years; duration of diabetes = 7.95 ± 3.83 years). The following 8 non-invasive autonomic testing were used for evaluation: heart rate at rest and in response to active standing (30:15 ratio), deep breathing and Valsalva maneuver (indicating parasympathetic function); blood pressure response to standing (orthostatic hypotension or OH), sustained handgrip and cold; and heart rate response to standing or positional orthostatic tachycardia syndrome or POTs (indicating sympathetic function). None had clinically manifest CAN. Compared to healthy children (5%), 36.67% of children with T1D had ≥ 2 abnormal tests (i.e., CAN) (P = 0.0001) which included significantly abnormal heart rate response to standing (POTs) (P = 0.052), active standing (30:15 ratio) (P = 0.0001) and Valsalva maneuver (P = 0.0001), indicating parasympathetic autonomic dysfunction, and blood pressure response to cold (P = 0.01), indicating sympathetic autonomic dysfunction. 54.55, 27.27 and 18.18% had early, definite and severe dysfunction of ANS. All patients had sensorimotor peripheral neuropathy. The longer duration of diabetes (> 5 years), presence of diabetic complications and worse glycemic control were significantly associated with CAN. The study concluded that both parasympathetic and sympathetic autonomic dysfunctions are common in children with T1D particularly with longer duration of diabetes and presence of microvascular complications. What is Known: • Cardiovascular autonomic neuropathy (CAN) is a major complication of type 1 diabetes (T1D). • Limited studies evaluated CAN in children with T1D. What is New: • CAN is common in children with T1D. • Cardiac autonomic functions should be assessed in children with T1D particularly in presence of microvascular complications.

Orthostatic Intolerance and Postural Orthostatic Tachycardia Syndrome in Joint Hypermobility Syndrome/Ehlers-Danlos Syndrome, Hypermobility Type: Neurovegetative Dysregulation or Autonomic Failure?

PubMed

Celletti, Claudia; Camerota, Filippo; Castori, Marco; Censi, Federica; Gioffrè, Laura; Calcagnini, Giovanni; Strano, Stefano

2017-01-01

Background . Joint hypermobility syndrome/Ehlers-Danlos syndrome, hypermobility type (JHS/EDS-HT), is a hereditary connective tissue disorder mainly characterized by generalized joint hypermobility, skin texture abnormalities, and visceral and vascular dysfunctions, also comprising symptoms of autonomic dysfunction. This study aims to further evaluate cardiovascular autonomic involvement in JHS/EDS-HT by a battery of functional tests. Methods . The response to cardiovascular reflex tests comprising deep breathing, Valsalva maneuver, 30/15 ratio, handgrip test, and head-up tilt test was studied in 35 JHS/EDS-HT adults. Heart rate and blood pressure variability was also investigated by spectral analysis in comparison to age and sex healthy matched group. Results . Valsalva ratio was normal in all patients, but 37.2% of them were not able to finish the test. At tilt, 48.6% patients showed postural orthostatic tachycardia, 31.4% orthostatic intolerance, 20% normal results. Only one patient had orthostatic hypotension. Spectral analysis showed significant higher baroreflex sensitivity values at rest compared to controls. Conclusions. This study confirms the abnormal cardiovascular autonomic profile in adults with JHS/EDS-HT and found the higher baroreflex sensitivity as a potential disease marker and clue for future research.

Quantification of cardiovascular and cardiorespiratory coupling during hypoxia with Joint Symbolic Dynamics.

PubMed

Reulecke, S; Schulz, S; Bauer, R; Witte, H; Voss, A

2011-01-01

Newborn mammals suffering from moderate hypoxia during or after birth are able to compensate a transitory lack of oxygen by adaptation of their vital functions. However, limited information is available about bivariate couplings of the underlying complex processes controlled by the autonomic nervous system. In this study an animal model of seven newborn piglets (2-3 days old, 1.71 ± 0.15 kg) was used. The aim of this study was to analyze the cardiovascular and cardiorespiratory interactions of autonomous nervous system during sustained hypoxia and the interrelationship of these autonomic time series after induced reoxygenation. For this purpose we applied a new high resolution version of the nonlinear method of Joint Symbolic Dynamics (JSD) for analysis of couplings between heart rate and blood pressure and respiration rate time series, respectively. This new method is characterized by using three defined symbols (JSD3) instead of two and the application of thresholds for the symbol transformation. Our results demonstrate that in contrast to the traditional JSD the comparison of cardiovascular interactions reveals only significant differences between normoxic and hypoxic conditions using JSD3 whereas for cardiorespiratory interactions significant differences were revealed by indices from both JSD2 and JSD3 due to reoxygenation. These results suggest that the application of JSD3 reveals more detailed information about cardiovascular and cardiorespiratory interactions of autonomic regulation and might be useful for monitoring of critical human newborns.

Heart rate variability in normal and pathological sleep.

PubMed

Tobaldini, Eleonora; Nobili, Lino; Strada, Silvia; Casali, Karina R; Braghiroli, Alberto; Montano, Nicola

2013-10-16

Sleep is a physiological process involving different biological systems, from molecular to organ level; its integrity is essential for maintaining health and homeostasis in human beings. Although in the past sleep has been considered a state of quiet, experimental and clinical evidences suggest a noteworthy activation of different biological systems during sleep. A key role is played by the autonomic nervous system (ANS), whose modulation regulates cardiovascular functions during sleep onset and different sleep stages. Therefore, an interest on the evaluation of autonomic cardiovascular control in health and disease is growing by means of linear and non-linear heart rate variability (HRV) analyses. The application of classical tools for ANS analysis, such as HRV during physiological sleep, showed that the rapid eye movement (REM) stage is characterized by a likely sympathetic predominance associated with a vagal withdrawal, while the opposite trend is observed during non-REM sleep. More recently, the use of non-linear tools, such as entropy-derived indices, have provided new insight on the cardiac autonomic regulation, revealing for instance changes in the cardiovascular complexity during REM sleep, supporting the hypothesis of a reduced capability of the cardiovascular system to deal with stress challenges. Interestingly, different HRV tools have been applied to characterize autonomic cardiac control in different pathological conditions, from neurological sleep disorders to sleep disordered breathing (SDB). In summary, linear and non-linear analysis of HRV are reliable approaches to assess changes of autonomic cardiac modulation during sleep both in health and diseases. The use of these tools could provide important information of clinical and prognostic relevance.

Heart Rate Recovery and Variability Following Combined Aerobic and Resistance Exercise Training in Adults with and without Down Syndrome

ERIC Educational Resources Information Center

Mendonca, Goncalo V.; Pereira, Fernando D.; Fernhall, Bo

2013-01-01

Persons with Down syndrome (DS) are at high risk for cardiovascular morbidity and mortality, and there is compelling evidence of autonomic dysfunction in these individuals. The main purpose of this study was to determine whether a combined aerobic and resistance exercise intervention produces similar results in cardiac autonomic function between…

Effects of whole-body vibration on heart rate variability: acute responses and training adaptations.

PubMed

Wong, Alexei; Figueroa, Arturo

2018-05-18

Heart rate variability (HRV) is a noninvasive and practical measure of cardiac autonomic nervous system function, mainly the sympathetic and parasympathetic modulations of heart rate. A low HRV has been shown to be indicative of compromised cardiovascular health. Interventions that enhance HRV are therefore beneficial to cardiovascular health. Whole-body vibration (WBV) training has been proposed as an alternative time-efficient exercise intervention for the improvement of cardiovascular health. In this review, we discuss the effect of WBV both acute and after training on HRV. WBV training appears to be a useful therapeutic intervention to improve cardiac autonomic function in different populations, mainly through decreases in sympathovagal balance. Although the mechanisms by which WBV training improves symphathovagal balance are not yet well understood; enhancement of baroreflex sensitivity, nitric oxide bioavailability and angiotensin II levels seem to play an important role. © 2018 Scandinavian Society of Clinical Physiology and Nuclear Medicine. Published by John Wiley & Sons Ltd.

Impact of exercise training associated to pyridostigmine treatment on autonomic function and inflammatory profile after myocardial infarction in rats.

PubMed

Feriani, Daniele J; Souza, Gabriel I H; Carrozzi, Nicolle M; Mostarda, Cristiano; Dourado, Paulo M M; Consolim-Colombo, Fernanda M; De Angelis, Kátia; Moreno, Heitor; Irigoyen, Maria Cláudia; Rodrigues, Bruno

2017-01-15

The effects of exercise training (ET) associated with pyridostigmine bromide (PYR) treatment on cardiac and autonomic function, as well as on inflammatory profile after myocardial infarction (MI), are unclear. Male Wistar rats were randomly assigned to: control (C); sedentary+infarcted (I); sedentary+infarcted treated with PYR (IP); infarcted submitted to aerobic exercise training (IT); and infarcted submitted to treatment with PYR and aerobic exercise training (ITP). After 12weeks of ET (50-70% maximal running speed; 1h a day, 5days a week) and/or PYR treatment (0.14mg/mL on drink water), hemodynamic, autonomic and cytokines expression were performed. We observed that both aerobic ET, associated or not with PYR treatment in MI animals, were able to: reduced MI area, improved systolic and diastolic function, baroreflex sensitivity, cardiovascular autonomic modulation, and tonic activity of the sympathetic and parasympathetic nervous system. Also, they led to a reduction of inflammatory profile measured at plasma, left ventricle and soleus skeletal muscle. However, additional effects were observed when ET and PYR were associated, such as an increase in vagal tonus and modulation, reduction of MI area, interferon-γ and tumor necrosis factor-α (TNF-α), as well as an increase of interleukin-10/TNF-α ratio on left ventricle. These data suggest that associating ET and PYR promotes some additional benefits on cardiovascular autonomic modulation and inflammatory profile in infarcted rats. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Cardiovascular Autonomic Dysfunction in Patients with Drug-Induced Parkinsonism

PubMed Central

Ryu, Dong-Woo; Oh, Ju-Hee; Lee, Yang-Hyun; Park, Sung-Jin; Jeon, Kipyung; Lee, Jong-Yun; Ho, Seong Hee; So, Jungmin; Im, Jin Hee; Lee, Kwang-Soo

2017-01-01

Background and Purpose Recent studies have shown that several nonmotor symptoms differ between Parkinson's disease (PD) and drug-induced parkinsonism (DIP). However, there have been no reports on cardiovascular autonomic function in DIP, and so this study investigated whether cardiovascular autonomic function differs between PD and DIP patients. Methods This study consecutively enrolled 20 DIP patients, 99 drug-naïve PD patients, and 25 age-matched healthy controls who underwent head-up tilt-table testing and 24-h ambulatory blood pressure monitoring. Results Orthostatic hypotension was more frequent in patients with PD or DIP than in healthy controls. In DIP, orthostatic hypotension was associated with the underlying psychiatric diseases and neuroleptics use, whereas prokinetics were not related to orthostatic hypotension. The supine blood pressure, nighttime blood pressure, and nocturnal blood pressure dipping did not differ significantly between the DIP and control groups. Supine hypertension and nocturnal hypertension were more frequent in PD patients than in controls. Conclusions The included DIP patients frequently exhibited orthostatic hypotension that was associated with the underlying diseases as well as the nature of and exposure time to the offending drugs. Clinicians should individualize the manifestations of DIP according to underlying diseases as well as the action mechanism of and exposure time to each offending drug. PMID:27730767

Heart rate variability and heart rate turbulence in patients with polycystic ovary syndrome.

PubMed

Özkeçeci, Gülay; Ünlü, Bekir Serdar; Dursun, Hüseyin; Akçi, Önder; Köken, Gülengül; Onrat, Ersel; Avşar, Alaettin

2016-05-01

Cardiac autonomic dysfunction may develop in patients with polycystic ovary syndrome (PCOS). Heart rate variability (HRV) and heart rate turbulence (HRT) are used in assessing cardiac autonomic functions. The goal of this study was to compare the cardiac autonomic functions in patients with PCOS and healthy controls. To our knowledge, this is the first study evaluating cardiac autonomic functions in patients with PCOS with respect to both HRV and HRT. Twenty-three patients with PCOS (mean age 22.8±3.9 years) and 25 healthy female volunteers who were matched for age and body mass index (BMI) (mean age 23.5±6.2 years) were enrolled in this as case-control study. Twenty-four hour ambulatory electrocardiogram recordings of all participants were taken using Pathfinder software. The time domain parameters of HRV and HRT, including turbulence onset (TO) and turbulence slope, were calculated. Diagnosis of PCOS was made with physical and laboratory findings of hirsutism or biochemical hyperandrogenism and chronic anovulation. Diabetes mellitus, other hormon disorders or hormon therapy, pregnancy, atrial fibrilation, obesite, chronic diseases, disorders of the autonomic nervous system, a history of drug use affecting the autonomic nervous system were excluded. There were no significant differences in HRV and HRT parameters between the two groups. Cardiovascular risk factors, such as BMI, blood pressure, fasting blood glucose, and lipid parameters, were also similar. Triangular index measure of HRV was negatively correlated with high density lipoprotein cholesterol levels (r=-0.47, p<0.05), while age and BMI were significantly correlated with TO (r=0.31 and 0.47, respectively; p<0.05 for all). Cardiac autonomic functions were not found to be altered in patients with PCOS in comparison with healthy controls. These results may be explained with the absence of concomitant cardiovascular risk factors with the patients being in the early stage of the disease.

Limits of clinical tests to screen autonomic function in diabetes type 1.

PubMed

Ducher, M; Bertram, D; Sagnol, I; Cerutti, C; Thivolet, C; Fauvel, J P

2001-11-01

A precocious detection of cardiac autonomic dysfunction is of major clinical interest that could lead to a more intensive supervision of diabetic patients. However, classical clinical exploration of cardiac autonomic function is not easy to undertake in a reproducible way. Thus, respective interests of autonomic nervous parameters provided by both clinical tests and computerized analysis of resting blood pressure were checked in type 1 diabetic patients without orthostatic hypotension and microalbuminuria. Thirteen diabetic subjects matched for age and gender to thirteen healthy subjects volunteered to participate to the study. From clinical tests (standing up, deep breathing, Valsalva maneuver, handgrip test), autonomic function was scored according to Ewing's methodology. Analysis of resting beat to beat blood pressure provided autonomic indices of the cardiac function (spectral analysis or Z analysis). 5 of the 13 diabetic patients exhibited a pathological score (more than one pathological response) suggesting the presence of cardiovascular autonomic dysfunction. The most discriminative test was the deep breathing test. However, spectral indices of BP recordings and baro-reflex sensitivity (BRS) of these 5 subjects were similar to those of healthy subjects and of remaining diabetic subjects. Alteration in Ewing's score given by clinical tests may not reflect an alteration of cardiac autonomic function in asymptomatic type 1 diabetic patients, because spectral indices of sympathetic and parasympathetic (including BRS) function were within normal range. Our results strongly suggest to confront results provided by both methodologies before concluding to an autonomic cardiac impairment in asymptomatic diabetic patients.

Validation of the Bulgarian version of Scales for Outcomes in Parkinson's Disease - Autonomic (SCOPA-AUT-BG).

PubMed

Mantarova, Stefka G; Velcheva, Irena V; Georgieva, Spaska O; Stambolieva, Katerina I

2013-01-01

The last twenty years have witnessed a surge of interest in the autonomic symptoms in Parkinson's disease (PD) and the possibilities to diagnose and treat them. The specialized questionnaire assessing the autonomic symptoms in Parkinson's disease (SCOPA-AUT) has been validated and available in English, Dutch and Spanish. In this study we aim at evaluating the validity, reliability and applicability of the Bulgarian version of SCOPA-AUT (SCOPA-AUT-BG). The study included 55 patients with idiopathic PD (mean age 64.4 +/- 8.9 yrs), and 40 healthy controls (mean age 58.5 +/- 9.4 yrs). Clinical severity and disease stage were assessed by United Parkinson's disease rating scale (UPRDS) and Hoen and Yahr (H&Y). Thirty-two of the PD patients completed SCOPA-AUT-BG again after a 7-day interval. Questionnaire reliability was analyzed by determining the internal consistency, homogeneity, discriminatory and construct validity and test-retest reliability. Analyses showed good internal consistency of the summary evaluation of SCOPA-AUT-BG (coefficient alpha of Cronbach = 0.79), which indicates the high reliability of the questionnaire. The lowest Cronbach's alpha coefficient (0.53) was found for the subscale "cardiovascular functions". A dominant role belongs to the subscales for gastrointestinal and urinary functions (Cronbach's Alpha > 0.7), where a significantly high correlation of PD with the UPDRS scale was observed. We found high test-retest reliability based on the responses associated with dysfunction of the gastrointestinal, urinary, thermoregulatory and pupillary autonomic systems. The correlation of the results of SCOPA-AUT-BG with UPDRS is higher than that with H&Y, and the construct validity is high except for the cardiovascular and pupillomotor functions subscales. The results of this study show that SCOPA-AUT-BG is a valid and reliable specialized questionnaire to evaluate autonomic function in patients with Parkinson's disease. Using it allows for more detailed clinical evaluation of these patients and justifies the need to refer them to specialized examination of autonomic functions.

eNOS gene haplotype is indirectly associated with the recovery of cardiovascular autonomic modulation from exercise.

PubMed

Silva, Bruno M; Barbosa, Thales C; Neves, Fabricia J; Sales, Allan K; Rocha, Natalia G; Medeiros, Renata F; Pereira, Felipe S; Garcia, Vinicius P; Cardoso, Fabiane T; Nobrega, Antonio C L

2014-12-01

Polymorphisms in the endothelial nitric oxide synthase (eNOS) gene decrease expression and activation of eNOS in vitro, which is associated with lower post-exercise increase in vasodilator reactivity in vivo. However, it is unknown whether such polymorphisms are associated with other eNOS-related phenotypes during recovery from exercise. Therefore, we investigated the impact of an eNOS haplotype containing polymorphic alleles at loci -786 and 894 on the recovery of cardiovascular autonomic function from exercise. Sedentary, non-obese, healthy subjects were enrolled [n = 107, age 32 ± 1 years (mean ± SEM)]. Resting autonomic modulation (heart rate variability, systolic blood pressure variability, and spontaneous baroreflex sensitivity) and vascular reactivity (forearm hyperemic response post-ischemia) were assessed at baseline, 10, 60, and 120 min after a maximal cardiopulmonary exercise test. Besides, autonomic function was assessed by heart rate recovery (HRR) immediately after peak exercise. Haplotype analysis showed that vagal modulation (i.e., HF n.u.) was significantly higher, combined sympathetic and vagal modulation (i.e., LF/HF) was significantly lower and total blood pressure variability was significantly lower post-exercise in a haplotype containing polymorphic alleles (H2) compared to a haplotype with wild type alleles (H1). HRR was similar between groups. Corroborating previous evidence, H2 had significantly lower post-exercise increase in vasodilator reactivity than H1. In conclusion, a haplotype containing polymorphic alleles at loci -786 and 894 had enhanced recovery of autonomic modulation from exercise, along with unchanged HRR, and attenuated vasodilator reactivity. Then, these results suggest an autonomic compensatory response of a direct deleterious effect of eNOS polymorphisms on the vascular function. Copyright © 2014 Elsevier B.V. All rights reserved.

A forward model-based validation of cardiovascular system identification

NASA Technical Reports Server (NTRS)

Mukkamala, R.; Cohen, R. J.

2001-01-01

We present a theoretical evaluation of a cardiovascular system identification method that we previously developed for the analysis of beat-to-beat fluctuations in noninvasively measured heart rate, arterial blood pressure, and instantaneous lung volume. The method provides a dynamical characterization of the important autonomic and mechanical mechanisms responsible for coupling the fluctuations (inverse modeling). To carry out the evaluation, we developed a computational model of the cardiovascular system capable of generating realistic beat-to-beat variability (forward modeling). We applied the method to data generated from the forward model and compared the resulting estimated dynamics with the actual dynamics of the forward model, which were either precisely known or easily determined. We found that the estimated dynamics corresponded to the actual dynamics and that this correspondence was robust to forward model uncertainty. We also demonstrated the sensitivity of the method in detecting small changes in parameters characterizing autonomic function in the forward model. These results provide confidence in the performance of the cardiovascular system identification method when applied to experimental data.

Health monitoring of Japanese payload specialist: Autonomic nervous and cardiovascular responses under reduced gravity condition (L-0)

NASA Technical Reports Server (NTRS)

Sekiguchi, Chiharu

1993-01-01

In addition to health monitoring of the Japanese Payload Specialists (PS) during the flight, this investigation also focuses on the changes of cardiovascular hemodynamics during flight which will be conducted under the science collaboration with the Lower Body Negative Pressure (LBNP) Experiment of NASA. For the Japanese, this is an opportunity to examine firsthand the effects of microgravity of human physiology. We are particularly interested in the adaption process and how it relates to space motion sickness and cardiovascular deconditioning. By comparing data from our own experiment to data collected by others, we hope to understand the processes involved and find ways to avoid these problems for future Japanese astronauts onboard Space Station Freedom and other Japanese space ventures. The primary objective of this experiment is to monitor the health condition of Japanese Payload Specialists to maintain a good health status during and after space flight. The second purpose is to investigate the autonomic nervous system's response to space motion sickness. To achieve this, the function of the autonomic nervous system will be monitored using non-invasive techniques. Data obtained will be employed to evaluate the role of autonomic nervous system in space motion sickness and to predict susceptibility to space motion sickness. The third objective is evaluation of the adaption process of the cardiovascular system to microgravity. By observation of the hemodynamics using an echocardiogram we will gain insight on cardiovascular deconditioning. The last objective is to create a data base for use in the health care of Japanese astronauts by obtaining control data in experiment L-O in the SL-J mission.

Abnormal cardiac autonomic regulation in mice lacking ASIC3.

PubMed

Cheng, Ching-Feng; Kuo, Terry B J; Chen, Wei-Nan; Lin, Chao-Chieh; Chen, Chih-Cheng

2014-01-01

Integration of sympathetic and parasympathetic outflow is essential in maintaining normal cardiac autonomic function. Recent studies demonstrate that acid-sensing ion channel 3 (ASIC3) is a sensitive acid sensor for cardiac ischemia and prolonged mild acidification can open ASIC3 and evoke a sustained inward current that fires action potentials in cardiac sensory neurons. However, the physiological role of ASIC3 in cardiac autonomic regulation is not known. In this study, we elucidate the role of ASIC3 in cardiac autonomic function using Asic3(-/-) mice. Asic3(-/-) mice showed normal baseline heart rate and lower blood pressure as compared with their wild-type littermates. Heart rate variability analyses revealed imbalanced autonomic regulation, with decreased sympathetic function. Furthermore, Asic3(-/-) mice demonstrated a blunted response to isoproterenol-induced cardiac tachycardia and prolonged duration to recover to baseline heart rate. Moreover, quantitative RT-PCR analysis of gene expression in sensory ganglia and heart revealed that no gene compensation for muscarinic acetylcholines receptors and beta-adrenalin receptors were found in Asic3(-/-) mice. In summary, we unraveled an important role of ASIC3 in regulating cardiac autonomic function, whereby loss of ASIC3 alters the normal physiological response to ischemic stimuli, which reveals new implications for therapy in autonomic nervous system-related cardiovascular diseases.

Impact of cancer and chemotherapy on autonomic nervous system function and cardiovascular reactivity in young adults with cancer: a case-controlled feasibility study.

PubMed

Adams, Scott C; Schondorf, Ronald; Benoit, Julie; Kilgour, Robert D

2015-05-18

Preliminary evidence suggests cancer- and chemotherapy-related autonomic nervous system (ANS) dysfunction may contribute to the increased cardiovascular (CV) morbidity- and mortality-risks in cancer survivors. However, the reliability of these findings may have been jeopardized by inconsistent participant screening and assessment methods. Therefore, good laboratory practices must be established before the presence and nature of cancer-related autonomic dysfunction can be characterized. The purpose of this study was to assess the feasibility of conducting concurrent ANS and cardiovascular evaluations in young adult cancer patients, according to the following criteria: i) identifying methodological pitfalls and proposing good laboratory practice criteria for ANS testing in cancer, and ii) providing initial physiologic evidence of autonomic perturbations in cancer patients using the composite autonomic scoring scale (CASS). Thirteen patients (mixed diagnoses) were assessed immediately before and after 4 cycles of chemotherapy. Their results were compared to 12 sex- and age-matched controls. ANS function was assessed using standardized tests of resting CV (tilt-table, respiratory sinus arrhythmia and Valsalva maneuver) and sudomotor (quantitative sudomotor axon reflex test) reactivity. Cardiovascular reactivity during exercise was assessed using a modified Astrand-Ryhming cycle ergometer protocol. Our feasibility criteria addressed: i) recruitment potential, ii) retention rates, iii) pre-chemotherapy assessment potential, iv) test performance/tolerability, and v) identification and minimizing the influence of potentially confounding medication. T-tests and repeated measures ANOVAs were used to assess between- and within-group differences at baseline and follow-up. The overall success rate in achieving our feasibility criteria was 98.4 %. According to the CASS, there was evidence of ANS impairment at baseline in 30.8 % of patients, which persisted in 18.2 % of patients at follow-up, compared to 0 % of controls at baseline or follow-up. Results from our feasibility assessment suggest that the investigation of ANS function in young adult cancer patients undergoing chemotherapy is possible. To the best of our knowledge, this is the first study to report CASS-based evidence of ANS impairment and sudomotor dysfunction in any cancer population. Moreover, we provide evidence of cancer- and chemotherapy-related parasympathetic dysfunction - as a possible contributor to the pathogenesis of CV disease in cancer survivors.

An anatomical and physiological basis for the cardiovascular autonomic nervous system consequences of sport-related brain injury.

PubMed

La Fountaine, Michael F

2017-11-29

Concussion is defined as a complex pathophysiological process affecting the brain that is induced by the application or transmission of traumatic biomechanical forces to the head. The result of the impact is the onset of transient symptoms that may be experienced for approximately 2weeks in most individuals. However, in some individuals, symptoms may not resolve and persist for a protracted period and a chronic injury ensues. Concussion symptoms are generally characterized by their emergence through changes in affect, cognition, or multi-sensory processes including the visual and vestibular systems. An emerging consequence of concussion is the presence of cardiovascular autonomic nervous system dysfunction that is most apparent through hemodynamic perturbations and provocations. Further interrogation of data that are derived from continuous digital electrocardiograms and/or beat-to-beat blood pressure monitoring often reveal an imbalance of parasympathetic or sympathetic nervous system activity during a provocation after an injury. The disturbance is often greatest early after injury and a resolution of the dysfunction occurs in parallel with other symptoms. The possibility exists that the disturbance may remain if the concussion does not resolve. Unfortunately, there is little evidence in humans to support the etiology for the emergence of this post-injury dysfunction. As such, evidence from experimental models of traumatic brain injury and casual observations from human studies of concussion implicate a transient abnormality of the anatomical structures and functions of the cardiovascular autonomic nervous system. The purpose of this review article is to provide a mechanistic narrative of multi-disciplinary evidence to support the anatomical and physiological basis of cardiovascular autonomic nervous system dysfunction after concussion. The review article will identify the anatomical structures of the autonomic nervous system and propose a theoretical framework to demonstrate the potential effects of concussive head trauma on corresponding outcome measurements. Evidence from experimental models will be used to describe abnormal cellular functions and provide a hypothetical mechanistic basis for the respective responses of the anatomical structures to concussive head trauma. When available, example observations from the human concussion literature will be presented to demonstrate the effects of concussive head trauma that may be related to anomalous activity in the respective anatomical structures of the autonomic nervous system. Copyright © 2017 Elsevier B.V. All rights reserved.

Cardiovascular response to lower body negative pressure stimulation before, during, and after space flight

NASA Technical Reports Server (NTRS)

Baisch, F.; Beck, L.; Blomqvist, G.; Wolfram, G.; Drescher, J.; Rome, J. L.; Drummer, C.

2000-01-01

BACKGROUND: It is well known that space travel cause post-flight orthostatic hypotension and it was assumed that autonomic cardiovascular control deteriorates in space. Lower body negative pressure (LBNP) was used to assess autonomic function of the cardiovascular system. METHODS: LBNP tests were performed on six crew-members before and on the first days post-flight in a series of three space missions. Additionally, two of the subjects performed LBNP tests in-flight. LBNP mimics fluid distribution of upright posture in a gravity independent way. It causes an artificial sequestration of blood, reduces preload, and filtrates plasma into the lower part of the body. Fluid distribution was assessed by bioelectrical impedance and anthropometric measurements. RESULTS: Heart rate, blood pressure, and total peripheral resistance increased significantly during LBNP experiments in-flight. The decrease in stroke volume, the increased pooling of blood, and the increased filtration of plasma into the lower limbs during LBNP indicated that a plasma volume reduction and a deficit of the interstitial volume of lower limbs rather than a change in cardiovascular control was responsible for the in-flight response. Post-flight LBNP showed no signs of cardiovascular deterioration. The still more pronounced haemodynamic changes during LBNP reflected the expected behaviour of cardiovascular control faced with less intravascular volume. In-flight, the status of an intra-and extravascular fluid deficit increases sympathetic activity, the release of vasoactive substances and consequently blood pressure. Post-flight, blood pressure decreases significantly below pre-flight values after restoration of volume deficits. CONCLUSION: We conclude that the cardiovascular changes in-flight are a consequence of a fluid deficit rather than a consequence of changes in autonomic signal processing.

Effects of Escitalopram on Autonomic Function in Posttraumatic Stress Disorder Among Veterans of Operations Enduring Freedom and Iraqi Freedom (OEF/OIF).

PubMed

Ramaswamy, Sriram; Selvaraj, Vithyalakshmi; Driscoll, David; Madabushi, Jayakrishna S; Bhatia, Subhash C; Yeragani, Vikram

2015-01-01

Posttraumatic stress disorder is a chronic, debilitating condition that has become a growing concern among combat veterans. Previous research suggests that posttraumatic stress disorder disrupts normal autonomic responding and may increase the risk of cardiovascular disease and mortality. Measures of heart rate variability and QT interval variability have been used extensively to characterize sympathetic and parasympathetic influences on heart rate in a variety of psychiatric populations. The objective of this study was to better understand the effects of pharmacological treatment on autonomic reactivity in posttraumatic stress disorder. A 12-week, Phase IV, prospective, open-label trial of escitalopram in veterans with combat-related posttraumatic stress disorder and comorbid depression. An outpatient mental health clinic at a Veterans Affairs Medical Center. Eleven male veterans of Operations Enduring Freedom and Iraqi Freedom diagnosed with posttraumatic stress disorder and comorbid depression. Autonomic reactivity was measured by examining heart rate variability and QT interval variability. Treatment safety and efficacy were also evaluated pre- and post-treatment. We observed a reduction in posttraumatic stress disorder and depression symptoms from pre- to post-treatment, and escitalopram was generally well tolerated in our sample. In addition, we observed a decrease in high frequency heart rate variability and an increase in QT variability, indicating a reduction in cardiac vagal function and heightened sympathetic activation. These findings suggest that escitalopram treatment in patients with posttraumatic stress disorder and depression can trigger changes in autonomic reactivity that may adversely impact cardiovascular health.

Sex Differences in Autonomic Correlates of Conduct Problems and Aggression

PubMed Central

BEAUCHAINE, THEODORE P.; HONG, JAMES; MARSH, PENNY

2009-01-01

Objective To examine sex differences in autonomic nervous system functioning in children and adolescents with conduct problems and to evaluate the role of aggression in predicting autonomic nervous system functioning, over and above the effects of disruptive behavior. Although deficiencies in autonomic responding among boys with oppositional defiant disorder and/or conduct disorder are well documented, it remains unclear whether such findings extend to girls or apply only to children with aggressive forms of conduct problems. Method Electrodermal responding, cardiac pre-ejection period, and respiratory sinus arrhythmia were recorded while boys (n = 110; 53 with conduct problems, 57 controls) and girls (n = 65; 33 with conduct problems, 32 controls) between the ages of 8 and 12 sat for an extended baseline, then played a game with conditions of reward and frustrative nonreward. Results Both sex effects and aggression effects were found. Aggressive boys with conduct problems demonstrated reduced autonomic functioning, consistent with previous research. In contrast, aggressive girls with conduct problems exhibited greater electrodermal responding than controls, with no differences in cardiovascular reactivity to incentives. Conclusions Observed sex differences in the autonomic correlates of conduct problems and aggression may suggest different etiological mechanisms of externalizing psychopathology for girls compared with boys. PMID:18520959

The Frequency-Dependent Aerobic Exercise Effects of Hypothalamic GABAergic Expression and Cardiovascular Functions in Aged Rats

PubMed Central

Li, Yan; Zhao, Ziqi; Cai, Jiajia; Gu, Boya; Lv, Yuanyuan; Zhao, Li

2017-01-01

A decline in cardiovascular modulation is a feature of the normal aging process and associated with cardiovascular diseases (CVDs) such as hypertension and stroke. Exercise training is known to promote cardiovascular adaptation in young animals and positive effects on motor and cognitive capabilities, as well as on brain plasticity for all ages in mice. Here, we examine the question of whether aerobic exercise interventions may impact the GABAergic neurons of the paraventricular nucleus (PVN) in aged rats which have been observed to have a decline in cardiovascular integration function. In the present study, young (2 months) and old (24 months) male Wistar rats were divided into young control (YC), old sedentary, old low frequency exercise (20 m/min, 60 min/day, 3 days/week, 12 weeks) and old high frequency exercise (20 m/min, 60 min/day, 5 days/week, 12 weeks). Exercise training indexes were obtained, including resting heart rate (HR), blood pressure (BP), plasma norepinephrine (NE), and heart weight (HW)-to-body weight (BW) ratios. The brain was removed and processed according to the immunofluorescence staining and western blot used to analyze the GABAergic terminal density, the proteins of GAD67, GABAA receptor and gephyrin in the PVN. There were significant changes in aged rats compared with those in the YC. Twelve weeks aerobic exercise training has volume-dependent ameliorated effects on cardiovascular parameters, autonomic nervous activities and GABAergic system functions. These data suggest that the density of GABAergic declines in the PVN is associated with imbalance in autonomic nervous activities in normal aging. Additionally, aerobic exercise can rescue aging-related an overactivity of the sympathetic nervous system and induces modifications the resting BP and HR to lower values via improving the GABAergic system in the PVN. PMID:28713263

Preliminary Evidence for the Impact of Combat Experiences on Gray Matter Volume of the Posterior Insula

PubMed Central

Clausen, Ashley N.; Billinger, Sandra A.; Sisante, Jason-Flor V.; Suzuki, Hideo; Aupperle, Robin L.

2017-01-01

Background: Combat-exposed veteran populations are at an increased risk for developing cardiovascular disease. The anterior cingulate cortex (ACC) and insula have been implicated in both autonomic arousal to emotional stressors and homeostatic processes, which may contribute to cardiovascular dysfunction in combat veteran populations. The aim of the present study was to explore the intersecting relationships of combat experiences, rostral ACC and posterior insula volume, and cardiovascular health in a sample of combat veterans. Method: Twenty-four male combat veterans completed clinical assessment of combat experiences and posttraumatic stress symptoms. Subjects completed a magnetic resonance imaging scan and autosegmentation using FreeSurfer was used to estimate regional gray matter volume (controlling for total gray matter volume) of the rostral ACC and posterior insula. Flow-mediated dilation (FMD) was conducted to assess cardiovascular health. Theil-sen robust regressions and Welch's analysis of variance were used to examine relationships of combat experiences and PTSD symptomology with (1) FMD and (2) regional gray matter volume. Results: Increased combat experiences, deployment duration, and multiple deployments were related to smaller posterior insula volume. Combat experiences were marginally associated with poorer cardiovascular health. However, cardiovascular health was not related to rostral ACC or posterior insula volume. Conclusion: The present study provides initial evidence for the relationships of combat experiences, deployment duration, and multiple deployments with smaller posterior insula volume. Results may suggest that veterans with increased combat experiences may exhibit more dysfunction regulating the autonomic nervous system, a key function of the posterior insula. However, the relationship between combat and cardiovascular health was not mediated by regional brain volume. Future research is warranted to further clarify the cardiovascular or functional impact of smaller posterior insula volume in combat veterans. PMID:29312038

Autonomic Cardiovascular Control and Executive Function in Chronic Hypotension.

PubMed

Duschek, Stefan; Hoffmann, Alexandra; Reyes Del Paso, Gustavo A; Ettinger, Ulrich

2017-06-01

Chronic low blood pressure (hypotension) is characterized by complaints such as fatigue, reduced drive, dizziness, and cold limbs. Additionally, deficits in attention and memory have been observed. Autonomic dysregulation is considered to be involved in the origin of this condition. The study explored autonomic cardiovascular control in the context of higher cognitive processing (executive function) in hypotension. Hemodynamic recordings were performed in 40 hypotensive and 40 normotensive participants during execution of four classical executive function tasks (number-letter task, n-back task, continuous performance test, and flanker task). Parameters of cardiac sympathetic control, i.e., stroke volume, cardiac output, pre-ejection period, total peripheral resistance, and parasympathetic control, i.e., respiratory sinus arrhythmia and baroreflex sensitivity, were obtained. The hypotensive group exhibited lower stroke volume and cardiac output, as well as higher pre-ejection period and baroreflex sensitivity during task execution. Increased error rates in hypotensive individuals were observed in the n-back and flanker tasks. In the total sample, there were positive correlations of error rates with pre-ejection period, baroreflex sensitivity and respiratory sinus arrhythmia, and negative correlations with cardiac output. Group differences in stroke volume, cardiac output, and pre-ejection period suggest diminished beta-adrenergic myocardial drive during executive function processing in hypotension, in addition to increased baroreflex function. Although further research is warranted to quantify the extent of executive function impairment in hypotension, the results from correlation analysis add evidence to the notion that higher sympathetic inotropic influences and reduced parasympathetic cardiac influences are accompanied by better cognitive performance.

Evaluation of the health status of six volunteers from the Mars 500 project using pulse analysis.

PubMed

Shi, Hong-Zhi; Fan, Quan-Chun; Gao, Jian-Yi; Liu, Jun-Lian; Bai, Gui-E; Mi, Tao; Zhao, Shuang; Liu, Yu; Xu, Dong; Guo, Zhi-Feng; Li, Yong-Zhi

2017-08-01

To comprehensively evaluate the health status of 6 volunteers from the Mars 500 Project through analyzing their pulse graphs and determining the changes in cardiovascular function, degree of fatigue and autonomic nervous function. Six volunteers were recruited; all were male aged 26-38 years (average 31.83±4.96 years). Characteristic parameters reflflecting the status of cardiovascular functions were extracted, which included left ventricular contraction, vascular elasticity and peripheral resistance. The degree of fatigue was determined depending on the difference between the calendar age and biological age, which was calculated through the analysis of blood pressure value and characteristic parameters. Based on the values of pulse height variation and pulse time variation on a 30-s pulse graph, autonomic nervous function was evaluated. All parameters examined were marked on an equilateral polygon to form an irregular polygon of the actual fifigure, then health status was evaluated based on the coverage area of the actual fifigure. The results demonstrated: (1) volunteers developed weakened pulse power, increased vascular tension and peripheral resistance, and slight decreased ventricular systolic function; (2) the degree of fatigue was basically mild or moderate; and (3) autonomic nervous function was excited but generally balanced. These volunteers were in the state of sub-health. According to Chinese medicine theories, such symptoms are mainly caused by the weakening of healthy qi, Gan (Liver) failing in free coursing, and disharmony between Gan and Wei (Stomach), which manifests as a weak and string-like pulse.

Relationship between autonomic cardiovascular control, case definition, clinical symptoms, and functional disability in adolescent chronic fatigue syndrome: an exploratory study.

PubMed

Wyller, Vegard B; Helland, Ingrid B

2013-02-07

Chronic Fatigue Syndrome (CFS) is characterized by severe impairment and multiple symptoms. Autonomic dysregulation has been demonstrated in several studies. We aimed at exploring the relationship between indices of autonomic cardiovascular control, the case definition from Centers for Disease Control and Prevention (CDC criteria), important clinical symptoms, and disability in adolescent chronic fatigue syndrome. 38 CFS patients aged 12-18 years were recruited according to a wide case definition (ie. not requiring accompanying symptoms) and subjected to head-up tilt test (HUT) and a questionnaire. The relationships between variables were explored with multiple linear regression analyses. In the final models, disability was positively associated with symptoms of cognitive impairments (p<0.001), hypersensitivity (p<0.001), fatigue (p=0.003) and age (p=0.007). Symptoms of cognitive impairments were associated with age (p=0.002), heart rate (HR) at baseline (p=0.01), and HR response during HUT (p=0.02). Hypersensitivity was associated with HR response during HUT (p=0.001), high-frequency variability of heart rate (HF-RRI) at baseline (p=0.05), and adherence to the CDC criteria (p=0.005). Fatigue was associated with gender (p=0.007) and adherence to the CDC criteria (p=0.04). In conclusion, a) The disability of CFS patients is not only related to fatigue but to other symptoms as well; b) Altered cardiovascular autonomic control is associated with certain symptoms; c) The CDC criteria are poorly associated with disability, symptoms, and indices of altered autonomic nervous activity.

Chronic mercury exposure impairs the sympathovagal control of the rat heart.

PubMed

Simões, M R; Azevedo, B F; Fiorim, J; Jr Freire, D D; Covre, E P; Vassallo, D V; Dos Santos, L

2016-11-01

Mercury is known to cause harmful neural effects affecting the cardiovascular system. Here, we evaluated the chronic effects of low-dose mercury exposure on the autonomic control of the cardiovascular system. Wistar rats were treated for 30 days with HgCl 2 (1st dose 4.6 μg/kg followed by 0.07 μg/kg per day, intramuscular) or saline. The femoral artery and vein were then cannulated for evaluation of autonomic control of the hemodynamic function, which was evaluated in awake rats. The following tests were performed: baroreflex sensitivity, Von Bezold-Jarisch reflex, heart rate variability (HRV) and pharmacological blockade with methylatropine and atenolol to test the autonomic tone of the heart. Exposure to HgCl 2 for 30 days slightly increased the mean arterial pressure and heart rate (HR). There was a significant reduction in the baroreflex gain of animals exposed to HgCl 2 . Moreover, haemodynamic responses to the activation of the Von Bezold-Jarisch reflex were also reduced. The changes in the spectral analysis of HRV suggested a shift in the sympathovagal balance toward a sympathetic predominance after mercury exposure, which was confirmed by autonomic pharmacological blockade in the HgCl 2 group. This group also exhibited reduced intrinsic HR after the double block suggesting that the pacemaker activity of the sinus node was also affected. These findings suggested that the autonomic modulation of the heart was significantly altered by chronic mercury exposure, thus reinforcing that even at low concentrations such exposure might be associated with increased cardiovascular risk. © 2016 John Wiley & Sons Australia, Ltd.

Cardiovascular and respiratory dynamics during normal and pathological sleep

NASA Astrophysics Data System (ADS)

Penzel, Thomas; Wessel, Niels; Riedl, Maik; Kantelhardt, Jan W.; Rostig, Sven; Glos, Martin; Suhrbier, Alexander; Malberg, Hagen; Fietze, Ingo

2007-03-01

Sleep is an active and regulated process with restorative functions for physical and mental conditions. Based on recordings of brain waves and the analysis of characteristic patterns and waveforms it is possible to distinguish wakefulness and five sleep stages. Sleep and the sleep stages modulate autonomous nervous system functions such as body temperature, respiration, blood pressure, and heart rate. These functions consist of a sympathetic tone usually related to activation and to parasympathetic (or vagal) tone usually related to inhibition. Methods of statistical physics are used to analyze heart rate and respiration to detect changes of the autonomous nervous system during sleep. Detrended fluctuation analysis and synchronization analysis and their applications to heart rate and respiration during sleep in healthy subjects and patients with sleep disorders are presented. The observed changes can be used to distinguish sleep stages in healthy subjects as well as to differentiate normal and disturbed sleep on the basis of heart rate and respiration recordings without direct recording of brain waves. Of special interest are the cardiovascular consequences of disturbed sleep because they present a risk factor for cardiovascular disorders such as arterial hypertension, cardiac ischemia, sudden cardiac death, and stroke. New derived variables can help to find indicators for these health risks.

A deletion in the alpha2B-adrenergic receptor gene and autonomic nervous function in central obesity.

PubMed

Sivenius, Katariina; Niskanen, Leo; Laakso, Markku; Uusitupa, Matti

2003-08-01

We investigated the impact of a three-amino acid deletion (12Glu9) polymorphism in the alpha(2B)-adrenergic receptor gene on autonomic nervous function. The short form (Glu(9)/Glu(9)) of the polymorphism has previously been associated with a reduced basal metabolic rate in obese subjects. Because autonomic nervous function participates in the regulation of energy metabolism, there could be a link between this polymorphism and autonomic nervous function. Data of a 10-year follow-up study with 126 nondiabetic control subjects and 84 type 2 diabetic patients were used to determine the effects of the 12Glu9 polymorphism on autonomic nervous function. A deep breathing test and an orthostatic test were used to investigate parasympathetic and sympathetic autonomic nervous function. In addition, cardiovascular autonomic function was studied using power spectral analysis of heart rate variability. No significant differences were found in the frequency of the 12Glu9 deletion polymorphism between nondiabetic and diabetic subjects. The nondiabetic men with the Glu(9)/Glu(9) genotype, especially those with abdominal obesity, had significantly lower total and low-frequency power values in the power spectral analysis when compared with other men. Furthermore, in a longitudinal analysis of 10 years, the decrease in parasympathetic function was greater in nondiabetic men with the Glu(9)/Glu(9) genotype than in the men with the Glu(9)/Glu(12) or Glu(12)/Glu(12) genotypes. The results of the present study suggest that the 12Glu9 polymorphism of the alpha(2B)-adrenergic receptor gene modulates autonomic nervous function in Finnish nondiabetic men. In the nondiabetic men with the Glu(9)/Glu(9) genotype, the general autonomic tone is depressed, and vagal activity especially becomes impaired with time. Furthermore, this association is accentuated by central obesity.

Chemokines and Heart Disease: A Network Connecting Cardiovascular Biology to Immune and Autonomic Nervous Systems

PubMed Central

Dusi, Veronica; Ghidoni, Alice; Ravera, Alice; De Ferrari, Gaetano M.; Calvillo, Laura

2016-01-01

Among the chemokines discovered to date, nineteen are presently considered to be relevant in heart disease and are involved in all stages of cardiovascular response to injury. Chemokines are interesting as biomarkers to predict risk of cardiovascular events in apparently healthy people and as possible therapeutic targets. Moreover, they could have a role as mediators of crosstalk between immune and cardiovascular system, since they seem to act as a “working-network” in deep linkage with the autonomic nervous system. In this paper we will describe the single chemokines more involved in heart diseases; then we will present a comprehensive perspective of them as a complex network connecting the cardiovascular system to both the immune and the autonomic nervous systems. Finally, some recent evidences indicating chemokines as a possible new tool to predict cardiovascular risk will be described. PMID:27242392

Measures of cardiovascular autonomic activity in insomnia disorder: A systematic review

PubMed Central

Fonseca, Pedro; Vullings, Rik; Aarts, Ronald M.

2017-01-01

Background Insomnia disorder is a widespread sleep disorder with a prevalence of approximately 10%. Even though the link between insomnia and cardiovascular activity is not exactly clear, it is generally assumed that cardiovascular autonomic modifications could occur as a result of sleeplessness, or, alternatively, that autonomic alterations could be an expression of a hyper-arousal state. This review investigates whether cardiovascular measures are different between insomniacs and controls. Methods Electronic databases were systematically searched, and 34 studies were identified. Heart rate variability features, the association of cardiac and EEG activity, physiologic complexity measures, and cardiovascular activity, assessed by measures such as pre-ejection time, blood pressure, and heart rate dynamics were studied. Given the heterogeneity of the studies, a narrative synthesis of the findings was performed. Results This review study found overall differences in cardiovascular activity between insomniacs and controls in most of the observational studies (21/26), while the expression of cardiovascular regulation varied between the examined insomniac groups. All the studies that investigated the association of cardiac activity and EEG power reported an altered relation between autonomic activity and EEG parameters in insomniacs. Conclusion Autonomic regulation tends to be consistent between insomniacs, as long as they are grouped according to their respective phenotype, as shown in the insomnia subgroup with objectively short sleep duration. Our hypothesis is that these differences in the expression of cardiovascular activity could be explained by the heterogeneity of the disorder. Therefore, the determination of insomnia phenotypes, and the study of cardiovascular measures, rather than heart rate variability alone, will give more insight into the link between insomnia and cardiovascular regulation. This study suggests that cardiovascular activity differs between insomniacs and controls. These new findings are of interest to clinicians and researchers for a more accurate insomnia assessment, and the development of personalized technological solutions in insomnia. PMID:29059210

Cardiovascular and metabolic consequences of the association between chronic stress and high-fat diet in rats.

PubMed

Simas, Bruna B; Nunes, Everson A; Crestani, Carlos C; Speretta, Guilherme F

2018-05-01

Obesity and chronic stress are considered independent risk factors for the development of cardiovascular diseases and changes in autonomic system activity. However, the cardiovascular consequences induced by the association between high-fat diet (HFD) and chronic stress are not fully understood. We hypothesized that the association between HFD and exposure to a chronic variable stress (CVS) protocol for four weeks might exacerbate the cardiovascular and metabolic disturbances in rats when compared to these factors singly. To test this hypothesis, male Wistar rats were divided into four groups: control-standard chow diet (SD; n = 8); control-HFD (n = 8); CVS-SD (n = 8); and CVS-HFD (n = 8). The CVS consisted of repeated exposure of the rats to different inescapable and unpredictable stressors (restraint tress; damp sawdust, cold, swim stress and light cycle inversion). We evaluated cardiovascular function, autonomic activity, dietary intake, adiposity and metabolism. The HFD increased body weight, adiposity and blood glucose concentration (∼15%) in both control and CVS rats. The CVS-HFD rats showed decreased insulin sensitivity (25%) compared to CVS-SD rats. The control-HFD and CVS-HFD rats presented increased intrinsic heart rate (HR) values (∼8%). CVS increased cardiac sympathetic activity (∼65%) in both SD- and HFD-fed rats. The HFD increased basal HR (∼10%). Blood pressure and baroreflex analyzes showed no differences among the experimental groups. In conclusion, the present data indicate absence of interaction on autonomic imbalance evoked by either CVS or HFD. Additionally, HFD increased HR and evoked metabolic disruptions which are independent of stress exposure.

[Association of cardiovascular autonomic neuropathy and prolonged QT interval with cardiovascular morbidity and mortality in patients with type 2 diabetes mellitus].

PubMed

Ticse Aguirre, Ray; Villena, Jaime E

2011-03-01

In order to evaluate the relationship between cardiovascular autonomic neuropathy and corrected QT interval (QTc) with cardiovascular morbidity and mortality in patients with type 2 diabetes mellitus, we followed up for 5 years 67 patients attending the outpatient Endocrinology Service. 82% completed follow-up and cardiovascular events occurred in 16 patients. We found that long QTc interval was the only variable significantly associated with cardiovascular morbidity and mortality in the multiple logistic regression analysis (RR: 13.56, 95% CI: 2.01-91.36) (p = 0.0074).

Effects of Incretin-Based Therapies on Neuro-Cardiovascular Dynamic Changes Induced by High Fat Diet in Rats.

PubMed

Marques-Neto, Silvio Rodrigues; Castiglione, Raquel Carvalho; Pontes, Aiza; Oliveira, Dahienne Ferreira; Ferraz, Emanuelle Baptista; Nascimento, José Hamilton Matheus; Bouskela, Eliete

2016-01-01

Obesity promotes cardiac and cerebral microcirculatory dysfunction that could be improved by incretin-based therapies. However, the effects of this class of compounds on neuro-cardiovascular system damage induced by high fat diet remain unclear. The aim of this study was to investigate the effects of incretin-based therapies on neuro-cardiovascular dysfunction induced by high fat diet in Wistar rats. We have evaluated fasting glucose levels and insulin resistance, heart rate variability quantified on time and frequency domains, cerebral microcirculation by intravital microscopy, mean arterial blood pressure, ventricular function and mitochondrial swelling. High fat diet worsened biometric and metabolic parameters and promoted deleterious effects on autonomic, myocardial and haemodynamic parameters, decreased capillary diameters and increased functional capillary density in the brain. Biometric and metabolic parameters were better improved by glucagon like peptide-1 (GLP-1) compared with dipeptdyl peptidase-4 (DPP-4) inhibitor. On the other hand, both GLP-1 agonist and DPP-4 inhibitor reversed the deleterious effects of high fat diet on autonomic, myocardial, haemodynamic and cerebral microvascular parameters. GLP-1 agonist and DPP-4 inhibitor therapy also increased mitochondrial permeability transition pore resistance in brain and heart tissues of rats subjected to high fat diet. Incretin-based therapies improve deleterious cardiovascular effects induced by high fat diet and may have important contributions on the interplay between neuro-cardiovascular dynamic controls through mitochondrial dysfunction associated to metabolic disorders.

System identification of closed-loop cardiovascular control mechanisms: diabetic autonomic neuropathy

NASA Technical Reports Server (NTRS)

Mukkamala, R.; Mathias, J. M.; Mullen, T. J.; Cohen, R. J.; Freeman, R.

1999-01-01

We applied cardiovascular system identification (CSI) to characterize closed-loop cardiovascular regulation in patients with diabetic autonomic neuropathy (DAN). The CSI method quantitatively analyzes beat-to-beat fluctuations in noninvasively measured heart rate, arterial blood pressure (ABP), and instantaneous lung volume (ILV) to characterize four physiological coupling mechanisms, two of which are autonomically mediated (the heart rate baroreflex and the coupling of respiration, measured in terms of ILV, to heart rate) and two of which are mechanically mediated (the coupling of ventricular contraction to the generation of the ABP wavelet and the coupling of respiration to ABP). We studied 37 control and 60 diabetic subjects who were classified as having minimal, moderate, or severe DAN on the basis of standard autonomic tests. The autonomically mediated couplings progressively decreased with increasing severity of DAN, whereas the mechanically mediated couplings were essentially unchanged. CSI identified differences between the minimal DAN and control groups, which were indistinguishable based on the standard autonomic tests. CSI may provide a powerful tool for assessing DAN.

Visual- and Vestibular-Autonomic Influence on Short-Term Cardiovascular Regulatory Mechanisms

NASA Technical Reports Server (NTRS)

Mullen, Thomas J.; Ramsdell, Craig D.

1999-01-01

This synergy project was a one-year effort conducted cooperatively by members of the NSBRI Cardiovascular Alterations and Neurovestibular Adaptation Teams in collaboration with NASA Johnson Space Center (JSC) colleagues. The objective of this study was to evaluate visual autonomic interactions on short-term cardiovascular regulatory mechanisms. Based on established visual-vestibular and vestibular-autonomic shared neural pathways, we hypothesized that visually induced changes in orientation will trigger autonomic cardiovascular reflexes. A second objective was to compare baroreflex changes during postural changes as measured with the new Cardiovascular System Identification (CSI) technique with those measured using a neck barocuff. While the neck barocuff stimulates only the carotid baroreceptors, CSI provides a measure of overall baroreflex responsiveness. This study involved a repeated measures design with 16 healthy human subjects (8 M, 8 F) to examine cardiovascular regulatory responses during actual and virtual head-upright tilts. Baroreflex sensitivity was first evaluated with subjects in supine and upright positions during actual tilt-table testing using both neck barocuff and CSI methods. The responses to actual tilts during this first session were then compared to responses during visually induced tilt and/or rotation obtained during a second session.

Children's Sleep and Autonomic Function: Low Sleep Quality Has an Impact on Heart Rate Variability

PubMed Central

Michels, Nathalie; Clays, Els; De Buyzere, Marc; Vanaelst, Barbara; De Henauw, Stefaan; Sioen, Isabelle

2013-01-01

Objectives: Short sleep duration and poor sleep quality in children have been associated with concentration, problem behavior, and emotional instability, but recently also with disrupted autonomic nervous function, which predicts cardiovascular health. Heart rate variability (HRV) was used as noninvasive indicator of autonomic function to examine the influence of sleep. Design: Cross-sectional and longitudinal observational study on the effect of sleep on HRV Participants: Belgian children (5-11 years) of the ChiBS study in 2010 (N = 334) and 2011 (N = 293). Interventions: N/A. Methods: Sleep duration was reported and in a subgroup sleep quality (efficiency, latency, awakenings) was measured with accelerometry. High-frequency (HF) power and autonomic balance (LF/HF) were calculated on supine 5-minute HRV measurements. Stress was measured by emotion and problem behavior questionnaires. Sleep duration and quality were used as HRV predictors in corrected cross-sectional and longitudinal regressions. Stress was tested as mediator (intermediate pathway) or moderator (interaction) in sleep-HRV associations. Results: In both cross-sectional and longitudinal analyses, long sleep latency could predict lower HF (parasympathetic activity), while nocturnal awakenings, sleep latency, low sleep efficiency, and low corrected sleep duration were related to higher LF/HF (sympathetic/parasympathetic balance). Parental reported sleep duration was not associated with HRV. The significances remained after correction for stress. Stress was not a mediator, but a moderator (enhancer) in the relationship between sleep quality and HRV. Conclusions: Low sleep quality but not parent-reported low sleep duration leads to an unhealthier heart rate variability pattern (sympathetic over parasympathetic dominance). This stresses the importance of good sleep quality for cardiovascular health in children. Citation: Michels N; Clays E; De Buyzere M; Vanaelst B; De Henauw S; Sioen I. Children's sleep and autonomic function: low sleep quality has an impact on heart rate variability. SLEEP 2013;36(12):1939-1946. PMID:24293769

Children's sleep and autonomic function: low sleep quality has an impact on heart rate variability.

PubMed

Michels, Nathalie; Clays, Els; De Buyzere, Marc; Vanaelst, Barbara; De Henauw, Stefaan; Sioen, Isabelle

2013-12-01

Short sleep duration and poor sleep quality in children have been associated with concentration, problem behavior, and emotional instability, but recently also with disrupted autonomic nervous function, which predicts cardiovascular health. Heart rate variability (HRV) was used as noninvasive indicator of autonomic function to examine the influence of sleep. Cross-sectional and longitudinal observational study on the effect of sleep on HRV. Belgian children (5-11 years) of the ChiBS study in 2010 (N = 334) and 2011 (N = 293). N/A. Sleep duration was reported and in a subgroup sleep quality (efficiency, latency, awakenings) was measured with accelerometry. High-frequency (HF) power and autonomic balance (LF/HF) were calculated on supine 5-minute HRV measurements. Stress was measured by emotion and problem behavior questionnaires. Sleep duration and quality were used as HRV predictors in corrected cross-sectional and longitudinal regressions. Stress was tested as mediator (intermediate pathway) or moderator (interaction) in sleep-HRV associations. In both cross-sectional and longitudinal analyses, long sleep latency could predict lower HF (parasympathetic activity), while nocturnal awakenings, sleep latency, low sleep efficiency, and low corrected sleep duration were related to higher LF/HF (sympathetic/parasympathetic balance). Parental reported sleep duration was not associated with HRV. The significances remained after correction for stress. Stress was not a mediator, but a moderator (enhancer) in the relationship between sleep quality and HRV. Low sleep quality but not parent-reported low sleep duration leads to an unhealthier heart rate variability pattern (sympathetic over parasympathetic dominance). This stresses the importance of good sleep quality for cardiovascular health in children.

[Analysis of time domain and frequency domain heart rate variability in fighter pilot before and after upright tilt].

PubMed

Wang, L; Wu, L; Ji, G; Zhang, X; Chen, T; Wang, L

1998-12-01

Effects of upright tilt on mechanism of autonomic nervous regulation of cardiovascular system and characteristics of heart rate variability (HRV) were observed in sixty healthy male pilots. Relation between time domain and frequency domain indexes of short-time HRV (5 min) were analysed before and after upright tilt. The results showed that there are significant difference in short time HRV parameters before and after upright tilt. Significant relationship was formed between time domain and frequency domain indexes of HRV. It suggests that time domain and frequency domain HRV analysis is capable of revealing certain informations embedded in a short series of R-R intervals and can help to evaluate the status of autonomic regulation of cardiovascular function in pilots.

Sudomotor, skin vasomotor, and cardiovascular reflexes in 3 clinical forms of Lewy body disease.

PubMed

Akaogi, Y; Asahina, M; Yamanaka, Y; Koyama, Y; Hattori, T

2009-07-07

To elucidate the differences among dementia with Lewy bodies (DLB), Parkinson disease with dementia (PDD), and Parkinson disease without dementia (PD), with respect to the involvement of the autonomic nervous system, we clinically investigated the cutaneous and cardiovascular autonomic functions in patients with Lewy body disease. We studied 36 patients with Lewy body disorders, including 12 patients with DLB (age, 75.4 +/- 5.9 years), 12 patients with PDD (71.0 +/- 6.8 years), and 12 patients with PD (70.9 +/- 4.2 years), and 12 healthy control subjects (69.9 +/- 5.3 years). Sympathetic sweat response (SSwR) and skin vasomotor reflex (SkVR) on the palm were recorded to estimate the cutaneous sympathetic function, and the head-up tilt test was performed and coefficient of variation of R-R intervals (CV(R-R)) was studied to estimate the cardiovascular function. The patients with DLB, patients with PDD, and patients with PD showed severely reduced SSwR amplitudes, significantly lower than that in the controls. The mean SkVR amplitudes in the patients with DLB and patients with PDD were significantly lower than that in the controls, but not in the patients with PD. The mean decreases in the systolic blood pressure during the head-up tilt test in the patients with DLB and patients with PDD were less than that in the controls. The mean CV(R-R) value was significantly lower in the patients with DLB. Sudomotor function on the palm may be severely affected in Lewy body disorders, while skin vasomotor function and the cardiovascular system may be more severely affected in dementia with Lewy bodies and Parkinson disease with dementia than in Parkinson disease.

Cardiovascular autonomic adaptation in lunar and martian gravity during parabolic flight.

PubMed

Widjaja, Devy; Vandeput, Steven; Van Huffel, Sabine; Aubert, André E

2015-06-01

Weightlessness has a well-known effect on the autonomic control of the cardiovascular system. With future missions to Mars in mind, it is important to know what the effect of partial gravity is on the human body. We aim to study the autonomic response of the cardiovascular system to partial gravity levels, as present on the Moon and on Mars, during parabolic flight. ECG and blood pressure were continuously recorded during parabolic flight. A temporal analysis of blood pressure and heart rate to changing gravity was conducted to study the dynamic response. In addition, cardiovascular autonomic control was quantified by means of heart rate (HR) and blood pressure (BP) variability measures. Zero and lunar gravity presented a biphasic cardiovascular response, while a triphasic response was noted during martian gravity. Heart rate and blood pressure are positively correlated with gravity, while the general variability of HR and BP, as well as vagal indices showed negative correlations with increasing gravity. However, the increase in vagal modulation during weightlessness is not in proportion when compared to the increase during partial gravity. Correlations were found between the gravity level and modulations in the autonomic nervous system during parabolic flight. Nevertheless, with future Mars missions in mind, more studies are needed to use these findings to develop appropriate countermeasures.

Effects of work stress and home stress on autonomic nervous function in Japanese male workers

PubMed Central

MAEDA, Eri; IWATA, Toyoto; MURATA, Katsuyuki

2014-01-01

Autonomic imbalance is one of the important pathways through which psychological stress contributes to cardiovascular diseases/sudden death. Although previous studies have focused mainly on stress at work (work stress), the association between autonomic function and stress at home (home stress) is still poorly understood. The purpose was to clarify the effect of work/home stress on autonomic function in 1,809 Japanese male workers. We measured corrected QT (QTc) interval and QT index on the electrocardiogram along with blood pressure and heart rate. Participants provided self-reported information about the presence/absence of work/home stress and the possible confounders affecting QT indicators. Home stress was related positively to QT index (p=0.040) after adjusting for the possible confounders, though work stress did not show a significant relation to QTc interval or QT index. The odds ratio of home stress to elevated QT index (≥105) was 2.677 (95% CI, 1.050 to 6.822). Work/home stress showed no significant relation to blood pressure or heart rate. These findings suggest that autonomic imbalance, readily assessed by QT indicators, can be induced by home stress in Japanese workers. Additional research is needed to identify different types of home stress that are strongly associated with autonomic imbalance. PMID:25382383

Effects of work stress and home stress on autonomic nervous function in Japanese male workers.

PubMed

Maeda, Eri; Iwata, Toyoto; Murata, Katsuyuki

2015-01-01

Autonomic imbalance is one of the important pathways through which psychological stress contributes to cardiovascular diseases/sudden death. Although previous studies have focused mainly on stress at work (work stress), the association between autonomic function and stress at home (home stress) is still poorly understood. The purpose was to clarify the effect of work/home stress on autonomic function in 1,809 Japanese male workers. We measured corrected QT (QTc) interval and QT index on the electrocardiogram along with blood pressure and heart rate. Participants provided self-reported information about the presence/absence of work/home stress and the possible confounders affecting QT indicators. Home stress was related positively to QT index (p=0.040) after adjusting for the possible confounders, though work stress did not show a significant relation to QTc interval or QT index. The odds ratio of home stress to elevated QT index (≥105) was 2.677 (95% CI, 1.050 to 6.822). Work/home stress showed no significant relation to blood pressure or heart rate. These findings suggest that autonomic imbalance, readily assessed by QT indicators, can be induced by home stress in Japanese workers. Additional research is needed to identify different types of home stress that are strongly associated with autonomic imbalance.

Cardiorespiratory Fitness and Cardiac Autonomic Function in Diabetes.

PubMed

Röhling, Martin; Strom, Alexander; Bönhof, Gidon J; Roden, Michael; Ziegler, Dan

2017-10-23

This review summarizes the current knowledge on the relationship of physical activity, exercise, and cardiorespiratory fitness (CRF) with cardiovascular autonomic neuropathy (CAN) based on epidemiological, clinical, and interventional studies. The prevalence of CAN increases with age and duration of diabetes. Further risk factors for CAN comprise poor glycemic control, dyslipidemia, abdominal obesity, hypertension, and the presence of diabetic complications. CAN has been also linked to reduced CRF. We recently showed that CRF parameters (e.g., maximal oxidative capacity or oxidative capacity at the anaerobic threshold) are associated with cardiac autonomic function in patients recently diagnosed with type 1 or type 2 diabetes. Exercise interventions have shown that physical activity can increase cardiovagal activity and reduce sympathetic overactivity. In particular, long-term and regularly, but also supervised, performed endurance and high-intense and high-volume exercise improves cardiac autonomic function in patients with type 2 diabetes. By contrast, the evidence in those with type 1 diabetes and also in individuals with prediabetes or metabolic syndrome is weaker. Overall, the studies reviewed herein addressing the question whether favorably modulating the autonomic nervous system may improve CRF during exercise programs support the therapeutic concept to promote physical activity and to achieve physical fitness. However, high-quality exercise interventions, especially in type 1 diabetes and metabolic syndrome including prediabetes, are further required to better understand the relationship between physical activity, fitness, and cardiac autonomic function.

Exercise-induced neuronal plasticity in central autonomic networks: role in cardiovascular control.

PubMed

Michelini, Lisete C; Stern, Javier E

2009-09-01

It is now well established that brain plasticity is an inherent property not only of the developing but also of the adult brain. Numerous beneficial effects of exercise, including improved memory, cognitive function and neuroprotection, have been shown to involve an important neuroplastic component. However, whether major adaptive cardiovascular adjustments during exercise, needed to ensure proper blood perfusion of peripheral tissues, also require brain neuroplasticity, is presently unknown. This review will critically evaluate current knowledge on proposed mechanisms that are likely to underlie the continuous resetting of baroreflex control of heart rate during/after exercise and following exercise training. Accumulating evidence indicates that not only somatosensory afferents (conveyed by skeletal muscle receptors, baroreceptors and/or cardiopulmonary receptors) but also projections arising from central command neurons (in particular, peptidergic hypothalamic pre-autonomic neurons) converge into the nucleus tractus solitarii (NTS) in the dorsal brainstem, to co-ordinate complex cardiovascular adaptations during dynamic exercise. This review focuses in particular on a reciprocally interconnected network between the NTS and the hypothalamic paraventricular nucleus (PVN), which is proposed to act as a pivotal anatomical and functional substrate underlying integrative feedforward and feedback cardiovascular adjustments during exercise. Recent findings supporting neuroplastic adaptive changes within the NTS-PVN reciprocal network (e.g. remodelling of afferent inputs, structural and functional neuronal plasticity and changes in neurotransmitter content) will be discussed within the context of their role as important underlying cellular mechanisms supporting the tonic activation and improved efficacy of these central pathways in response to circulatory demand at rest and during exercise, both in sedentary and in trained individuals. We hope this review will stimulate more comprehensive studies aimed at understanding cellular and molecular mechanisms within CNS neuronal networks that contribute to exercise-induced neuroplasticity and cardiovascular adjustments.

Viewing nature scenes positively affects recovery of autonomic function following acute-mental stress.

PubMed

Brown, Daniel K; Barton, Jo L; Gladwell, Valerie F

2013-06-04

A randomized crossover study explored whether viewing different scenes prior to a stressor altered autonomic function during the recovery from the stressor. The two scenes were (a) nature (composed of trees, grass, fields) or (b) built (composed of man-made, urban scenes lacking natural characteristics) environments. Autonomic function was assessed using noninvasive techniques of heart rate variability; in particular, time domain analyses evaluated parasympathetic activity, using root-mean-square of successive differences (RMSSD). During stress, secondary cardiovascular markers (heart rate, systolic and diastolic blood pressure) showed significant increases from baseline which did not differ between the two viewing conditions. Parasympathetic activity, however, was significantly higher in recovery following the stressor in the viewing scenes of nature condition compared to viewing scenes depicting built environments (RMSSD; 50.0 ± 31.3 vs 34.8 ± 14.8 ms). Thus, viewing nature scenes prior to a stressor alters autonomic activity in the recovery period. The secondary aim was to examine autonomic function during viewing of the two scenes. Standard deviation of R-R intervals (SDRR), as change from baseline, during the first 5 min of viewing nature scenes was greater than during built scenes. Overall, this suggests that nature can elicit improvements in the recovery process following a stressor.

Viewing Nature Scenes Positively Affects Recovery of Autonomic Function Following Acute-Mental Stress

PubMed Central

2013-01-01

A randomized crossover study explored whether viewing different scenes prior to a stressor altered autonomic function during the recovery from the stressor. The two scenes were (a) nature (composed of trees, grass, fields) or (b) built (composed of man-made, urban scenes lacking natural characteristics) environments. Autonomic function was assessed using noninvasive techniques of heart rate variability; in particular, time domain analyses evaluated parasympathetic activity, using root-mean-square of successive differences (RMSSD). During stress, secondary cardiovascular markers (heart rate, systolic and diastolic blood pressure) showed significant increases from baseline which did not differ between the two viewing conditions. Parasympathetic activity, however, was significantly higher in recovery following the stressor in the viewing scenes of nature condition compared to viewing scenes depicting built environments (RMSSD; 50.0 ± 31.3 vs 34.8 ± 14.8 ms). Thus, viewing nature scenes prior to a stressor alters autonomic activity in the recovery period. The secondary aim was to examine autonomic function during viewing of the two scenes. Standard deviation of R-R intervals (SDRR), as change from baseline, during the first 5 min of viewing nature scenes was greater than during built scenes. Overall, this suggests that nature can elicit improvements in the recovery process following a stressor. PMID:23590163

Vestibular influences on autonomic cardiovascular control in humans

NASA Technical Reports Server (NTRS)

Biaggioni, I.; Costa, F.; Kaufmann, H.; Robertson, D. (Principal Investigator)

1998-01-01

There is substantial evidence that anatomical connections exist between vestibular and autonomic nuclei. Animal studies have shown functional interactions between the vestibular and autonomic systems. The nature of these interactions, however, is complex and has not been fully defined. Vestibular stimulation has been consistently found to reduce blood pressure in animals. Given the potential interaction between vestibular and autonomic pathways this finding could be explained by a reduction in sympathetic activity. However, rather than sympathetic inhibition, vestibular stimulation has consistently been shown to increase sympathetic outflow in cardiac and splanchnic vascular beds in most experimental models. Several clinical observations suggest that a link between vestibular and autonomic systems may also exist in humans. However, direct evidence for vestibular/autonomic interactions in humans is sparse. Motion sickness has been found to induce forearm vasodilation and reduce baroreflex gain, and head down neck flexion induces transient forearm and calf vasoconstriction. On the other hand, studies using optokinetic stimulation have found either very small, variable, or inconsistent changes in heart rate and blood pressure, despite substantial symptoms of motion sickness. Furthermore, caloric stimulation severe enough to produce nystagmus, dizziness, and nausea had no effect on sympathetic nerve activity measured directly with microneurography. No effect was observed on heart rate, blood pressure, or plasma norepinephrine. Several factors may explain the apparent discordance of these results, but more research is needed before we can define the potential importance of vestibular input to cardiovascular regulation and orthostatic tolerance in humans.

Contemporary Cardiovascular Concerns after Spinal Cord Injury: Mechanisms, Maladaptations, and Management.

PubMed

Phillips, Aaron A; Krassioukov, Andrei V

2015-12-15

Cardiovascular (CV) issues after spinal cord injury (SCI) are of paramount importance considering they are the leading cause of death in this population. Disruption of autonomic pathways leads to a highly unstable CV system, with impaired blood pressure (BP) and heart rate regulation. In addition to low resting BP, on a daily basis the majority of those with SCI suffer from transient episodes of aberrantly low and high BP (termed orthostatic hypotension and autonomic dysreflexia, respectively). In fact, autonomic issues, including resolution of autonomic dysreflexia, are frequently ranked by individuals with high-level SCI to be of greater priority than walking again. Owing to a combination of these autonomic disturbances and a myriad of lifestyle factors, the pernicious process of CV disease is accelerated post-SCI. Unfortunately, these secondary consequences of SCI are only beginning to receive appropriate clinical attention. Immediately after high-level SCI, major CV abnormalities present in the form of neurogenic shock. After subsiding, new issues related to BP instability arise, including orthostatic hypotension and autonomic dysreflexia. This review describes autonomic control over the CV system before injury and the mechanisms underlying CV abnormalities post-SCI, while also detailing the end-organ consequences, including those of the heart, as well as the systemic and cerebral vasculature. The tertiary impact of CV dysfunction will also be discussed, such as the potential impediment of rehabilitation, and impaired cognitive function. In the recent past, our understanding of autonomic dysfunctions post-SCI has been greatly enhanced; however, it is vital to further develop our understanding of the long-term consequences of these conditions, which will equip us to better manage CV disease morbidity and mortality in this population.

Trait anxiety mimics age-related cardiovascular autonomic modulation in young adults.

PubMed

Sanchez-Gonzalez, M A; Guzik, P; May, R W; Koutnik, A P; Hughes, R; Muniz, S; Kabbaj, M; Fincham, F D

2015-04-01

Anxiety produces maladaptive cardiovascular changes and accelerates biological aging. We evaluated cardiovascular reactivity in young and middle-aged individuals with varying anxiety scores to test the hypothesis that anxiety mimics cardiovascular aging by influencing cardiovascular autonomic modulation. The State-Trait Anxiety Inventory was used to classify healthy young individuals (20-29 years) into high (YHA, n=22;10 men) and low (YLA, n=21;10 men) anxiety, and to identify middle-aged individuals (50-60 years) with low anxiety (MLA, n=22;11 men). Heart rate, blood pressure (BP) and their variability (HRV and BPV, respectively) and baroreflex function were analyzed from beat-to-beat finger BP and electrocardiogram recordings collected during 5-min baseline, 6-min speech task (ST) and 3-min post ST recovery. Analyses of covariance showed significant differences (P<0.05) at baseline for HRV, BPV and barorelfex, and low-frequency power of systolic BP variability (LFSBP) was lower, whereas baroreflex and high frequency (HF) normalized units were higher in the YLA compared with YHA and MLA groups. Compared with YLA, YHA and MLA displayed attenuated vagal withdraw response (HF) to ST. BP and LFSBP responses to ST in YHA and MLA were higher compared with the YLA group. These findings suggest that anxiety could be linked to cardiovascular aging as it attenuates cardiac reactivity and exaggerates vascular responses to stress.

Effect of working hours on cardiovascular-autonomic nervous functions in engineers in an electronics manufacturing company.

PubMed

Sasaki, T; Iwasaki, K; Oka, T; Hisanaga, N; Ueda, T; Takada, Y; Fujiki, Y

1999-01-01

A field survey of 147 engineers (23-49 years) in an electronics manufacturing company was conducted to investigate the effect of working hours on cardiovascular-autonomic nervous functions (urinary catecholamines, heart rate variability and blood pressure). The subjects were divided into 3 groups by age: 23-29 (n = 49), 30-39 (n = 74) and 40-49 (n = 24) year groups. Subjects in each age group were further divided into shorter (SWH) and longer (LWH) working hour subgroups according to the median of weekly working hours. In the 30-39 year group, urinary noradrenaline in the afternoon for LWH was significantly lower than that for SWH and a similar tendency was found in the LF/HF ratio of heart rate variability at rest. Because these two autonomic nervous indices are related to sympathetic nervous activity, the findings suggested that sympathetic nervous activity for LWH was lower than that for SWH in the 30-39 year group. Furthermore, there were significant relationships both between long working hours and short sleeping hours, and between short sleeping hours and high complaint rates of "drowsiness and dullness" in the morning in this age group. Summarizing these results, it appeared that long working hours might lower sympathetic nervous activity due to chronic sleep deprivation.

Proceedings of the First Joint NASA Cardiopulmonary Workshop

NASA Technical Reports Server (NTRS)

Fortney, Suzanne M. (Editor); Hargens, Alan R. (Editor)

1991-01-01

The topics covered include the following: flight echocardiography, pulmonary function, central hemodynamics, glycerol hyperhydration, spectral analysis, lower body negative pressure countermeasures, orthostatic tolerance, autonomic function, cardiac deconditioning, fluid and renal responses to head-down tilt, local fluid regulation, endocrine regulation during bed rest, autogenic feedback, and chronic cardiovascular measurements. The program ended with a general discussion of weightlessness models and countermeasures.

Involvement of Type 1 Angiontensin II Receptor (AT1) in Cardiovascular Changes Induced by Chronic Emotional Stress: Comparison between Homotypic and Heterotypic Stressors.

PubMed

Costa-Ferreira, Willian; Vieira, Jonas O; Almeida, Jeferson; Gomes-de-Souza, Lucas; Crestani, Carlos C

2016-01-01

Consistent evidence has shown an important role of emotional stress in pathogenesis of cardiovascular diseases. Additionally, studies in animal models have demonstrated that daily exposure to different stressor (heterotypic stressor) evokes more severe changes than those resulting from repeated exposure to the same aversive stimulus (homotypic stressor), possibly due to the habituation process upon repeated exposure to the same stressor. Despite these pieces of evidence, the mechanisms involved in the stress-evoked cardiovascular dysfunction are poorly understood. Therefore, the present study investigated the involvement of angiotensin II (Ang II) acting on the type 1 Ang II receptor (AT1) in the cardiovascular dysfunctions evoked by both homotypic and heterotypic chronic emotional stresses in rats. For this purpose, we compared the effect of the chronic treatment with the AT1 receptor antagonist losartan (30 mg/kg/day, p.o.) on the cardiovascular and autonomic changes evoked by the heterotypic stressor chronic variable stress (CVS) and the homotypic stressor repeated restraint stress (RRS). RRS increased the sympathetic tone to the heart and decreased the cardiac parasympathetic activity, whereas CVS decreased the cardiac parasympathetic activity. Additionally, both stressors impaired the baroreflex function. Alterations in the autonomic activity and the baroreflex impairment were inhibited by losartan treatment. Additionally, CVS reduced the body weight and increased the circulating corticosterone; however, these effects were not affected by losartan. In conclusion, these findings indicate the involvement of angiotensin II/AT1 receptors in the autonomic changes evoked by both homotypic and heterotypic chronic stressors. Moreover, the present results provide evidence that the increase in the circulating corticosterone and body weight reduction evoked by heterotypic stressors are independent of AT1 receptors.

[The condition of the cardiovascular prevention in Spain].

PubMed

Royo-Bordonada, Miguel Ángel; Lobos, José Maria; Brotons, Carlos; Villar, Fernando; de Pablo, Carmen; Armario, Pedro; Cortés, Olga; Gil Nuñez, Antonio; Lizcano, Angel; de Santiago, Ana; Sans, Susana

2014-01-07

In Spain, where cardiovascular diseases are the leading cause of death, control of their risk factors is low. This study analyzes the implementation of cardiovascular risk (CVR) assessment in clinical practice and the existence of control objectives amongst quality care indicators and professional incentive systems. Between 2010 and 2011, data from each autonomous community were collected, by means of a specific questionnaire concerning prevalence and control of major CVR factors, CVR assessment, and implementation of control objectives amongst quality care indicators and primary care incentive systems. Fifteen out of 17 autonomous communities filled in the questionnaire. CVR was calculated through SCORE in 9 autonomous communities, REGICOR in 3 and Framingham in 3, covering 3.4 to 77.6% of target population. The resulting control of the main CVR factors was low and variable: hypertension (22.7-61.3%), dyslipidemia (11-45.1%), diabetes (18.5-84%) and smoking (20-50.5%). Most autonomous communities did not consider CVR assessment and control amongst quality care indicators or incentive systems, highlighting the lack of initiatives on lifestyles. Variability exists in cardiovascular prevention policies among autonomous communities. It is necessary to implement a common agreed cardiovascular prevention guide, to encourage physicians to implement CVR in electronic clinical history, and to promote CVR assessment and control inclusion amongst quality care indicators and professional incentive systems, focusing on lifestyles management. Copyright © 2012 Elsevier España, S.L. All rights reserved.

Comparison of 24-hour cardiovascular and autonomic function in paraplegia, tetraplegia, and control groups: implications for cardiovascular risk.

PubMed

Rosado-Rivera, Dwindally; Radulovic, M; Handrakis, John P; Cirnigliaro, Christopher M; Jensen, A Marley; Kirshblum, Steve; Bauman, William A; Wecht, Jill Maria

2011-01-01

Fluctuations in 24-hour cardiovascular hemodynamics, specifically heart rate (HR) and blood pressure (BP), are thought to reflect autonomic nervous system (ANS) activity. Persons with spinal cord injury (SCI) represent a model of ANS dysfunction, which may affect 24-hour hemodynamics and predispose these individuals to increased cardiovascular disease risk. To determine 24-hour cardiovascular and ANS function among individuals with tetraplegia (n=20; TETRA: C4-C8), high paraplegia (n=10; HP: T2-T5), low paraplegia (n=9; LP: T7-T12), and non-SCI controls (n=10). Twenty-four-hour ANS function was assessed by time domain parameters of heart rate variability (HRV); the standard deviation of the 5-minute average R-R intervals (SDANN; milliseconds/ms), and the root-mean square of the standard deviation of the R-R intervals (rMSSD; ms). Subjects wore 24-hour ambulatory monitors to record HR, HRV, and BP. Mixed analysis of variance (ANOVA) revealed significantly lower 24-hour BP in the tetraplegic group; however, BP did not differ between the HP, LP, and control groups. Mixed ANOVA suggested significantly elevated 24-hour HR in the HP and LP groups compared to the TETRA and control groups (P<0.05); daytime HR was higher in both paraplegic groups compared to the TETRA and control groups (P<0.01) and nighttime HR was significantly elevated in the LP group compared to the TETRA and control groups (P<0.01). Twenty-four-hour SDANN was significantly increased in the HP group compared to the LP and TETRA groups (P<0.05) and rMSSD was significantly lower in the LP compared to the other three groups (P<0.05). Elevated 24-hour HR in persons with paraplegia, in concert with altered HRV dynamics, may impart significant adverse cardiovascular consequences, which are currently unappreciated.

THE EFFECTS OF NON-FUNCTIONAL OVERREACHING AND OVERTRAINING ON AUTONOMIC NERVOUS SYSTEM FUNCTION IN HIGHLY TRAINED ATHLETES.

PubMed

Kajaia, T; Maskhulia, L; Chelidze, K; Akhalkatsi, V; Kakhabrishvili, Z

2017-03-01

Aim of the study was to compare the ANS functioning, as measured by heart rate variability (HRV), in athletes with non-functional overreaching (NFO) and overtraining syndrome (OTS) and in athletes without NFO/OTS. In 43 athletes with NFO/OTS, 40 athletes without NFO/OTS, as well as in 35 sedentary subjects the ANS function was evaluated with the Autonomic Balance Test, based on the HRV analysis of resting heart rate recordings. Results of the study show lower HRV and lower vagal influence along with increased sympathetic cardiovascular control in athletes with non-functional overreaching and particularly in athletes with overtraining, than in highly trained athletes without NFO/OTS. "Stress Response" in athletes with NFO, as well as in some athletes with OTS, showing sympathetic dominance, considered as a sign of physical or mental fatigue and chronic stress, whereas "Total Autonomic Dystonia" in most of the athletes with OTS (67%) reflects more advanced stage of maladaptation associated with depressed regulatory function of the ANS, both sympathetic, as well as vagal influences. Most frequently NFO and OTS were seen in wrestling, which needs further investigation and regular medical monitoring. Thus, results of the study show progression of autonomic imbalance and depression of regulatory function of the autonomic nervous system in athletes with OTS. The cardiac autonomic imbalance observed in overtrained athletes implies changes in HRV and therefore would consider that heart rate variability may provide useful information in detection of overtraining in athletes and can be a valuable adjacent tool for optimising athlete's training program as well as for timely diagnosis and prevention of progression of NFO/OTS.

TRPA1 mediates changes in heart rate variability and cardiac mechanical function in mice exposed to acrolein

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kurhanewicz, Nicole

Short-term exposure to ambient air pollution is linked with adverse cardiovascular effects. While previous research focused primarily on particulate matter-induced responses, gaseous air pollutants also contribute to cause short-term cardiovascular effects. Mechanisms underlying such effects have not been adequately described, however the immediate nature of the response suggests involvement of irritant neural activation and downstream autonomic dysfunction. Thus, this study examines the role of TRPA1, an irritant sensory receptor found in the airways, in the cardiac response of mice to acrolein and ozone. Conscious unrestrained wild-type C57BL/6 (WT) and TRPA1 knockout (KO) mice implanted with radiotelemeters were exposed once tomore » 3 ppm acrolein, 0.3 ppm ozone, or filtered air. Heart rate (HR) and electrocardiogram (ECG) were recorded continuously before, during and after exposure. Analysis of ECG morphology, incidence of arrhythmia and heart rate variability (HRV) were performed. Cardiac mechanical function was assessed using a Langendorff perfusion preparation 24 h post-exposure. Acrolein exposure increased HRV independent of HR, as well as incidence of arrhythmia. Acrolein also increased left ventricular developed pressure in WT mice at 24 h post-exposure. Ozone did not produce any changes in cardiac function. Neither gas produced ECG effects, changes in HRV, arrhythmogenesis, or mechanical function in KO mice. These data demonstrate that a single exposure to acrolein causes cardiac dysfunction through TRPA1 activation and autonomic imbalance characterized by a shift toward parasympathetic modulation. Furthermore, it is clear from the lack of ozone effects that although gaseous irritants are capable of eliciting immediate cardiac changes, gas concentration and properties play important roles. - Highlights: • Acute acrolein exposure causes autonomic imbalance and altered CV function in mice. • TRPA1 mediates acrolein-induced autonomic nervous system cardiac effects. • Sensory irritation contributes to acrolein-induced cardiac arrhythmia & dysfunction.« less

Cardiovascular autonomic dysfunction and carotid stiffness in adults with repaired tetralogy of Fallot.

PubMed

Novaković, Marko; Prokšelj, Katja; Starc, Vito; Jug, Borut

2017-06-01

Adults after surgical repair of tetralogy of Fallot (ToF) may have impaired vascular and cardiac autonomic function. Thus, we wanted to assess interrelations between heart rate variability (HRV) and heart rate recovery (HRR), as parameters of cardiac autonomic function, and arterial stiffness, as a parameter of vascular function, in adults with repaired ToF as compared to healthy controls. In a case-control study of adults with repaired ToF and healthy age-matched controls we measured: 5-min HRV variability (with time and frequency domain data collected), carotid artery stiffness (through pulse-wave analysis using echo-tracking ultrasound) and post-exercise HRR (cycle ergometer exercise testing). Twenty-five patients with repaired ToF (mean age 38 ± 10 years) and 10 healthy controls (mean age 39 ± 8 years) were included. Selected HRR and HRV (time-domain) parameters, but not arterial stiffness were significantly reduced in adults after ToF repair. Moreover, a strong association between late/slow HRR (after 2, 3 and 4 min) and carotid artery stiffness was detected in ToF patients (r = -0.404, p = 0.045; r = -0.545, p = 0.005 and r = -0.545, p = 0.005, respectively), with statistical significance retained even after adjusting for age, gender, resting heart rate and β-blockers use (r = -0.393, p = 0.024 for HRR after 3 min). Autonomic cardiac function is impaired in patients with repaired ToF, and independently associated with vascular function in adults after ToF repair, but not in age-matched healthy controls. These results might help in introducing new predictors of cardiovascular morbidity in a growing population of adults after surgical repair of ToF.

Mathematical biomarkers for the autonomic regulation of cardiovascular system.

PubMed

Campos, Luciana A; Pereira, Valter L; Muralikrishna, Amita; Albarwani, Sulayma; Brás, Susana; Gouveia, Sónia

2013-10-07

Heart rate and blood pressure are the most important vital signs in diagnosing disease. Both heart rate and blood pressure are characterized by a high degree of short term variability from moment to moment, medium term over the normal day and night as well as in the very long term over months to years. The study of new mathematical algorithms to evaluate the variability of these cardiovascular parameters has a high potential in the development of new methods for early detection of cardiovascular disease, to establish differential diagnosis with possible therapeutic consequences. The autonomic nervous system is a major player in the general adaptive reaction to stress and disease. The quantitative prediction of the autonomic interactions in multiple control loops pathways of cardiovascular system is directly applicable to clinical situations. Exploration of new multimodal analytical techniques for the variability of cardiovascular system may detect new approaches for deterministic parameter identification. A multimodal analysis of cardiovascular signals can be studied by evaluating their amplitudes, phases, time domain patterns, and sensitivity to imposed stimuli, i.e., drugs blocking the autonomic system. The causal effects, gains, and dynamic relationships may be studied through dynamical fuzzy logic models, such as the discrete-time model and discrete-event model. We expect an increase in accuracy of modeling and a better estimation of the heart rate and blood pressure time series, which could be of benefit for intelligent patient monitoring. We foresee that identifying quantitative mathematical biomarkers for autonomic nervous system will allow individual therapy adjustments to aim at the most favorable sympathetic-parasympathetic balance.

Mathematical biomarkers for the autonomic regulation of cardiovascular system

PubMed Central

Campos, Luciana A.; Pereira, Valter L.; Muralikrishna, Amita; Albarwani, Sulayma; Brás, Susana; Gouveia, Sónia

2013-01-01

Heart rate and blood pressure are the most important vital signs in diagnosing disease. Both heart rate and blood pressure are characterized by a high degree of short term variability from moment to moment, medium term over the normal day and night as well as in the very long term over months to years. The study of new mathematical algorithms to evaluate the variability of these cardiovascular parameters has a high potential in the development of new methods for early detection of cardiovascular disease, to establish differential diagnosis with possible therapeutic consequences. The autonomic nervous system is a major player in the general adaptive reaction to stress and disease. The quantitative prediction of the autonomic interactions in multiple control loops pathways of cardiovascular system is directly applicable to clinical situations. Exploration of new multimodal analytical techniques for the variability of cardiovascular system may detect new approaches for deterministic parameter identification. A multimodal analysis of cardiovascular signals can be studied by evaluating their amplitudes, phases, time domain patterns, and sensitivity to imposed stimuli, i.e., drugs blocking the autonomic system. The causal effects, gains, and dynamic relationships may be studied through dynamical fuzzy logic models, such as the discrete-time model and discrete-event model. We expect an increase in accuracy of modeling and a better estimation of the heart rate and blood pressure time series, which could be of benefit for intelligent patient monitoring. We foresee that identifying quantitative mathematical biomarkers for autonomic nervous system will allow individual therapy adjustments to aim at the most favorable sympathetic-parasympathetic balance. PMID:24109456

Monitoring fetal maturation—objectives, techniques and indices of autonomic function*

PubMed Central

Hoyer, Dirk; Żebrowski, Jan; Cysarz, Dirk; Gonçalves, Hernâni; Pytlik, Adelina; Amorim-Costa, Célia; Bernardes, João; Ayres-de-Campos, Diogo; Witte, Otto W; Schleußner, Ekkehard; Stroux, Lisa; Redman, Christopher; Georgieva, Antoniya; Payne, Stephen; Clifford, Gari; Signorini, Maria G; Magenes, Giovanni; Andreotti, Fernando; Malberg, Hagen; Zaunseder, Sebastian; Lakhno, Igor; Schneider, Uwe

2017-01-01

Objective Monitoring the fetal behavior does not only have implications for acute care but also for identifying developmental disturbances that burden the entire later life. The concept, of ‘fetal programming’, also known as ‘developmental origins of adult disease hypothesis’, e.g. applies for cardiovascular, metabolic, hyperkinetic, cognitive disorders. Since the autonomic nervous system is involved in all of those systems, cardiac autonomic control may provide relevant functional diagnostic and prognostic information. Approach The fetal heart rate patterns (HRP) are one of the few functional signals in the prenatal period that relate to autonomic control and, therefore, is key to fetal autonomic assessment. The development of sensitive markers of fetal maturation and its disturbances requires the consideration of physiological fundamentals, recording technology and HRP parameters of autonomic control. Main Results Based on the ESGCO2016 special session on monitoring the fetal maturation we herein report the most recent results on: (i) functional fetal autonomic brain age score (fABAS), Recurrence Quantitative Analysis and Binary Symbolic Dynamics of complex HRP resolve specific maturation periods, (ii) magnetocardiography (MCG) based fABAS was validated for cardiotocography (CTG), (iii) 30 min recordings are sufficient for obtaining episodes of high variability, important for intrauterine growth restriction (IUGR) detection in handheld Doppler, (iv) novel parameters from PRSA to identify Intra IUGR fetuses, (v) evaluation of fetal electrocardiographic (ECG) recordings, (vi) correlation between maternal and fetal HRV is disturbed in pre-eclampsia. Significance The reported novel developments significantly extend the possibilities for the established CTG methodology. Novel HRP indices improve the accuracy of assessment due to their more appropriate consideration of complex autonomic processes across the recording technologies (CTG, handheld Doppler, MCG, ECG). The ultimate objective is their dissemination into routine practice and studies of fetal developmental disturbances with implications for programming of adult diseases. PMID:28186000

Autonomic and inflammatory consequences of posttraumatic stress disorder and the link to cardiovascular disease.

PubMed

Brudey, Chevelle; Park, Jeanie; Wiaderkiewicz, Jan; Kobayashi, Ihori; Mellman, Thomas A; Marvar, Paul J

2015-08-15

Stress- and anxiety-related disorders are on the rise in both military and general populations. Over the next decade, it is predicted that treatment of these conditions, in particular, posttraumatic stress disorder (PTSD), along with its associated long-term comorbidities, will challenge the health care system. Multiple organ systems are adversely affected by PTSD, and PTSD is linked to cancer, arthritis, digestive disease, and cardiovascular disease. Evidence for a strong link between PTSD and cardiovascular disease is compelling, and this review describes current clinical data linking PTSD to cardiovascular disease, via inflammation, autonomic dysfunction, and the renin-angiotensin system. Recent clinical and preclinical evidence regarding the role of the renin-angiotensin system in the extinction of fear memory and relevance in PTSD-related immune and autonomic dysfunction is also addressed. Copyright © 2015 the American Physiological Society.

Cardiac and peripheral adjustments induced by early exercise training intervention were associated with autonomic improvement in infarcted rats: role in functional capacity and mortality.

PubMed

Jorge, Luciana; Rodrigues, Bruno; Rosa, Kaleizu Teodoro; Malfitano, Christiane; Loureiro, Tatiana Carolina Alba; Medeiros, Alessandra; Curi, Rui; Brum, Patricia Chakur; Lacchini, Silvia; Montano, Nicola; De Angelis, Kátia; Irigoyen, Maria-Cláudia

2011-04-01

To test the effects of early exercise training (ET) on left ventricular (LV) and autonomic functions, haemodynamics, tissues blood flows (BFs), maximal oxygen consumption (VO(2) max), and mortality after myocardial infarction (MI) in rats. Male Wistar rats were divided into: control (C), sedentary-infarcted (SI), and trained-infarcted (TI). One week after MI, TI group underwent an ET protocol (90 days, 50-70% VO(2) max). Left ventricular function was evaluated non-invasively and invasively. Baroreflex sensitivity, heart rate variability, and pulse interval were measured. Cardiac output (CO) and regional BFs were determined using coloured microspheres. Infarcted area was reduced in TI (19 ± 6%) compared with SI (34 ± 5%) after ET. Exercise training improved the LV and autonomic functions, the CO and regional BF changes induced by MI, as well as increased SERCA2 expression and mRNA vascular endothelial growth factor levels. These changes brought about by ET resulted in mortality rate reduction in the TI (13%) group compared with the SI (54%) group. Early aerobic ET reduced cardiac and peripheral dysfunctions and preserved cardiovascular autonomic control after MI in trained rats. Consequently, these ET-induced changes resulted in improved functional capacity and survival after MI.

Evaluation of Cardiovascular Risk Factors in the Wistar Audiogenic Rat (WAR) Strain

PubMed Central

Fazan, Rubens; Silva, Carlos Alberto A.; Oliveira, José Antônio Cortes; Salgado, Helio Cesar; Montano, Nicola; Garcia-Cairasco, Norberto

2015-01-01

Introduction Risk factors for life-threatening cardiovascular events were evaluated in an experimental model of epilepsy, the Wistar Audiogenic Rat (WAR) strain. Methods We used long-term ECG recordings in conscious, one year old, WAR and Wistar control counterparts to evaluate spontaneous arrhythmias and heart rate variability, a tool to assess autonomic cardiac control. Ventricular function was also evaluated using the pressure-volume conductance system in anesthetized rats. Results Basal RR interval (RRi) was similar between WAR and Wistar rats (188±5 vs 199±6 ms). RRi variability strongly suggests that WAR present an autonomic imbalance with sympathetic overactivity, which is an isolated risk factor for cardiovascular events. Anesthetized WAR showed lower arterial pressure (92±3 vs 115±5 mmHg) and exhibited indices of systolic dysfunction, such as higher ventricle end-diastolic pressure (9.2±0.6 vs 5.6±1 mmHg) and volume (137±9 vs 68±9 μL) as well as lower rate of increase in ventricular pressure (5266±602 vs 7320±538 mmHg.s-1). Indices of diastolic cardiac function, such as lower rate of decrease in ventricular pressure (-5014±780 vs -7766±998 mmHg.s-1) and a higher slope of the linear relationship between end-diastolic pressure and volume (0.078±0.011 vs 0.036±0.011 mmHg.μL), were also found in WAR as compared to Wistar control rats. Moreover, Wistar rats had 3 to 6 ventricular ectopic beats, whereas WAR showed 15 to 30 ectopic beats out of the 20,000 beats analyzed in each rat. Conclusions The autonomic imbalance observed previously at younger age is also present in aged WAR and, additionally, a cardiac dysfunction was also observed in the rats. These findings make this experimental model of epilepsy a valuable tool to study risk factors for cardiovascular events in epilepsy. PMID:26029918

Autonomic and Renal Alterations in the Offspring of Sleep-Restricted Mothers During Late Pregnancy.

PubMed

Raimundo, Joyce R S; Bergamaschi, Cassia T; Campos, Ruy R; Palma, Beatriz D; Tufik, Sergio; Gomes, Guiomar N

2016-09-01

Considering that changes in the maternal environment may result in changes in progeny, the aim of this study was to investigate the influence of sleep restriction during the last week of pregnancy on renal function and autonomic responses in male descendants at an adult age. After confirmation of pregnancy, female Wistar rats were randomly assigned to either a control or a sleep restriction group. The sleep-restricted rats were subjected to sleep restriction using the multiple platforms method for over 20 hours per day between the 14th and 20th day of pregnancy. After delivery, the litters were limited to 6 offspring that were designated as offspring from control and offspring from sleep-restricted mothers. Indirect measurements of systolic blood pressure (BPi), renal plasma flow, glomerular filtration rate, glomerular area and number of glomeruli per field were evaluated at three months of age. Direct measurements of cardiovascular function (heart rate and mean arterial pressure), cardiac sympathetic tone, cardiac parasympathetic tone, and baroreflex sensitivity were evaluated at four months of age. The sleep-restricted offspring presented increases in BPi, glomerular filtration rate and glomerular area compared with the control offspring. The sleep-restricted offspring also showed higher basal heart rate, increased mean arterial pressure, increased sympathetic cardiac tone, decreased parasympathetic cardiac tone and reduced baroreflex sensitivity. Our data suggest that reductions in sleep during the last week of pregnancy lead to alterations in cardiovascular autonomic regulation and renal morpho-functional changes in offspring, triggering increases in blood pressure.

N(N)-nicotinic blockade as an acute human model of autonomic failure

NASA Technical Reports Server (NTRS)

Jordan, J.; Shannon, J. R.; Black, B. K.; Lance, R. H.; Squillante, M. D.; Costa, F.; Robertson, D.

1998-01-01

Pure autonomic failure has been conceptualized as deficient sympathetic and parasympathetic innervation. Several recent observations in chronic autonomic failure, however, cannot be explained simply by loss of autonomic innervation, at least according to our current understanding. To simulate acute autonomic failure, we blocked N(N)-nicotinic receptors with intravenous trimethaphan (6+/-0.4 mg/min) in 7 healthy subjects (4 men, 3 women, aged 32+/-3 years, 68+/-4 kg, 171+/-5 cm). N(N)-Nicotinic receptor blockade resulted in near-complete interruption of sympathetic and parasympathetic efferents as indicated by a battery of autonomic function tests. With trimethaphan, small postural changes from the horizontal were associated with significant blood pressure changes without compensatory changes in heart rate. Gastrointestinal motility, pupillary function, saliva production, and tearing were profoundly suppressed with trimethaphan. Plasma norepinephrine level decreased from 1.1+/-0.12 nmol/L (180+/-20 pg/mL) at baseline to 0.23+/-0.05 nmol/L (39+/-8 pg/mL) with trimethaphan (P<.001). There was a more than 16-fold increase in plasma vasopressin (P<.01) and no change in plasma renin activity. We conclude that blockade of N(N)-cholinergic receptors is useful to simulate the hemodynamic alterations of acute autonomic failure in humans. The loss of function with acute N(N)-cholinergic blockade is more complete than in most cases of chronic autonomic failure. This difference may be exploited to elucidate the contributions of acute denervation and chronic adaptation to the pathophysiology of autonomic failure. N(N)-Cholinergic blockade may also be applied to study human cardiovascular physiology and pharmacology in the absence of confounding baroreflexes.

Characterizing the Severity of Autonomic Cardiovascular Dysfunction after Spinal Cord Injury Using a Novel 24 Hour Ambulatory Blood Pressure Analysis Software.

PubMed

Popok, David W; West, Christopher R; Hubli, Michele; Currie, Katharine D; Krassioukov, Andrei V

2017-02-01

Cardiovascular disease is one of the leading causes of morbidity and mortality in the spinal cord injury (SCI) population. SCI may disrupt autonomic cardiovascular homeostasis, which can lead to persistent hypotension, irregular diurnal rhythmicity, and the development of autonomic dysreflexia (AD). There is currently no software available to perform automated detection and evaluation of cardiovascular autonomic dysfunction(s) such as those generated from 24 h ambulatory blood pressure monitoring (ABPM) recordings in the clinical setting. The objective of this study is to compare the efficacy of a novel 24 h ABPM Autonomic Dysfunction Detection Software against manual detection and to use the software to demonstrate the relationships between level of injury and the degree of autonomic cardiovascular impairment in a large cohort of individuals with SCI. A total of 46 individuals with cervical (group 1, n = 37) or high thoracic (group 2, n = 9) SCI participated in the study. Outcome measures included the frequency and severity of AD, frequency of hypotensive events, and diurnal variations in blood pressure and heart rate. There was good agreement between the software and manual detection of AD events (Bland-Altman limits of agreement = ±1.458 events). Cervical SCI presented with more frequent (p = 0.0043) and severe AD (p = 0.0343) than did high thoracic SCI. Cervical SCI exhibited higher systolic and diastolic blood pressure during the night and lower heart rate during the day than high thoracic SCI. In conclusion, our ABPM AD Detection Software was equally as effective in detecting the frequency and severity of AD and hypotensive events as manual detection, suggesting that this software can be used in the clinical setting to expedite ABPM analyses.

Widespread cardiovascular autonomic dysfunction in primary amyloidosis: does spontaneous hyperventilation have a compensatory role against postural hypotension?

PubMed Central

Bernardi, L; Passino, C; Porta, C; Anesi, E; Palladini, G; Merlini, G

2002-01-01

Objective: To investigate the possible causes of abnormal blood pressure control in light chain related (primary, AL) amyloidosis. Design: Cardiovascular, autonomic, and respiratory response to passive tilting were investigated in 51 patients with primary amyloidosis (mean (SEM) age 56 (2) years) and in 20 age matched controls. Spontaneous fluctuations in RR interval, respiration, end tidal carbon dioxide, blood pressure, and skin microcirculation were recorded during supine rest and with tilting. The values were subjected to spectral analysis to assess baroreflex sensitivity and the autonomic modulation of cardiac and vascular responses. Setting: Tertiary referral centre. Results: Autonomic modulation of the heart and blood pressure was nearly absent in the patients with amyloidosis: thus baroreflex sensitivity and the low frequency (0.1 Hz) fluctuations in all cardiovascular signals were severely reduced (p < 0.01 or more), as were respiratory fluctuations in the RR interval, and no change was observed upon tilting. Despite reduced autonomic modulation, blood pressure remained relatively stable in the amyloid group from supine to tilting. End tidal carbon dioxide was reduced in the amyloid patients (p < 0.001) indicating persistent hyperventilation; the breathing rate correlated inversely with the fall in blood pressure on tilting (p < 0.05). Conclusions: In primary amyloidosis, pronounced abnormalities in arterial baroreflexes and cardiovascular autonomic modulation to the heart and the vessels may be partly compensated for by hyperventilation at a slow breathing rate. PMID:12433892

A comparative analysis of alternative approaches for quantifying nonlinear dynamics in cardiovascular system.

PubMed

Chen, Yun; Yang, Hui

2013-01-01

Heart rate variability (HRV) analysis has emerged as an important research topic to evaluate autonomic cardiac function. However, traditional time and frequency-domain analysis characterizes and quantify only linear and stationary phenomena. In the present investigation, we made a comparative analysis of three alternative approaches (i.e., wavelet multifractal analysis, Lyapunov exponents and multiscale entropy analysis) for quantifying nonlinear dynamics in heart rate time series. Note that these extracted nonlinear features provide information about nonlinear scaling behaviors and the complexity of cardiac systems. To evaluate the performance, we used 24-hour HRV recordings from 54 healthy subjects and 29 heart failure patients, available in PhysioNet. Three nonlinear methods are evaluated not only individually but also in combination using three classification algorithms, i.e., linear discriminate analysis, quadratic discriminate analysis and k-nearest neighbors. Experimental results show that three nonlinear methods capture nonlinear dynamics from different perspectives and the combined feature set achieves the best performance, i.e., sensitivity 97.7% and specificity 91.5%. Collectively, nonlinear HRV features are shown to have the promise to identify the disorders in autonomic cardiovascular function.

Dose-response relationship of the cardiovascular adaptation to endurance training in healthy adults: how much training for what benefit?

PubMed

Iwasaki, Ken-Ichi; Zhang, Rong; Zuckerman, Julie H; Levine, Benjamin D

2003-10-01

Occupational or recreational exercise reduces mortality from cardiovascular disease. The potential mechanisms for this reduction may include changes in blood pressure (BP) and autonomic control of the circulation. Therefore, we conducted the present long-term longitudinal study to quantify the dose-response relationship between the volume and intensity of exercise training, and regulation of heart rate (HR) and BP. We measured steady-state hemodynamics and analyzed dynamic cardiovascular regulation by spectral and transfer function analysis of cardiovascular variability in 11 initially sedentary subjects during 1 yr of progressive endurance training sufficient to allow them to complete a marathon. From this, we found that 1) moderate exercise training for 3 mo decreased BP, HR, and total peripheral resistance, and increased cardiovascular variability and arterial baroreflex sensitivity; 2) more prolonged and intense training did not augment these changes further; and 3) most of these changes returned to control values at 12 mo despite markedly increased training duration and intensity equivalent to that routinely observed in competitive athletes. In conclusion, increases in R-wave-R-wave interval and cardiovascular variability indexes are consistent with an augmentation of vagal modulation of HR after exercise training. It appears that moderate doses of training for 3 mo are sufficient to achieve this response as well as a modest hypotensive effect from decreasing vascular resistance. However, more prolonged and intense training does not necessarily lead to greater enhancement of circulatory control and, therefore, may not provide an added protective benefit via autonomic mechanisms against death by cardiovascular disease.

Autonomic control of circulation in fish: a comparative view.

PubMed

Sandblom, Erik; Axelsson, Michael

2011-11-16

The autonomic nervous system has a central role in the control and co-ordination of the cardiovascular system in all vertebrates. In fish, which represent the largest and most diverse vertebrate group, the autonomic control of the circulation displays a vast variation with a number of interesting deviations from the typical vertebrate pattern. This diversity ranges from virtually no known nervous control of the circulation in hagfish, to a fully developed dual control from both cholinergic and adrenergic nerves in teleost, much resembling the situation found in other vertebrate groups. This review summarizes current knowledge on the role of the autonomic nervous system in the control of the cardiovascular system in fish. We set out by providing an overview of the general trends and patterns in the major fish groups, and then a summary of how the autonomic nervous control is involved in normal daily activities such as barostatic control of blood pressure, as well as adjustments of the cardiovascular system during feeding and environmental hypoxia. Copyright © 2011 Elsevier B.V. All rights reserved.

Autonomic Cardiovascular Responses in Acclimatized Lowlanders on Prolonged Stay at High Altitude: A Longitudinal Follow Up Study

PubMed Central

Dhar, Priyanka; Sharma, Vijay K.; Hota, Kalpana B.; Das, Saroj K.; Hota, Sunil K.; Srivastava, Ravi B.; Singh, Shashi B.

2014-01-01

Acute exposure to hypobaric hypoxia at high altitude is reported to cause sympathetic dominance that may contribute to the pathophysiology of high altitude illnesses. The effect of prolonged stay at high altitude on autonomic functions, however, remains to be explored. Thus, the present study aimed at investigating the effect of high altitude on autonomic neural control of cardiovascular responses by monitoring heart rate variability (HRV) during chronic hypobaric hypoxia. Baseline electrocardiography (ECG) data was acquired from the volunteers at mean sea level (MSL) (<250 m) in Rajasthan. Following induction of the study population to high altitude (4500–4800 m) in Ladakh region, ECG data was acquired from the volunteers after 6 months (ALL 6) and 18 months of induction (ALL 18). Out of 159 volunteers who underwent complete investigation during acquisition of baseline data, we have only included the data of 104 volunteers who constantly stayed at high altitude for 18 months to complete the final follow up after 18 months. HRV parameters, physiological indices and biochemical changes in serum were investigated. Our results show sympathetic hyperactivation along with compromise in parasympathetic activity in ALL 6 and ALL 18 when compared to baseline data. Reduction of sympathetic activity and increased parasympathetic response was however observed in ALL 18 when compared to ALL 6. Our findings suggest that autonomic response is regulated by two distinct mechanisms in the ALL 6 and ALL 18. While the autonomic alterations in the ALL 6 group could be attributed to increased sympathetic activity resulting from increased plasma catecholamine concentration, the sympathetic activity in ALL 18 group is associated with increased concentration of serum coronary risk factors and elevated homocysteine. These findings have important clinical implications in assessment of susceptibility to cardio-vascular risks in acclimatized lowlanders staying for prolonged duration at high altitude. PMID:24404157

Blood pressure responses to dietary sodium: Association with autonomic cardiovascular function in normotensive adults.

PubMed

Matthews, Evan L; Brian, Michael S; Edwards, David G; Stocker, Sean D; Wenner, Megan M; Farquhar, William B

2017-12-01

Blood pressure responses to dietary sodium vary widely person-to-person. Salt sensitive rodent models display altered autonomic function, a trait thought to contribute to poor cardiovascular health. Thus, we hypothesized that increased salt sensitivity (SS) in normotensive humans would be associated with increased muscle sympathetic nerve activity (MSNA), decreased high frequency heart rate variability (HF-HRV), and decreased baroreflex sensitivity. Healthy normotensive men and women completed 1week of high (300mmol·day -1 ) and 1week of low (20mmol·day -1 ) dietary sodium (random order) with 24h mean arterial pressure (MAP) assessed on the last day of each diet to assess SS. Participants returned to the lab under habitual sodium conditions for testing. Forty-two participants are presented in this analysis, 19 of which successful MSNA recordings were obtained (n=42: age 39±2yrs., BMI 24.3±0.5kg·(m 2 ) -1 , MAP 83±1mmHg, habitual urine sodium 93±7mmol·24h -1 ; n=19: MSNA burst frequency 20±2 bursts·min -1 ). The variables of interest were linearly regressed over the magnitude of SS. Higher SS was associated with increased MSNA (burst frequency: r=0.469, p=0.041), decreased HF-HRV (r=-0.349, p=0.046), and increased LF/HF-HRV (r=0.363, p=0.034). SS was not associated with sympathetic or cardiac baroreflex sensitivity (p>0.05). Multiple regression analysis accounting for age found that age, not SS, independently predicted HF-HRV (age adjusted no longer significant; p=0.369) and LF/HF-HRV (age adjusted p=0.273). These data suggest that age-related salt sensitivity of blood pressure in response to dietary sodium is associated with altered resting autonomic cardiovascular function. Copyright © 2017 Elsevier B.V. All rights reserved.

An explanation for sudden death in epilepsy (SUDEP).

PubMed

Stewart, Mark

2018-03-14

This review traces the examination of autonomic, cardiovascular, and respiratory derangements associated with seizure activity in the clinical and preclinical literature generally, and in the author's animal model specifically, and concludes with the author's views on the potential mechanisms for sudden death in epilepsy (SUDEP). An animal model that employs kainic acid-induced seizures on a background of urethane anesthesia has permitted unprecedented access to the behavior of autonomic, cardiovascular, and respiratory systems during seizure activity. The result is a detailed description of the major causes of death and how this animal model can be used to develop and test preventative and interventional strategies. A critical translational step was taken when the rat data were shown to directly parallel data from definite SUDEP cases in the clinical literature. The reasons why ventricular fibrillation as a cause of death is so rarely reported and tools for verifying that seizure-associated laryngospasm can induce obstructive apnea as a cause of death are discussed in detail. Many details of the specific kinetics of activation of brainstem neurons serving autonomic and respiratory function remain to be elucidated, but the boundary conditions described in this review provide an excellent framework for more focused studies. A number of studies conducted in animal models of seizure activity and in epilepsy patients have contributed information on the autonomic, cardiovascular, and respiratory consequences of seizure activity spreading through hypothalamus and brainstem to the periphery. The result is detailed information on the systemic impact of seizure spread and the development of an understanding of the essential mechanistic features of sudden unexpected death in epilepsy (SUDEP). This review summarizes translation of data obtained from animal models to biomarkers that are useful in evaluating data from epilepsy patients.

An epigenome-wide association analysis of cardiac autonomic responses among a population of welders.

PubMed

Zhang, Jinming; Liu, Zhonghua; Umukoro, Peter E; Cavallari, Jennifer M; Fang, Shona C; Weisskopf, Marc G; Lin, Xihong; Mittleman, Murray A; Christiani, David C

2017-02-01

DNA methylation is one of the potential epigenetic mechanisms associated with various adverse cardiovascular effects; however, its association with cardiac autonomic dysfunction, in particular, is unknown. In the current study, we aimed to identify epigenetic variants associated with alterations in cardiac autonomic responses. Cardiac autonomic responses were measured with two novel markers: acceleration capacity (AC) and deceleration capacity (DC). We examined DNA methylation levels at more than 472,506 CpG probes through the Illumina Infinium HumanMethylation450 BeadChip assay. We conducted separate linear mixed models to examine associations of DNA methylation levels at each CpG with AC and DC. One CpG (cg26829071) located in the GPR133 gene was negatively associated with DC values after multiple testing corrections through false discovery rate. Our study suggests the potential functional importance of methylation in cardiac autonomic responses. Findings from the current study need to be replicated in future studies in a larger population.

Ghrelin and the cardiovascular system.

PubMed

Tokudome, Takeshi; Kishimoto, Ichiro; Miyazato, Mikiya; Kangawa, Kenj

2014-01-01

Ghrelin is a peptide that was originally isolated from the stomach. It exerts potent growth hormone (GH)-releasing and orexigenic activities. Several studies have highlighted the therapeutic benefits of ghrelin for the treatment of cardiovascular disease. In animal models of chronic heart failure, the administration of ghrelin improved cardiac function and remodeling; these findings were replicated in human patients with heart failure. Moreover, in an animal study, ghrelin administration effectively reduced pulmonary hypertension induced by chronic hypoxia. In addition, repeated administration of ghrelin to cachectic patients with chronic obstructive pulmonary disease had positive effects on overall body function, including muscle wasting, functional capacity and sympathetic activity. The administration of ghrelin early after myocardial infarction (MI) reduced fatal arrhythmia and related mortality. In ghrelin-deficient mice, both exogenous and endogenous ghrelin were protective against fatal arrhythmia and promoted remodeling after MI. Although the mechanisms underlying the effects of ghrelin on the cardiovascular system remain unclear, there are indications that its beneficial effects are mediated through both direct physiological actions, including increased GH levels, improved energy balance and direct actions on cardiovascular cells, and regulation of autonomic nervous system activity. Therefore, ghrelin is a promising novel therapeutic agent for cardiovascular disease. © 2014 S. Karger AG, Basel.

BDNF - A key player in cardiovascular system.

PubMed

Pius-Sadowska, Ewa; Machaliński, Bogusław

2017-09-01

Neurotrophins (NTs) were first identified as target-derived survival factors for neurons of the central and peripheral nervous system (PNS). They are known to control neural cell fate, development and function. Independently of their neuronal properties, NTs exert unique cardiovascular activity. The heart is innervated by sensory, sympathetic and parasympathetic neurons, which require NTs during early development and in the establishment of mature properties, contributing to the maintenance of cardiovascular homeostasis. The identification of molecular mechanisms regulated by NTs and involved in the crosstalk between cardiac sympathetic nerves, cardiomyocytes, cardiac fibroblasts, and vascular cells, has a fundamental importance in both normal heart function and disease. The article aims to review the recent data on the effects of Brain-Derived Neurotrophic Factor (BDNF) on various cardiovascular neuronal and non-neuronal functions such as the modulation of synaptic properties of autonomic neurons, axonal outgrowth and sprouting, formation of the vascular and neural networks, smooth muscle migration, and control of endothelial cell survival and cardiomyocytes. Understanding these mechanisms may be crucial for developing novel therapeutic strategies, including stem cell-based therapies. Copyright © 2017 Elsevier Ltd. All rights reserved.

Cardiovascular physiology - Effects of microgravity

NASA Technical Reports Server (NTRS)

Convertino, V.; Hoffler, G. W.

1992-01-01

Experiments during spaceflight and its groundbase analog, bedrest, provide consistent data which demonstrate that numerous changes in cardiovascular function occur as part of the physiological adaptation process to the microgravity environment. These include elevated heart rate and venous compliance, lowered blood volume, central venous pressure and stroke volume, and attenuated autonomic reflex functions. Although most of these adaptations are not functionally apparent during microgravity exposure, they manifest themselves during the return to the gravitational challenge of earth's terrestrial environment as orthostatic hypotension and instability, a condition which could compromise safety, health and productivity. Development and application of effective and efficient countermeasures such as saline "loading," intermittent venous pooling, pharmacological treatments, and exercise have become primary emphases of the space life sciences research effort with only limited success. Successful development of countermeasures will require knowledge of the physiological mechanisms underlying cardiovascular adaptation to microgravity which can be obtained only through controlled, parallel groundbased research to complement carefully designed flight experiments. Continued research will provide benefits for both space and clinical applications as well as enhance the basic understanding of cardiovascular homeostasis in humans.

The relationship of autonomic imbalance, heart rate variability and cardiovascular disease risk factors.

PubMed

Thayer, Julian F; Yamamoto, Shelby S; Brosschot, Jos F

2010-05-28

Cardiovascular disease (CVD) is the leading cause of death and disability worldwide. The understanding of the risk factors for CVD may yield important insights into the prevention, etiology, course, and treatment of this major public health concern. Autonomic imbalance, characterized by a hyperactive sympathetic system and a hypoactive parasympathetic system, is associated with various pathological conditions. Over time, excessive energy demands on the system can lead to premature aging and diseases. Therefore, autonomic imbalance may be a final common pathway to increased morbidity and mortality from a host of conditions and diseases, including cardiovascular disease. Heart rate variability (HRV) may be used to assess autonomic imbalances, diseases and mortality. Parasympathetic activity and HRV have been associated with a wide range of conditions including CVD. Here we review the evidence linking HRV to established and emerging modifiable and non-modifiable CVD risk factors such as hypertension, obesity, family history and work stress. Substantial evidence exists to support the notion that decreased HRV precedes the development of a number of risk factors and that lowering risk profiles is associated with increased HRV. We close with a suggestion that a model of autonomic imbalance may provide a unifying framework within which to investigate the impact of risk factors, including psychosocial factors and work stress, on cardiovascular disease. Copyright 2009 Elsevier Ireland Ltd. All rights reserved.

Changes in autonomic regulation and ventricular repolarization induced by subclinical hyperthyroidism.

PubMed

Galetta, F; Franzoni, F; Fallahi, P; Tocchini, L; Graci, F; Gaddeo, C; Rossi, M; Cini, G; Carpi, A; Santoro, G; Antonelli, A

2010-10-01

The aim of the present study was to evaluate the effect of subclinical hyperthyroidism (SHT) on cardiovascular autonomic function and ventricular repolarization. Thirty subjects (25 females; mean age 49.6 ± 9.8 years) with SHT, as judged by reduced TSH serum levels and normal free T4 and T3 serum levels, and 30 age and sex-matched control subjects underwent standard 12-lead ECG, and 24h ambulatory ECG monitoring. The dispersion of the QT interval, an index of inhomogeneity of repolarization, and the heart rate variability (HRV), a measure of cardiac autonomic modulation, were studied. Patients with SHT showed higher QT dispersion (p<0.001) and lower HRV measures (0.01>p<0.001) than controls. In SHT patients, QT dispersion was inversely related to HRV (r=-0.47, p<0.01). The results of the present study demonstrated that SHT is associated with a sympathovagal imbalance, characterized by increased sympathetic activity in the presence of diminished vagal tone, and with an increased inhomogeneity of ventricular recovery times. The assessment of HRV and QT dispersion in patients with SHT may represent a useful tool in monitoring the cardiovascular risk of this condition. Copyright © 2009 Elsevier Masson SAS. All rights reserved.

Cardiac autonomic neuropathy risk estimated by sudomotor function and arterial stiffness in Chinese subjects.

PubMed

Zeng, Q; Dong, S-Y; Wang, M-L; Wang, F; Li, J-M; Zhao, X-L

2016-11-01

The SUDOSCAN test was recently developed to detect diabetic autonomic neuropathy early and screen for cardiac autonomic neuropathy (CAN) through assessment of sudomotor function. The aim of this study was to investigate the relationship of cardiac autonomic dysfunction estimated by the SUDOSCAN test with arterial stiffness. A total of 4019 subjects without diabetes or established cardiovascular disease were tested with SUDOSCAN, central systolic blood pressure (cSBP) and brachial-ankle pulse wave velocity (baPWV). Hands mean electrochemical skin conductance (ESC) measured by SUDOSCAN was 70±17 μS, feet mean ESC was 71±16 μS and the CAN risk score was 21±10%. The levels of cSBP and baPWV increased across quartiles of CAN risk score (P for trend <0.001 for all). In spearman correlation analyses, the CAN risk score was positively correlated with cSBP (r=0.391, P<0.001) and baPWV (r=0.305, P<0.001). In multivariable analyses, the values of cSBP and baPWV increased 0.17 mm Hg (P=0.002) and 2.01 cm per second (P=0.010), respectively, when CAN risk score increased 1%. The results were unchanged when stratified by glucose tolerance status. In conclusion, cardiac autonomic dysfunction estimated by sudomotor function was correlated with arterial stiffness independent of conventional factors and glucose tolerance status.

Influence of antipsychotic agents on heart rate variability in male WKY rats: implications for cardiovascular safety.

PubMed

Wang, Ying-Chieh; Chen, Chun-Yu; Kuo, Terry B J; Lai, Ching-Jung; Yang, Cheryl C H

2012-06-01

Sudden cardiac death is higher among schizophrenic patients and is associated with parasympathetic hypoactivity. Antipsychotic agents are highly suspected to be a precipitating factor. Thus, we aimed to test if the antipsychotics haloperidol, risperidone and clozapine affect cardiac autonomic function, excluding the confounding effect of altered sleep structure by the drugs. In this study, haloperidol, risperidone and clozapine were given separately by intraperitoneal injection to male Wistar-Kyoto rats for 5 days. Electroencephalogram (EEG), electromyogram (EMG) and electrocardiographic signals were recorded at baseline and 5 days after drug treatments. Sleep scoring was based on EEG and EMG signals. Cardiac autonomic function was assessed using heart rate variability analysis. Clozapine increased heart rate and suppressed cardiac sympathetic and parasympathetic activity. Cardiac acceleration was more severe during sleep. Haloperidol tended to decrease heart rate while risperidone mildly increased heart rate; however, their effects were less obvious than those of clozapine. There was a significant drug-by-stage interaction on several heart rate variability measures. Taking this evidence as a whole, we conclude that haloperidol has a better level of cardiovascular safety than either risperidone or clozapine. Application of this approach to other psychotropic agents in the future will be a useful and helpful way to evaluate the cardiovascular safety of the various psychotropic medications that are in clinical use. Copyright © 2012 S. Karger AG, Basel.

Cardiovascular Reactivity in Patients With Major Depressive Disorder With High- or Low-Level Depressive Symptoms: A Cross-Sectional Comparison of Cardiovascular Reactivity to Laboratory-Induced Mental Stress.

PubMed

Wang, Mei-Yeh; Chiu, Chen-Huan; Lee, Hsin-Chien; Su, Chien-Tien; Tsai, Pei-Shan

2016-03-01

Depression increases the risk of adverse cardiac events. Cardiovascular reactivity is defined as the pattern of cardiovascular responses to mental stress. An altered pattern of cardiovascular reactivity is an indicator of subsequent cardiovascular disease. Because depression and adverse cardiac events may have a dose-dependent association, this study examined the differences in cardiovascular reactivity to mental stress between patients with major depressive disorder (MDD) with high depression levels and those with low depression levels. Moreover, autonomic nervous system regulation is a highly plausible biological mechanism for the pattern of cardiovascular reactivity to mental stress. The association between cardiovascular reactivity and parameters of heart rate variability (HRV), an index for quantifying autonomic nervous system activity modulation, was thus examined. This study included 88 patients with MDD. HRV was measured before stress induction. The Stroop Color and Word Test and mirror star-tracing task were used to induce mental stress. We observed no significant association between depressive symptom level and any of the cardiovascular reactivity parameters. Cardiovascular reactivity to mental stress was comparable between patients with MDD with high-level depressive symptoms and those with low-level depressive symptoms. After adjusting for confounding variables, the high-frequency domain of HRV was found to be an independent predictor of the magnitude of heart rate reactivity (β = -.33, p = .002). In conclusion, the magnitude of cardiovascular reactivity may be independent of depression severity in patients with MDD. The autonomic regulation of cardiovascular responses to mental stress primarily influences heart rate reactivity in patients with MDD. © The Author(s) 2015.

Mercury Exposure and Heart Diseases

PubMed Central

Genchi, Giuseppe; Sinicropi, Maria Stefania; Carocci, Alessia; Lauria, Graziantonio; Catalano, Alessia

2017-01-01

Environmental contamination has exposed humans to various metal agents, including mercury. It has been determined that mercury is not only harmful to the health of vulnerable populations such as pregnant women and children, but is also toxic to ordinary adults in various ways. For many years, mercury was used in a wide variety of human activities. Nowadays, the exposure to this metal from both natural and artificial sources is significantly increasing. Recent studies suggest that chronic exposure, even to low concentration levels of mercury, can cause cardiovascular, reproductive, and developmental toxicity, neurotoxicity, nephrotoxicity, immunotoxicity, and carcinogenicity. Possible biological effects of mercury, including the relationship between mercury toxicity and diseases of the cardiovascular system, such as hypertension, coronary heart disease, and myocardial infarction, are being studied. As heart rhythm and function are under autonomic nervous system control, it has been hypothesized that the neurotoxic effects of mercury might also impact cardiac autonomic function. Mercury exposure could have a long-lasting effect on cardiac parasympathetic activity and some evidence has shown that mercury exposure might affect heart rate variability, particularly early exposures in children. The mechanism by which mercury produces toxic effects on the cardiovascular system is not fully elucidated, but this mechanism is believed to involve an increase in oxidative stress. The exposure to mercury increases the production of free radicals, potentially because of the role of mercury in the Fenton reaction and a reduction in the activity of antioxidant enzymes, such as glutathione peroxidase. In this review we report an overview on the toxicity of mercury and focus our attention on the toxic effects on the cardiovascular system. PMID:28085104

Mercury Exposure and Heart Diseases.

PubMed

Genchi, Giuseppe; Sinicropi, Maria Stefania; Carocci, Alessia; Lauria, Graziantonio; Catalano, Alessia

2017-01-12

Environmental contamination has exposed humans to various metal agents, including mercury. It has been determined that mercury is not only harmful to the health of vulnerable populations such as pregnant women and children, but is also toxic to ordinary adults in various ways. For many years, mercury was used in a wide variety of human activities. Nowadays, the exposure to this metal from both natural and artificial sources is significantly increasing. Recent studies suggest that chronic exposure, even to low concentration levels of mercury, can cause cardiovascular, reproductive, and developmental toxicity, neurotoxicity, nephrotoxicity, immunotoxicity, and carcinogenicity. Possible biological effects of mercury, including the relationship between mercury toxicity and diseases of the cardiovascular system, such as hypertension, coronary heart disease, and myocardial infarction, are being studied. As heart rhythm and function are under autonomic nervous system control, it has been hypothesized that the neurotoxic effects of mercury might also impact cardiac autonomic function. Mercury exposure could have a long-lasting effect on cardiac parasympathetic activity and some evidence has shown that mercury exposure might affect heart rate variability, particularly early exposures in children. The mechanism by which mercury produces toxic effects on the cardiovascular system is not fully elucidated, but this mechanism is believed to involve an increase in oxidative stress. The exposure to mercury increases the production of free radicals, potentially because of the role of mercury in the Fenton reaction and a reduction in the activity of antioxidant enzymes, such as glutathione peroxidase. In this review we report an overview on the toxicity of mercury and focus our attention on the toxic effects on the cardiovascular system.

[Systems analysis of colour music corrective effect].

PubMed

Gumeniuk, V A; Batova, N Ia; Mel'nikova, T S; Glazachev, O S; Golubeva, N K; Klimina, N V; Hubner, P

1998-01-01

In the context of P. K. Anokhin's theory of functional systems, the corrective effects of various combinations of medical therapeutical resonance music (MTRM) and dynamic colour exposure were analyzed. As compared to rehabilitative music programmes, MRTM was shown to have a more pronounced relaxing effect as manifested both in the optimization of emotion and in the activity of autonomic regulation of cardiovascular functions. On combined MRTM and dynamic colour flow exposures, the relaxing effect is most marked. In the examinees, the personality and situation anxieties diminish, mood improves, cardiovascular parameters become normal, the rate of metabolic processes and muscular rigidity reduce, the spectral power of alpha-rhythm increases, these occurring predominantly in the anterior region of the brain. The findings suggest the high efficiency of the chosen way of normalizing the functional status of man.

The influence of environmental factors on heart rate chronostructure depending on the individual characteristics of autonomic regulation. Results of long-term medical-ecological studies.

NASA Astrophysics Data System (ADS)

Isaeva, Olga; Zenchenko, Tatiana; Breus, Tamara; Chernikova, Anna; Baevsky, Roman

It was previously shown [Baevsky, Petrov, 1998] that during space flight under influence of geomagnetic disturbances there are both specific response of the autonomic regulation system in the form of vasomotor cardiovascular center activation (LF spectral components) and non-specific stress response, which depends on the actual autonomic balance [Breus, Baevsky, 2002]. Within the project "Mars-500" the parallel medical-ecological studies were conducted in 10 groups (10-16 people), that lived in different regions of the world under the influence of various environmental factors - climatic, geographic, industrial, social and other. It allowed us to obtain a sufficiently large number of variants of adaptive reactions caused by differences in external impacts. The main research method was the heart rate variability (HRV) analysis in short ECG samples (5 minutes) for assessing heart rate chronostructure and functional status of autonomic regulation. Results of studies have demonstrated that environmental loads on the regulatory mechanisms is higher in the northern and north-eastern regions of Russia - Magadan and Syktyvkar. Stress-index of regulatory systems and adaptive risk indicator is significantly higher in these groups [Baevsky, Berseneva, 2013]. The preliminary search of weather factors (atmospheric pressure, air temperature, humidity and magnetic index Kp) influence on the autonomic regulation of heart rate showed that there are no any significant changes and relationships in the entire group of participants. We have assumed that the character of adaptive responses, including responses to changing weather and geomagnetic conditions, is associated with the individual characteristics and the initial functional state of autonomic regulation. To test this hypothesis, we have identified two groups of subjects with different autonomic balance. The first group included individuals with a pronounced predominance of sympathetic regulation (n = 127), the second - with a strong predominance of parasympathetic activity (n = 64). The analysis of correlations between weather and heart rate chronostructure and functional condition of autonomic regulation revealed that attitude of low frequency (LF) and high frequency (HF) of heart rhythm spectrum higher in both groups at declining geomagnetic activity and lower at its growth. The comparison of other HRV indicators at decreasing and increasing geomagnetic activity displayed the opposite trends in these groups. Stress-index of regulatory systems (SI), which reflects the sympathetic activity, rises in group with sympathetic dominance at reducing geomagnetic activity, and at its growth - in group with parasympathetic dominance. So, we can see that specific adaptive reaction as response to changing geomagnetic situation, which manifested in activation of vasomotor cardiovascular center, is the similar in subjects with different autonomic balance. Non-specific component depends on initial dominance of one or another regulatory mechanism.

Cardiac regulation in the socially monogamous prairie vole

PubMed Central

Grippo, Angela J.; Lamb, Damon G.; Carter, C. Sue; Porges, Stephen W.

2007-01-01

Social experiences, both positive and negative, may influence cardiovascular regulation. Prairie voles (Microtus ochrogaster) are socially monogamous rodents that form social bonds similar to those seen in primates, and this species may provide a useful model for investigating neural and social regulation of cardiac function. Cardiac regulation has not been studied previously in the prairie vole. Radiotelemetry transmitters were implanted into adult female prairie voles under anesthesia, and electrocardiographic parameters were recorded. Autonomic blockade was performed using atenolol (8 mg/kg ip) and atropine methyl nitrate (4 mg/kg ip). Several variables were evaluated, including heart rate (HR), HR variability and the amplitude of respiratory sinus arrhythmia. Sympathetic blockade significantly reduced HR. Parasympathetic blockade significantly increased HR, and reduced HR variability and the amplitude of respiratory sinus arrhythmia. Combined autonomic blockade significantly increased HR, and reduced HR variability and respiratory sinus arrhythmia amplitude. The data indicate that autonomic function in prairie voles shares similarities with primates, with a predominant vagal influence on cardiac regulation. The current results provide a foundation for studying neural and social regulation of cardiac function during different behavioral states in this socially monogamous rodent model. PMID:17107695

Cardiovascular autonomic control in paraplegic and quadriplegic.

PubMed

de Carvalho Abreu, Elizângela Márcia; Dias, Lucas Pinto Salles; Lima, Fernanda Pupio Silva; de Paula Júnior, Alderico Rodrigues; Lima, Mário Oliveira

2016-04-01

Spinal cord injury (SCI) is commonly associated with devastating paralysis. This condition also results in cardiovascular autonomic dysfunction associated with increased mortality from cardiovascular disease. The purpose of this study was to explore the differences in cardiovascular autonomic modulation in individuals with and without SCI. The study included 60 individuals: 30 individuals without SCI, who formed the control group-CG and 30 individuals with SCI, who formed the SCI group-SCIG. The latter group was divided into two, one group of subjects with SCI above the spinal segment T6-SCIG (above T6) and a group of individuals with SCI below T6-SCIG (below T6). The subjects were evaluated by linear and nonlinear analysis of heart rate variability (HRV). The SCIG showed significantly lower square root of the mean squares differences of successive NN intervals (rMSSD), number of pairs of adjacent NN intervals differing by more than 50 ms (pNN50), standard deviation of short-term HRV (SD1), and high frequency power (HF). Their low frequency power (LF) in absolute units (ms(2)) was significantly lower and their normalized units (n.u.) were significantly higher. Their LF/HF ratio was significantly higher, and sample entropy (SampEn), which indicates the complexity and irregularity of the NN intervals time series, was significantly lower compared to the CG. The differences between the SCIG and CG were derived mainly from the SCIG (above T6). The correlation test revealed very low values between each of the parameters evaluated for CG and SCIG. The SCIG (above T6) showed greater cardiovascular autonomic impairment compared to SCIG (below T6) and CG. The SCIG (below T6) also presented some degree of autonomic dysfunction. All parameters, linear or nonlinear, are suitable to demonstrate the differences between the SCIG and CG.

Influence of cardiac nerve status on cardiovascular regulation and cardioprotection

PubMed Central

Kingma, John G; Simard, Denys; Rouleau, Jacques R

2017-01-01

Neural elements of the intrinsic cardiac nervous system transduce sensory inputs from the heart, blood vessels and other organs to ensure adequate cardiac function on a beat-to-beat basis. This inter-organ crosstalk is critical for normal function of the heart and other organs; derangements within the nervous system hierarchy contribute to pathogenesis of organ dysfunction. The role of intact cardiac nerves in development of, as well as protection against, ischemic injury is of current interest since it may involve recruitment of intrinsic cardiac ganglia. For instance, ischemic conditioning, a novel protection strategy against organ injury, and in particular remote conditioning, is likely mediated by activation of neural pathways or by endogenous cytoprotective blood-borne substances that stimulate different signalling pathways. This discovery reinforces the concept that inter-organ communication, and maintenance thereof, is key. As such, greater understanding of mechanisms and elucidation of treatment strategies is imperative to improve clinical outcomes particularly in patients with comorbidities. For instance, autonomic imbalance between sympathetic and parasympathetic nervous system regulation can initiate cardiovascular autonomic neuropathy that compromises cardiac stability and function. Neuromodulation therapies that directly target the intrinsic cardiac nervous system or other elements of the nervous system hierarchy are currently being investigated for treatment of different maladies in animal and human studies. PMID:28706586

Self-reported post-exertional fatigue in Gulf War veterans: roles of autonomic testing

PubMed Central

Li, Mian; Xu, Changqing; Yao, Wenguo; Mahan, Clare M.; Kang, Han K.; Sandbrink, Friedhelm; Zhai, Ping; Karasik, Pamela A.

2014-01-01

To determine if objective evidence of autonomic dysfunction exists from a group of Gulf War veterans with self-reported post-exertional fatigue, we evaluated 16 Gulf War ill veterans and 12 Gulf War controls. Participants of the ill group had self- reported, unexplained chronic post-exertional fatigue and the illness symptoms had persisted for years until the current clinical study. The controls had no self-reported post-exertional fatigue either at the time of initial survey nor at the time of the current study. We intended to identify clinical autonomic disorders using autonomic and neurophysiologic testing in the clinical context. We compared the autonomic measures between the 2 groups on cardiovascular function at both baseline and head-up tilt, and sudomotor function. We identified 1 participant with orthostatic hypotension, 1 posture orthostatic tachycardia syndrome, 2 distal small fiber neuropathy, and 1 length dependent distal neuropathy affecting both large and small fiber in the ill group; whereas none of above definable diagnoses was noted in the controls. The ill group had a significantly higher baseline heart rate compared to controls. Compound autonomic scoring scale showed a significant higher score (95% CI of mean: 1.72–2.67) among ill group compared to controls (0.58–1.59). We conclude that objective autonomic testing is necessary for the evaluation of self-reported, unexplained post-exertional fatigue among some Gulf War veterans with multi-symptom illnesses. Our observation that ill veterans with self-reported post-exertional fatigue had objective autonomic measures that were worse than controls warrants validation in a larger clinical series. PMID:24431987

Use of an allostatic neurotechnology by adolescents with postural orthostatic tachycardia syndrome (POTS) is associated with improvements in heart rate variability and changes in temporal lobe electrical activity.

PubMed

Fortunato, John E; Tegeler, Catherine L; Gerdes, Lee; Lee, Sung W; Pajewski, Nicholas M; Franco, Meghan E; Cook, Jared F; Shaltout, Hossam A; Tegeler, Charles H

2016-03-01

Autonomic dysregulation and heterogeneous symptoms characterize postural orthostatic tachycardia syndrome (POTS). This study evaluated the effect of high-resolution, relational, resonance-based, electroencephalic mirroring (HIRREM(®)), a noninvasive, allostatic neurotechnology for relaxation and auto-calibration of neural oscillations, on heart rate variability, brain asymmetry, and autonomic symptoms, in adolescents with POTS. Seven subjects with POTS (three males, ages 15-18) underwent a median of 14 (10-16) HIRREM sessions over 13 (8-17) days. Autonomic function was assessed from 10-min continuous heart rate and blood pressure recordings, pre- and post-HIRREM. One-minute epochs of temporal high-frequency (23-36 Hz) brain electrical activity data (T3 and T4, eyes closed) were analyzed from baseline HIRREM assessment and subsequent sessions. Subjects rated autonomic symptoms before and after HIRREM. Four of seven were on fludrocortisone, which was stopped before or during their sessions. Heart rate variability in the time domain (standard deviation of the beat-to-beat interval) increased post-HIRREM (mean increase 51%, range 10-143, p = 0.03), as did baroreflex sensitivity (mean increase in high-frequency alpha 65%, range -6 to 180, p = 0.05). Baseline temporal electrical asymmetry negatively correlated with change in asymmetry from assessment to the final HIRREM session (p = 0.01). Summed high-frequency amplitudes at left and right temporal lobes decreased a median of 3.8 μV (p = 0.02). There was a trend for improvements in self-reported symptoms related to the autonomic nervous system. Use of HIRREM was associated with reduced sympathetic bias in autonomic cardiovascular regulation, greater symmetry and reduced amplitudes in temporal lobe high-frequency electrical activity, and a trend for reduced autonomic symptoms. Data suggest the potential for allostatic neurotechnology to facilitate increased flexibility in autonomic cardiovascular regulation, possibly through more balanced activity at regions of the neocortex responsible for autonomic management. Clinical trial registry "Tilt Table with Suspected postural orthostatic tachycardia syndrome (POTS) Subjects," Protocol Record: WFUBAHA01.

Assessment of the relationship between hypoglycaemia awareness and autonomic function following islet cell/pancreas transplantation.

PubMed

Kamel, Jordan T; Goodman, David J; Howe, Kathy; Cook, Mark J; Ward, Glenn M; Roberts, Leslie J

2015-09-01

This study assesses the autonomic function of patients who have regained awareness of hypoglycaemia following islet cell or whole pancreas transplant. Five patients with type 1 diabetes and either islet cell (four patients) or whole pancreas (one patient) transplant were assessed. These patients were age-matched and gender-matched to five patients with type 1 diabetes without transplant and preserved hypoglycaemia awareness and five healthy control participants without diabetes. All participants underwent (i) a battery of five cardiovascular autonomic function tests, (ii) quantitative sudomotor axonal reflex testing, and (iii) sympathetic skin response testing. Total recorded hypoglycaemia episodes per month fell from 76 pre-transplant to 13 at 0- to 3-month post-transplant (83% reduction). The percentage of hypoglycaemia episodes that patients were unaware of decreased from 97 to 69% at 0-3 months (p < 0.001, Fisher's exact test) and to 20% after 12 months (p < 0.0001, Fisher's exact test). This amelioration was maintained at the time of testing (mean time: 4.1 years later, range: 2-6 years). Presence of significant autonomic neuropathy was seen in all five transplanted patients (at least 2/3 above modalities abnormal) but in only one of the patients with diabetes without transplantation. The long-term maintenance of hypoglycaemia awareness that returns after islet cell/pancreas transplantation in patients with diabetes is not prevented by significant autonomic neuropathy and is better accounted for by other factors such as reversal of hypoglycaemia-associated autonomic failure. Copyright © 2015 John Wiley & Sons, Ltd.

Memory dysfunction and autonomic neuropathy in non-insulin-dependent (type 2) diabetic patients.

PubMed

Zaslavsky, L M; Gross, J L; Chaves, M L; Machado, R

1995-11-01

Considering the nervous system as a unit, it might be expected that diabetic patients with autonomic neuropathy could have a central abnormality expressed as cognitive dysfunction. To determine whether autonomic neuropathy is independently associated with cognitive dysfunction, we studied a cross-section of 20 non-insulin-dependent diabetic patients with autonomic neuropathy (14 males and six females; age (mean) = 60 + or - 1 years); 29 non-insulin-dependent diabetic patients without autonomic neuropathy (14 males and 15 females; age = 59 + or - 1 years) and 34 non-diabetic patients (10 males and 24 females; age = 58 + or - 1 years), matched by age, education and duration of disease. Cognitive function was evaluated by tests of immediate, recent and remote memory: verbal (digit span; word span) and visual (recognition of towers and famous faces). Diabetic patients with autonomic neuropathy scored (median) lower in visual memory tests than diabetic patients without autonomic neuropathy and controls (towers immediate = 5 versus 7 and 6; towers recent = 4 versus 6 and 6; faces = 16 versus 18 and 18; respectively; Kruskal-Wallis; P < 0.05). There was no difference in verbal memory performance (Kruskal-Wallis; P > 0.05). Entering age, education, duration of disease and fasting plasma glucose in a stepwise multiple regression, the performance in these tests remained associated with autonomic neuropathy (towers immediate, P = 0.0054, partial r2 = 0.166; towers recent, P = 0.0076, partial r2 = 0.163). Scores in visual tests correlated negatively with the number of abnormal cardiovascular tests (faces, r = -0.25; towers recent, r = -0.24; Spearman; P < 0.05). Decreased visual cognitive function in non-insulin-dependent diabetic patients is associated with the presence and degree of autonomic neuropathy.

Pharmacotherapy of Cardiovascular Autonomic Dysfunction in Parkinson Disease.

PubMed

Shibao, Cyndya A; Kaufmann, Horacio

2017-11-01

Cardiovascular autonomic dysfunctions, including neurogenic orthostatic hypotension, supine hypertension and post-prandial hypotension, are relatively common in patients with Parkinson disease. Recent evidence suggests that early autonomic impairment such as cardiac autonomic denervation and even neurogenic orthostatic hypotension occur prior to the appearance of the typical motor deficits associated with the disease. When neurogenic orthostatic hypotension develops, patients with Parkinson disease have an increased risk of mortality, falls, and trauma-related to falls. Neurogenic orthostatic hypotension reduces quality of life and contributes to cognitive decline and physical deconditioning. The co-existence of supine hypertension complicates the treatment of neurogenic orthostatic hypotension because it involves the use of drugs with opposing effects. Furthermore, treatment of neurogenic orthostatic hypotension is challenging because of few therapeutic options; in the past 20 years, the US Food and Drug Administration approved only two drugs for the treatment of this condition. Small, open-label or randomized studies using acute doses of different pharmacologic probes suggest benefit of other drugs as well, which could be used in individual patients under close monitoring. This review describes the pathophysiology of neurogenic orthostatic hypotension and supine hypertension in Parkinson disease. We discuss the mode of action and therapeutic efficacy of different pharmacologic agents used in the treatment of patients with cardiovascular autonomic failure.

The relationship between traffic-related air pollutants and cardiac autonomic function in a panel of healthy adults: a further analysis with existing data.

PubMed

Wu, Shaowei; Deng, Furong; Niu, Jie; Huang, Qinsheng; Liu, Youcheng; Guo, Xinbiao

2011-04-01

Epidemiological studies have linked particulate matter (PM) and carbon monoxide (CO) exposures with alterations in cardiac autonomic function as measured by heart rate variability (HRV) in populations. Recently, we reported association of several HRV indices with marked changes in particulate air pollution around the Beijing 2008 Olympic Games in a panel of healthy adults. We further investigated the cardiac effects of traffic-related air pollutants over wide exposure ranges with expanded data set in this panel of healthy adults. We obtained real-time data on nine taxi drivers' in-car exposures to PM ≤ 2.5 µm in aerodynamic diameter (PM₂.₅) and CO and on multiple HRV indices during a separate daily work shift in four study periods with dramatically changing air pollution levels around the Beijing 2008 Olympic Games. Mixed effect models and a less smoother method were used to investigate the associations of exposures with HRV indices. Results showed overall negative associations of traffic-related air pollutants with HRV indices across periods, as well as differences in period-specific and individual associations. After stratifying the individuals into two different response groups (positive/negative), cardiac effects of air pollutants became stronger within each group. Exposure-response modeling identified changed curvilinear relationships between air pollution exposures and HRV indices with threshold effects. Our results support the association of exposure to traffic-related air pollution with altered cardiac autonomic function in young healthy adults free of cardiovascular compromises. These results suggest a complicated mechanism that traffic-related air pollutants influence the cardiovascular system of healthy adults.

Evidence for cardiovascular autonomic dysfunction in neonates with coarctation of the aorta.

PubMed

Polson, Jaimie W; McCallion, Naomi; Waki, Hidefumi; Thorne, Gareth; Tooley, Mark A; Paton, Julian F R; Wolf, Andrew R

2006-06-20

Coarctation of the aorta (CoA) is associated with hypertension and abnormalities of blood pressure control, which persist after late repair. Assumptions that neonatal repair would prevent development of blood pressure abnormalities have not been supported by recent data. We hypothesized that early pathological adjustment of autonomic cardiovascular function may already be established in the neonate with coarctation. We studied 8 otherwise well neonates with simple CoA and compared measures of spontaneous baroreflex sensitivity, heart rate variability, and blood pressure variability with 13 healthy newborn babies. Spontaneous baroreflex sensitivity was calculated with sequence methodology from an ECG, and noninvasive blood pressure was recorded with a Portapres. Heart rate variability was determined with time- and frequency-domain measures. Blood pressure variability was measured in the frequency domain. In comparison with normal controls, neonates with CoA had raised blood pressure (78.9+/-3.8 versus 67.1+/-2.1 mm Hg), depressed baroreflex sensitivity (8.7+/-1.5 versus 13.8+/-1.1 ms/mm Hg), reduced heart rate variability (total power 16.5+/-3.1 versus 31.5+/-2.2 ms2), and an increase in the high-frequency component of blood pressure variability (3.1+/-0.3 versus 2.2+/-0. 2 mm Hg2). This is not the pattern expected if neonates with CoA simply had subclinical cardiac failure. These data suggest that infants with CoA already show signs of pathological adjustment of autonomic cardiovascular homeostasis. Further longitudinal studies are required to determine whether these alterations play a role in the increased risk of late hypertension in these patients.

School burnout: increased sympathetic vasomotor tone and attenuated ambulatory diurnal blood pressure variability in young adult women.

PubMed

May, Ross W; Sanchez-Gonzalez, Marcos A; Fincham, Frank D

2015-01-01

Two studies examined autonomic and cardiovascular functioning that may link school burnout to cardiovascular risk factors in young healthy adult females. Study 1 (N = 136) investigated whether school burnout was related to resting values of blood pressure (BP) and blood pressure variability (BPV) through laboratory beat-to-beat BP assessment. Study 2 (N = 94) examined the link between school burnout and diurnal BPV through ambulatory BP monitoring. Controlling for anxiety and depressive symptomatology, school burnout demonstrated strong positive relationships with indices of cardiac sympathovagal tone, sympathetic vasomotor tone, inefficient myocardial oxygen consumption, increased 24-h ambulatory heart rate and BP, blunted BP diurnal variability, and increased arterial stiffness. These studies establish cardiovascular biomarkers of school burnout and suggest that even in a seemingly healthy sample school burnout may predispose females to increased cardiovascular risk. Several future lines of research are outlined.

Mitochondria and Cardiovascular Aging

PubMed Central

Dai, Dao-Fu; Ungvari, Zoltan

2013-01-01

Old age is a major risk factor for cardiovascular diseases. Several lines of evidence in experimental animal models have indicated the central role of mitochondria both in lifespan determination and cardiovascular aging. In this article we review the evidence supporting the role of mitochondrial oxidative stress, mitochondrial damage and biogenesis as well as the crosstalk between mitochondria and cellular signaling in cardiac and vascular aging. Intrinsic cardiac aging in the murine model closely recapitulates age-related cardiac changes in humans (left ventricular hypertrophy, fibrosis and diastolic dysfunction), while the phenotype of vascular aging include endothelial dysfunction, reduced vascular elasticity and chronic vascular inflammation. Both cardiac and vascular aging involve neurohormonal signaling (e.g. renin-angiotensin, adrenergic, insulin-IGF1 signaling) and cell-autonomous mechanisms. The potential therapeutic strategies to improve mitochondrial function in aging and cardiovascular diseases are also discussed, with a focus on mitochondrial-targeted antioxidants, calorie restriction, calorie restriction mimetics and exercise training. PMID:22499901

The reliability of a single protocol to determine endothelial, microvascular and autonomic functions in adolescents.

PubMed

Bond, Bert; Williams, Craig A; Barker, Alan R

2017-11-01

Impairments in macrovascular, microvascular and autonomic function are present in asymptomatic youths with clustered cardiovascular disease risk factors. This study determines the within-day reliability and between-day reliability of a single protocol to non-invasively assess these outcomes in adolescents. Forty 12- to 15-year-old adolescents (20 boys) visited the laboratory in a fasted state on two occasions, approximately 1 week apart. One hour after a standardized cereal breakfast, macrovascular function was determined via flow-mediated dilation (FMD). Heart rate variability (root mean square of successive R-R intervals; RMSSD) was determined from the ECG-gated ultrasound images acquired during the FMD protocol prior to cuff occlusion. Microvascular function was simultaneously quantified as the peak (PRH) and total (TRH) hyperaemic response to occlusion in the cutaneous circulation of the forearm via laser Doppler imaging. To address within-day reliability, a subset of twenty adolescents (10 boys) repeated these measures 90 min afterwards on one occasion. The within-day typical error and between-day typical error expressed as a coefficient of variation of these outcomes are as follows: ratio-scaled FMD, 5·1% and 10·6%; allometrically scaled FMD, 4·4% and 9·4%; PRH, 11% and 13·3%; TRH, 29·9% and 23·1%; and RMSSD, 17·6% and 17·6%. The within- and between-day test-retest correlation coefficients for these outcomes were all significant (r > 0·54 for all). Macrovascular, microvascular and autonomic functions can be simultaneously and non-invasively determined in adolescents using a single protocol with an appropriate degree of reproducibility. Determining these outcomes may provide greater understanding of the progression of cardiovascular disease and aid early intervention. © 2016 Scandinavian Society of Clinical Physiology and Nuclear Medicine. Published by John Wiley & Sons Ltd.

Cardiac autonomic regulation is disturbed in children with euthyroid Hashimoto thyroiditis.

PubMed

Kilic, Ayhan; Gulgun, Mustafa; Tascilar, Mehmet Emre; Sari, Erkan; Yokusoglu, Mehmet

2012-03-01

Hashimoto thyroiditis (chronic autoimmune thyroiditis) is the most common form of thyroiditis in childhood. Previous studies have found autonomic dysfunction of varying magnitude in patients with autoimmune diseases, which is considered a cardiovascular risk factor. We aimed to evaluate the heart rate variability (HRV), a measure of cardiac autonomic modulation, in children with euthyroid Hashimoto thyroiditis (eHT). The study included 32 patients with eHT (27 girls and 5 boys; mean age 11 ± 4.1 years, range 8-16; body mass index 0.47 ± 0.69 kg/m(2)), as judged by normal or minimally elevated serum TSH levels (normal range: 0.34-5.6 mIU/l) and normal levels of free thyroid hormones (FT4 and FT3) and 38 euthyroid age-matched controls. Patients with eHT and control subjects underwent physical examination and 24-hour ambulatory ECG monitoring. Time-domain parameters of HRV were evaluated for cardiac autonomic functions. Children with eHT displayed significantly lower values of time-domain parameters of SDANN (standard deviation of the averages of NN intervals), RMSSD (square root of the mean of the sum of the squares of differences between adjacent NN intervals), NN50 counts (number of pairs of adjacent NN intervals differing by more than 50 ms) and PNN50 (NN50 count divided by the total number of all NN intervals) for each 5-min interval, compared to healthy controls (p < 0.05 for each), indicating the decreased beat-to-beat variation of heart rate. In conclusion, eHT is associated with disturbed autonomic regulation of heart rate. Hence, the children with eHT are at higher risk for developing cardiovascular diseases.

Autonomic cardiovascular modulation with three different anesthetic strategies during neurosurgical procedures.

PubMed

Guzzetti, S; Bassani, T; Latini, R; Masson, S; Barlera, S; Citerio, G; Porta, A

2015-01-01

Autonomic cardiovascular modulation during surgery might be affected by different anesthetic strategies. Aim of the present study was to assess autonomic control during three different anesthetic strategies in the course of neurosurgical procedures by the linear and non-linear analysis of two cardiovascular signals. Heart rate (EKG-RR intervals) and systolic arterial pressure (SAP) signals were analyzed in 93 patients during elective neurosurgical procedures at fixed points: anesthetic induction, dura mater opening, first and second hour of surgery, dura mater and skin closure. Patients were randomly assigned to three anesthetic strategies: sevoflurane+fentanyl (S-F), sevoflurane+remifentanil (S-R) and propofol+remifentanil (P-R). All the three anesthetic strategies were characterized by a reduction of RR and SAP variability. A more active autonomic sympathetic modulation, as ratio of low to high frequency spectral components of RR variability (LF/HF), was present in the P-R group vs. S-R group. This is confirmed by non-linear symbolic analysis of RR series and SAP variability analysis. In addition, an increased parasympathetic modulation was suggested by symbolic analysis of RR series during the second hour of surgery in S-F group. Despite an important reduction of cardiovascular signal variability, the analysis of RR and SAP signals were capable to detect information about autonomic control during anesthesia. Symbolic analysis (non-linear) seems to be able to highlight the differences of both the sympathetic (slow) and vagal (fast) modulation among anesthetics, while spectral analysis (linear) underlines the same differences but only in terms of balance between the two neural control systems.

Exploratory studies of physiological components of motion sickness: Cardiopulmonary differences between high and low susceptibles

NASA Technical Reports Server (NTRS)

Naifeh, K.

1985-01-01

A comprehensive examination of cardiovascular autonomic response to motion sickness was studied and whether differences in cardiopulmonary function exist in high and low susceptibility groups were determined. Measurement techniques were developed as was test equipment for its ability to provide accurately new measures of interest and to test the adequately of these new measures in differentiating between susceptibility groups. It was concluded that these groups can be differentiated using simple, brief stressors and measurements of cardiodynamic function.

[Burnout syndrome: a "true" cardiovascular risk factor].

PubMed

Cursoux, Pauline; Lehucher-Michel, Marie-Pascale; Marchetti, Hélène; Chaumet, Guillaume; Delliaux, Stéphane

2012-11-01

The burnout syndrome is characterized by emotional exhaustion, depersonalization and reduced personal accomplishment in individuals professionally involved with others. The burnout syndrome is poorly recognized, particularly in France, as a distinct nosology from adaptation troubles, stress, depression, or anxiety. Several tools quantifying burnout and emotional exhaustion exist, the most spread is the questionnaire called Maslach Burnout Inventory. The burnout syndrome alters cardiovascular function and its neuroregulation by autonomic nervous system and is associated with: increased sympathetic tone to heart and vessels after mental stress, lowered physiological post-stress vagal rebound to heart, and lowered arterial baroreflex sensitivity. Job strain as burnout syndrome seems to be a real independent cardiovascular risk factor. Oppositely, training to manage emotions could increase vagal tone to heart and should be cardio-protective. Copyright © 2012 Elsevier Masson SAS. All rights reserved.

Exercise protects the cardiovascular system: effects beyond traditional risk factors

PubMed Central

Joyner, Michael J; Green, Daniel J

2009-01-01

In humans, exercise training and moderate to high levels of physical activity are protective against cardiovascular disease. In fact they are ∼40% more protective than predicted based on the changes in traditional risk factors (blood lipids, hypertension, diabetes etc.) that they cause. In this review, we highlight the positive effects of exercise on endothelial function and the autonomic nervous system. We also ask if these effects alone, or in combination, might explain the protective effects of exercise against cardiovascular disease that appear to be independent of traditional risk factor modification. Our goal is to use selected data from our own work and that of others to stimulate debate on the nature and cause of the ‘risk factor gap’ associated with exercise and physical activity. PMID:19736305

Assessing and conceptualizing orgasm after a spinal cord injury.

PubMed

Courtois, Frédérique; Charvier, Kathleen; Vézina, Jean-Guy; Journel, Nicolas Morel; Carrier, Serge; Jacquemin, Géraldine; Côté, Isabelle

2011-11-01

To provide a questionnaire for assessing the sensations characterizing orgasm. To test the hypothesis that orgasm is related to autonomic hyperreflexia (AHR) in individuals with a spinal cord injury (SCI). A total of 97 men with SCI, of whom 50 showed AHR at ejaculation and 39 showed no AHR, were compared. Ejaculation was obtained through natural stimulation, vibrostimulation or vibrostimulation combined with midodrine (5-25 mg). Cardiovascular measures were recorded before, at, and after each test. Responses to the questionnaire were divided into four categories: cardiovascular, muscular, autonomic and dysreflexic sensations. Significantly more sensations were described at ejaculation than with sexual stimulation alone. Men with SCI who experienced AHR at ejaculation reported significantly more cardiovascular, muscular, autonomic and dysreflexic responses than those who did not. There was no difference between men with complete and those with incomplete lesions. The findings show that the questionnaire is a useful tool to assess orgasm and to guide patients in identifying the bodily sensations that accompany or build up to orgasm. The findings also support the hypothesis that orgasm may be related to the presence of AHR in individuals with SCI. Data from able-bodied men also suggest that AHR could be related to orgasm, as increases in blood pressure are observed at ejaculation along with cardiovascular, autonomic and muscular sensations. © 2011 THE AUTHORS. BJU INTERNATIONAL © 2011 BJU INTERNATIONAL.

Pulse wave velocity and cardiac autonomic function in type 2 diabetes mellitus.

PubMed

Chorepsima, Stamatina; Eleftheriadou, Ioanna; Tentolouris, Anastasios; Moyssakis, Ioannis; Protogerou, Athanasios; Kokkinos, Alexandros; Sfikakis, Petros P; Tentolouris, Nikolaos

2017-05-19

Increased carotid-femoral pulse wave velocity (PWV) has been associated with incident cardiovascular disease, independently of traditional risk factors. Cardiac autonomic dysfunction is a common complication of diabetes and has been associated with reduced aortic distensibility. However, the association of cardiac autonomic dysfunction with PWV is not known. In this study we examined the association between cardiac autonomic function and PWV in subjects with type 2 diabetes mellitus. A total of 290 patients with type 2 diabetes were examined. PWV was measured at the carotid-femoral segment with applanation tonometry. Central mean arterial blood pressure (MBP) was determined by the same apparatus. Participants were classified as having normal (n = 193) or abnormal (n = 97) PWV values using age-corrected values. Cardiac autonomic nervous system activity was determined by measurement of parameters of heart rate variability (HRV). Subjects with abnormal PWV were older, had higher arterial blood pressure and higher heart rate than those with normal PWV. Most of the values of HRV were significantly lower in subjects with abnormal than in those with normal PWV. Multivariate analysis, after controlling for various confounding factors, demonstrated that abnormal PWV was associated independently only with peripheral MBP [odds ratio (OR) 1.049, 95% confidence intervals (CI) 1.015-1.085, P = 0.005], central MBP (OR 1.052, 95% CI 1.016-1.088, P = 0.004), log total power (OR 0.490, 95% CI 0.258-0.932, P = 0.030) and log high frequency power (OR 0.546, 95% CI 0.301-0.991, P = 0.047). In subjects with type 2 diabetes, arterial blood pressure and impaired cardiac autonomic function is associated independently with abnormal PWV.

Differential responses of autonomic function in sea level residents, acclimatized lowlanders at >3500 m and Himalayan high altitude natives at >3500 m: A cross-sectional study.

PubMed

Dhar, Priyanka; Sharma, Vijay K; Das, Saroj K; Barhwal, Kalpana; Hota, Sunil K; Singh, Shashi B

2018-04-09

We studied the differential responses of autonomic function in sea level residents (SLR), acclimatized lowlanders (ALH) in high altitude (HA) and HA natives (HAN) at >3500 m. Out of 771 male volunteers included in this cross-sectional study, SLR, ALH and HAN groups were comprised of 351, 307 and 113 volunteers, respectively. Our results showed persistent sympathetic dominance with significantly reduced (p < 0.05) parasympathetic response in ALH as compared to SLR and HAN populations. This may be attributed to significantly increased (p < 0.05) concentration of coronary risk factors and plasma catecholamines in ALH as compared to SLR and HAN. The ALH also showed significantly increased (p < 0.05) level of serum homocysteine as compared to SLR. The HAN exhibited no changes in autonomic function despite significantly elevated (p < 0.05) homocysteine level as compared to SLR. Our findings may have clinical relevance for assessment of susceptibility to cardiovascular risks in HA dwellers, native highlanders and patients with hypoxemia. Copyright © 2018 Elsevier B.V. All rights reserved.

Ghrelin potentiates cardiac reactivity to stress by modulating sympathetic control and beta-adrenergic response.

PubMed

Camargo-Silva, Gabriel; Turones, Larissa Córdova; da Cruz, Kellen Rosa; Gomes, Karina Pereira; Mendonça, Michelle Mendanha; Nunes, Allancer; de Jesus, Itamar Guedes; Colugnati, Diego Basile; Pansani, Aline Priscila; Pobbe, Roger Luis Henschel; Santos, Robson; Fontes, Marco Antônio Peliky; Guatimosim, Silvia; de Castro, Carlos Henrique; Ianzer, Danielle; Ferreira, Reginaldo Nassar; Xavier, Carlos Henrique

2018-03-01

Prior evidence indicates that ghrelin is involved in the integration of cardiovascular functions and behavioral responses. Ghrelin actions are mediated by the growth hormone secretagogue receptor subtype 1a (GHS-R1a), which is expressed in peripheral tissues and central areas involved in the control of cardiovascular responses to stress. In the present study, we assessed the role of ghrelin - GHS-R1a axis in the cardiovascular reactivity to acute emotional stress in rats. Ghrelin potentiated the tachycardia evoked by restraint and air jet stresses, which was reverted by GHS-R1a blockade. Evaluation of the autonomic balance revealed that the sympathetic branch modulates the ghrelin-evoked positive chronotropy. In isolated hearts, the perfusion with ghrelin potentiated the contractile responses caused by stimulation of the beta-adrenergic receptor, without altering the amplitude of the responses evoked by acetylcholine. Experiments in isolated cardiomyocytes revealed that ghrelin amplified the increases in calcium transient changes evoked by isoproterenol. Taken together, our results indicate that the Ghrelin-GHS-R1a axis potentiates the magnitude of stress-evoked tachycardia by modulating the autonomic nervous system and peripheral mechanisms, strongly relying on the activation of cardiac calcium transient and beta-adrenergic receptors. Copyright © 2018 Elsevier Inc. All rights reserved.

Methods of assessment of the post-exercise cardiac autonomic recovery: A methodological review.

PubMed

Peçanha, Tiago; Bartels, Rhenan; Brito, Leandro C; Paula-Ribeiro, Marcelle; Oliveira, Ricardo S; Goldberger, Jeffrey J

2017-01-15

The analysis of post-exercise cardiac autonomic recovery is a practical clinical tool for the assessment of cardiovascular health. A reduced heart rate recovery - an indicator of autonomic dysfunction - has been found in a broad range of cardiovascular diseases and has been associated with increased risks of both cardiac and all-cause mortality. For this reason, over the last several years, non-invasive methods for the assessment of cardiac autonomic recovery after exercise - either based on heart rate recovery or heart rate variability indices - have been proposed. However, for the proper implementation of such methods in daily clinical practice, the discussion of their clinical validity, physiologic meaning, mathematical formulation and reproducibility should be better addressed. Therefore, the aim of this methodological review is to present some of the most employed methods of post-exercise cardiac autonomic recovery in the literature and comprehensively discuss their strengths and weaknesses. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Differentiation in the angiotensin II receptor 1 blocker class on autonomic function.

PubMed

Krum, H

2001-09-01

Autonomic function is disordered in cardiovascular disease states such as chronic heart failure (CHF) and hypertension. Interactions between the renin-angiotensin-aldosterone system (RAAS) and the sympathetic nervous system (SNS) may potentially occur at a number of sites. These include central sites (eg, rostral ventrolateral medulla), at the level of baroreflex control, and at the sympathetic prejunctional angiotensin II receptor 1 (AT(1)) receptor, which is facilitatory for norepinephrine release from the sympathetic nerve terminal. Therefore, drugs that block the RAAS may be expected to improve autonomic dysfunction in cardiovascular disease states. In order to test the hypothesis that RAAS inhibition directly reduces SNS activity, a pithed rat model of sympathetic stimulation has been established. In this model, an increase in frequency of stimulation results in a pressor response that is sympathetically mediated and highly reproducible. This pressor response is enhanced in the presence of angiotensin II and is reduced in the presence of nonselective AIIRAs that block both AT(1) and AT(2) receptor subtypes (eg, saralasin). AT(1)-selective antagonists have also been studied in this model, at pharmacologically relevant doses. In one such study, only the AT(1) blocker eprosartan reduced sympathetically stimulated increases in blood pressure, whereas comparable doses of losartan, valsartan, and irbesartan did not. The reason(s) for the differences between eprosartan and other agents of this class on sympathetic modulation are not clear, but may relate to the chemical structure of the drug (a non- biphenyl tetrazole structure that is chemically distinct from the structure of other AIIRAs), receptor binding characteristics (competitive), or unique effects on presynaptic AT(1) receptors.

General pharmacology of loracarbef in animals.

PubMed

Shetler, T; Bendele, A; Buening, M; Clemens, J; Colbert, W; Deldar, A; Helton, D; McGrath, J; Shannon, H; Turk, J

1993-01-01

Loracarbef ((6R, 7S)-7-[(R)-2-amino-2-phenyl-acetamido]-3-chloro-8-oxo-1- azabicyclo [4.2.0]oct-2-ene-2-carboxylic acid, monohydrate, LY 163892, CAS 121961-22-6) is a carbacephem antibiotic targeted for use in the treatment of infectious disease. The potential pharmacological effects of this agent were examined on cardiovascular, respiratory, gastrointestinal, central nervous and autonomic nervous systems. Also examined were local anesthetic activity, effects on platelet aggregation, circulating blood glucose, primary antibody production, renal function, blood coagulation, ocular irritation, and the acute inflammatory response. Doses of 100, 1000, and 2000 mg/kg given by the oral route were selected for most in vivo studies. Concentrations up to 3 x 10(-3) mol/l were used in vitro. Loracarbef was essentially inactive in the tests of central and autonomic nervous system function, platelet aggregation, renal function, blood hemolysis, primary antibody production, blood coagulation, and ocular irritation. It had no local anesthetic activity. At high oral or intravenous doses, representing significant multiples of the therapeutic dose, loracarbef caused changes in gastrointestinal (decrease in gastric acid production and gastric fluid volume; increased biliary output), cardiovascular (increased mean pressure, cardiac output, heart rate, and femoral flow), blood glucose (increased glucose levels), and anti-inflammatory tests (suppressed acute inflammatory response). In summary, loracarbef exhibited minimal activity in these pharmacodynamic studies. These results indicate loracarbef has a low potential to produce adverse effects at therapeutic doses.

Phase Synchronization of Hemodynamic Variables at Rest and after Deep Breathing Measured during the Course of Pregnancy

PubMed Central

Papousek, Ilona; Roessler, Andreas; Hinghofer-Szalkay, Helmut; Lang, Uwe; Kolovetsiou-Kreiner, Vassiliki

2013-01-01

Background The autonomic nervous system plays a central role in the functioning of systems critical for the homeostasis maintenance. However, its role in the cardiovascular adaptation to pregnancy-related demands is poorly understood. We explored the maternal cardiovascular systems throughout pregnancy to quantify pregnancy-related autonomic nervous system adaptations. Methodology Continuous monitoring of heart rate (R-R interval; derived from the 3-lead electrocardiography), blood pressure, and thoracic impedance was carried out in thirty-six women at six time-points throughout pregnancy. In order to quantify in addition to the longitudinal effects on baseline levels throughout gestation the immediate adaptive heart rate and blood pressure changes at each time point, a simple reflex test, deep breathing, was applied. Consequently, heart rate variability and blood pressure variability in the low (LF) and high (HF) frequency range, respiration and baroreceptor sensitivity were analyzed in resting conditions and after deep breathing. The adjustment of the rhythms of the R-R interval, blood pressure and respiration partitioned for the sympathetic and the parasympathetic branch of the autonomic nervous system were quantified by the phase synchronization index γ, which has been adopted from the analysis of weakly coupled chaotic oscillators. Results Heart rate and LF/HF ratio increased throughout pregnancy and these effects were accompanied by a continuous loss of baroreceptor sensitivity. The increases in heart rate and LF/HF ratio levels were associated with an increasing decline in the ability to flexibly respond to additional demands (i.e., diminished adaptive responses to deep breathing). The phase synchronization index γ showed that the observed effects could be explained by a decreased coupling of respiration and the cardiovascular system (HF components of heart rate and blood pressure). Conclusions/Significance The findings suggest that during the course of pregnancy the individual systems become increasingly independent to meet the increasing demands placed on the maternal cardiovascular and respiratory system. PMID:23577144

A pilot study on pupillary and cardiovascular changes induced by stereoscopic video movies

PubMed Central

Oyamada, Hiroshi; Iijima, Atsuhiko; Tanaka, Akira; Ukai, Kazuhiko; Toda, Haruo; Sugita, Norihiro; Yoshizawa, Makoto; Bando, Takehiko

2007-01-01

Background Taking advantage of developed image technology, it is expected that image presentation would be utilized to promote health in the field of medical care and public health. To accumulate knowledge on biomedical effects induced by image presentation, an essential prerequisite for these purposes, studies on autonomic responses in more than one physiological system would be necessary. In this study, changes in parameters of the pupillary light reflex and cardiovascular reflex evoked by motion pictures were examined, which would be utilized to evaluate the effects of images, and to avoid side effects. Methods Three stereoscopic video movies with different properties were field-sequentially rear-projected through two LCD projectors on an 80-inch screen. Seven healthy young subjects watched movies in a dark room. Pupillary parameters were measured before and after presentation of movies by an infrared pupillometer. ECG and radial blood pressure were continuously monitored. The maximum cross-correlation coefficient between heart rate and blood pressure, ρmax, was used as an index to evaluate changes in the cardiovascular reflex. Results Parameters of pupillary and cardiovascular reflexes changed differently after subjects watched three different video movies. Amplitudes of the pupillary light reflex, CR, increased when subjects watched two CG movies (movies A and D), while they did not change after watching a movie with the real scenery (movie R). The ρmax was significantly larger after presentation of the movie D. Scores of the questionnaire for subjective evaluation of physical condition increased after presentation of all movies, but their relationship with changes in CR and ρmax was different in three movies. Possible causes of these biomedical differences are discussed. Conclusion The autonomic responses were effective to monitor biomedical effects induced by image presentation. Further accumulation of data on multiple autonomic functions would contribute to develop the tools which evaluate the effects of image presentation to select applicable procedures and to avoid side effects in the medical care and rehabilitation. PMID:17915031

A pilot study on pupillary and cardiovascular changes induced by stereoscopic video movies.

PubMed

Oyamada, Hiroshi; Iijima, Atsuhiko; Tanaka, Akira; Ukai, Kazuhiko; Toda, Haruo; Sugita, Norihiro; Yoshizawa, Makoto; Bando, Takehiko

2007-10-04

Taking advantage of developed image technology, it is expected that image presentation would be utilized to promote health in the field of medical care and public health. To accumulate knowledge on biomedical effects induced by image presentation, an essential prerequisite for these purposes, studies on autonomic responses in more than one physiological system would be necessary. In this study, changes in parameters of the pupillary light reflex and cardiovascular reflex evoked by motion pictures were examined, which would be utilized to evaluate the effects of images, and to avoid side effects. Three stereoscopic video movies with different properties were field-sequentially rear-projected through two LCD projectors on an 80-inch screen. Seven healthy young subjects watched movies in a dark room. Pupillary parameters were measured before and after presentation of movies by an infrared pupillometer. ECG and radial blood pressure were continuously monitored. The maximum cross-correlation coefficient between heart rate and blood pressure, rho max, was used as an index to evaluate changes in the cardiovascular reflex. Parameters of pupillary and cardiovascular reflexes changed differently after subjects watched three different video movies. Amplitudes of the pupillary light reflex, CR, increased when subjects watched two CG movies (movies A and D), while they did not change after watching a movie with the real scenery (movie R). The rho max was significantly larger after presentation of the movie D. Scores of the questionnaire for subjective evaluation of physical condition increased after presentation of all movies, but their relationship with changes in CR and rho max was different in three movies. Possible causes of these biomedical differences are discussed. The autonomic responses were effective to monitor biomedical effects induced by image presentation. Further accumulation of data on multiple autonomic functions would contribute to develop the tools which evaluate the effects of image presentation to select applicable procedures and to avoid side effects in the medical care and rehabilitation.

Autonomic function in manganese alloy workers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Barrington, W.W.; Angle, C.R.; Willcockson, N.K.

1998-07-01

The observation of orthostatic hypotension in an index case of manganese toxicity lead to this prospective attempt to evaluate cardiovascular autonomic function and cognitive and emotional neurotoxicity in eight manganese alloy welders and machinists. The subjects consisted of a convenience sample consisting of an index case of manganese dementia, his four co-workers in a frog shop for gouging, welding, and grinding repair of high manganese railway track and a convenience sample of three mild steel welders with lesser manganese exposure also referred because of cognitive or autonomic symptoms. Frog shop air manganese samples 9.6--10 years before and 1.2--3.4 years aftermore » the diagnosis of the index case exceeded 1.0 mg/m{sup 3} in 29% and 0.2 mg/m{sup 3} in 62%. Twenty-four-hour electrocardiographic (Holter) monitoring was used to determine the temporal variability of the heartrate (RR{prime} interval) and the rates of change at low frequency and high frequency. MMPI and MCMI personality assessment and short-term memory, figure copy, controlled oral word association, and symbol digit tests were used.« less

Affective brain areas and sleep disordered breathing

PubMed Central

Harper, Ronald M.; Kumar, Rajesh; Macey, Paul M.; Woo, Mary A.; Ogren, Jennifer A.

2014-01-01

The neural damage accompanying the hypoxia, reduced perfusion, and other consequences of sleep-disordered breathing found in obstructive sleep apnea, heart failure (HF), and congenital central hypoventilation syndrome (CCHS), appears in areas that serve multiple functions, including emotional drives to breathe, and involve systems that serve affective, cardiovascular, and breathing roles. The damage, assessed with structural magnetic resonance imaging (MRI) procedures, shows tissue loss or water content and diffusion changes indicative of injury, and impaired axonal integrity between structures; damage is preferentially unilateral. Functional MRI responses in affected areas also are time- or amplitude- distorted to ventilatory or autonomic challenges. Among the structures injured are the insular, cingulate, and ventral medial prefrontal cortices, as well as cerebellar deep nuclei and cortex, anterior hypothalamus, raphé, ventrolateral medulla, basal ganglia and, in CCHS, the locus coeruleus. Raphé and locus coeruleus injury may modify serotonergic and adrenergic modulation of upper airway and arousal characteristics. Since both axons and gray matter show injury, the consequences to function, especially to autonomic, cognitive, and mood regulation, are major. Several affected rostral sites, including the insular and cingulate cortices and hippocampus, mediate aspects of dyspnea, especially in CCHS, while others, including the anterior cingulate and thalamus, participate in initiation of inspiration after central breathing pauses, and the medullary injury can impair baroreflex and breathing control. The ancillary injury associated with sleep-disordered breathing to central structures can elicit multiple other distortions in cardiovascular, cognitive, and emotional functions in addition to effects on breathing regulation. PMID:24746053

Emotional Stress and Cardiovascular Complications in Animal Models: A Review of the Influence of Stress Type

PubMed Central

Crestani, Carlos C.

2016-01-01

Emotional stress has been recognized as a modifiable risk factor for cardiovascular diseases. The impact of stress on physiological and psychological processes is determined by characteristics of the stress stimulus. For example, distinct responses are induced by acute vs. chronic aversive stimuli. Additionally, the magnitude of stress responses has been reported to be inversely related to the degree of predictability of the aversive stimulus. Therefore, the purpose of the present review was to discuss experimental research in animal models describing the influence of stressor stimulus characteristics, such as chronicity and predictability, in cardiovascular dysfunctions induced by emotional stress. Regarding chronicity, the importance of cardiovascular and autonomic adjustments during acute stress sessions and cardiovascular consequences of frequent stress response activation during repeated exposure to aversive threats (i.e., chronic stress) is discussed. Evidence of the cardiovascular and autonomic changes induced by chronic stressors involving daily exposure to the same stressor (predictable) vs. different stressors (unpredictable) is reviewed and discussed in terms of the impact of predictability in cardiovascular dysfunctions induced by stress. PMID:27445843

Modified Clonidine Testing for Growth Hormone Stimulation Reveals α2-Adrenoreceptor Sub Sensitivity in Children with Idiopathic Growth Hormone Deficiency.

PubMed

Willaschek, Christian; Meint, Sebastian; Rager, Klaus; Buchhorn, Reiner

2015-01-01

The association between short stature and increased risk of ischemic heart disease has been subject to studies for decades. The recent discussion of cardiovascular risk during growth hormone therapy has given new importance to this question. We have hypothesized that the autonomic system is a crucial element relating to this subject. Heart rate variability calculated from 24-hour electrocardiogram data is providing insight into the regulatory state of the autonomous nervous system and is an approved surrogate parameter for estimating cardiovascular risk. We have calculated heart rate variability during clonidine testing for growth hormone stimulation of 56 children. As clonidine is a well-known effector of the autonomous system, stimulating vagal tone and decreasing sympathetic activity, we compared the autonomous reactions of children with constitutional growth delay (CGD), growth hormone deficiency (GHD) and former small for gestational age (SGA). During clonidine testing children with CGD showed the expected α2-adrenoreceptor mediated autonomous response of vagal stimulation for several hours. This vagal reaction was significantly reduced in the SGA group and nearly non- existent in the GHD group. Children with GHD show a reduced autonomous response to clonidine indicating α2-adrenoreceptor sub sensitivity. This can be found prior to the start of growth hormone treatment. Since reduction of HRV is an approved surrogate parameter, increased cardiovascular risk has to be assumed for patients with GHD. In the SGA group a similar but less severe reduction of the autonomous response to clonidine was found. These findings may enrich the interpretation of the data on growth hormone therapy, which are being collected by the SAGhE study group.

Physical training associated with Enalapril but not to Losartan, results in better cardiovascular autonomic effects.

PubMed

Maida, Karina Delgado; Gastaldi, Ada Clarice; de Paula Facioli, Tabata; de Araújo, João Eduardo; de Souza, Hugo Celso Dutra

2017-03-01

We investigated the cardiovascular autonomic effects of physical training associated with Enalapril or Losartan pharmacological treatments in spontaneously hypertensive rats (SHR). SHRs, 18weeks of age (N=48) was assigned to either sedentary (N=24) and trained (N=24; aerobic training by swimming for 10wk). Each group was subdivided in 3 subgroups (N=8) vehicle (control); Enalapril (10mg·kg -1 ·d -1 ); and Losartan (5mg·kg -1 ·d -1 ). All animals received a 10-week treatment in drinking water. In the last week of the treatments, the animals had their femoral artery and vein cannulated for blood pressure recording and drug injection, respectively. The autonomic assessment was performed by means of different approaches: double cardiac autonomic block with atropine and propranolol, spectral analysis of heart rate variability (HRV) and systolic arterial pressure (SAPV) and assessment of baroreflex sensitivity (BRS). The groups treated with Enalapril, sedentary and trained, showed more significant decrease in blood pressure when compared to the other groups. Autonomic evaluation showed that the sedentary group treated with Enalapril or Losartan had similar results, characterized by decreased effect of sympathetic tone and/or increased effect of cardiac vagal tone associated with improved BRS. Isolated physical training attenuated only the effect of sympathetic tone. The association of physical training with Enalapril showed the best results, characterized by the predominance of vagal tone in cardiac autonomic balance, increased HRV, reduced SAPV and increased BRS. Enalapril and Losartan promoted similar beneficial cardiovascular autonomic effects in sedentary animals, while only the association of physical training with Enalapril potentiated these effects. Copyright © 2017 Elsevier B.V. All rights reserved.

One night on-call: sleep deprivation affects cardiac autonomic control and inflammation in physicians.

PubMed

Tobaldini, Eleonora; Cogliati, Chiara; Fiorelli, Elisa M; Nunziata, Vanessa; Wu, Maddalena A; Prado, Marta; Bevilacqua, Maurizio; Trabattoni, Daria; Porta, Alberto; Montano, Nicola

2013-10-01

Sleep loss is associated with increased cardiovascular morbidity and mortality. It is known that chronic sleep restriction affects autonomic cardiovascular control and inflammatory response. However, scanty data are available on the effects of acute sleep deprivation (ASD) due to night shifts on the cardiovascular system and its capability to respond to stressor stimuli. The aim of our study was to investigate whether a real life model of ASD, such as "one night on-call", might alter the autonomic dynamic response to orthostatic challenge and modify the immune response in young physicians. Fifteen healthy residents in Internal Medicine were studied before and after one night on-call at Rest and during a gravitational stimulus (head up-tilt test, HUT). Heart rate variability (HRV), blood pressure variability (BPV) and baroreflex sensitivity (BRS) were analyzed during Rest and HUT before and after ASD. Plasmatic hormones (epinephrine, norepinephrine, cortisol, renin, aldosterone, ACTH) and tissue inflammatory cytokines were measured at baseline and after ASD. HRV analysis revealed a predominant sympathetic modulation and a parasympathetic withdrawal after ASD. During HUT, the sympathovagal balance shifted towards a sympathetic predominance before and after ASD. However, the magnitude of the autonomic response was lower after ASD. BPV and BRS remained unchanged before and after ASD as the hormone levels, while IFN-γ increased after ASD compared to baseline. In summary, one night of sleep deprivation, at least in this real-life model, seems to affect cardiovascular autonomic response and immune modulation, independently by the activation of the hypothalamic-pituitary axis. Copyright © 2013 European Federation of Internal Medicine. Published by Elsevier B.V. All rights reserved.

Clinical review: Cardiovascular consequences of ovarian disruption: a focus on functional hypothalamic amenorrhea in physically active women.

PubMed

O'Donnell, Emma; Goodman, Jack M; Harvey, Paula J

2011-12-01

Evidence indicates that hypoestrogenemia is linked with accelerated progression of atherosclerosis. Premenopausal women presenting with ovulatory disruption due to functional hypothalamic amenorrhea (FHA) are characterized by hypoestrogenemia. One common and reversible form of FHA in association with energy deficiency is exercise-associated amenorrhea (EAA). Articles were found via PubMed search for both original and review articles based on peer review publications between 1974 and 2011 reporting on cardiovascular changes in women with FHA, with emphasis placed on women with EAA. Despite participation in regular exercise training, hypoestrogenic women with EAA demonstrate paradoxical changes in cardiovascular function, including endothelial dysfunction, a known permissive factor for the progression and development of atherosclerosis. Such alterations suggest that the beneficial effects of regular exercise training on vascular function are obviated in the face of hypoestrogenemia. The long-term cardiovascular consequences of altered vascular function in response to ovulatory disruption in women with EAA remain to be determined. Retrospective data, however, suggest premature development and progression of coronary artery disease in older premenopausal women reporting a history of hypothalamic ovulatory disruption. Importantly, in women with EAA, estrogen therapy, folic acid supplementation without change in menstrual status, and resumption of menses restores endothelial function. In this review, we focus on the influence of hypoestrogenemia in association with energy deficiency in mediating changes in cardiovascular function in women with EAA, including endothelial function, regional blood flow, lipid profile, and autonomic control of blood pressure, heart rate, and baroreflex sensitivity. The influence of exercise training is also considered. With the premenopausal years typically considered to be cardioprotective in association with normal ovarian function, ovarian disruption in women with EAA is of importance. Further investigation of the short-term, and potentially long-term, cardiovascular consequences of hypoestrogenemia in women with EAA is recommended.

Nature's Autonomous Oscillators

NASA Technical Reports Server (NTRS)

Mayr, H. G.; Yee, J.-H.; Mayr, M.; Schnetzler, R.

2012-01-01

Nonlinearity is required to produce autonomous oscillations without external time dependent source, and an example is the pendulum clock. The escapement mechanism of the clock imparts an impulse for each swing direction, which keeps the pendulum oscillating at the resonance frequency. Among nature's observed autonomous oscillators, examples are the quasi-biennial oscillation and bimonthly oscillation of the Earth atmosphere, and the 22-year solar oscillation. The oscillations have been simulated in numerical models without external time dependent source, and in Section 2 we summarize the results. Specifically, we shall discuss the nonlinearities that are involved in generating the oscillations, and the processes that produce the periodicities. In biology, insects have flight muscles, which function autonomously with wing frequencies that far exceed the animals' neural capacity; Stretch-activation of muscle contraction is the mechanism that produces the high frequency oscillation of insect flight, discussed in Section 3. The same mechanism is also invoked to explain the functioning of the cardiac muscle. In Section 4, we present a tutorial review of the cardio-vascular system, heart anatomy, and muscle cell physiology, leading up to Starling's Law of the Heart, which supports our notion that the human heart is also a nonlinear oscillator. In Section 5, we offer a broad perspective of the tenuous links between the fluid dynamical oscillators and the human heart physiology.

Orthostatic intolerance and motion sickness after parabolic flight

NASA Technical Reports Server (NTRS)

Schlegel, T. T.; Brown, T. E.; Wood, S. J.; Benavides, E. W.; Bondar, R. L.; Stein, F.; Moradshahi, P.; Harm, D. L.; Fritsch-Yelle, J. M.; Low, P. A.

2001-01-01

Because it is not clear that the induction of orthostatic intolerance in returning astronauts always requires prolonged exposure to microgravity, we investigated orthostatic tolerance and autonomic cardiovascular function in 16 healthy subjects before and after the brief micro- and hypergravity of parabolic flight. Concomitantly, we investigated the effect of parabolic flight-induced vomiting on orthostatic tolerance, R-wave-R-wave interval and arterial pressure power spectra, and carotid-cardiac baroreflex and Valsalva responses. After parabolic flight 1) 8 of 16 subjects could not tolerate 30 min of upright tilt (compared to 2 of 16 before flight); 2) 6 of 16 subjects vomited; 3) new intolerance to upright tilt was associated with exaggerated falls in total peripheral resistance, whereas vomiting was associated with increased R-wave-R-wave interval variability and carotid-cardiac baroreflex responsiveness; and 4) the proximate mode of new orthostatic failure differed in subjects who did and did not vomit, with vomiters experiencing comparatively isolated upright hypocapnia and cerebral vasoconstriction and nonvomiters experiencing signs and symptoms reminiscent of the clinical postural tachycardia syndrome. Results suggest, first, that syndromes of orthostatic intolerance resembling those developing after space flight can develop after a brief (i.e., 2-h) parabolic flight and, second, that recent vomiting can influence the results of tests of autonomic cardiovascular function commonly utilized in returning astronauts.

Autonomic cardiovascular modulation in masters and young cyclists following high-intensity interval training.

PubMed

Borges, Nattai R; Reaburn, Peter R; Doering, Thomas M; Argus, Christos K; Driller, Matthew W

2017-04-01

This study aimed at examining the autonomic cardiovascular modulation in well-trained masters and young cyclists following high-intensity interval training (HIT). Nine masters (age 55.6 ± 5.0 years) and eight young cyclists (age 25.9 ± 3.0 years) completed a HIT protocol of 6 x 30 sec at 175% of peak power output, with 4.5-min' rest between efforts. Immediately following HIT, heart rate and R-R intervals were monitored for 30-min during passive supine recovery. Autonomic modulation was examined by i) heart rate recovery in the first 60-sec of recovery (HRR 60 ); ii) the time constant of the 30-min heart rate recovery curve (HRRτ); iii) the time course of the root mean square for successive 30-sec R-R interval (RMSSD 30 ); and iv) time and frequency domain analyses of subsequent 5-min R-R interval segments. No significant between-group differences were observed for HRR 60 (P = 0.096) or HRR τ (P = 0.617). However, a significant interaction effect was found for RMSSD 30 (P = 0.021), with the master cyclists showing higher RMSSD 30 values following HIT. Similar results were observed in the time and frequency domain analyses with significant interaction effects found for the natural logarithm of the RMSSD (P = 0.008), normalised low-frequency power (P = 0.016) and natural logarithm of high-frequency power (P = 0.012). Following high-intensity interval training, master cyclists demonstrated greater post-exercise parasympathetic reactivation compared to young cyclists, indicating that physical training at older ages has significant effects on autonomic function.

The relation of autonomic function to physical fitness in patients suffering from alcohol dependence.

PubMed

Herbsleb, Marco; Schulz, Steffen; Ostermann, Stephanie; Donath, Lars; Eisenträger, Daniela; Puta, Christian; Voss, Andreas; Gabriel, Holger W; Bär, Karl-Jürgen

2013-10-01

Reduced cardio-vascular health has been found in patients suffering from alcohol dependence. Low cardio-respiratory fitness is an independent predictor of cardio-vascular disease. We investigated physical fitness in 22 alcohol-dependent patients 10 days after acute alcohol withdrawal and compared results with matched controls. The standardized 6-min walk test (6 MWT) was used to analyze the relationship of autonomic dysfunction and physical fitness. Ventilatory indices and gas exchanges were assessed using a portable spiroergometric system while heart rate recordings were obtained separately. We calculated walking distance, indices of heart rate variability and efficiency parameters of heart rate and breathing. In addition, levels of exhaled carbon monoxide were measured in all participants to account for differences in smoking behaviour. Multivariate analyses of variance (MANOVA) were performed to investigate differences between patients and controls with regard to autonomic and efficiency parameters. Patients walked a significantly shorter distance in comparison to healthy subjects during the 6 MWT. Significantly decreased heart rate variability was observed before and after the test in patients when compared to controls, while no such difference was observed during exercise. The efficiency parameters indicated significantly reduced efficiency in physiological regulation when the obtained parameters were normalized to the distance. The 6 MWT is an easily applied instrument to measure physical fitness in alcohol dependent patients. It can also be used during exercise interventions. Reduced physical fitness, as observed in our study, might partly be caused by autonomic dysfunction, leading to less efficient regulation of physiological processes during exercise. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Sympathetic nerve dysfunction is common in patients with chronic intestinal pseudo-obstruction.

PubMed

Mattsson, Tomas; Roos, Robert; Sundkvist, Göran; Valind, Sven; Ohlsson, Bodil

2008-02-01

To clarify whether disturbances in the autonomic nervous system, reflected in abnormal cardiovascular reflexes, could explain symptoms of impaired heat regulation in patients with intestinal pseudo-obstruction. Chronic intestinal pseudo-obstruction is a clinical syndrome characterized by diffuse, unspecific gastrointestinal symptoms due to damage to the enteric nervous system or the smooth muscle cells. These patients often complain of excessive sweating or feeling cold, suggesting disturbances in the autonomic nervous system. Earlier studies have pointed to a coexistence of autonomic disturbances in the enteric and cardiovascular nervous system. Thirteen consecutive patients (age range 23 to 79, mean 44 y) fulfilling the criteria for chronic intestinal pseudo-obstruction were investigated. Six of them complained of sweating or a feeling of cold. Examination of autonomic reflexes included heart rate variation to deep-breathing (expiration/inspiration index), heart rate reaction to tilt (acceleration index, brake index), and vasoconstriction (VAC) due to indirect cooling by laser doppler (VAC-index; high index indicates impaired VAC). Test results in patients were compared with healthy individuals. Patients had significantly higher (more abnormal) median VAC-index compared with healthy controls [1.79 (interquartile ranges 1.89) vs. 0.08 (interquartile ranges 1.29); P=0.0007]. However, symptoms of impaired heat regulation were not related to the VAC-index. There were no differences in expiration/inspiration, acceleration index, or brake index between patients and controls. The patients with severe gastrointestinal dysmotility showed impaired sympathetic nerve function which, however, did not seem to be associated with symptoms of impaired heat regulation.

Validation of Spectral Analysis as a Noninvasive Tool to Assess Autonomic Regulation of Cardiovascular Function

NASA Technical Reports Server (NTRS)

Knapp, Charles F.; Evans, Joyce M.

1996-01-01

A major focus of our program has been to develop a sensitive noninvasive procedure to quantify early weightlessness-induced changes in cardiovascular function or potential dysfunction. Forty studies of healthy young volunteers (10 men and 10 women, each studied twice) were conducted to determine changes in the sympatho-vagal balance of autonomic control of cardiovascular regulation during graded headward and footward blood volume shifts. Changes in sympatho-vagal balance were classified by changes in the mean levels and spectral content of cardiovascular variables and verified by changes in circulating levels of catecholamines and pancreatic polypeptide. Possible shifts in intra/extravascular fluid were assessed from changes in hematocrit and plasma mass density while changes in the stimulus to regulate plasma volume were determined from Plasma Renin Activity (PRA). Autonomic blockade was used to unmask the relative contribution of sympathetic and parasympathetic efferent influences in response to 10 min each of 0, 20 and 40 mmHg Lower Body Negative Pressure (LBNP) and 15 and 30 mmHg Positive Pressure (LBPP). The combination of muscarinic blockade with graded LBNP and LBPP was used to evoke graded increases and decreases in sympathetic activity without parasympathetic contributions. The combination of beta blockade with graded LBNP and LBPP was used to produce graded increases and decreases in parasympathetic activity without beta sympathetic contributions. Finally, a combination of both beta and muscarinic blockades with LBNP and LBPP was used to determine the contribution from other, primarily alpha adrenergic, sources. Mean values, spectral analyses and time frequency analysis of R-R interval (HR), Arterial Pressure (AP), peripheral blood flow (RF), Stroke Volume (SV) and peripheral resistance (TPR) were performed for all phases of the study. Skin blood Flow (SF) was also measured in other studies and similarly analyzed. Spectra were examined for changes in three frequency regions (low 0.006 - 0.005 Hz (LF), mid 0.05 - 0.15 Hz (W), and high 0.15 - 0.45 Hz (EF)). The primary objective of the study was to indicate which changes in the mean values and/or spectra of cardiovascular variables consistently correlated with changes in sympatho-vagal balance in response to headward and footward fluid shifts. A secondaey objective was to quantify the vascular and extravascular fluid shifts evoked by LBNP and LBPP. The principal hypothesis being tested was that headward fluid shifts would evoke an increase in parasympathetic activity and footward fluid shifts would evoke an increase in sympathetic activity both of which would be detected by spectral analysis and verified by circulating hormones. Hematocrit (HCT), plasma mass density and plasma renin activity increased with muscarinic blockade and with LBNP, a response indicative of a plasma shift to extravascular spaces. Beta blockade alone or after muscarinic blockade had no effect on HCT or plasma mass density. With respect to intravascular fluid volume distribution, LBNP and LBPP produced sufficient upper body vascular fluid shifts to evoke appropriate autonomic regulatory responses.

Abnormal cardiovascular response to exercise in hypertension: contribution of neural factors.

PubMed

Mitchell, Jere H

2017-06-01

During both dynamic (e.g., endurance) and static (e.g., strength) exercise there are exaggerated cardiovascular responses in hypertension. This includes greater increases in blood pressure, heart rate, and efferent sympathetic nerve activity than in normal controls. Two of the known neural factors that contribute to this abnormal cardiovascular response are the exercise pressor reflex (EPR) and functional sympatholysis. The EPR originates in contracting skeletal muscle and reflexly increases sympathetic efferent nerve activity to the heart and blood vessels as well as decreases parasympathetic efferent nerve activity to the heart. These changes in autonomic nerve activity cause an increase in blood pressure, heart rate, left ventricular contractility, and vasoconstriction in the arterial tree. However, arterial vessels in the contracting skeletal muscle have a markedly diminished vasoconstrictor response. The markedly diminished vasoconstriction in contracting skeletal muscle has been termed functional sympatholysis. It has been shown in hypertension that there is an enhanced EPR, including both its mechanoreflex and metaboreflex components, and an impaired functional sympatholysis. These conditions set up a positive feedback or vicious cycle situation that causes a progressively greater decrease in the blood flow to the exercising muscle. Thus these two neural mechanisms contribute significantly to the abnormal cardiovascular response to exercise in hypertension. In addition, exercise training in hypertension decreases the enhanced EPR, including both mechanoreflex and metaboreflex function, and improves the impaired functional sympatholysis. These two changes, caused by exercise training, improve the muscle blood flow to exercising muscle and cause a more normal cardiovascular response to exercise in hypertension. Copyright © 2017 the American Physiological Society.

Acupuncture Effects on Cardiac Functions Measured by Cardiac Magnetic Resonance Imaging in a Feline Model

PubMed Central

Lin, Jen-Hsou; Shih, Chen-Haw; Kaphle, Krishna; Wu, Leang-Shin; Tseng, Weng-Yih; Chiu, Jen-Hwey; Lee, Tzu-chi

2010-01-01

The usefulness of acupuncture (AP) as a complementary and/or alternative therapy in animals is well established but more research is needed on its clinical efficacy relative to conventional therapy, and on the underlying mechanisms of the effects of AP. Cardiac magnetic resonance imaging (CMRI), an important tool in monitoring cardiovascular diseases, provides a reliable method to monitor the effects of AP on the cardiovascular system. This controlled experiment monitored the effect electro-acupuncture (EA) at bilateral acupoint Neiguan (PC6) on recovery time after ketamine/xylazine cocktail anesthesia in healthy cats. The CMRI data established the basic feline cardiac function index (CFI), including cardiac output and major vessel velocity. To evaluate the effect of EA on the functions of the autonomic nervous and cardiovascular systems, heart rate, respiration rate, electrocardiogram and pulse rate were also measured. Ketamine/xylazine cocktail anesthesia caused a transient hypertension in the cats; EA inhibited this anesthetic-induced hypertension and shortened the post-anesthesia recovery time. Our data support existing knowledge on the cardiovascular benefits of EA at PC6, and also provide strong evidence for the combination of anesthesia and EA to shorten post-anesthesia recovery time and counter the negative effects of anesthetics on cardiac physiology. PMID:18955311

Long-term moderate exercise accelerates the recovery of stress-evoked cardiovascular responses.

PubMed

Hsu, Yuan-Chang; Tsai, Sheng-Feng; Yu, Lung; Chuang, Jih-Ing; Wu, Fong-Sen; Jen, Chauying J; Kuo, Yu-Min

2016-01-01

Psychological stress is an important global health problem. It is well documented that stress increases the incidences of various cardiovascular disorders. Regular exercise is known to reduce resting blood pressure (BP) and heart rate (HR). This study was designed to clarify the effects of long-term exercise on stress-evoked cardiovascular responses and to emphasize post-stress recovery effects. Male Wistar rats underwent 8 weeks of moderate treadmill training, with cardiovascular responses, autonomic nervous system activities and local Fos reactivity changes in the cardiovascular regulation center were monitored before, during and after immobilization stress. A spectral analysis of cardiovascular parameters was used to examine autonomic nervous activities. We found that long-term exercise (i) lowered resting BP, HR and sympathetic activity, but increased resting parasympathetic activity and baroreflex sensitivity (BRS); (ii) accelerated post-stress recovery of stress-evoked cardiovascular and sympathetic responses along with increased BRS and (iii) accelerated post-stress recovery of stress-evoked neuron activations in the paraventricular nucleus, but delayed it in the nucleus of the tractus solitarius. We conclude that, in rats, long-term exercise accelerated recovery of stress-evoked cardiovascular responses differentially altering hypothalamic and medullar neuron activities.

Nine months in space: effects on human autonomic cardiovascular regulation.

PubMed

Cooke, W H; Ames JE, I V; Crossman, A A; Cox, J F; Kuusela, T A; Tahvanainen, K U; Moon, L B; Drescher, J; Baisch, F J; Mano, T; Levine, B D; Blomqvist, C G; Eckberg, D L

2000-09-01

We studied three Russian cosmonauts to better understand how long-term exposure to microgravity affects autonomic cardiovascular control. We recorded the electrocardiogram, finger photoplethysmographic pressure, and respiratory flow before, during, and after two 9-mo missions to the Russian space station Mir. Measurements were made during four modes of breathing: 1) uncontrolled spontaneous breathing; 2) stepwise breathing at six different frequencies; 3) fixed-frequency breathing; and 4) random-frequency breathing. R wave-to-R wave (R-R) interval standard deviations decreased in all and respiratory frequency R-R interval spectral power decreased in two cosmonauts in space. Two weeks after the cosmonauts returned to Earth, R-R interval spectral power was decreased, and systolic pressure spectral power was increased in all. The transfer function between systolic pressures and R-R intervals was reduced in-flight, was reduced further the day after landing, and had not returned to preflight levels by 14 days after landing. Our results suggest that long-duration spaceflight reduces vagal-cardiac nerve traffic and decreases vagal baroreflex gain and that these changes may persist as long as 2 wk after return to Earth.

Physical Activity and Heart Rate Variability in Older Adults: The Cardiovascular Health Study

PubMed Central

Soares-Miranda, Luisa; Sattelmair, Jacob; Chaves, Paulo; Duncan, Glen; Siscovick, David S; Stein, Phyllis K; Mozaffarian, Dariush

2014-01-01

Background Cardiac mortality and electrophysiologic dysfunction both increase with age. Heart rate variability (HRV) provides indices of autonomic function and electrophysiology that are associated with cardiac risk. How habitual physical activity (PA) among older adults prospectively relates to HRV, including nonlinear indices of erratic sinus patterns, is not established. We hypothesized that increasing levels of both total leisure-time activity and walking would be prospectively associated with more favorable time-domain, frequency-domain, and nonlinear HRV measures in older adults. Methods and Results We evaluated serial longitudinal measures of both PA and 24-hour Holter HRV over 5 years among 985 older US adults in the community-based Cardiovascular Health Study. After multivariable adjustment, greater total leisure-time activity, walking distance, and walking pace were each prospectively associated with specific, more favorable HRV indices, including higher 24-hour standard-deviation-of-all-normal-to-normal-intervals (SDNN, p-trend=0.009, 0.02, 0.06, respectively) and ultra-low-frequency-power (p-trend=0.02, 0.008, 0.16, respectively). Greater walking pace was also associated with higher short-term-fractal-scaling-exponent (p-trend=0.003) and lower Poincare ratio (p-trend=0.02), markers of less erratic sinus patterns. Conclusions Greater total leisure-time activity, as well as walking alone, were prospectively associated with more favorable and specific indices of autonomic function in older adults, including several suggestive of more normal circadian fluctuations and less erratic sinoatrial firing. Our results suggest potential mechanisms that might contribute to lower cardiovascular mortality with habitual PA later in life. PMID:24799513

Orthostatic Hypotension: A Practical Approach to Investigation and Management.

PubMed

Arnold, Amy C; Raj, Satish R

2017-12-01

The maintenance of blood pressure upon the assumption of upright posture depends on rapid cardiovascular adaptations driven primarily by the autonomic nervous system. Failure of these compensatory mechanisms can result in orthostatic hypotension (OH), defined as sustained reduction in systolic blood pressure > 20 mm Hg or diastolic blood pressure > 10 mm Hg within 3 minutes of standing or > 60° head-up tilt. OH is a common finding, particularly in elderly populations, associated with cardiovascular and cerebrovascular morbidity and mortality. Therefore, it is important to identify OH in the clinical setting. The detection of OH requires blood pressure measurements in the supine and standing positions. A more practical approach in clinics might be measurement of seated and standing blood pressure, but this can produce smaller depressor responses because of reduced gravitational stress. Heart rate responses to standing should be concomitantly measured to assess integrity of baroreflex function. Patients with OH can present with symptoms of cerebral hypoperfusion on standing predisposing to syncope and falls; however, many patients are asymptomatic. When the diagnosis of OH is established, it is important to document potentially deleterious medications and comorbidities and to assess for neurogenic autonomic impairment to establish underlying causes. Treatment should be initiated in a structured and stepwise approach starting with nonpharmacological interventions (eg, lifestyle modifications and physical countermanoeuvres), and adding pharmacological interventions as needed in patients with severe OH (eg, midodrine, droxidopa, fludrocortisone). The treatment goal in OH should be to improve symptoms and functional status, and not to target arbitrary blood pressure values. Copyright © 2017 Canadian Cardiovascular Society. Published by Elsevier Inc. All rights reserved.

Favorable effects of carotid endarterectomy on baroreflex sensitivity and cardiovascular neural modulation: a 4-month follow-up.

PubMed

Dalla Vecchia, Laura; Barbic, Franca; Galli, Andrea; Pisacreta, Massimo; Gornati, Rosella; Porretta, Tiziano; Porta, Alberto; Furlan, Raffaello

2013-06-15

Carotid surgery variably modifies carotid afferent innervation, thus affecting arterial baroreceptor sensitivity. Low arterial baroreflex sensitivity is a well-known independent risk factor for cardiovascular diseases. The aim of this study was to assess the 4-mo effects of carotid endarterectomy (CEA) on arterial baroreceptor sensitivity and cardiovascular autonomic profile in patients with unilateral carotid stenosis. We enrolled 20 patients (72 ± 8 yr) with unilateral >70% carotid stenosis. ECG, beat-by-beat blood pressure, and respiration were continuously recorded before and 126 ± 9 days after CEA, at rest and during a 75° head-up tilt. Both pharmacological (modified Oxford technique, BRS) and spontaneous (index α, spectral analysis) arterial baroreflex sensitivity were assessed. Cardiovascular autonomic profile was evaluated by plasma catecholamines and spectral indexes of cardiac sympathovagal modulation [low-frequency R-R interval (LFRR), low frequency-to high frequency ratio (LF/HF), high-frequency R-R interval (HFRR)] and sympathetic vasomotor control [low-frequency systolic arterial pressure (LFSAP)] obtained from heart rate and SAP variability. After CEA, both the index α and BRS were higher (P < 0.02) at rest. SAP variance decreased both at rest and during tilt (P < 0.02). Before surgery, tilt did not modify the autonomic profile compared with baseline. After CEA, tilt increased LF/HF and LFSAP and reduced HFRR compared with rest (P < 0.02). Four months after CEA was performed, arterial baroreflex sensitivity was enhanced. Accordingly, the patients' autonomic profile had shifted toward reduced cardiac and vascular sympathetic activation and enhanced cardiac vagal activity. The capability to increase cardiovascular sympathetic activation in response to orthostasis was restored. Baroreceptor sensitivity improvement might play an additional role in the more favorable outcome observed in patients after carotid surgery.

Systemic Sympathoexcitation Was Associated with Paraventricular Hypothalamic Phosphorylation of Synaptic CaMKIIα and MAPK/ErK.

PubMed

Ogundele, Olalekan M; Rosa, Fernando A; Dharmakumar, Rohan; Lee, Charles C; Francis, Joseph

2017-01-01

Systemic administration of adrenergic agonist (Isoproterenol; ISOP) is known to facilitate cardiovascular changes associated with heart failure through an upregulation of cardiac toll-like receptor 4 (TLR4). Furthermore, previous studies have shown that cardiac tissue-specific deletion of TLR4 protects the heart against such damage. Since the autonomic regulation of systemic cardiovascular function originates from pre-autonomic sympathetic centers in the brain, it is unclear how a systemically driven sympathetic change may affect the pre-autonomic paraventricular hypothalamic nuclei (PVN) TLR4 expression. Here, we examined how change in PVN TLR4 was associated with alterations in the neurochemical cytoarchitecture of the PVN in systemic adrenergic activation. After 48 h of intraperitoneal 150 mg/kg ISOP treatment, there was a change in PVN CaMKIIα and MAPK/ErK expression, and an increase in TLR4 in expression. This was seen as an increase in p-MAPK/ErK, and a decrease in synaptic CaMKIIα expression in the PVN ( p < 0.01) of ISOP treated mice. Furthermore, there was an upregulation of vesicular glutamate transporter (VGLUT 2; p < 0.01) and a decreased expression of GABA in the PVN of Isoproterenol (ISOP) treated WT mice ( p < 0.01). However, after a PVN-specific knockdown of TLR4, the effect of systemic administration of ISOP was attenuated, as indicated by a decrease in p-MAPK/ErK ( p < 0.01) and upregulation of CaMKIIα ( p < 0.05). Additionally, loss of inhibitory function was averted while VGLUT2 expression decreased when compared with the ISOP treated wild type mice and the control. Taken together, the outcome of this study showed that systemic adrenergic activation may alter the expression, and phosphorylation of preautonomic MAPK/ErK and CaMKIIα downstream of TLR4. As such, by outlining the roles of these kinases in synaptic function, we have identified the significance of neural TLR4 in the progression, and attenuation of synaptic changes in the pre-autonomic sympathetic centers.

Consensus statement on the definition of neurogenic supine hypertension in cardiovascular autonomic failure by the American Autonomic Society (AAS) and the European Federation of Autonomic Societies (EFAS) : Endorsed by the European Academy of Neurology (EAN) and the European Society of Hypertension (ESH).

PubMed

Fanciulli, Alessandra; Jordan, Jens; Biaggioni, Italo; Calandra-Buonaura, Giovanna; Cheshire, William P; Cortelli, Pietro; Eschlboeck, Sabine; Grassi, Guido; Hilz, Max J; Kaufmann, Horacio; Lahrmann, Heinz; Mancia, Giuseppe; Mayer, Gert; Norcliffe-Kaufmann, Lucy; Pavy-Le Traon, Anne; Raj, Satish R; Robertson, David; Rocha, Isabel; Struhal, Walter; Thijs, Roland; Tsioufis, Konstantinos P; van Dijk, J Gert; Wenning, Gregor K

2018-05-15

Patients suffering from cardiovascular autonomic failure often develop neurogenic supine hypertension (nSH), i.e., high blood pressure (BP) in the supine position, which falls in the upright position owing to impaired autonomic regulation. A committee was formed to reach consensus among experts on the definition and diagnosis of nSH in the context of cardiovascular autonomic failure. As a first and preparatory step, a systematic search of PubMed-indexed literature on nSH up to January 2017 was performed. Available evidence derived from this search was discussed in a consensus expert round table meeting in Innsbruck on February 16, 2017. Statements originating from this meeting were further discussed by representatives of the American Autonomic Society and the European Federation of Autonomic Societies and are summarized in the document presented here. The final version received the endorsement of the European Academy of Neurology and the European Society of Hypertension. In patients with neurogenic orthostatic hypotension, nSH is defined as systolic BP ≥ 140 mmHg and/or diastolic BP ≥ 90 mmHg, measured after at least 5 min of rest in the supine position. Three severity degrees are recommended: mild, moderate and severe. nSH may also be present during nocturnal sleep, with reduced-dipping, non-dipping or rising nocturnal BP profiles with respect to mean daytime BP values. Home BP monitoring and 24-h-ambulatory BP monitoring provide relevant information for a customized clinical management. The establishment of expert-based criteria to define nSH should standardize diagnosis and allow a better understanding of its epidemiology, prognosis and, ultimately, treatment.

Understanding changes in cardiovascular pathophysiology.

PubMed

Chummun, Harry

Cardiovascular pathophysiological changes, such as hypertension and enlarged ventricles, reflect the altered functions of the heart and its circulation during ill-health. This article examines the normal and altered anatomy of the cardiac valves, the contractile elements and enzymes of the myocardium, the significance of the different factors associated with cardiac output, and the role of the autonomic nervous system in the heart beat. It also explores how certain diseases alter these functions and result in cardiac symptoms. Nurses can benefit from knowledge of these specific changes, for example, by being able to ask relevant questions in order to ascertain the nature of a patients condition, by being able to take an effective patient history and by being able to read diagnostic results, such as electrocardiograms and cardiac enzyme results. All this will help nurses to promote sound cardiac care based on a physiological rationale.

Cardiovascular actions of L-cysteine and L-cysteine sulfinic acid in the nucleus tractus solitarius of the rat.

PubMed

Takemoto, Yumi

2014-07-01

The sulfur-containing excitatory amino acid (EAA) L-cysteine sulfinic acid (CSA), a neurotransmitter candidate, is endogenously synthesized from L-cysteine (Cys). Exogenous Cys administration into the brain produces cardiovascular effects; these effects likely occur via synaptic stimulation of central nervous system (CNS) neurons that regulate peripheral cardiovascular function. However, the cardiovascular responses produced by CNS Cys administration could result from CSA biosynthesized in synapse. The present study examined the role of CSA in Cys-induced cardiovascular responses within the nucleus tractus solitarius (NTS) of anesthetized rats. The NTS receives input from various visceral afferents that gate autonomic reflexes, including cardiovascular reflexes. Within the NTS, both Cys and CSA microinjections produced decrease responses in arterial blood pressure and heart rate that were similar to those produced by L-glutamate. Co-injection of the ionotropic EAA receptor antagonist kynurenic acid abolished Cys-, but not CSA-, induced cardiovascular responses. This finding suggests that only Cys-induced cardiovascular responses are mediated by kynurenate-sensitive receptors. This study provides the first demonstration that Cys- and CSA-induced cardiovascular responses occur via different mechanisms in the NTS of rats. Further, this study also indicates that Cys-induced cardiovascular responses do not occur via CSA. Thus, within the NTS, endogenous Cys and/or CSA might be involved in cardiovascular regulation.

Left atrial phasic function and heart rate variability in asymptomatic diabetic patients.

PubMed

Tadic, Marijana; Vukomanovic, Vladan; Cuspidi, Cesare; Suzic-Lazic, Jelena; Stanisavljevic, Dejana; Celic, Vera

2017-03-01

We evaluated left atrial (LA) phasic function and heart rate variability (HRV) in asymptomatic diabetic patients, and the relationship between HRV indices and LA phasic function assessed by volumes and speckle tracking imaging. This cross-sectional study included 55 asymptomatic patients with type 2 diabetes and 50 healthy controls without cardiovascular risk factors. All study subjects underwent laboratory analyses, complete two-dimensional echocardiography examination (2DE) and 24-h Holter monitoring. Maximum, minimum LA and pre-A LA volumes and volume indexes are significantly higher in diabetic patients. Total and passive LA emptying fractions (EF), representing the LA reservoir and conduit function, are significantly lower in diabetic subjects. Active LA EF, the parameter of the LA booster pump function, is compensatory increased in diabetic patients. Similar results were obtained by 2DE strain analysis. Cardiac autonomic function, assessed by HRV, is significantly deteriorated in diabetic patients. Time and frequency-domain HRV measures are significantly lower in diabetic subjects than in controls. HbA1c, LV mass index and HRV are associated with total LA EF and longitudinal LA strain independently of age, body mass index and LV diastolic function in the whole study population. LA phasic function and cardiac autonomic nervous system assessed by HRV are impacted by diabetes. HbA1c and HRV are independently associated with LA reservoir function evaluated by volumetric and strain methods in the whole study population. This study emphasizes the importance of determination of LA function and HRV as important markers of preclinical cardiac damage and autonomic function impairment in diabetic patients.

Whole-body cryostimulation increases parasympathetic outflow and decreases core body temperature.

PubMed

Zalewski, Pawel; Bitner, Anna; Słomko, Joanna; Szrajda, Justyna; Klawe, Jacek J; Tafil-Klawe, Malgorzata; Newton, Julia L

2014-10-01

The cardiovascular, autonomic and thermal response to whole-body cryostimulation exposure are not completely known. Thus the aim of this study was to evaluate objectively and noninvasively autonomic and thermal reactions observed after short exposure to very low temperatures. We examined 25 healthy men with mean age 30.1 ± 3.7 years and comparable anthropomorphical characteristic. Each subject was exposed to cryotherapeutic temperatures in a cryogenic chamber for 3 min (approx. -120 °C). The cardiovascular and autonomic parameters were measured noninvasively with Task Force Monitor. The changes in core body temperature were determined with the Vital Sense telemetric measurement system. Results show that 3 min to cryotherapeutic temperatures causes significant changes in autonomic balance which are induced by peripheral and central blood volume changes. Cryostimulation also induced changes in core body temperature, maximum drop of core temperature was observed 50-60 min after the stimulation. Autonomic and thermal reactions to cryostimulation were observed up to 6 h after the exposure and were not harmful for examined subjects. Copyright © 2014 Elsevier Ltd. All rights reserved.

Rotigotine Improves Abnormal Circadian Rhythm of Blood Pressure in Parkinson's Disease.

PubMed

Oka, Hisayoshi; Nakahara, Atuso; Umehara, Tadashi

2018-05-15

Cardiovascular autonomic failure is commonly associated with Parkinson's disease (PD), affecting the daily lives of patients. Rotigotine was recently reported not to influence cardiovascular autonomic responses in contrast to other dopaminergic drugs. The effect of rotigotine on daily blood pressure (BP) fluctuations might reflect autonomic failure in patients with PD. Twenty-five PD patients who were receiving rotigotine and 12 patients not receiving rotigotine were recruited. Systolic BP during the daytime and nighttime was measured by 24-h BP monitoring at an interval of 2 years. The patients were divided into 3 groups according to the BP fluctuation type: dippers (nocturnal fall in BP ≥10%), non-dippers (0-10%), and risers (< 0%). The time course of BP was compared between the patients given rotigotine and those not given rotigotine. Among the 25 patients who received rotigotine, the BP type worsened in 2 patients, was unchanged in 16 patients, and improved in 7 patients. Among the 12 patients who were not receiving rotigotine, the BP type worsened in 5 patients, was unchanged in 4 patients, and improved only in 3 patients (p = 0.042). Rotigotine improves the abnormal circadian rhythm of BP in patients with PD. Rotigotine was suggested to have favorable effects on cardiovascular autonomic responses and circadian rhythm in patients with PD. © 2018 S. Karger AG, Basel.

Responses of Caudal Vestibular Nucleus Neurons of Conscious Cats to Rotations in Vertical Planes, Before and After a Bilateral Vestibular Neurectomy

PubMed Central

Miller, D. M.; Cotter, L. A.; Gandhi, N. J.; Schor, R. H.; Cass, S. P.; Huff, N. O.; Raj, S. G.; Shulman, J. A; Yates, B. J.

2008-01-01

Although many previous experiments have considered the responses of vestibular nucleus neurons to rotations and translations of the head, little data are available regarding cells in the caudalmost portions of the vestibular nuclei (CVN), which mediate vestibulo-autonomic responses among other functions. This study examined the responses of CVN neurons of conscious cats to rotations in vertical planes, both before and after a bilateral vestibular neurectomy. None of the units included in the data sample had eye movement-related activity. In labyrinth-intact animals, some CVN neurons (22%) exhibited graviceptive responses consistent with inputs from otolith organs, but most (55%) had dynamic responses with phases synchronized with stimulus velocity. Furthermore, the large majority of CVN neurons had response vector orientations that were aligned either near the roll or vertical canal planes, and only 18% of cells were preferentially activated by pitch rotations. Sustained head-up rotations of the body provide challenges to the cardiovascular system and breathing, and thus the response dynamics of the large majority of CVN neurons were dissimilar to those of posturally-related autonomic reflexes. These data suggest that vestibular influences on autonomic control mediated by the CVN are more complex than previously envisioned, and likely involve considerable processing and integration of signals by brainstem regions involved in cardiovascular and respiratory regulation. Following a bilateral vestibular neurectomy, CVN neurons regained spontaneous activity within 24 h, and a very few neurons (<10%) responded to vertical tilts <15° in amplitude. These findings indicate that nonlabyrinthine inputs are likely important in sustaining the activity of CVN neurons; thus, these inputs may play a role in functional recovery following peripheral vestibular lesions. PMID:18368395

Low arterial compliance in young African-American males.

PubMed

Zion, Adrienne S; Bond, Vernon; Adams, Richard G; Williams, Deborah; Fullilove, Robert E; Sloan, Richard P; Bartels, Matthew N; Downey, John A; De Meersman, Ronald E

2003-08-01

Hypertension remains a common public health challenge because of its prevalence and increase in co-morbid cardiovascular diseases. Black males have disproportionate pathophysiological consequences of hypertension compared with any other group in the United States. Alterations in arterial wall compliance and autonomic function often precede the onset of disease. Accordingly, our purpose was to investigate whether differences exist in arterial compliance and autonomic function between young, healthy African-American males without evidence of hypertension and age- and gender-matched non-African-American males. All procedures were carried out noninvasively following rest. Arterial compliance was calculated as the integrated area starting at the well-defined nadir of the incisura of the dicrotic notch to the end of diastole of the radial artery pulse wave. Power spectral analysis of heart rate and blood pressure variability provided distributions representative of parasympathetic and sympathetic modulations and sympathovagal balance. Baroreflex sensitivity (BRS) was calculated using the sequence method. Thirty-two African-American and twenty-nine non-African-American males were comparable in anthropometrics and negative family history of hypertension. t-Tests revealed lower arterial compliance (5.8 +/- 2.4 vs. 8.6 +/- 4.0 mmHg. s; P = 0.0017), parasympathetic modulation (8.9 +/- 1.1 vs. 9.7 +/- 1.1 ln ms2; P = 0.0063), and BRS (13.7 +/- 7.3 vs. 21.1 +/- 8.5 ms/mmHg; P = 0.0007) and higher sympathovagal balance (2.9 +/- 3.2 vs. 1.5 +/- 1.1; P = 0.03) in the African-American group. In summary, differences exist in arterial compliance and autonomic balance in African-American males. These alterations may be antecedent markers of disease and valuable in the detection of degenerative cardiovascular processes in individuals at risk.

Evaluation of autonomic functions of patients with multiple system atrophy and Parkinson's disease by head-up tilt test.

PubMed

Watano, Chikako; Shiota, Yuri; Onoda, Keiichi; Sheikh, Abdullah Md; Mishima, Seiji; Nitta, Eri; Yano, Shozo; Yamaguchi, Shuhei; Nagai, Atsushi

2018-02-01

The aim of this study was to evaluate the autonomic neural function in Parkinson's disease (PD) and multiple system atrophy (MSA) with head-up tilt test and spectral analysis of cardiovascular parameters. This study included 15 patients with MSA, 15 patients with PD, and 29 healthy control (HC) subjects. High frequency power of the RR interval (RR-HF), the ratio of low frequency power of RR interval to RR-HF (RR-LF/HF) and LF power of systolic BP were used to evaluate parasympathetic, cardiac sympathetic and vasomotor sympathetic functions, respectively. Both patients with PD and MSA showed orthostatic hypotension and lower parasympathetic function (RR-HF) at tilt position as compared to HC subjects. Cardiac sympathetic function (RR-LF/HF) was significantly high in patients with PD than MSA at supine position. RR-LF/HF tended to increase in MSA and HC, but decreased in PD by tilting. Consequently, the change of the ratio due to tilting (ΔRR-LF/HF) was significantly lower in patients with PD than in HC subjects. Further analysis showed that compared to mild stage of PD, RR-LF/HF at the supine position was significantly higher in advanced stage. By tilting, it was increased in mild stage and decreased in the advanced stage of PD, causing ΔRR-LF/HF to decrease significantly in the advanced stage. Thus, we demonstrated that spectral analysis of cardiovascular parameters is useful to identify sympathetic and parasympathetic disorders in MSA and PD. High cardiac sympathetic function at the supine position, and its reduction by tilting might be a characteristic feature of PD, especially in the advanced stage.

Role of the autonomic nervous system and baroreflex in stress-evoked cardiovascular responses in rats.

PubMed

Dos Reis, Daniel Gustavo; Fortaleza, Eduardo Albino Trindade; Tavares, Rodrigo Fiacadori; Corrêa, Fernando Morgan Aguiar

2014-07-01

Restraint stress (RS) is an experimental model to study stress-related cardiovascular responses, characterized by sustained pressor and tachycardiac responses. We used pharmacologic and surgical procedures to investigate the role played by sympathetic nervous system (SNS) and parasympathetic nervous system (PSNS) in the mediation of stress-evoked cardiovascular responses. Ganglionic blockade with pentolinium significantly reduced RS-evoked pressor and tachycardiac responses. Intravenous treatment with homatropine methyl bromide did not affect the pressor response but increased tachycardia. Pretreatment with prazosin reduced the pressor and increased the tachycardiac response. Pretreatment with atenolol did not affect the pressor response but reduced tachycardia. The combined treatment with atenolol and prazosin reduced both pressor and tachycardiac responses. Adrenal demedullation reduced the pressor response without affecting tachycardia. Sinoaortic denervation increased pressor and tachycardiac responses. The results indicate that: (1) the RS-evoked cardiovascular response is mediated by the autonomic nervous system without an important involvement of humoral factors; (2) hypertension results primarily from sympathovascular and sympathoadrenal activation, without a significant involvement of the cardiac sympathetic component (CSNS); (3) the abrupt initial peak in the hypertensive response to restraint is sympathovascular-mediated, whereas the less intense but sustained hypertensive response observed throughout the remaining restraint session is mainly mediated by sympathoadrenal activation and epinephrine release; (4) tachycardia results from CSNS activation, and not from PSNS inhibition; (5) RS evokes simultaneous CSNS and PSNS activation, and heart rate changes are a vector of both influences; (6) the baroreflex is functional during restraint, and modulates both the vascular and cardiac responses to restraint.

Heart rate variability.

PubMed

Cygankiewicz, Iwona; Zareba, Wojciech

2013-01-01

Heart rate variability (HRV) provides indirect insight into autonomic nervous system tone, and has a well-established role as a marker of cardiovascular risk. Recent decades brought an increasing interest in HRV assessment as a diagnostic tool in detection of autonomic impairment, and prediction of prognosis in several neurological disorders. Both bedside analysis of simple markers of HRV, as well as more sophisticated HRV analyses including time, frequency domain and nonlinear analysis have been proven to detect early autonomic involvement in several neurological disorders. Furthermore, altered HRV parameters were shown to be related with cardiovascular risk, including sudden cardiac risk, in patients with neurological diseases. This chapter aims to review clinical and prognostic application of HRV analysis in diabetes, stroke, multiple sclerosis, muscular dystrophies, Parkinson's disease and epilepsy. © 2013 Elsevier B.V. All rights reserved.

Cardiovascular and temperature changes in spinal cord injured rats at rest and during autonomic dysreflexia

PubMed Central

Laird, A S; Carrive, P; Waite, P M E

2006-01-01

In patients with high spinal cord injuries autonomic dysfunction can be dangerous, leading to medical complications such as postural hypotension, autonomic dysreflexia and temperature disturbance. While animal models have been developed to study autonomic dysreflexia, associated temperature changes have not been documented. Our aim here was to use radiotelemetry and infrared thermography in rodents to record the development of cardiovascular and skin temperature changes following complete T4 transection. In adult male Wistar rats (n = 5), responses were assessed prior to spinal cord injury (intact) and for 6 weeks following injury. Statistical analysis by a repeated-measure ANOVA revealed that following spinal cord injury (SCI), rats exhibited decreased mean arterial pressure (MAP, average decrease of 26 mmHg; P < 0.035) and elevated heart rate (HR, average increase of 65 bpm, P < 0.035) at rest. The basal core body temperature following SCI was also significantly lower than intact levels (−0.9°C; P < 0.0035). Associated with this decreased basal core temperature following SCI was an increased skin temperature of the mid-tail and hindpaw (+5.6 and +4.0°C, respectively; P < 0.0003) consistent with decreased cutaneous vasoconstrictor tone. Autonomic dysreflexia, in response to a 1 min colorectal distension (25 mmHg), was fully developed by 4 weeks after spinal cord transection, producing increases in MAP greater than 25 mmHg (P < 0.0003). In contrast to the tachycardia seen in intact animals in response to colorectal distension, SCI animals exhibited bradycardia (P < 0.0023). During episodes of autonomic dysreflexia mid-tail surface temperature decreased (approx. −1.7°C, P < 0.012), consistent with cutaneous vasoconstriction. This is the first study to compare cardiovascular dysfunction with temperature changes following spinal cord transection in rats. PMID:16973703

Eyeball Pressure Stimulation Unveils Subtle Autonomic Cardiovascular Dysfunction in Persons with a History of Mild Traumatic Brain Injury.

PubMed

Hilz, Max J; Aurnhammer, Felix; Flanagan, Steven R; Intravooth, Tassanai; Wang, Ruihao; Hösl, Katharina M; Pauli, Elisabeth; Koehn, Julia

2015-11-15

After mild traumatic brain injury (mTBI), patients have increased long-term mortality rates, persisting even beyond 13 years. Pathophysiology is unclear. Yet, central autonomic network dysfunction may contribute to cardiovascular dysregulation and increased mortality. Purely parasympathetic cardiovascular challenge by eyeball pressure stimulation (EP), might unveil subtle autonomic dysfunction in post-mTBI patients. We investigated whether mild EP shows autonomic cardiovascular dysregulation in post-mTBI patients. In 24 patients (34 ± 12 years; 5-86 months post-injury) and 27 controls (30 ± 11 years), we monitored respiration, electrocardiographic RR intervals (RRI), systolic and diastolic blood pressure (BPsys, BPdia) before and during 2 min of 30 mm Hg EP, applied by an ophthalmologic ocular pressure device (Okulopressor(®)). We calculated spectral powers of RRI in the mainly sympathetic low frequency (LF; 0.04-0.15 Hz) and parasympathetic high frequency (HF; 0.15-0.5 Hz) ranges, and of BP in the sympathetic LF range, the RRI-LF/HF ratio as index of the sympathetic-parasympathetic balance, normalized (nu) RRI-LF- and HF-powers, and LF- and HF-powers after natural logarithmic transformation (ln). Parameters before and during EP in post-mTBI patients and controls were compared by repeated measurement analysis of variance with post hoc analysis (p < 0.05). During EP, BPsys and BPdia increased in post-mTBI patients. Only in controls but not in post-mTBI patients, EP increased RRI-HFnu-powers and decreased RRI-LF-powers, RRI-LFnu-powers, BPsys-LF-powers, BPsys-lnLF-powers and BPdia-lnLF-powers. RRI-LF/HF ratios slightly increased in post-mTBI patients but slightly decreased in controls upon EP. Even with only mild EP, our controls showed normal EP responses and shifted sympathetic-parasympathetic balance towards parasympathetic predominance. In contrast, our post-mTBI patients could not increase parasympathetic heart rate modulation but increased BP upon EP, indicating a paradox sympathetic activation. The findings support the hypothesis that central autonomic dysfunction might contribute to an increased cardiovascular risk, even years after mTBI.

Shift work is associated with reduced heart rate variability among men but not women.

PubMed

Hulsegge, Gerben; Gupta, Nidhi; Proper, Karin I; van Lobenstein, Natasja; IJzelenberg, Wilhelmina; Hallman, David M; Holtermann, Andreas; van der Beek, Allard J

2018-05-01

Imbalance in the autonomic nervous system due to a disrupted circadian rhythm may be a cause of shift work-related cardiovascular diseases. We aimed to determine the association between shift work and cardiac autonomic activity in blue-collar workers. The study included 665 blue-collar workers aged 18-68 years in different occupations from two Danish cohort studies. Time and frequency domain parameters of heart rate variability (HRV) were measured during sleep using the Actiheart monitor, and used as markers of cardiac autonomic function. Multiple linear regression analyses were used to investigate differences in HRV between day and shift workers. Shift workers had no significantly different HRV parameters than day workers, except for a lower VLF (B: 0.21; 95% CI: -0.36-0.05). The lower VLF was only present among non-night shift workers (p < 0.05) and not among night shift workers (p > 0.05). Results differed significantly by gender (p for interaction < 0.10): among men, shift work was negatively associated with RMSSD (B: -7.83; 95% CI: -14.28-1.38), SDNN (B: -7.0; 95% CI: -12.27-1.78), VLF (B: -0.27; 95% CI: -0.46-0.09) and Total Power (B: -0.61; 95% CI: -1.20-0.03), while among women, shift work was only associated with the LF/HF ratio (B: -0.29; 95% CI: -0.54-0.03). Shift work was particularly associated with lower HRV during sleep among men. This indicates that shift work causes imbalance in the autonomic nervous system among men, which might increase their risk of cardiovascular diseases. Copyright © 2018 The Authors. Published by Elsevier B.V. All rights reserved.

Low vagally-mediated heart rate variability and increased susceptibility to ventricular arrhythmias in rats bred for high anxiety.

PubMed

Carnevali, Luca; Trombini, Mimosa; Graiani, Gallia; Madeddu, Denise; Quaini, Federico; Landgraf, Rainer; Neumann, Inga D; Nalivaiko, Eugene; Sgoifo, Andrea

2014-04-10

In humans, there is a documented association between anxiety disorders and cardiovascular disease. Putative underlying mechanisms may include an impairment of the autonomic nervous system control of cardiac function. The primary objective of the present study was to characterize cardiac autonomic modulation and susceptibility to arrhythmias in genetic lines of rats that differ largely in their anxiety level. To reach this goal, electrocardiographic recordings were performed in high-anxiety behavior (HAB, n=10) and low-anxiety behavior (LAB, n=10) rats at rest, during stressful stimuli and under autonomic pharmacological manipulations, and analyzed by means of time- and frequency-domain indexes of heart rate variability. During resting conditions, HAB rats displayed a reduced heart rate variability, mostly in terms of lower parasympathetic (vagal) modulation compared to LAB rats. In HAB rats, this relatively low cardiac vagal control was associated with smaller heart rate responsiveness to acute stressors compared to LAB counterparts. In addition, beta-adrenergic pharmacological stimulation induced a larger incidence of ventricular tachyarrhythmias in HABs compared to LABs. At sacrifice, a moderate increase in heart-body weight ratio was observed in HAB rats. We conclude that high levels of anxiety-related behavior in rats are associated with signs of i) impaired autonomic modulation of heart rate (low vagally-mediated heart rate variability), ii) poor adaptive heart rate responsiveness to stressful stimuli, iii) increased arrhythmia susceptibility, and iv) cardiac hypertrophy. These results highlight the utility of the HAB/LAB model for investigating the mechanistic basis of the comorbidity between anxiety disorders and cardiovascular disease. Copyright © 2014 Elsevier Inc. All rights reserved.

Emotional dampening in persons with elevated blood pressure: affect dysregulation and risk for hypertension.

PubMed

McCubbin, James A; Loveless, James P; Graham, Jack G; Hall, Gabrielle A; Bart, Ryan M; Moore, DeWayne D; Merritt, Marcellus M; Lane, Richard D; Thayer, Julian F

2014-02-01

Persons with higher blood pressure have emotional dampening in some contexts. This may reflect interactive changes in central nervous system control of affect and autonomic function in the early stages of hypertension development. The purpose of this study is to determine the independence of cardiovascular emotional dampening from alexithymia to better understand the role of affect dysregulation in blood pressure elevations. Ninety-six normotensives were assessed for resting systolic and diastolic (DBP) blood pressure, recognition of emotions in faces and sentences using the Perception of Affect Task (PAT), alexithymia, anxiety, and defensiveness. Resting DBP significantly predicted PAT emotion recognition accuracy in men after adjustment for age, self-reported affect, and alexithymia. Cardiovascular emotional dampening is independent of alexithymia and affect in men. Dampened emotion recognition could potentially influence interpersonal communication and psychosocial distress, thereby further contributing to BP dysregulation and increased cardiovascular risk.

Association between respiratory mechanics and autonomic function in morbid obesity.

PubMed

Sant' Anna, M; Carvalhal, R F; Carneiro, J R I; Lapa, M S; Zin, W A; Lugon, J R; Guimarães, F S

2014-01-01

This study aimed to investigate the association between respiratory mechanics and autonomic modulation in morbidly obese patients. We evaluated 10 morbidly obese subjects (BMI=52.9±11.2kg/m(2)), aged 23-58 years. Assessment of respiratory mechanics was done by the forced oscillation technique (FOT), and cardiovascular autonomic function was recorded by heart rate variability analysis (HRV). The Pearson correlation coefficient was used to test the associations between respiratory mechanics and HRV variables. There were associations between the standard deviation of all RR intervals (SDNN) and airway resistance (Rm) (r=-0.82; p=0.004), SDNN and respiratory system resistance (R0) (r=-0.79; p=0.006), root mean square of successive differences between adjacent normal RR intervals (rMSSD) and respiratory system resistance (R5) (r=-0.643; p=0.0451), rMSSD and R0 (r=-0.64; p=0.047), and rMSSD and Rm (r=-0.658; p=0.039). We concluded that the airway and respiratory system resistances are negatively associated with parasympathetic activity in patients with morbid obesity. Copyright © 2013 Sociedade Portuguesa de Pneumologia. Published by Elsevier España. All rights reserved.

Evaluative procedures to detect, characterize, and assess the severity of diabetic neuropathy.

PubMed

Dyck, P J

1991-01-01

Minimal criteria for diabetic neuropathy need to be defined and universally applied. Standardized evaluative procedures need to be agreed and normal ranges determined from healthy volunteers. Types and stages of neuropathy should be established and assessments performed on representative populations of both Type 1 and Type 2 diabetic patients. Potential minimal criteria include absent ankle reflexes and vibratory sensation, and abnormalities of nerve conduction. However, the preferred criterion is the identification of more than two statistically defined abnormalities among symptoms and deficits, nerve conduction, quantitative sensory examination or quantitative autonomic examination. Various evaluative procedures are available. Symptoms should be assessed and scores can be assigned to neurological deficits. However, assessments of nerve conduction provide the most specific, objective, sensitive, and repeatable procedures, although these may be the least meaningful. Many techniques are available for quantitative sensory examination, but are poorly standardized and normal values are not available. For quantitative autonomic examination, tests are available for the adequacy of cardiovascular and peripheral vascular reflexes and increasingly for other autonomic functions. In any assessment of nerve function the conditions should be optimized and standardized, and stimuli defined. Specific instructions should be given and normal ranges established in healthy volunteers.

Synergistic effect of energy drinks and overweight/obesity on cardiac autonomic testing using the Valsalva maneuver in university students.

PubMed

Majeed, Farrukh; Yar, Talay; Alsunni, Ahmed; Alhawaj, Ali Fouad; AlRahim, Ahmed; Alzaki, Muneer

2017-01-01

Obesity and caffeine consumption may lead to autonomic disturbances that can result in a wide range of cardiovascular disorders. To determine autonomic disturbances produced by the synergistic effects of overweight or obesity (OW/OB) and energy drinks. Cross-sectional, analytical. Physiology department at a university in Saudi Arabia. University students, 18-22 years of age, of normal weight (NW) and OW/OB were recruited by convenience sampling. Autonomic testing by the Valsalva ratio (VR) along with systolic and diastolic blood pressure, pulse pressure, and mean arterial blood pressure were measured at baseline (0 minute) and 60 minutes after energy drink consumption. Autonomic disturbance, hemodynamic changes. In 50 (27 males and 23 females) subjects, 21 NW and 29 OW/OB, a significant decrease in VR was observed in OW/OB subjects and in NW and OW/OB females at 60 minutes after energy drink consumption. Values of systolic and diastolic blood pressure, pulse pressure and mean arterial blood pressure were also significantly higher in OW/OB and in females as compared to NW and males. BMI was negatively correlated with VR and diastolic blood pressure at 60 minutes. Obesity and energy drinks alter autonomic functions. In some individuals, OW/OB may augment these effects. Due to time and resource restraints, only the acute effects of energy drinks were examined.

Autonomic Recovery Is Delayed in Chinese Compared with Caucasian following Treadmill Exercise.

PubMed

Sun, Peng; Yan, Huimin; Ranadive, Sushant M; Lane, Abbi D; Kappus, Rebecca M; Bunsawat, Kanokwan; Baynard, Tracy; Hu, Min; Li, Shichang; Fernhall, Bo

2016-01-01

Caucasian populations have a higher prevalence of cardiovascular disease (CVD) when compared with their Chinese counterparts and CVD is associated with autonomic function. It is unknown whether autonomic function during exercise recovery differs between Caucasians and Chinese. The present study investigated autonomic recovery following an acute bout of treadmill exercise in healthy Caucasians and Chinese. Sixty-two participants (30 Caucasian and 32 Chinese, 50% male) performed an acute bout of treadmill exercise at 70% of heart rate reserve. Heart rate variability (HRV) and baroreflex sensitivity (BRS) were obtained during 5-min epochs at pre-exercise, 30-min, and 60-min post-exercise. HRV was assessed using frequency [natural logarithm of high (LnHF) and low frequency (LnLF) powers, normalized high (nHF) and low frequency (nLF) powers, and LF/HF ratio] and time domains [Root mean square of successive differences (RMSSD), natural logarithm of RMSSD (LnRMSSD) and R-R interval (RRI)]. Spontaneous BRS included both up-up and down-down sequences. At pre-exercise, no group differences were observed for any HR, HRV and BRS parameters. During exercise recovery, significant race-by-time interactions were observed for LnHF, nHF, nLF, LF/HF, LnRMSSD, RRI, HR, and BRS (up-up). The declines in LnHF, nHF, RMSSD, RRI and BRS (up-up) and the increases in LF/HF, nLF and HR were blunted in Chinese when compared to Caucasians from pre-exercise to 30-min to 60-min post-exercise. Chinese exhibited delayed autonomic recovery following an acute bout of treadmill exercise. This delayed autonomic recovery may result from greater sympathetic dominance and extended vagal withdrawal in Chinese. Chinese Clinical Trial Register ChiCTR-IPR-15006684.

Autonomic Recovery Is Delayed in Chinese Compared with Caucasian following Treadmill Exercise

PubMed Central

Sun, Peng; Yan, Huimin; Ranadive, Sushant M.; Lane, Abbi D.; Kappus, Rebecca M.; Bunsawat, Kanokwan; Baynard, Tracy; Hu, Min; Li, Shichang; Fernhall, Bo

2016-01-01

Caucasian populations have a higher prevalence of cardiovascular disease (CVD) when compared with their Chinese counterparts and CVD is associated with autonomic function. It is unknown whether autonomic function during exercise recovery differs between Caucasians and Chinese. The present study investigated autonomic recovery following an acute bout of treadmill exercise in healthy Caucasians and Chinese. Sixty-two participants (30 Caucasian and 32 Chinese, 50% male) performed an acute bout of treadmill exercise at 70% of heart rate reserve. Heart rate variability (HRV) and baroreflex sensitivity (BRS) were obtained during 5-min epochs at pre-exercise, 30-min, and 60-min post-exercise. HRV was assessed using frequency [natural logarithm of high (LnHF) and low frequency (LnLF) powers, normalized high (nHF) and low frequency (nLF) powers, and LF/HF ratio] and time domains [Root mean square of successive differences (RMSSD), natural logarithm of RMSSD (LnRMSSD) and R–R interval (RRI)]. Spontaneous BRS included both up-up and down-down sequences. At pre-exercise, no group differences were observed for any HR, HRV and BRS parameters. During exercise recovery, significant race-by-time interactions were observed for LnHF, nHF, nLF, LF/HF, LnRMSSD, RRI, HR, and BRS (up-up). The declines in LnHF, nHF, RMSSD, RRI and BRS (up-up) and the increases in LF/HF, nLF and HR were blunted in Chinese when compared to Caucasians from pre-exercise to 30-min to 60-min post-exercise. Chinese exhibited delayed autonomic recovery following an acute bout of treadmill exercise. This delayed autonomic recovery may result from greater sympathetic dominance and extended vagal withdrawal in Chinese. Trial Registration: Chinese Clinical Trial Register ChiCTR-IPR-15006684 PMID:26784109

Effect of thyroxine therapy on autonomic status in hypothyroid patients.

PubMed

Lakshmi, Vijaya; Vaney, N; Madhu, S V

2009-01-01

The aim of the present study was to evaluate the impact of hypothyroidism on the autonomic regulation of the cardiovascular system by analyzing sympathetic and parasympathetic influences on the heart and the effect of thyroxine replacement. Thirty newly diagnosed female hypothyroid patients with mean age 32.73 +/- 9.98 years were recruited from the Thyroid Clinic, GTB Hospital, Delhi. Various Autonomic function tests to assess Basal heart rate variability, parasympathetic activity (E:I Ratio, 30:15 Ratio, Valsalva Ratio) and sympathetic activity (Postural Challenge test, Sustained handgrip test) were done before and after attainment of euthyroidism. There was significant increase in parasympathetic activity on achieving euthyroid state. The sympathetic activity too significantly improved after L-thyroxine supplementation. Lipid profile parameters significantly decreased after achieving euthyroid state. Our findings are consistent with previous reports that thyroxine therapy appears to restore the efferent vagal activity and alters the relative contribution of systems that maintain resting blood pressure and heart rate.

Pathophysiological relationships between heart failure and depression and anxiety.

PubMed

Chapa, Deborah W; Akintade, Bimbola; Son, Heesook; Woltz, Patricia; Hunt, Dennis; Friedmann, Erika; Hartung, Mary Kay; Thomas, Sue Ann

2014-04-01

Depression and anxiety are common comorbid conditions in patients with heart failure. Patients with heart failure and depression have increased mortality. The association of anxiety with increased mortality in patients with heart failure is not established. The purpose of this article is to illustrate the similarities of the underlying pathophysiology of heart failure, depression, and anxiety by using the Biopsychosocial Holistic Model of Cardiovascular Health. Depression and anxiety affect biological processes of cardiovascular function in patients with heart failure by altering neurohormonal function via activation of the hypothalamic-pituitary-adrenal axis, autonomic dysregulation, and activation of cytokine cascades and platelets. Patients with heart failure and depression or anxiety may exhibit a continued cycle of heart failure progression, increased depression, and increased anxiety. Understanding the underlying pathophysiological relationships in patients with heart failure who experience comorbid depression and/or anxiety is critical in order to implement appropriate treatments, educate patients and caregivers, and educate other health professionals.

Walks4Work: assessing the role of the natural environment in a workplace physical activity intervention.

PubMed

Brown, Daniel K; Barton, Jo L; Pretty, Jules; Gladwell, Valerie F

2014-07-01

The primary aim of this study was to examine the impact of physical activity (PA) in the natural environment (eg, "green exercise") on resting autonomic function in the Walks4Work intervention. A secondary aim was to assess the feasibility of Walks4Work in terms of adherence, change in PA levels, and cardiovascular health parameters. In an 8-week randomized control trial, 94 office workers in an international company were allocated to one of three groups: control, nature (NW), or built (BW) lunchtime walking route. Both walking groups were required to undertake two lunchtime walks each week. The NW route centered around trees, maintained grass, and public footpaths. In contrast, the BW consisted of pavement routes through housing estates and industrial areas. Data were collected at baseline and following the intervention. To investigate the impact of the intervention, mixed-design analysis of variance (ANOVA) were performed. A total of 73 participants completed the intervention (drop-out rate of 22%). No difference was observed in resting autonomic function between the groups. Self-reported mental health improved for the NW group only. PA levels increased at the intervention mid-point for all groups combined but adherence to the intervention was low with rates of 42% and 43% within the BW and NW groups, respectively. Accompanying a guideline of two active lunchtimes per week with low facilitator input appears inadequate for increasing the number of active lunchtimes and modifying cardiovascular health parameters in an office population. However, this population fell within normal ranges for cardiovascular measures and future research should consider investigating at-risk populations, particularly hypertensive individuals.

DAILY VARIATION OF PARTICULATE AIR POLLUTION AND POOR CARDIAC AUTONOMIC CONTROL IN THE ELDERLY

EPA Science Inventory

Particulate matter air pollution (PM) has been related to cardiovascular disease mortality in a number of recent studies. The pathophysiologic mechanisms for this association are under study. Low heart rate variability, a marker of poor cardiac autonomic control, is associated wi...

Cardiovascular autonomic control during short-term thermoneutral and cool head-out immersion.

PubMed

Mourot, Laurent; Bouhaddi, Malika; Gandelin, Emmanuel; Cappelle, Sylvie; Dumoulin, Gilles; Wolf, Jean-Pierre; Rouillon, Jean Denis; Regnard, Jacques

2008-01-01

Moderately cold head-out water immersion stimulates both baro- and cold-receptors, and triggers complex and contradictory effects on the cardiovascular system and its autonomic nervous control. To assess the effects of water immersion and cold on cardiovascular status and related autonomic nervous activity. Hemodynamic variables and indexes of autonomic nervous activity (analysis of heart rate and blood pressure variability) were evaluated in 12 healthy subjects during 3 exposures of 20 min each in the upright position, i.e., in air (AIR, 24-25 degrees C), and during head-out water immersion at 35-36 degrees C (WIn) and 26-27 degrees C (WIc). Plasma noradrenaline, systolic and diastolic blood pressure, and total peripheral resistances were reduced during WIn compared to AIR (263.9 +/- 39.4 vs. 492.5 +/- 35.7 pg x ml(-1), 116.5 +/- 3.7 and 65.4 +/- 1.7 mmHg vs. 140.8 +/- 4.7 and 89.8 +/- 2.8 mmHg, 14.1 +/- 1.0 vs. 16.3 +/- 0.9 mmHg x L(-1) x min, respectively) while they were increased during WIc (530.8 +/- 84.7 pg ml(-1), 148.0 +/- 7.0 mmHg, 80.8 +/- 3.0 mmHg, and 25.8 +/- 1.9 mmHg x L(-1) x min, respectively). The blood pressure variability was reduced to the same extent during WIc and Win compared to AIR. Heart rate decreased during WIn (67.8 +/- 2.7 vs. 81.2 +/- 2.7 bpm during AIR), in parallel with an increased cardiac parasympathetic activity. This pattern was strengthened during WIc (55.3 +/- 2.2 bpm). Thermoneutral WI lowered sympathetic activity and arterial tone, while moderate whole-body skin cooling triggered vascular sympathetic activation. Conversely, both WI and cold triggered cardiac parasympathetic activation, highlighting a complex autonomic control of the cardiovascular system.

The different role of sex hormones on female cardiovascular physiology and function: not only oestrogens.

PubMed

Salerni, Sara; Di Francescomarino, Samanta; Cadeddu, Christian; Acquistapace, Flavio; Maffei, Silvia; Gallina, Sabina

2015-06-01

Human response to different physiologic stimuli and cardiovascular (CV) adaptation to various pathologies seem to be gender specific. Sex-steroid hormones have been postulated as the major contributors towards these sex-related differences. This review will discuss current evidence on gender differences in CV function and remodelling, and will present the different role of the principal sex-steroid hormones on female heart. Starting from a review of sex hormones synthesis, receptors and CV signalling, we will summarize the current knowledge concerning the role of sex hormones on the regulation of our daily activities throughout the life, via the modulation of autonomic nervous system, excitation-contraction coupling pathway and ion channels activity. Many unresolved questions remain even if oestrogen effects on myocardial remodelling and function have been extensively studied. So this work will focus attention also on the controversial and complex relationship existing between androgens, progesterone and female heart. © 2015 Stichting European Society for Clinical Investigation Journal Foundation.

Thyroid hormone and the central control of homeostasis.

PubMed

Warner, Amy; Mittag, Jens

2012-08-01

It has long been known that thyroid hormone has profound direct effects on metabolism and cardiovascular function. More recently, it was shown that the hormone also modulates these systems by actions on the central autonomic control. Recent studies that either manipulated thyroid hormone signalling in anatomical areas of the brain or analysed seasonal models with an endogenous fluctuation in hypothalamic thyroid hormone levels revealed that the hormone controls energy turnover. However, most of these studies did not progress beyond the level of anatomical nuclei; thus, the neuronal substrates as well as the molecular mechanisms remain largely enigmatic. This review summarises the evidence for a role of thyroid hormone in the central autonomic control of peripheral homeostasis and advocates novel strategies to address thyroid hormone action in the brain on a cellular level.

Cardiac autonomic and haemodynamic recovery after a single session of aerobic exercise with and without blood flow restriction in older adults.

PubMed

Ferreira, Marina Lívia Venturini; Sardeli, Amanda Veiga; Souza, Giovana Vergínia De; Bonganha, Valéria; Santos, Lucas Do Carmo; Castro, Alex; Cavaglieri, Cláudia Regina; Chacon-Mikahil, Mara Patrícia Traina

2017-12-01

This study investigated the autonomic and haemodynamic responses to different aerobic exercise loads, with and without blood flow restriction (BFR). In a crossover study, 21 older adults (8 males and 13 females) completed different aerobic exercise sessions: low load without BFR (LL) (40% VO 2 max ), low load with BFR (LL-BFR) (40% VO 2 max + 50% BFR) and high load without BFR (HL) (70% VO 2 max ). Heart rate variability and haemodynamic responses were recorded during rest and throughout 30 min of recovery. HL reduced R-R interval, the root mean square of successive difference of R-R intervals and high frequency during 30 min of recovery at a greater magnitude compared with LL and LL-BFR. Sympathetic-vagal balance increased the values for HL during 30 min of recovery at a greater magnitude when compared with LL and LL-BFR. Post-exercise haemodynamic showed reduced values of double product at 30 min of recovery compared to rest in LL-BFR, while HL showed higher values compared to rest, LL-BFR and LL. Reduced systolic blood pressure was observed for LL-BFR (30 min) compared to rest. Autonomic and haemodynamic responses indicate lower cardiovascular stress after LL-BFR compared to HL, being this method, besides the functional adaptations, a potential choice to attenuate the cardiovascular stress after exercise in older adults.

Controlled breathing protocols probe human autonomic cardiovascular rhythms

NASA Technical Reports Server (NTRS)

Cooke, W. H.; Cox, J. F.; Diedrich, A. M.; Taylor, J. A.; Beightol, L. A.; Ames, J. E. 4th; Hoag, J. B.; Seidel, H.; Eckberg, D. L.

1998-01-01

The purpose of this study was to determine how breathing protocols requiring varying degrees of control affect cardiovascular dynamics. We measured inspiratory volume, end-tidal CO2, R-R interval, and arterial pressure spectral power in 10 volunteers who followed the following 5 breathing protocols: 1) uncontrolled breathing for 5 min; 2) stepwise frequency breathing (at 0.3, 0.25, 0.2, 0.15, 0.1, and 0.05 Hz for 2 min each); 3) stepwise frequency breathing as above, but with prescribed tidal volumes; 4) random-frequency breathing (approximately 0.5-0.05 Hz) for 6 min; and 5) fixed-frequency breathing (0.25 Hz) for 5 min. During stepwise breathing, R-R interval and arterial pressure spectral power increased as breathing frequency decreased. Control of inspired volume reduced R-R interval spectral power during 0.1 Hz breathing (P < 0.05). Stepwise and random-breathing protocols yielded comparable coherence and transfer functions between respiration and R-R intervals and systolic pressure and R-R intervals. Random- and fixed-frequency breathing reduced end-tidal CO2 modestly (P < 0.05). Our data suggest that stringent tidal volume control attenuates low-frequency R-R interval oscillations and that fixed- and random-rate breathing may decrease CO2 chemoreceptor stimulation. We conclude that autonomic rhythms measured during different breathing protocols have much in common but that a stepwise protocol without stringent control of inspired volume may allow for the most efficient assessment of short-term respiratory-mediated autonomic oscillations.

Ambulatory ECG and analysis of heart rate variability in Parkinson's disease.

PubMed

Haapaniemi, T H; Pursiainen, V; Korpelainen, J T; Huikuri, H V; Sotaniemi, K A; Myllylä, V V

2001-03-01

Cardiovascular reflex tests have shown both sympathetic and parasympathetic failure in Parkinson's disease. These tests, however, describe the autonomic responses during a restricted time period and have great individual variability, providing a limited view of the autonomic cardiac control mechanisms. Thus, they do not reflect tonic autonomic regulation. The aim was to examine tonic autonomic cardiovascular regulation in untreated patients with Parkinson's disease. 24 Hour ambulatory ECG was recorded in 54 untreated patients with Parkinson's disease and 47 age matched healthy subjects. In addition to the traditional spectral (very low frequency, VLF; low frequency, LF; high frequency, HF) and non-spectral components of heart rate variability, instantaneous beat to beat variability (SD1) and long term continuous variability (SD2) derived from Poincaré plots, and the slope of the power law relation were analysed. All spectral components (p<0.01) and the slope of the power-law relation (p<0.01) were lower in the patients with Parkinson's disease than in the control subjects. The Unified Parkinson's disease rating scale total and motor scores had a negative correlation with VLF and LF power spectrum values and the power law relation slopes. Patients with mild hypokinesia had higher HF values than patients with more severe hypokinesia. Tremor and rigidity were not associated with the HR variability parameters. Parkinson's disease causes dysfunction of the diurnal autonomic cardiovascular regulation as demonstrated by the spectral measures of heart rate variability and the slope of the power law relation. This dysfunction seems to be more profound in patients with more severe Parkinson's disease.

Peptides, serotonin, and breathing: the role of the raphe in the control of respiration.

PubMed

Pilowsky, Paul M

2014-01-01

Over the last 20 years, it has become clear that many functionally defined autonomic neurons in the brainstem contain many more than one neurotransmitter. Here, the possible role and functions of colocalized neuropeptides in the caudal raphe nuclei of the medulla oblongata are discussed. Caudal raphe neurons provide an extensive input to neurons throughout the brainstem and spinal cord, including respiratory and cardiovascular neurons. It is concluded that one plausible function of colocalized neuropeptides is to maintain the membrane potential of target neurons within a defined window so that they remain able to function at extremes of activity. © 2014 Elsevier B.V. All rights reserved.

Autonomic neuropathy in an alcoholic population.

PubMed

Barter, F; Tanner, A R

1987-12-01

Autonomic nervous system integrity has been assessed in 30 alcoholic subjects and 30 age-sex matched controls using five simple tests of cardiovascular responses. There was evidence of parasympathetic neuropathy alone in five of the alcoholic subjects (16%) and of combined parasympathetic and sympathetic neuropathy in an additional six (20%). None of the controls showed any abnormality. Within the alcoholic group, those with autonomic neuropathy were older, were more likely to be female and to have established alcoholic liver disease. Symptoms were a poor guide to the presence or absence of autonomic neuropathy.

Synchronisation and coupling analysis: applied cardiovascular physics in sleep medicine.

PubMed

Wessel, Niels; Riedl, Maik; Kramer, Jan; Muller, Andreas; Penzel, Thomas; Kurths, Jurgen

2013-01-01

Sleep is a physiological process with an internal program of a number of well defined sleep stages and intermediate wakefulness periods. The sleep stages modulate the autonomous nervous system and thereby the sleep stages are accompanied by different regulation regimes for the cardiovascular and respiratory system. The differences in regulation can be distinguished by new techniques of cardiovascular physics. The number of patients suffering from sleep disorders increases unproportionally with the increase of the human population and aging, leading to very high expenses in the public health system. Therefore, the challenge of cardiovascular physics is to develop highly-sophisticated methods which are able to, on the one hand, supplement and replace expensive medical devices and, on the other hand, improve the medical diagnostics with decreasing the patient's risk. Methods of cardiovascular physics are used to analyze heart rate, blood pressure and respiration to detect changes of the autonomous nervous system in different diseases. Data driven modeling analysis, synchronization and coupling analysis and their applications to biosignals in healthy subjects and patients with different sleep disorders are presented. Newly derived methods of cardiovascular physics can help to find indicators for these health risks.

Linking an Anxiety-Related Personality Trait to Cardiac Autonomic Regulation in Well-Defined Healthy Adults: Harm Avoidance and Resting Heart Rate Variability.

PubMed

Kao, Lien-Cheng; Liu, Yu-Wen; Tzeng, Nian-Sheng; Kuo, Terry B J; Huang, San-Yuan; Chang, Chuan-Chia; Chang, Hsin-An

2016-07-01

Anxiety trait, anxiety and depression states have all been reported to increase risks for cardiovascular disease (CVD), possibly through altering cardiac autonomic regulation. Our aim was to investigate whether the relationship between harm avoidance (HA, an anxiety-related personality trait) and cardiac autonomic regulation is independent of anxiety and depression states in healthy adults. We recruited 535 physically and mentally healthy volunteers. Participants completed the Beck Anxiety Inventory (BAI), Beck Depression Inventory (BDI) and Tri-dimensional Personality Questionnaire. Participants were divided into high or low HA groups as discriminated by the quartile value. Cardiac autonomic function was evaluated by measuring heart rate variability (HRV). We obtained the time and frequency-domain indices of HRV including variance (total HRV), the low-frequency power (LF; 0.05-0.15 Hz), which may reflect baroreflex function, the high-frequency power (HF; 0.15-0.40 Hz), which reflects cardiac parasympathetic activity, as well as the LF/HF ratio. The BDI and HA scores showed associations with HRV parameters. After adjustment for the BDI scores and other control variables, HA is still associated with reduced variance, LF and HF power. Compared with the participants with low HA, those with high HA displayed significant reductions in variance, LF and HF power and a significant increase in their LF/HF ratio. This study highlights the independent role of HA in contributing to decreased autonomic cardiac regulation in healthy adults and provides a potential underlying mechanism for anxiety trait to confer increased risk for CVD.

Linking an Anxiety-Related Personality Trait to Cardiac Autonomic Regulation in Well-Defined Healthy Adults: Harm Avoidance and Resting Heart Rate Variability

PubMed Central

Kao, Lien-Cheng; Liu, Yu-Wen; Tzeng, Nian-Sheng; Kuo, Terry B. J.; Huang, San-Yuan

2016-01-01

Objective Anxiety trait, anxiety and depression states have all been reported to increase risks for cardiovascular disease (CVD), possibly through altering cardiac autonomic regulation. Our aim was to investigate whether the relationship between harm avoidance (HA, an anxiety-related personality trait) and cardiac autonomic regulation is independent of anxiety and depression states in healthy adults. Methods We recruited 535 physically and mentally healthy volunteers. Participants completed the Beck Anxiety Inventory (BAI), Beck Depression Inventory (BDI) and Tri-dimensional Personality Questionnaire. Participants were divided into high or low HA groups as discriminated by the quartile value. Cardiac autonomic function was evaluated by measuring heart rate variability (HRV). We obtained the time and frequency-domain indices of HRV including variance (total HRV), the low-frequency power (LF; 0.05–0.15 Hz), which may reflect baroreflex function, the high-frequency power (HF; 0.15–0.40 Hz), which reflects cardiac parasympathetic activity, as well as the LF/HF ratio. Results The BDI and HA scores showed associations with HRV parameters. After adjustment for the BDI scores and other control variables, HA is still associated with reduced variance, LF and HF power. Compared with the participants with low HA, those with high HA displayed significant reductions in variance, LF and HF power and a significant increase in their LF/HF ratio. Conclusion This study highlights the independent role of HA in contributing to decreased autonomic cardiac regulation in healthy adults and provides a potential underlying mechanism for anxiety trait to confer increased risk for CVD. PMID:27482240

Soluble TNFα Signaling within the Spinal Cord Contributes to the Development of Autonomic Dysreflexia and Ensuing Vascular and Immune Dysfunction after Spinal Cord Injury.

PubMed

Mironets, Eugene; Osei-Owusu, Patrick; Bracchi-Ricard, Valerie; Fischer, Roman; Owens, Elizabeth A; Ricard, Jerome; Wu, Di; Saltos, Tatiana; Collyer, Eileen; Hou, Shaoping; Bethea, John R; Tom, Veronica J

2018-04-25

Cardiovascular disease and susceptibility to infection are leading causes of morbidity and mortality for individuals with spinal cord injury (SCI). A major contributor to these is autonomic dysreflexia (AD), an amplified reaction of the autonomic nervous system (hallmarked by severe hypertension) in response to sensory stimuli below the injury. Maladaptive plasticity of the spinal sympathetic reflex circuit below the SCI results in AD intensification over time. Mechanisms underlying this maladaptive plasticity are poorly understood, restricting the identification of treatments. Thus, no preventative treatments are currently available. Neuroinflammation has been implicated in other pathologies associated with hyperexcitable neural circuits. Specifically, the soluble form of TNFα (sTNFα) is known to play a role in neuroplasticity. We hypothesize that persistent expression of sTNFα in spinal cord underlies AD exacerbation. To test this, we intrathecally administered XPro1595, a biologic that renders sTNFα nonfunctional, after complete, high-level SCI in female rats. This dramatically attenuated the intensification of colorectal distension-induced and naturally occurring AD events. This improvement is mediated via decreased sprouting of nociceptive primary afferents and activation of the spinal sympathetic reflex circuit. We also examined peripheral vascular function using ex vivo pressurized arterial preparations and immune function via flow cytometric analysis of splenocytes. Diminishing AD via pharmacological inhibition of sTNFα mitigated ensuing vascular hypersensitivity and immune dysfunction. This is the first demonstration that neuroinflammation-induced sTNFα is critical for altering the spinal sympathetic reflex circuit, elucidating a novel mechanism for AD. Importantly, we identify the first potential pharmacological, prophylactic treatment for this life-threatening syndrome. SIGNIFICANCE STATEMENT Autonomic dysreflexia (AD), a disorder that develops after spinal cord injury (SCI) and is hallmarked by sudden, extreme hypertension, contributes to cardiovascular disease and susceptibility to infection, respectively, two leading causes of mortality and morbidity in SCI patients. We demonstrate that neuroinflammation-induced expression of soluble TNFα plays a critical role in AD, elucidating a novel underlying mechanism. We found that intrathecal administration after SCI of a biologic that inhibits soluble TNFα signaling dramatically attenuates AD and significantly reduces AD-associated peripheral vascular and immune dysfunction. We identified mechanisms behind diminished plasticity of neuronal populations within the spinal sympathetic reflex circuit. This study is the first to pinpoint a potential pharmacological, prophylactic strategy to attenuate AD and ensuing cardiovascular and immune dysfunction. Copyright © 2018 the authors 0270-6474/18/384147-17$15.00/0.

Exploring violence against women and adverse health outcomes in middle age to promote women's health

USDA-ARS?s Scientific Manuscript database

A history of intimate partner violence (IPV) is linked to cardiovascular disorders among women. Static autonomic nervous system (ANS) imbalance may result from chronic stress associated with exposure to IPV. Autonomic nervous system imbalance is associated with an excessive proinflammatory response ...

Investigating Autonomic Control of the Cardiovascular System: A Battery of Simple Tests

ERIC Educational Resources Information Center

Johnson, Christopher D.; Roe, Sean; Tansey, Etain A.

2013-01-01

Sympathetic and parasympathetic divisions of the autonomic nervous system constantly control the heart (sympathetic and parasympathetic divisions) and blood vessels (predominantly the sympathetic division) to maintain appropriate blood pressure and organ blood flow over sometimes widely varying conditions. This can be adversely affected by…

Regular Football Practice Improves Autonomic Cardiac Function in Male Children.

PubMed

Fernandes, Luis; Oliveira, Jose; Soares-Miranda, Luisa; Rebelo, Antonio; Brito, Joao

2015-09-01

The role of the autonomic nervous system (ANS) in the cardiovascular regulation is of primal importance. Since it has been associated with adverse conditions such as cardiac arrhythmias, sudden death, sleep disorders, hypertension and obesity. The present study aimed to investigate the impact of recreational football practice on the autonomic cardiac function of male children, as measured by heart rate variability. Forty-seven male children aged 9 - 12 years were selected according to their engagement with football oriented practice outside school context. The children were divided into a football group (FG; n = 22) and a control group (CG; n = 25). The FG had regular football practices, with 2 weekly training sessions and occasional weekend matches. The CG was not engaged with any physical activity other than complementary school-based physical education classes. Data from physical activity, physical fitness, and heart rate variability measured in time and frequency domains were obtained. The anthropometric and body composition characteristics were similar in both groups (P > 0.05). The groups were also similar in time spent daily on moderate-to-vigorous physical activities (FG vs. CG: 114 ± 64 vs. 87 ± 55 minutes; P > 0.05). However, the FG performed better (P < 0.05) in Yo-Yo intermittent endurance test (1394 ± 558 vs. 778 ± 408 m) and 15-m sprint test (3.06 ± 0.17 vs. 3.20 ± 0.23 s). Also, the FG presented enhanced autonomic function. Significant differences were detected (P < 0.05) between groups for low frequency normalized units (38.0 ± 15.2 vs. 47.3 ± 14.2 n.u (normalized units)), high frequency normalized units (62.1 ± 15.2 vs. 52.8 ± 14.2 n.u.), and LF:HF ratio (0.7 ± 0.4 vs. 1.1 ± 0.6 ms(2)). Children engaged with regular football practice presented enhanced physical fitness and autonomic function, by increasing vagal tone at rest.

Regular Football Practice Improves Autonomic Cardiac Function in Male Children

PubMed Central

Fernandes, Luis; Oliveira, Jose; Soares-Miranda, Luisa; Rebelo, Antonio; Brito, Joao

2015-01-01

Background: The role of the autonomic nervous system (ANS) in the cardiovascular regulation is of primal importance. Since it has been associated with adverse conditions such as cardiac arrhythmias, sudden death, sleep disorders, hypertension and obesity. Objectives: The present study aimed to investigate the impact of recreational football practice on the autonomic cardiac function of male children, as measured by heart rate variability. Patients and Methods: Forty-seven male children aged 9 - 12 years were selected according to their engagement with football oriented practice outside school context. The children were divided into a football group (FG; n = 22) and a control group (CG; n = 25). The FG had regular football practices, with 2 weekly training sessions and occasional weekend matches. The CG was not engaged with any physical activity other than complementary school-based physical education classes. Data from physical activity, physical fitness, and heart rate variability measured in time and frequency domains were obtained. Results: The anthropometric and body composition characteristics were similar in both groups (P > 0.05). The groups were also similar in time spent daily on moderate-to-vigorous physical activities (FG vs. CG: 114 ± 64 vs. 87 ± 55 minutes; P > 0.05). However, the FG performed better (P < 0.05) in Yo-Yo intermittent endurance test (1394 ± 558 vs. 778 ± 408 m) and 15-m sprint test (3.06 ± 0.17 vs. 3.20 ± 0.23 s). Also, the FG presented enhanced autonomic function. Significant differences were detected (P < 0.05) between groups for low frequency normalized units (38.0 ± 15.2 vs. 47.3 ± 14.2 n.u (normalized units)), high frequency normalized units (62.1 ± 15.2 vs. 52.8 ± 14.2 n.u.), and LF:HF ratio (0.7 ± 0.4 vs. 1.1 ± 0.6 ms2). Conclusions: Children engaged with regular football practice presented enhanced physical fitness and autonomic function, by increasing vagal tone at rest. PMID:26448848

Mechanisms underpinning sympathetic nervous activity and its modulation using transcutaneous vagus nerve stimulation.

PubMed

Deuchars, Susan A; Lall, Varinder K; Clancy, Jennifer; Mahadi, Mohd; Murray, Aaron; Peers, Lucy; Deuchars, Jim

2018-03-01

What is the topic of this review? This review briefly considers what modulates sympathetic nerve activity and how it may change as we age or in pathological conditions. It then focuses on transcutaneous vagus nerve stimulation, a method of neuromodulation in autonomic cardiovascular control. What advances does it highlight? The review considers the pathways involved in eliciting the changes in autonomic balance seen with transcutaneous vagus nerve stimulation in relationship to other neuromodulatory techniques. The autonomic nervous system, consisting of the sympathetic and parasympathetic branches, is a major contributor to the maintenance of cardiovascular variables within homeostatic limits. As we age or in certain pathological conditions, the balance between the two branches changes such that sympathetic activity is more dominant, and this change in dominance is negatively correlated with prognosis in conditions such as heart failure. We have shown that non-invasive stimulation of the tragus of the ear increases parasympathetic activity and reduces sympathetic activity and that the extent of this effect is correlated with the baseline cardiovascular parameters of different subjects. The effects could be attributable to activation of the afferent branch of the vagus and, potentially, other sensory nerves in that region. This indicates that tragus stimulation may be a viable treatment in disorders where autonomic activity to the heart is compromised. © 2017 The Authors. Experimental Physiology published by John Wiley & Sons Ltd on behalf of The Physiological Society.

Balance of autonomic nervous system in children having signs of endothelial dysfunction, that were born and are domiciled in contaminated territories.

PubMed

Kondrashova, V G; Kolpakov, I E; Vdovenko, V Yu; Leonovych, O S; Lytvynets, O M; Stepanova, E I

2014-09-01

Objective. The study examined the features of functional state of the autonomic nervous system in children having endothelial dysfunction and permanently residing in contaminated areas. Materials and methods. Clinical and instrumental examination of 101 children aged 7-18 years that were born and are domiciled in contaminated territories, including 37 persons with signs of endothelial dysfunction (subgroup IA) and 64 ones with no signs of endothelial dysfunction (IB subgroup) was conducted. The control group being comparable to the subgroups IA and IB by age, gender and clinical examination results included 37 children neither been domiciled in contaminated areas nor were belonging to the contingent of Chornobyl accident survivors. There were 20 apparently healthy children also examined. Results. Due to peculiarities of physiological pathways providing adaptive responses the children having signs of endothelial dysfunction are characterized by a more pronounced dysregulation of autonomous nervous system both in a resting state and under a functional load simulation, and also by a high strain of adaptation pathways. The lack of autonomous support of cardiovascular system is caused by inadequate adaptive responses of both central regulatory bodies (hypothalamus, vasomotor center) and peripheral receptors. Mainly the failure of segmental autonomous (parasympathetic) structures was revealed. The mode of their response to stress in this case corresponds to that in healthy individuals but at a lower functional level. There is a reduced aerobic capacity of the organism by the Robinson index, contributing to low adaptive range to non-specific stress in children being domiciled on contaminated territories including children having the endothelial dysfunction. Conclusions. Endothelial dysfunction was associated with more pronounced manifestations of autonomic dysregulation and reduced aerobic capacity of the organism being the risk factors of development of a range of somatic diseases requiring the development of prevention measures in children permanently residing in contaminated areas. autonomous nervous system balance, endothelial dysfunction, children, Chornobyl accident. V. G. Kondrashova, I. E. Kolpakov, V. Yu. Vdovenko, O. S. Leonovych, O. M. Lytvynets, E. I. Stepanova.

The prognostic value of the frontal QRS-T angle is comparable to cardiovascular autonomic neuropathy regarding long-term mortality in people with diabetes. A population based study.

PubMed

May, O; Graversen, C B; Johansen, M Ø; Arildsen, H

2018-06-09

Cardiovascular autonomic neuropathy (CAN) is a well known prognostic marker in diabetes. A large angle between the QRS- and the T-wave vector (QRS-T angle) in the electrocardiogram (ECG) has recently been introduced as another marker of poor prognosis. To assess and compare the long-term predictive power of the frontal plane QRS-T angle with CAN in people with diabetes. In 1992-93 people with diabetes in the municipality of Horsens, Denmark, were identified by the prescription method andan age and gender stratified sample of 240 individuals with diabetes were randomly selected. The presence of CAN was defined using the heart rate response to Valsalva manoeuvre. The QRS-T angle was read using the method described by Gandhi. In July 2015 vital statistics were obtained fromthe Danish Civil Registration System. 178 individuals accepted to participate in the study, of which 153 (86%) completed the Valsalva manoeuvre and had sinus rhythm. Total observation time was 21.5 (0.18) years, in which 99 (65%) individuals died. An elevated QRS-T angle and the presence of cardiovascular autonomic neuropathy were both found to be significant predictors of death. In Cox regression analyses, adjusting for the effect of gender, age, duration of diabetes, BMI, total-cholesterol, diabetes type, haemoglobin A1c, smoking status, hypertension and previous MI, an independent prognostic value was found for the QRS-T angle as well as the Valsalva ratio. A large QRS-T angle and the presence of cardiovascular autonomic neuropathy are both strong and independent long-term predictors of all-cause mortality in people with diabetes. Copyright © 2018. Published by Elsevier B.V.

Regulation of sympathetic nervous system function after cardiovascular deconditioning

NASA Technical Reports Server (NTRS)

Hasser, E. M.; Moffitt, J. A.

2001-01-01

Humans subjected to prolonged periods of bed rest or microgravity undergo deconditioning of the cardiovascular system, characterized by resting tachycardia, reduced exercise capability, and a predisposition for orthostatic intolerance. These changes in cardiovascular function are likely due to a combination of factors, including changes in control of body fluid balance or cardiac alterations resulting in inadequate maintenance of stroke volume, altered arterial or venous vascular function, reduced activation of cardiovascular hormones, and diminished autonomic reflex function. There is evidence indicating a role for each of these mechanisms. Diminished reflex activation of the sympathetic nervous system and subsequent vasoconstriction appear to play an important role. Studies utilizing the hindlimb-unloaded (HU) rat, an animal model of deconditioning, evaluated the potential role of altered arterial baroreflex control of the sympathetic nervous system. These studies indicate that HU results in blunted baroreflex-mediated activation of both renal and lumbar sympathetic nerve activity in response to a hypotensive stimulus. HU rats are less able to maintain arterial pressure during hemorrhage, suggesting that diminished ability to increase sympathetic activity has functional consequences for the animal. Reflex control of vasopressin secretion appears to be enhanced following HU. Blunted baroreflex-mediated sympathoexcitation appears to involve altered central nervous system function. Baroreceptor afferent activity in response to changes in arterial pressure is unaltered in HU rats. However, increases in efferent sympathetic nerve activity for a given decrease in afferent input are blunted after HU. This altered central nervous system processing of baroreceptor inputs appears to involve an effect at the rostral ventrolateral medulla (RVLM). Specifically, it appears that tonic GABAA-mediated inhibition of the RVLM is enhanced after HU. Augmented inhibition apparently arises from sources other than the caudal ventrolateral medulla. If similar alterations in control of the sympathetic nervous system occur in humans in response to cardiovascular deconditioning, it is likely that they play an important role in the observed tendency for orthostatic intolerance. Combined with potential changes in vascular function, cardiac function, and hypovolemia, the predisposition for orthostatic intolerance following cardiovascular deconditioning would be markedly enhanced by blunted ability to reflexly activate the sympathetic nervous system.

Spectral indices of cardiovascular adaptations to short-term simulated microgravity exposure

NASA Technical Reports Server (NTRS)

Patwardhan, A. R.; Evans, J. M.; Berk, M.; Grande, K. J.; Charles, J. B.; Knapp, C. F.

1995-01-01

We investigated the effects of exposure to microgravity on the baseline autonomic balance in cardiovascular regulation using spectral analysis of cardiovascular variables measured during supine rest. Heart rate, arterial pressure, radial flow, thoracic fluid impedance and central venous pressure were recorded from nine volunteers before and after simulated microgravity, produced by 20 hours of 6 degrees head down bedrest plus furosemide. Spectral powers increased after simulated microgravity in the low frequency region (centered at about 0.03 Hz) in arterial pressure, heart rate and radial flow, and decreased in the respiratory frequency region (centered at about 0.25 Hz) in heart rate. Reduced heart rate power in the respiratory frequency region indicates reduced parasympathetic influence on the heart. A concurrent increase in the low frequency power in arterial pressure, heart rate, and radial flow indicates increased sympathetic influence. These results suggest that the baseline autonomic balance in cardiovascular regulation is shifted towards increased sympathetic and decreased parasympathetic influence after exposure to short-term simulated microgravity.

Cardiovascular disease in spinal cord injury: an overview of prevalence, risk, evaluation, and management.

PubMed

Myers, Jonathan; Lee, Matthew; Kiratli, Jenny

2007-02-01

Cardiovascular disease is a growing concern for the spinal cord-injured (SCI) population. For long-term SCI, morbidity and mortality from cardiovascular causes now exceeds that caused by renal and pulmonary conditions, the primary causes of mortality in previous decades. Although risk estimates commonly used for ambulatory individuals have not been established from follow-up studies in SCI, nearly all risk factors tend to be more prevalent in SCI subjects compared with ambulatory subjects. These risks include a greater prevalence of obesity, lipid disorders, metabolic syndrome, and diabetes. Daily energy expenditure is significantly lower in SCI individuals, not only because of a lack of motor function, but also because of a lack of accessibility and fewer opportunities to engage in physical activity. Autonomic dysfunction caused by SCI is also associated with several conditions that contribute to heightened cardiovascular risk, including abnormalities in blood pressure, heart rate variability, arrhythmias, and a blunted cardiovascular response to exercise that can limit the capacity to perform physical activity. Thus, screening, recognition, and treatment of cardiovascular disease should be an essential component of managing individuals with SCI, and judicious treatment of risk factors can play an important role in minimizing the incidence of cardiovascular disease in these individuals. This article reviews the cardiovascular consequences of chronic SCI, including the prevalence of cardiovascular disease and risk factors unique to these individuals, and provides a synopsis of management of cardiovascular disease in this population.

Mechanisms of Cardiopulmonary Adaptation to Microgravity. Part 2

NASA Technical Reports Server (NTRS)

1997-01-01

Session TP1 contains short reports concerning: (1) Autonomic Regulation of Circulation and Mechanical Function of Heart at Different Stages of 14th Month Space Flight; (2) Cardiovascular Oxygen Transport in Exercising Humans in Microgravity; (3) Venous Hemodynamic Changes Assessed by Air Plethysmography During a 16-Day Space Flight; (4) Respiratory Mechanics After 180 Days Space Mission (EUROMIR'95); (5) Assessment of the Sympathetic and the Parasympathetic Nervous Activity During Parabolic Flight by Pupillary Light Reflex; and(6) Vascular Response to Different Gravity.

Blunted heart rate recovery is improved following exercise training in overweight adults with obstructive sleep apnea.

PubMed

Kline, Christopher E; Crowley, E Patrick; Ewing, Gary B; Burch, James B; Blair, Steven N; Durstine, J Larry; Davis, J Mark; Youngstedt, Shawn D

2013-08-20

Obstructive sleep apnea (OSA) predisposes individuals to cardiovascular morbidity, and cardiopulmonary exercise test (CPET) markers prognostic for cardiovascular disease have been found to be abnormal in adults with OSA. Due to the persistence of OSA and its cardiovascular consequences, whether the cardiovascular adaptations normally conferred by exercise are blunted in adults not utilizing established OSA treatment is unknown. The aims of this study were to document whether OSA participants have abnormal CPET responses and determine whether exercise modifies these CPET markers in individuals with OSA. The CPET responses of 43 sedentary, overweight adults (body mass index [BMI]>25) with untreated OSA (apnea-hypopnea index [AHI]≥ 15) were compared against matched non-OSA controls (n=9). OSA participants were then randomized to a 12-week exercise training (n=27) or stretching control treatment (n=16), followed by a post-intervention CPET. Measures of resting, exercise, and post-exercise recovery heart rate (HRR), blood pressure, and ventilation, as well as peak oxygen consumption (VO(2peak)), were obtained. OSA participants had blunted HRR compared to non-OSA controls at 1 (P=.03), 3 (P=.02), and 5-min post-exercise (P=.03). For OSA participants, exercise training improved VO2 peak (P=.04) and HRR at 1 (P=.03), 3 (P<.01), and 5-min post-exercise (P<.001) compared to control. AHI change was associated with change in HRR at 5-min post-exercise (r=-.30, P<.05), but no other CPET markers. These results suggest that individuals with OSA have autonomic dysfunction, and that exercise training, by increasing HRR and VO2 peak, may attenuate autonomic imbalance and improve functional capacity independent of OSA severity reduction. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

Blunted Heart Rate Recovery Is Improved Following Exercise Training in Overweight Adults with Obstructive Sleep Apnea

PubMed Central

Kline, Christopher E.; Crowley, E. Patrick; Ewing, Gary B.; Burch, James B.; Blair, Steven N.; Durstine, J. Larry; Davis, J. Mark; Youngstedt, Shawn D.

2012-01-01

Background Obstructive sleep apnea (OSA) predisposes individuals to cardiovascular morbidity, and cardiopulmonary exercise test (CPET) markers prognostic for cardiovascular disease have been found to be abnormal in adults with OSA. Due to the persistence of OSA and its cardiovascular consequences, whether the cardiovascular adaptations normally conferred by exercise are blunted in adults not utilizing established OSA treatment is unknown. The aims of this study were to document whether OSA participants have abnormal CPET responses and determine whether exercise modifies these CPET markers in individuals with OSA. Methods The CPET responses of 43 sedentary, overweight adults (body mass index [BMI]>25) with untreated OSA (apnea-hypopnea index [AHI]≥15) were compared against matched non-OSA controls (n=9). OSA participants were then randomized to a 12-week exercise training (n=27) or stretching control treatment (n=16), followed by a post-intervention CPET. Measures of resting, exercise, and post-exercise recovery heart rate (HRR), blood pressure, and ventilation, as well as peak oxygen consumption (VO2peak), were obtained. Results OSA participants had blunted HRR compared to non-OSA controls at 1 (P=.03), 3 (P=.02), and 5 min post-exercise (P=.03). For OSA participants, exercise training improved VO2peak (P=.04) and HRR at 1 (P=.03), 3 (P<.01), and 5 min post-exercise (P<.001) compared to control. AHI change was associated with change in HRR at 5-min post-exercise (r=−.30, P<.05), but no other CPET markers. Conclusions These results suggest that individuals with OSA have autonomic dysfunction, and that exercise training, by increasing HRR and VO2peak, may attenuate autonomic imbalance and improve functional capacity independent of OSA severity reduction. PMID:22572632

Heart rate variability in male shift workers in automobile manufacturing factories in South Korea.

PubMed

Lee, Sangyoon; Kim, Ho; Kim, Dae-Hwan; Yum, Myunggul; Son, Mia

2015-10-01

The aim of this study was to determine the effect of circadian rhythm disruption on cardiovascular autonomic regulation by examining potential differences in heart rate variability (HRV) between day- and night-shift workers. The study population consisted of 162 workers who worked both day and night shifts in two automobile manufacturing companies who underwent ambulatory 24-h electrocardiogram recording and completed questionnaires and sleep diaries. Both time and frequency domain indices of HRV were compared. HRV parameters (mean RR, SDNN, RMSSD, pNN50, TP, HF, LF, LF/HF ratio) reflecting sympathetic and parasympathetic modulation varied less with activity in night-shift workers. Circadian rhythm-mediated changes in autonomic regulation of the cardiovascular system were blunted in night-shift workers, which could contribute to an increased risk for cardiovascular disease in overnight workers.

Depolarizing Actions of Hydrogen Sulfide on Hypothalamic Paraventricular Nucleus Neurons

PubMed Central

Khademullah, C. Sahara; Ferguson, Alastair V.

2013-01-01

Hydrogen sulfide (H2S) is a novel neurotransmitter that has been shown to influence cardiovascular functions as well and corticotrophin hormone (CRH) secretion. Since the paraventricular nucleus of the hypothalamus (PVN) is a central relay center for autonomic and endocrine functions, we sought to investigate the effects of H2S on the neuronal population of the PVN. Whole cell current clamp recordings were acquired from the PVN neurons and sodium hydrosulfide hydrate (NaHS) was bath applied at various concentrations (0.1, 1, 10, and 50 mM). NaHS (1, 10, and 50 mM) elicited a concentration-response relationship from the majority of recorded neurons, with almost exclusively depolarizing effects following administration. Cells responded and recovered from NaHS administration quickly and the effects were repeatable. Input differences from baseline and during the NaHS-induced depolarization uncovered a biphasic response, implicating both a potassium and non-selective cation conductance. The results from the neuronal population of the PVN shed light on the possible physiological role that H2S has in autonomic and endocrine function. PMID:23691233

Evolution and physiology of neural oxygen sensing

PubMed Central

Costa, Kauê M.; Accorsi-Mendonça, Daniela; Moraes, Davi J. A.; Machado, Benedito H.

2014-01-01

Major evolutionary trends in animal physiology have been heavily influenced by atmospheric O2 levels. Amongst other important factors, the increase in atmospheric O2 which occurred in the Pre-Cambrian and the development of aerobic respiration beckoned the evolution of animal organ systems that were dedicated to the absorption and transportation of O2, e.g., the respiratory and cardiovascular systems of vertebrates. Global variations of O2 levels in post-Cambrian periods have also been correlated with evolutionary changes in animal physiology, especially cardiorespiratory function. Oxygen transportation systems are, in our view, ultimately controlled by the brain related mechanisms, which senses changes in O2 availability and regulates autonomic and respiratory responses that ensure the survival of the organism in the face of hypoxic challenges. In vertebrates, the major sensorial system for oxygen sensing and responding to hypoxia is the peripheral chemoreflex neuronal pathways, which includes the oxygen chemosensitive glomus cells and several brainstem regions involved in the autonomic regulation of the cardiovascular system and respiratory control. In this review we discuss the concept that regulating O2 homeostasis was one of the primordial roles of the nervous system. We also review the physiology of the peripheral chemoreflex, focusing on the integrative repercussions of chemoreflex activation and the evolutionary importance of this system, which is essential for the survival of complex organisms such as vertebrates. The contribution of hypoxia and peripheral chemoreflex for the development of diseases associated to the cardiovascular and respiratory systems is also discussed in an evolutionary context. PMID:25161625

The relevance of central command for the neural cardiovascular control of exercise.

PubMed

Williamson, J W

2010-11-01

This paper briefly reviews the role of central command in the neural control of the circulation during exercise. While defined as a feedforward component of the cardiovascular control system, central command is also associated with perception of effort or effort sense. The specific factors influencing perception of effort and their effect on autonomic regulation of cardiovascular function during exercise can vary according to condition. Centrally mediated integration of multiple signals occurring during exercise certainly involves feedback mechanisms, but it is unclear whether or how these signals modify central command via their influence on perception of effort. As our understanding of central neural control systems continues to develop, it will be important to examine more closely how multiple sensory signals are prioritized and processed centrally to modulate cardiovascular responses during exercise. The purpose of this article is briefly to review the concepts underlying central command and its assessment via perception of effort, and to identify potential areas for future studies towards determining the role and relevance of central command for neural control of exercise.

The relevance of central command for the neural cardiovascular control of exercise

PubMed Central

Williamson, J W

2010-01-01

This paper briefly reviews the role of central command in the neural control of the circulation during exercise. While defined as a feedfoward component of the cardiovascular control system, central command is also associated with perception of effort or effort sense. The specific factors influencing perception of effort and their effect on autonomic regulation of cardiovascular function during exercise can vary according to condition. Centrally mediated integration of multiple signals occurring during exercise certainly involves feedback mechanisms, but it is unclear whether or how these signals modify central command via their influence on perception of effort. As our understanding of central neural control systems continues to develop, it will be important to examine more closely how multiple sensory signals are prioritized and processed centrally to modulate cardiovascular responses during exercise. The purpose of this article is briefly to review the concepts underlying central command and its assessment via perception of effort, and to identify potential areas for future studies towards determining the role and relevance of central command for neural control of exercise. PMID:20696787

System identification of closed-loop cardiovascular control: effects of posture and autonomic blockade

NASA Technical Reports Server (NTRS)

Mullen, T. J.; Appel, M. L.; Mukkamala, R.; Mathias, J. M.; Cohen, R. J.

1997-01-01

We applied system identification to the analysis of fluctuations in heart rate (HR), arterial blood pressure (ABP), and instantaneous lung volume (ILV) to characterize quantitatively the physiological mechanisms responsible for the couplings between these variables. We characterized two autonomically mediated coupling mechanisms [the heart rate baroreflex (HR baroreflex) and respiratory sinus arrhythmia (ILV-HR)] and two mechanically mediated coupling mechanisms [the blood pressure wavelet generated with each cardiac contraction (circulatory mechanics) and the direct mechanical effects of respiration on blood pressure (ILV-->ABP)]. We evaluated the method in humans studied in the supine and standing postures under control conditions and under conditions of beta-sympathetic and parasympathetic pharmacological blockades. Combined beta-sympathetic and parasympathetic blockade abolished the autonomically mediated couplings while preserving the mechanically mediated coupling. Selective autonomic blockade and postural changes also altered the couplings in a manner consistent with known physiological mechanisms. System identification is an "inverse-modeling" technique that provides a means for creating a closed-loop model of cardiovascular regulation for an individual subject without altering the underlying physiological control mechanisms.

High job control enhances vagal recovery in media work.

PubMed

Lindholm, Harri; Sinisalo, Juha; Ahlberg, Jari; Jahkola, Antti; Partinen, Markku; Hublin, Christer; Savolainen, Aslak

2009-12-01

Job strain has been linked to increased risk of cardiovascular diseases. In modern media work, time pressures, rapidly changing situations, computer work and irregular working hours are common. Heart rate variability (HRV) has been widely used to monitor sympathovagal balance. Autonomic imbalance may play an additive role in the development of cardiovascular diseases. To study the effects of work demands and job control on the autonomic nervous system recovery among the media personnel. From the cross-sectional postal survey of the employees in Finnish Broadcasting Company (n = 874), three age cohorts (n = 132) were randomly selected for an analysis of HRV in 24 h electrocardiography recordings. In the middle-aged group, those who experienced high job control had significantly better vagal recovery than those with low or moderate control (P < 0.01). Among young and ageing employees, job control did not associate with autonomic recovery. High job control over work rather than low demands seemed to enhance autonomic recovery in middle-aged media workers. This was independent of poor health habits such as smoking, physical inactivity or alcohol consumption.

Mass Transport: Circulatory System with Emphasis on Nonendothermic Species.

PubMed

Crossley, Dane A; Burggren, Warren W; Reiber, Carl L; Altimiras, Jordi; Rodnick, Kenneth J

2016-12-06

Mass transport can be generally defined as movement of material matter. The circulatory system then is a biological example given its role in the movement in transporting gases, nutrients, wastes, and chemical signals. Comparative physiology has a long history of providing new insights and advancing our understanding of circulatory mass transport across a wide array of circulatory systems. Here we focus on circulatory function of nonmodel species. Invertebrates possess diverse convection systems; that at the most complex generate pressures and perform at a level comparable to vertebrates. Many invertebrates actively modulate cardiovascular function using neuronal, neurohormonal, and skeletal muscle activity. In vertebrates, our understanding of cardiac morphology, cardiomyocyte function, and contractile protein regulation by Ca2+ highlights a high degree of conservation, but differences between species exist and are coupled to variable environments and body temperatures. Key regulators of vertebrate cardiac function and systemic blood pressure include the autonomic nervous system, hormones, and ventricular filling. Further chemical factors regulating cardiovascular function include adenosine, natriuretic peptides, arginine vasotocin, endothelin 1, bradykinin, histamine, nitric oxide, and hydrogen sulfide, to name but a few. Diverse vascular morphologies and the regulation of blood flow in the coronary and cerebral circulations are also apparent in nonmammalian species. Dynamic adjustments of cardiovascular function are associated with exercise on land, flying at high altitude, prolonged dives by marine mammals, and unique morphology, such as the giraffe. Future studies should address limits of gas exchange and convective transport, the evolution of high arterial pressure across diverse taxa, and the importance of the cardiovascular system adaptations to extreme environments. © 2017 American Physiological Society. Compr Physiol 7:17-66, 2017. Copyright © 2017 John Wiley & Sons, Inc.

Whole and particle-free diesel exhausts differentially affect cardiac electrophysiology, blood pressure, and autonomic balance in heart failure-prone rats

EPA Science Inventory

Epidemiologic studies strongly link short-term exposures to vehicular traffic and particulate matter (PM) air pollution with adverse cardiovascular events, especially in those with preexisting cardiovascular disease. Diesel engine exhaust (DE) is a key contributor to urban ambien...

Bilateral Renal Denervation Ameliorates Isoproterenol-Induced Heart Failure through Downregulation of the Brain Renin-Angiotensin System and Inflammation in Rat

PubMed Central

Li, Jian-Dong; Cheng, Ai-Yuan; Huo, Yan-Li; Fan, Jie; Zhang, Yu-Ping; Fang, Zhi-Qin; Sun, Hong-Sheng; Peng, Wei; Zhang, Jin-Shun

2016-01-01

Heart failure (HF) is characterized by cardiac dysfunction along with autonomic unbalance that is associated with increased renin-angiotensin system (RAS) activity and elevated levels of proinflammatory cytokines (PICs). Renal denervation (RD) has been shown to improve cardiac function in HF, but the protective mechanisms remain unclear. The present study tested the hypothesis that RD ameliorates isoproterenol- (ISO-) induced HF through regulation of brain RAS and PICs. Chronic ISO infusion resulted in remarked decrease in blood pressure (BP) and increase in heart rate and cardiac dysfunction, which was accompanied by increased BP variability and decreased baroreflex sensitivity and HR variability. Most of these adverse effects of ISO on cardiac and autonomic function were reversed by RD. Furthermore, ISO upregulated mRNA and protein expressions of several components of the RAS and PICs in the lamina terminalis and hypothalamic paraventricular nucleus, two forebrain nuclei involved in cardiovascular regulations. RD significantly inhibited the upregulation of these genes. Either intracerebroventricular AT1-R antagonist, irbesartan, or TNF-α inhibitor, etanercept, mimicked the beneficial actions of RD in the ISO-induced HF. The results suggest that the RD restores autonomic balance and ameliorates ISO-induced HF and that the downregulated RAS and PICs in the brain contribute to these beneficial effects of RD. PMID:27746855

A prominent role for amygdaloid complexes in the Variability in Heart Rate (VHR) during Rapid Eye Movement (REM) sleep relative to wakefulness.

PubMed

Desseilles, Martin; Vu, Thanh Dang; Laureys, Steven; Peigneux, Philippe; Degueldre, Christian; Phillips, Christophe; Maquet, Pierre

2006-09-01

Rapid eye movement sleep (REMS) is associated with intense neuronal activity, rapid eye movements, muscular atonia and dreaming. Another important feature in REMS is the instability in autonomic, especially in cardiovascular regulation. The neural mechanisms underpinning the variability in heart rate (VHR) during REMS are not known in detail, especially in humans. During wakefulness, the right insula has frequently been reported as involved in cardiovascular regulation but this might not be the case during REMS. We aimed at characterizing the neural correlates of VHR during REMS as compared to wakefulness and to slow wave sleep (SWS), the other main component of human sleep, in normal young adults, based on the statistical analysis of a set of H(2)(15)O positron emission tomography (PET) sleep data acquired during SWS, REMS and wakefulness. The results showed that VHR correlated more tightly during REMS than during wakefulness with the rCBF in the right amygdaloid complex. Moreover, we assessed whether functional relationships between amygdala and any brain area changed depending the state of vigilance. Only the activity within in the insula was found to covary with the amygdala, significantly more tightly during wakefulness than during REMS in relation to the VHR. The functional connectivity between the amygdala and the insular cortex, two brain areas involved in cardiovascular regulation, differs significantly in REMS as compared to wakefulness. This suggests a functional reorganization of central cardiovascular regulation during REMS.

Neural Control of the Circulation: How Sex and Age Differences Interact in Humans

PubMed Central

Joyner, Michael J.; Barnes, Jill N.; Hart, Emma C.; Wallin, B. Gunnar; Charkoudian, Nisha

2015-01-01

The autonomic nervous system is a key regulator of cardiovascular system. In this review we focus on how sex and aging influence autonomic regulation of blood pressure in humans in an effort to understand general issues related to how the autonomic nervous system regulates blood pressure, and the cardiovascular system as a whole. Younger women generally have lower blood pressure and sympathetic activity than younger men. However, both sexes show marked inter-individual variability across age groups with significant overlap seen. Additionally, while men across the lifespan show a clear relationship between markers of whole body sympathetic activity and vascular resistance, such a relationship is not seen in young women. In this context, the ability of the sympathetic nerves to evoke vasoconstriction is lower in young women likely as a result of concurrent β2 mediated vasodilation that offsets α-adrenergic vasoconstriction. These differences reflect both central sympatho-inhibitory effects of estrogen and also its influence on peripheral vasodilation at the level of the vascular smooth muscle and endothelium. By contrast post-menopausal women show a clear relationship between markers of whole body sympathetic traffic and vascular resistance, and sympathetic activity rises progressively in both sexes with aging. These central findings in humans are discussed in the context of differences in population-based trends in blood pressure and orthostatic intolerance. The many areas where there is little sex-specific data on how the autonomic nervous system participates in the regulation of the human cardiovascular system are highlighted. PMID:25589269

Effect of inspiratory muscle training with load compared with sham training on blood pressure in individuals with hypertension: study protocol of a double-blind randomized clinical trial.

PubMed

Posser, Simone Regina; Callegaro, Carine Cristina; Beltrami-Moreira, Marina; Moreira, Leila Beltrami

2016-08-02

Hypertension is a complex chronic condition characterized by elevated arterial blood pressure. Management of hypertension includes non-pharmacologic strategies, which may include techniques that effectively reduce autonomic sympathetic activity. Respiratory exercises improve autonomic control over cardiovascular system and attenuate muscle metaboreflex. Because of these effects, respiratory exercises may be useful to lower blood pressure in subjects with hypertension. This randomized, double-blind clinical trial will test the efficacy of inspiratory muscle training in reducing blood pressure in adults with essential hypertension. Subjects are randomly allocated to intervention or control groups. Intervention consists of inspiratory muscle training loaded with 40 % of maximum inspiratory pressure, readjusted weekly. Control sham intervention consists of unloaded exercises. Systolic and diastolic blood pressures are co-primary endpoint measures assessed with 24 h ambulatory blood pressure monitoring. Secondary outcome measures include cardiovascular autonomic control, inspiratory muscle metaboreflex, cardiopulmonary capacity, and inspiratory muscle strength and endurance. Previously published work suggests that inspiratory muscle training reduces blood pressure in persons with hypertension, but the effectiveness of this intervention is yet to be established. We propose an adequately sized randomized clinical trial to test this hypothesis rigorously. If an effect is found, this study will allow for the investigation of putative mechanisms to mediate this effect, including autonomic cardiovascular control and metaboreflex. ClinicalTrials.gov NCT02275377 . Registered on 30 September 2014.

Assessment of cardiac autonomic functions by heart rate recovery, heart rate variability and QT dynamicity parameters in patients with acromegaly.

PubMed

Dural, Muhammet; Kabakcı, Giray; Cınar, Neşe; Erbaş, Tomris; Canpolat, Uğur; Gürses, Kadri Murat; Tokgözoğlu, Lale; Oto, Ali; Kaya, Ergün Barış; Yorgun, Hikmet; Sahiner, Levent; Dağdelen, Selçuk; Aytemir, Kudret

2014-04-01

Cardiovascular complications are the most common causes of morbidity and mortality in acromegaly. However, there is little data regarding cardiac autonomic functions in these patients. Herein, we aimed to investigate several parameters of cardiac autonomic functions in patients with acromegaly compared to healthy subjects. We enrolled 20 newly diagnosed acromegalic patients (55% female, age:45.7 ± 12.6 years) and 32 age- and gender-matched healthy subjects. All participants underwent 24 h Holter recording. Heart rate recovery (HRR) indices were calculated by subtracting 1st, 2nd and 3rd minute heart rates from maximal heart rate. All patients underwent heart rate variability (HRV) and QT dynamicity analysis. Baseline characteristics were similar except diabetes mellitus and hypertension among groups. Mean HRR1 (29.2 ± 12.3 vs 42.6 ± 6.5, p = 0.001), HRR2 (43.5 ± 15.6 vs 61.1 ± 10.8, p = 0.001) and HRR3 (46.4 ± 16.2 vs 65.8 ± 9.8, p = 0.001) values were significantly higher in control group. HRV parameters as, SDNN [standard deviation of all NN intervals] (p = 0.001), SDANN [SD of the 5 min mean RR intervals] (p = 0.001), RMSSD [root square of successive differences in RR interval] (p = 0.001), PNN50 [proportion of differences in successive NN intervals >50 ms] (p = 0.001) and high-frequency [HF] (p = 0.001) were significantly decreased in patients with acromegaly; but low frequency [LF] (p = 0.046) and LF/HF (p = 0.001) were significantly higher in acromegaly patients. QTec (p = 0.009), QTac/RR slope (p = 0.017) and QTec/RR slope (p = 0.01) were significantly higher in patients with acromegaly. Additionally, there were significant negative correlation of disease duration with HRR2, HRR3, SDNN, PNN50, RMSSD, variability index. Our study results suggest that cardiac autonomic functions are impaired in patients with acromegaly. Further large scale studies are needed to exhibit the prognostic significance of impaired autonomic functions in patients with acromegaly.

Chronic stress impacts the cardiovascular system: animal models and clinical outcomes.

PubMed

Golbidi, Saeid; Frisbee, Jefferson C; Laher, Ismail

2015-06-15

Psychological stresses are associated with cardiovascular diseases to the extent that cardiovascular diseases are among the most important group of psychosomatic diseases. The longstanding association between stress and cardiovascular disease exists despite a large ambiguity about the underlying mechanisms. An array of possibilities have been proposed including overactivity of the autonomic nervous system and humoral changes, which then converge on endothelial dysfunction that initiates unwanted cardiovascular consequences. We review some of the features of the two most important stress-activated systems, i.e., the humoral and nervous systems, and focus on alterations in endothelial function that could ensue as a result of these changes. Cardiac and hematologic consequences of stress are also addressed briefly. It is likely that activation of the inflammatory cascade in association with oxidative imbalance represents key pathophysiological components of stress-induced cardiovascular changes. We also review some of the commonly used animal models of stress and discuss the cardiovascular outcomes reported in these models of stress. The unique ability of animals for adaptation under stressful conditions lessens the extrapolation of laboratory findings to conditions of human stress. An animal model of unpredictable chronic stress, which applies various stress modules in a random fashion, might be a useful solution to this predicament. The use of stress markers as indicators of stress intensity is also discussed in various models of animal stress and in clinical studies. Copyright © 2015 the American Physiological Society.

Living alongside railway tracks: Long-term effects of nocturnal noise on sleep and cardiovascular reactivity as a function of age.

PubMed

Tassi, Patricia; Rohmer, Odile; Schimchowitsch, Sarah; Eschenlauer, Arnaud; Bonnefond, Anne; Margiocchi, Florence; Poisson, Franck; Muzet, Alain

2010-10-01

Very few studies were devoted to permanent effects of nocturnal railway noise on sleep and cardiovascular reactivity. We investigated the effects of nocturnal railway noise on sleep and cardiovascular response in young and middle-aged adults living for many years either near a railway track or in a quiet area. Forty subjects (50% males) divided into two age groups (juniors: 26.2+/-3.6 and seniors: 56.2+/-4.2) participated in this experiment. Half of them lived near a railway track (RW group: 2.6 to 19 years) and the other half in a quiet environment (QE group: 8.1 to 14.2 years). After an adaptation night, all subjects underwent two nights in the laboratory: one control night and one noisy night (30 by-passes of a freight train). Sleep and cardiovascular modifications were assessed in response to noise. Sleep fragmentation indices were lower in RW subjects compared to QE whatever their age. In response to noise, there was a higher cardiovascular response rate to noise in RW juniors and a lower cardiovascular response rate in RW seniors compared to their age-paired QE counterparts. In conclusion, permanent exposure to nocturnal railway noise leads to decreased sleep fragmentation and to cardiovascular habituation. It is suggested that during the initial period experienced by residents living near railway tracks, nocturnal railway noise could induce a sensitization process on the autonomic response to noise reflecting a startle/defense reflex due to its functional significance, which progressively turns to habituation in the long-term if no adverse effect is experienced. Copyright 2010 Elsevier Ltd. All rights reserved.

Noninvasive methods in space cardiology.

PubMed

Baevsky, R M

1997-01-01

The development and application of noninvasive methods in space cardiology is discussed. These methods are used in astronautics both to gain new insights into the impact of weightlessness conditions on the human organism and to help solve problems involved in the medical monitoring of space crew members. The cardiovascular system is a major target for the action of microgravity. Noninvasive methods used to examine the cardiovascular system during space flights over the past 30 years are listed. Special attention is given to methods for studying heart rate variability and contactless recording of physiologic functions during night sleep. Analysis of heart rate variability highlights an important principle of space cardiology-gaining the maximum amount of information while recording as little data as possible. With this method, the degree of strain experienced by the systems of autonomic regulation and the adaptational capabilities of the body can be assessed at various stages of a space flight. Discriminant analysis of heart rate variability data enables the psycho-emotional component of stress to be separated from the component associated with the impact of weightlessness. A major advance in space medicine has been the development of techniques for contactless recording of pulse rates, breathing frequency, myocardial contractility, and motor activity during sleep using a sensor installed on the cosmonaut's sleeping bag. The data obtained can be used to study ultradian rhythms, which reflect the activity of higher autonomic centers. An important role of these centers in mobilizing functional reserves of the body to ensure its relatively stable adaptation to weightless conditions is shown.

Diurnal and nocturnal cardiovascular variability and heart rate arousal response in idiopathic hypersomnia.

PubMed

Sforza, Emilia; Roche, Frédéric; Barthélémy, Jean Claude; Pichot, Vincent

2016-08-01

Autonomic nervous system dysfunction has been described in narcolepsy with cataplexy affecting sympathetic functions. In this study we analyzed whether altered diurnal and nocturnal cardiovascular control is present in idiopathic hypersomnia (IH). Fourteen drug-free patients aged 26.2 ± 7 years and 14 age-matched controls were examined. Clinical data, 24-h polysomnography, heart rate (HR) variability, and the HR response to spontaneous arousal were available. Sleep macrostructure was comparable between controls and patients, with the latter having significantly longer sleep time, a higher number of sleep cycles (p < 0.0001), and low sleep efficiency (p < 0.01). The HR variability indices did not differ between groups, except for the rise of high frequency (HF) and HFnu in patients (p < 0.05) associated with blunted sympathetic indices (p < 0.01). These parasympathetic alterations were present for light, slow wave, and rapid eye-movement sleep and persisted for all sleep cycles. Compared to controls, the HR arousal response was significantly higher (p < 0.01) in patients starting before the arousal onset and persisting into the post-arousal period. In IH patients a dysfunction of the parasympathetic activity during awake and sleep and an altered autonomic response to arousals are present. These findings suggest an impaired parasympathetic function that may explain some vegetative symptoms present in this type of central hypersomnia. Copyright © 2016 Elsevier B.V. All rights reserved.

Autoimmune Basis for Postural Tachycardia Syndrome

ClinicalTrials.gov

2018-01-23

Postural Orthostatic Tachycardia Syndrome; Postural Tachycardia Syndrome; Tachycardia; Arrhythmias, Cardiac; Autonomic Nervous System Diseases; Orthostatic Intolerance; Cardiovascular Diseases; Primary Dysautonomias

Autonomic control of the heart is altered in Sprague-Dawley rats with spontaneous hydronephrosis

PubMed Central

Arnold, Amy C.; Shaltout, Hossam A.; Gilliam-Davis, Shea; Kock, Nancy D.

2011-01-01

The renal medulla plays an important role in cardiovascular regulation, through interactions with the autonomic nervous system. Hydronephrosis is characterized by substantial loss of renal medullary tissue. However, whether alterations in autonomic control of the heart are observed in this condition is unknown. Thus we assessed resting hemodynamics and baroreflex sensitivity (BRS) for control of heart rate in urethane/chloralose-anesthetized Sprague-Dawley rats with normal or hydronephrotic kidneys. While resting arterial pressure was similar, heart rate was higher in rats with hydronephrosis (290 ± 12 normal vs. 344 ± 11 mild/moderate vs. 355 ± 13 beats/min severe; P < 0.05). The evoked BRS to increases, but not decreases, in pressure was lower in hydronephrotic rats (1.06 ± 0.06 normal vs. 0.72 ± 0.10 mild/moderate vs. 0.63 ± 0.07 ms/mmHg severe; P < 0.05). Spectral analysis methods confirmed reduced parasympathetic function in hydronephrosis, with no differences in measures of indirect sympathetic activity among conditions. As a secondary aim, we investigated whether autonomic dysfunction in hydronephrosis is associated with activation of the renin-angiotensin system (RAS). There were no differences in circulating angiotensin peptides among conditions, suggesting that the impaired autonomic function in hydronephrosis is independent of peripheral RAS activation. A possible site for angiotensin II-mediated BRS impairment is the solitary tract nucleus (NTS). In normal and mild/moderate hydronephrotic rats, NTS administration of the angiotensin II type 1 receptor antagonist candesartan significantly improved the BRS, suggesting that angiotensin II provides tonic suppression to the baroreflex. In contrast, angiotensin II blockade produced no significant effect in severe hydronephrosis, indicating that at least within the NTS baroreflex suppression in these animals is independent of angiotensin II. PMID:21460193

Diagnosing and treating neurogenic orthostatic hypotension in primary care.

PubMed

Kuritzky, Louis; Espay, Alberto J; Gelblum, Jeffrey; Payne, Richard; Dietrich, Eric

2015-01-01

In response to a change in posture from supine or sitting to standing, autonomic reflexes normally maintain blood pressure (BP) by selective increases in arteriovenous resistance and by increased cardiac output, ensuring continued perfusion of the central nervous system. In neurogenic orthostatic hypotension (NOH), inadequate vasoconstriction and cardiac output cause BP to drop excessively, resulting in inadequate perfusion, with predictable symptoms such as dizziness, lightheadedness and falls. The condition may represent a central failure of baroreceptor signals to modulate cardiovascular function, a peripheral failure of norepinephrine release from cardiovascular sympathetic nerve endings, or both. Symptomatic patients may benefit from both non-pharmacologic and pharmacologic interventions. Among the latter, two pressor agents have been approved by the US Food and Drug Administration: the sympathomimetic prodrug midodrine, approved in 1996 for symptomatic orthostatic hypotension, and the norepinephrine prodrug droxidopa, approved in 2014, which is indicated for the treatment of symptomatic neurogenic orthostatic hypotension caused by primary autonomic failure (Parkinson's disease, multiple system atrophy and pure autonomic failure). A wide variety of off-label options also have been described (e.g. the synthetic mineralocorticoid fludrocortisone). Because pressor agents may promote supine hypertension, NOH management requires monitoring of supine BP and also lifestyle measures to minimize supine BP increases (e.g. head-of-bed elevation). However, NOH has been associated with cognitive impairment and increases a patient's risk of syncope and falls, with the potential for serious consequences. Hence, concerns about supine hypertension - for which the long-term prognosis in patients with NOH is yet to be established - must sometimes be balanced by the need to address a patient's immediate risks.

Rapid-onset obesity with hypothalamic dysfunction, hypoventilation, and autonomic dysregulation (ROHHAD): Response to ventilatory challenges.

PubMed

Carroll, Michael S; Patwari, Pallavi P; Kenny, Anna S; Brogadir, Cindy D; Stewart, Tracey M; Weese-Mayer, Debra E

2015-12-01

Hypoventilation is a defining feature of Rapid-onset Obesity with Hypothalamic dysfunction, Hypoventilation and Autonomic Dysregulation (ROHHAD), a rare respiratory and autonomic disorder. This chronic hypoventilation has been explained as the result of dysfunctional chemosensory control circuits, possibly affecting peripheral afferent input, central integration, or efferent motor control. However, chemosensory function has never been quantified in a cohort of ROHHAD patients. Therefore, the purpose of this study was to assess the response to awake ventilatory challenge testing in children and adolescents with ROHHAD. The ventilatory, cardiovascular and cerebrovascular responses in 25 distinct comprehensive physiological recordings from seven unique ROHHAD patients to three different gas mixtures were analyzed at breath-to-breath and beat-to-beat resolution as absolute measures, as change from baseline, or with derived metrics. Physiologic measures were recorded during a 3-min baseline period of room air, a 3-min gas exposure (of 100% O2; 95% O2, 5% CO2; or 14% O2, 7% CO2 balanced with N2), and a 3-min recovery period. An additional hypoxic challenge was conducted which consisted of either five or seven tidal breaths of 100% N2. While ROHHAD cases showed a diminished VT and inspiratory drive response to hypoxic hypercapnia and absent behavioral awareness of the physiologic compromise, most ventilatory, cardiovascular, and cerebrovascular measures were similar to those of previously published controls using an identical protocol, suggesting a mild chemosensory deficit. Nonetheless, the high mortality rate, comorbidity and physiological fragility of patients with ROHHAD demand continued clinical vigilance. © 2015 Wiley Periodicals, Inc.

Cardiovascular Safety of Droxidopa in Patients With Symptomatic Neurogenic Orthostatic Hypotension.

PubMed

White, William B; Hauser, Robert A; Rowse, Gerald J; Ziemann, Adam; Hewitt, L Arthur

2017-04-01

The norepinephrine prodrug droxidopa improves symptoms of neurogenic orthostatic hypotension, a condition that is associated with diseases of neurogenic autonomic failure (e.g., Parkinson disease, multiple system atrophy, pure autonomic failure). These conditions are more prevalent in older patients who also have cardiovascular co-morbidities. Hence, we evaluated the cardiovascular safety of droxidopa in patients with symptomatic neurogenic orthostatic hypotension who participated in randomized controlled studies (short-term studies of 1 to 2 weeks and an intermediate 8- to 10-week study) and long-term open-label studies. Rates of cardiovascular adverse events (AEs) for patients treated with droxidopa were 4.4% in the intermediate study and 10.8% in the long-term open-label studies. Adjusting for exposure time, cardiovascular AE rates were 0.30 events/patient-year in the short-term and intermediate studies and 0.15 events/patient-year in the long-term open-label studies. The incidence of treatment discontinuation due to blood pressure-related events was approximately 2.5%. Among patients with a history of cardiac disorders at baseline, the rates of cardiovascular-related and blood pressure-related AEs were nominally higher with droxidopa compared to placebo. Most of these events were minor atrial arrhythmias; none were major adverse cardiovascular events or deaths. In conclusion, small increases in cardiovascular AEs were observed with droxidopa compared to placebo; this was most evident in patients with preexisting cardiac disorders. Copyright © 2017 The Author(s). Published by Elsevier Inc. All rights reserved.

Heart Rate Complexity in Response to Upright Tilt in Persons with Down Syndrome

ERIC Educational Resources Information Center

Agiovlasitis, Stamatis; Baynard, Tracy; Pitetti, Kenneth H.; Fernhall, Bo

2011-01-01

People with Down syndrome (DS) show altered autonomic response to sympatho-excitation. Cardiac autonomic modulation may be examined with heart rate (HR) complexity which is associated uniquely with cardiovascular risk. This study examined whether the response of HR complexity to passive upright tilt differs between persons with and without DS and…

Historical Review of Lower Body Negative Pressure Research in Space Medicine.

PubMed

Campbell, Mark R; Charles, John B

2015-07-01

Cephalad redistribution of intravascular and extravascular fluid occurs as a result of weightlessness during spaceflight. This provokes cardiovascular, cardiopulmonary, and autonomic nervous system responses. The resulting altered functional state can result in orthostatic hypotension and intolerance upon landing and return to a gravity environment. In-flight lower body negative pressure (LBNP) transiently restores normal body fluid distribution. Early in the U.S. space program, LBNP was devised as a way to test for orthostatic intolerance. With the development of the Skylab Program and longer duration spaceflight, it was realized that it could provide a method of monitoring orthostatic intolerance in flight and predicting the post-landing orthostatic response. LBNP was also investigated not only as an in-flight cardiovascular orthostatic stress test, but also as a countermeasure to cardiovascular deconditioning on Soviet space stations, Skylab, and the Shuttle. It is still being used by the Russian program on the International Space Station as an end-of-flight countermeasure.

Depression and cardiovascular disease: Epidemiological evidence on their linking mechanisms.

PubMed

Penninx, Brenda W J H

2017-03-01

Depression's burden of disease goes beyond functioning and quality of life and extends to somatic health. Results from longitudinal cohort studies converge in illustrating that major depressive disorder (MDD) subsequently increases the risk of cardiovascular morbidity and mortality with about 80%. The impact of MDD on cardiovascular health may be partly explained by mediating mechanisms such as unhealthy lifestyle (smoking, excessive alcohol use, physical inactivity, unhealthy diet, therapy non-compliance) and unfavorable pathophysiological disturbances (autonomic, HPA-axis, metabolic and immuno-inflammatory dysregulations). A summary of the literature findings as well as relevant results from the large-scale Netherlands Study of Depression and Anxiety (N=2981) are presented. Persons with MDD have significantly worse lifestyles as well as more pathophysiological disturbances as compared to healthy controls. Some of these differences seem to be specific for (typical versus 'atypical', or antidepressant treated versus drug-naive) subgroups of MDD patients. Alternative explanations are also present, namely undetected confounding, iatrogenic effects or 'third factors' such as genetics. Copyright © 2016 Elsevier Ltd. All rights reserved.

Metabolic, autonomic and immune markers for cardiovascular disease in posttraumatic stress disorder

PubMed Central

Kibler, Jeffrey L; Tursich, Mischa; Ma, Mindy; Malcolm, Lydia; Greenbarg, Rachel

2014-01-01

Posttraumatic stress disorder (PTSD) has been associated with significantly greater incidence of heart disease. Numerous studies have indicated that health problems for individuals with PTSD occur earlier in life than in the general population. Multiple mechanistic pathways have been suggested to explain cardiovascular disese (CVD) risk in PTSD, including neurochemical, behavioral, and immunological changes. The present paper is a review of recent research that examines cardiovascular and immune risk profiles of individuals with PTSD. First, we address the relatively new evidence that the constellation of risk factors commonly experienced in PTSD fits the profile of metabolic syndrome. Next we examine the findings concerning hypertension/blood pressure in particular. The literature on sympathetic and parasympathetic responsivity in PTSD is reviewed. Last, we discuss recent findings concerning immune functioning in PTSD that may have a bearing on the high rates of CVD and other illnesses. Our primary goal is to synthesize the existing literature by examining factors that overlap mechanistically to increase the risk of developing CVD in PTSD. PMID:24976918

Cholinergic stimulation with pyridostigmine improves autonomic function in infarcted rats.

PubMed

de La Fuente, Raquel N; Rodrigues, Bruno; Moraes-Silva, Ivana C; Souza, Leandro E; Sirvente, Raquel; Mostarda, Cristiano; De Angelis, Kátia; Soares, Pedro P; Lacchini, Silvia; Consolim-Colombo, Fernanda; Irigoyen, Maria-Cláudia

2013-09-01

In the present study we evaluated the effects of short-term pyridostigmine bromide (0.14 mg/mL) treatment started early after myocardial infarction (MI) on left ventricular (LV) and autonomic functions in rats. Male Wistar rats were divided into control, pyridostigmine, infarcted and infarcted + pyridostigmine-treated groups. Pyridostigmine was administered in the drinking water, starting immediately after MI or sham operation, for 11 days. Left ventricular function was evaluated indirectly by echocardiography and directly by LV catheterization. Cardiovascular autonomic control was evaluated by baroreflex sensitivity (BRS), heart rate variability (HRV) and pharmacological blockade. All evaluations started after 7 days pyridostigmine treatment and were finalized after 11 days treatment. Pyridostigmine prevented the impairment of +dP/dT and reduced the MI area in infarcted + pyridostigmine compared with infarcted rats (7 ± 3% vs 17 ± 4%, respectively). Mean blood pressure was restored in infarcted + pyridostigmine compared with infarcted rats (103 ± 3 vs 94 ± 3 mmHg, respectively). In addition, compared with the infarcted group, pyridostigmine improved BRS, as evaluated by tachycardic (1.6 ± 0.2 vs 2.5 ± 0.2 b.p.m./mmHg, respectively) and bradycardic (-0.42 ± 0.01 vs -1.9 ± 0.1 b.p.m./mmHg) responses, and reduced the low frequency/high frequency ratio of HRV (0.81 ± 0.11 vs 0.24 ± 0.14, respectively). These improvements are probably associated with increased vagal tone and reduced sympathetic tone in infarcted + pyridostigmine compared with infarcted rats. In conclusion, the data suggest that short-term pyridostigmine treatment started early after MI can improve BRS, HRV and parasympathetic and sympathetic tone in experimental rats. These data may have potential clinical implications because autonomic markers have prognostic significance after MI. © 2013 Wiley Publishing Asia Pty Ltd.

Effectiveness of a Novel Qigong Meditative Movement Practice for Impaired Health in Flight Attendants Exposed to Second-Hand Cigarette Smoke.

PubMed

Payne, Peter; Fiering, Steven; Leiter, James C; Zava, David T; Crane-Godreau, Mardi A

2017-01-01

This single-arm non-randomized pilot study explores an intervention to improve the health of flight attendants (FA) exposed to second-hand cigarette smoke prior to the smoking ban on commercial airlines. This group exhibits an unusual pattern of long-term pulmonary dysfunction. We report on Phase I of a two-phase clinical trial; the second Phase will be a randomized controlled trial testing digital delivery of the intervention. Subjects were recruited in the Northeastern US; testing and intervention were administered in 4 major cities. The intervention involved 12 h of training in Meditative Movement practices. Based on recent research on the effects of nicotine on fear learning, and the influence of the autonomic nervous system on immune function, our hypothesis was that this training would improve autonomic function and thus benefit a range of health measures. Primary outcomes were the 6-min walk test and blood levels of C-reactive protein. Pulmonary, cardiovascular, autonomic, and affective measures were also taken. Fourteen participants completed the training and post-testing. There was a 53% decrease in high sensitivity C-Reactive Protein ( p ≤ 0.05), a 7% reduction in systolic blood pressure ( p ≤ 0.05), a 13% increase in the 6-min walk test ( p ≤ 0.005), and significant positive changes in several other outcomes. These results tend to confirm the hypothesized benefits of MM training for this population, and indicate that autonomic function may be important in the etiology and treatment of their symptoms. No adverse effects were reported. This trial is registered at ClinicalTrials.gov (https://clinicaltrials.gov/ct2/show/NCT02612389/), and is supported by a grant from the Flight Attendant Medical Research Institute (FAMRI).

Dynamic interactions between musical, cardiovascular, and cerebral rhythms in humans.

PubMed

Bernardi, Luciano; Porta, Cesare; Casucci, Gaia; Balsamo, Rossella; Bernardi, Nicolò F; Fogari, Roberto; Sleight, Peter

2009-06-30

Reactions to music are considered subjective, but previous studies suggested that cardiorespiratory variables increase with faster tempo independent of individual preference. We tested whether compositions characterized by variable emphasis could produce parallel instantaneous cardiovascular/respiratory responses and whether these changes mirrored music profiles. Twenty-four young healthy subjects, 12 musicians (choristers) and 12 nonmusician control subjects, listened (in random order) to music with vocal (Puccini's "Turandot") or orchestral (Beethoven's 9th Symphony adagio) progressive crescendos, more uniform emphasis (Bach cantata), 10-second period (ie, similar to Mayer waves) rhythmic phrases (Giuseppe Verdi's arias "Va pensiero" and "Libiam nei lieti calici"), or silence while heart rate, respiration, blood pressures, middle cerebral artery flow velocity, and skin vasomotion were recorded.Common responses were recognized by averaging instantaneous cardiorespiratory responses regressed against changes in music profiles and by coherence analysis during rhythmic phrases. Vocal and orchestral crescendos produced significant (P=0.05 or better) correlations between cardiovascular or respiratory signals and music profile, particularly skin vasoconstriction and blood pressures, proportional to crescendo, in contrast to uniform emphasis, which induced skin vasodilation and reduction in blood pressures. Correlations were significant both in individual and group-averaged signals. Phrases at 10-second periods by Verdi entrained the cardiovascular autonomic variables. No qualitative differences in recorded measurements were seen between musicians and nonmusicians. Music emphasis and rhythmic phrases are tracked consistently by physiological variables. Autonomic responses are synchronized with music, which might therefore convey emotions through autonomic arousal during crescendos or rhythmic phrases.

[Hypertension, cardiovascular reactivity to stress and sensibility to pain].

PubMed

Conde-Guzón, P A; Bartolomé-Albistegui, M T; Quirós-Expósito, P; Grzib-Schlosky, G

To provide a review of empirical evidence of decreased pain perception in hypertensive persons or exaggerated cardiovascular reactivity to stress. To following article will briefly review the existing literature on the association between hypoalgesia and high blood pressure. In particular, evidence of hypoalgesia in normotensive individuals at increased risk for hypertension (exaggerated cardiovascular reactivity to stress) will be offered in support of the notion that high cardiovascular reactivity to stress and decreased pain perception may result from a common physiological dysfunction. Cardiovascular reactivity refers to changes in cardiovascular activity associated primarily with exposure to psychological stress. Different individuals show different amounts of reactivity under the same conditions. The greater cardiovascular reactivity to behavioral stressors may play some role in the development of sustained arterial hypertension. Central opioid hyposensitivity is hypothesized as a mechanism of both hypoalgesia and exaggerated autonomic and neuroendocrine responses to stress in individuals at risk for hypertension. The paraventricular nucleus of the hypothalamus (PVN) serves the crucial function of integrating cardiovascular and painful responses. The central opioid hyposensitivity model of hypoalgesia asserts that attenuation of inhibitory opioid input to the PVN may have important consequences for pain modulation. These consequences includes: 1) greater activation of baroreceptor reflex arcs, 2) enhanced release of endogenous opioids during stress, and 3) increased stimulation of descending pain modulation pathways. High elevated thresholds to painful thermal stressors might serve as a behavioral marker of risk for hypertension before the onset of high blood pressure levels.

Reduced cardiac vagal activity in obese children and adolescents.

PubMed

Dangardt, Frida; Volkmann, Reinhard; Chen, Yun; Osika, Walter; Mårild, Staffan; Friberg, Peter

2011-03-01

  Obese children present with various cardiovascular risk factors affecting their future health. In adults, cardiac autonomic function is a major risk factor, predicting cardiovascular morbidity and mortality. We hypothesized that obese children and adolescents had a lower cardiac vagal activity than lean subjects. We measured cardiac spontaneous baroreflex sensitivity (BRS), reflecting the dynamic regulation of cardiac vagal function, in large groups of obese and lean young individuals.   Cardiac BRS, using the sequence approach, was assessed in 120 obese (59 girls), 43 overweight (23 girls) and 148 lean subjects (78 girls). Obese subjects showed a decreased BRS compared to both overweight and lean subjects [16±7 versus 21±9 (P<0·01) and 22±10 ms per mmHg (P<0·0001), respectively]. The differences remained after correcting for age, gender and pubertal status.   Children with obesity had low vagal activity at rest, and there was no gender difference. © 2010 The Authors. Clinical Physiology and Functional Imaging © 2010 Scandinavian Society of Clinical Physiology and Nuclear Medicine.

Autonomic Nervous System in Paralympic Athletes with Spinal Cord Injury.

PubMed

Walter, Matthias; Krassioukov, Andrei V

2018-05-01

Individuals sustaining a spinal cord injury (SCI) frequently suffer from sensorimotor and autonomic impairment. Damage to the autonomic nervous system results in cardiovascular, respiratory, bladder, bowel, and sexual dysfunctions, as well as temperature dysregulation. These complications not only impede quality of life, but also affect athletic performance of individuals with SCI. This article summarizes existing evidence on how damage to the spinal cord affects the autonomic nervous system and impacts the performance in athletes with SCI. Also discussed are frequently used performance-enhancing strategies, with a special focus on their legal aspect and implication on the athletes' health. Copyright © 2018 Elsevier Inc. All rights reserved.

Heart Rate Variability Indexes in Dementia: A Systematic Review with a Quantitative Analysis.

PubMed

da Silva, Vanessa Pereira; Ramalho Oliveira, Bruno Ribeiro; Tavares Mello, Roger Gomes; Moraes, Helena; Deslandes, Andrea Camaz; Laks, Jerson

2018-01-01

Decreased heart rate variability (HRV) indexes indicate low vagal activity and may be associated with development of dementia. The neurodegenerative process is associated with the cardiovascular autonomic control. The aim of this systematic review was to investigate the effect size (ES) magnitude of the HRV indexes in the evaluation of autonomic dysfunction in older persons with dementia. PubMed (Medline), Web of Science, Scopus, Scielo, Lilacs, and APA Psycnet were consulted. Complete original articles published in English or Portuguese, investigating the association between autonomic dysfunction and dementia, using the HRV indexes were included. The search identified 97 potentially relevant articles. After screening the full text, eight articles were included in the qualitative analysis and six were included in the quantitative analysis. Almost all indexes showed a negative ES for all types of dementia and mild cognitive impairment. The most common frequency band of the power spectrum density function was the high frequency, which was reported by six studies. The meta-analysis of high frequency power in Alzheimer's disease group showed high heterogeneity and inconsistent results. The negative effect size suggests an autonomic dysfunction in all types of dementia as well as mild cognitive impairment. However, further analysis is necessary to support these results. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Review of somatic symptoms in post-traumatic stress disorder.

PubMed

Gupta, Madhulika A

2013-02-01

Post-traumatic stress disorder (PTSD) is associated with both (1) 'ill-defined' or 'medically unexplained' somatic syndromes, e.g. unexplained dizziness, tinnitus and blurry vision, and syndromes that can be classified as somatoform disorders (DSM-IV-TR); and (2) a range of medical conditions, with a preponderance of cardiovascular, respiratory, musculoskeletal, neurological, and gastrointestinal disorders, diabetes, chronic pain, sleep disorders and other immune-mediated disorders in various studies. Frequently reported medical co-morbidities with PTSD across various studies include cardiovascular disease, especially hypertension, and immune-mediated disorders. PTSD is associated with limbic instability and alterations in both the hypothalamic- pituitary-adrenal and sympatho-adrenal medullary axes, which affect neuroendocrine and immune functions, have central nervous system effects resulting in pseudo-neurological symptoms and disorders of sleep-wake regulation, and result in autonomic nervous system dysregulation. Hypervigilance, a central feature of PTSD, can lead to 'local sleep' or regional arousal states, when the patient is partially asleep and partially awake, and manifests as complex motor and/or verbal behaviours in a partially conscious state. The few studies of the effects of standard PTSD treatments (medications, CBT) on PTSD-associated somatic syndromes report a reduction in the severity of ill-defined and autonomically mediated somatic symptoms, self-reported physical health problems, and some chronic pain syndromes.

Cardiovascular Consequences of Childhood Second Hand Tobacco Smoke Exposure

PubMed Central

Raghuveer, Geetha; White, David A.; Hayman, Laura L.; Woo, Jessica G.; Villafane, Juan; Celermajer, David; Ward, Kenneth D.; de Ferranti, Sarah D.; Zachariah, Justin

2016-01-01

Background Although public health programs have led to a substantial decrease in the prevalence of tobacco smoking, the adverse health effects of tobacco smoking is by no means a thing of the past. In the U.S, four out of 10 school aged children and 1 out of 3 adolescents are involuntarily exposed to second-hand tobacco smoke (SHS) with children of minority ethnic backgrounds and those living in low socioeconomic status households being disproportionately affected (68% and 43% respectively). Children are particularly vulnerable with little control over home and social environment and lack the understanding, agency, and ability to avoid SHS exposure on their own volition; they also have physiological or behavioral characteristics that render them especially susceptible to effects of SHS. Side stream smoke (the smoke burned directly off the end of the cigarette), a major component of SHS, contains a higher concentration of some toxins than mainstream smoke (inhaled by the smoker directly), making SHS potentially more dangerous than direct smoking. Compelling animal and human evidence shows that SHS exposure during childhood is detrimental to arterial function and structure resulting in premature atherosclerosis and its cardiovascular consequences. Childhood SHS exposure is also related to impaired cardiac autonomic function and changes in heart rate variability. In addition, childhood SHS exposure is associated with clustering of cardiometabolic risk factors such as obesity, dyslipidemia, and insulin resistance. Individualized interventions to reduce childhood exposure to SHS are shown to be at least modestly effective, so are broader based policy initiatives such as community smoking bans and increased taxation. Purpose The purpose of this statement is to summarize the available evidence on the cardiovascular health consequences of childhood SHS exposure which will support ongoing efforts to reduce and eliminate SHS exposure in this vulnerable population. This statement reviews relevant data from epidemiologic studies; laboratory based experiments, and controlled behavioral trials, concerning SHS and cardiovascular disease risk in children. Information regarding the effects of SHS exposure on the cardiovascular system in animal and pediatric studies, including vascular disruption and platelet activation, oxidation and inflammation, endothelial dysfunction, increased vascular stiffness, changes in vascular structure, and autonomic dysfunction are examined. Conclusion The epidemiological, observational and experimental evidence accumulated to date, demonstrates the detrimental long-term cardiovascular consequences of SHS exposure in children. Implications Increased awareness of these adverse effects will facilitate the development of targeted individual, family-centered and community public health interventions to reduce and ideally eliminate SHS exposure in the vulnerable pediatric population. This evidence calls for a robust public health policy that embraces “zero tolerance” to childhood SHS exposure. PMID:27619923

Gaussian Mixture Model of Heart Rate Variability

PubMed Central

Costa, Tommaso; Boccignone, Giuseppe; Ferraro, Mario

2012-01-01

Heart rate variability (HRV) is an important measure of sympathetic and parasympathetic functions of the autonomic nervous system and a key indicator of cardiovascular condition. This paper proposes a novel method to investigate HRV, namely by modelling it as a linear combination of Gaussians. Results show that three Gaussians are enough to describe the stationary statistics of heart variability and to provide a straightforward interpretation of the HRV power spectrum. Comparisons have been made also with synthetic data generated from different physiologically based models showing the plausibility of the Gaussian mixture parameters. PMID:22666386

The effects of short-term relaxation therapy on indices of heart rate variability and blood pressure in young adults.

PubMed

Pal, Gopal Krushna; Ganesh, Venkata; Karthik, Shanmugavel; Nanda, Nivedita; Pal, Pravati

2014-01-01

Assessment of short-term practice of relaxation therapy on autonomic and cardiovascular functions in first-year medical students. Case-control, interventional study. Medical college laboratory. Sixty-seven medical students, divided into two groups: study group (n = 35) and control group (n = 32). Study group subjects practiced relaxation therapy (shavasana with a soothing background music) daily 1 hour for 6 weeks. Control group did not practice relaxation techniques. Cardiovascular parameters and spectral indices of heart rate variability (HRV) were recorded before and after the 6-week practice of relaxation therapy. The data between the groups and the data before and after practice of relaxation techniques were analyzed by one-way analysis of variance and Student t-test. In the study group, prediction of low-frequency to high-frequency ratio (LF-HF) of HRV, the marker of sympathovagal balance, to blood pressure (BP) status was assessed by logistic regression. In the study group, there was significant reduction in heart rate (p = .0001), systolic (p = .0010) and diastolic (p = .0021) pressure, and rate pressure product (p < .0001), and improvement in HRV indices, following 6 weeks of relaxation therapy. As determined by regression model, prediction of LF-HF to BP status was more significant (odds ratio, 2.7; p = .009) after practice of relaxation therapy. There was no significant alteration in these parameters in control subjects. Short-term practice of relaxation therapy can improve autonomic balance and promote cardiovascular health of medical students. Sympathovagal balance is directly linked to BP status in these individuals.

Heart Rate and Cardiovascular Responses to Commercial Flights: Relationships with Physical Fitness.

PubMed

Oliveira-Silva, Iransé; Leicht, Anthony S; Moraes, Milton R; Simões, Herbert G; Del Rosso, Sebastián; Córdova, Cláudio; Boullosa, Daniel A

2016-01-01

The aim of this study was to examine the influence of physical fitness on cardiac autonomic control in passengers prior to, during and following commercial flights. Twenty-two, physically active men (36.4 ± 6.4 years) undertook assessments of physical fitness followed by recordings of 24-h heart rate (HR), heart rate variability (HRV), and blood pressure (BP) on a Control (no flight) and Experimental (flight) day. Recordings were analyzed using a two-way analysis of variance for repeated measures with relationships between variables examined via Pearson product-moment correlation coefficients. Compared to the Control day, 24-h HR was significantly greater (>7%) and HRV measures (5-39%) significantly lower on the Experimental day. During the 1-h flight, HR (24%), and BP (6%) were increased while measures of HRV (26-45%) were reduced. Absolute values of HRV during the Experimental day and relative changes in HRV measures (Control-Experimental) were significantly correlated with measures of aerobic fitness ( r = 0.43 to 0.51; -0.53 to -0.52) and body composition ( r = -0.63 to -0.43; 0.48-0.61). The current results demonstrated that short-term commercial flying significantly altered cardiovascular function including the reduction of parasympathetic modulations. Further, greater physical fitness and lower body fat composition were associated with greater cardiac autonomic control for passengers during flights. Enhanced physical fitness and leaner body composition may enable passengers to cope better with the cardiovascular stress and high allostatic load associated with air travel for enhanced passenger well-being.

Heart Rate and Cardiovascular Responses to Commercial Flights: Relationships with Physical Fitness

PubMed Central

Oliveira-Silva, Iransé; Leicht, Anthony S.; Moraes, Milton R.; Simões, Herbert G.; Del Rosso, Sebastián; Córdova, Cláudio; Boullosa, Daniel A.

2016-01-01

The aim of this study was to examine the influence of physical fitness on cardiac autonomic control in passengers prior to, during and following commercial flights. Twenty-two, physically active men (36.4 ± 6.4 years) undertook assessments of physical fitness followed by recordings of 24-h heart rate (HR), heart rate variability (HRV), and blood pressure (BP) on a Control (no flight) and Experimental (flight) day. Recordings were analyzed using a two-way analysis of variance for repeated measures with relationships between variables examined via Pearson product-moment correlation coefficients. Compared to the Control day, 24-h HR was significantly greater (>7%) and HRV measures (5–39%) significantly lower on the Experimental day. During the 1-h flight, HR (24%), and BP (6%) were increased while measures of HRV (26–45%) were reduced. Absolute values of HRV during the Experimental day and relative changes in HRV measures (Control-Experimental) were significantly correlated with measures of aerobic fitness (r = 0.43 to 0.51; −0.53 to −0.52) and body composition (r = −0.63 to −0.43; 0.48–0.61). The current results demonstrated that short-term commercial flying significantly altered cardiovascular function including the reduction of parasympathetic modulations. Further, greater physical fitness and lower body fat composition were associated with greater cardiac autonomic control for passengers during flights. Enhanced physical fitness and leaner body composition may enable passengers to cope better with the cardiovascular stress and high allostatic load associated with air travel for enhanced passenger well-being. PMID:28082914

Plasticity of cardiovascular function in snapping turtle embryos (Chelydra serpentina): chronic hypoxia alters autonomic regulation and gene expression.

PubMed

Eme, John; Rhen, Turk; Tate, Kevin B; Gruchalla, Kathryn; Kohl, Zachary F; Slay, Christopher E; Crossley, Dane A

2013-06-01

Reptile embryos tolerate large decreases in the concentration of ambient oxygen. However, we do not fully understand the mechanisms that underlie embryonic cardiovascular short- or long-term responses to hypoxia in most species. We therefore measured cardiac growth and function in snapping turtle embryos incubated under normoxic (N21; 21% O₂) or chronic hypoxic conditions (H10; 10% O₂). We determined heart rate (fH) and mean arterial pressure (Pm) in acute normoxic (21% O₂) and acute hypoxic (10% O₂) conditions, as well as embryonic responses to cholinergic, adrenergic, and ganglionic pharmacological blockade. Compared with N21 embryos, chronic H10 embryos had smaller bodies and relatively larger hearts and were hypotensive, tachycardic, and following autonomic neural blockade showed reduced intrinsic fH at 90% of incubation. Unlike other reptile embryos, cholinergic and ganglionic receptor blockade both increased fH. β-Adrenergic receptor blockade with propranolol decreased fH, and α-adrenergic blockade with phentolamine decreased Pm. We also measured cardiac mRNA expression. Cholinergic tone was reduced in H10 embryos, but cholinergic receptor (Chrm2) mRNA levels were unchanged. However, expression of adrenergic receptor mRNA (Adrb1, Adra1a, Adra2c) and growth factor mRNA (Igf1, Igf2, Igf2r, Pdgfb) was lowered in H10 embryos. Hypoxia altered the balance between cholinergic receptors, α-adrenoreceptor and β-adrenoreceptor function, which was reflected in altered intrinsic fH and adrenergic receptor mRNA levels. This is the first study to link gene expression with morphological and cardioregulatory plasticity in a developing reptile embryo.

Long-term clinical effects of epalrestat, an aldose reductase inhibitor, on diabetic peripheral neuropathy: the 3-year, multicenter, comparative Aldose Reductase Inhibitor-Diabetes Complications Trial.

PubMed

Hotta, Nigishi; Akanuma, Yasuo; Kawamori, Ryuzo; Matsuoka, Kempei; Oka, Yoshitomo; Shichiri, Motoaki; Toyota, Takayoshi; Nakashima, Mitsuyoshi; Yoshimura, Isao; Sakamoto, Nobuo; Shigeta, Yukio

2006-07-01

We sought to evaluate the long-term efficacy and safety of epalrestat, an aldose reductase inhibitor, on diabetic peripheral neuropathy. Subjects with diabetic neuropathy, median motor nerve conduction velocity (MNCV) >or=40 m/s, and HbA(1c)

Association between obesity and heart rate variability indices: an intuition toward cardiac autonomic alteration - a risk of CVD.

PubMed

Yadav, Ram Lochan; Yadav, Prakash Kumar; Yadav, Laxmi Kumari; Agrawal, Kopila; Sah, Santosh Kumar; Islam, Md Nazrul

2017-01-01

Obese people have a higher prevalence of cardiovascular disease, which is supposed to be due to autonomic dysfunction and/or metabolic disorder. The alterations in cardiac autonomic functions bring out the changes in the heart rate variability (HRV) indicators, an assessing tool for cardiac autonomic conditions. To compare the cardiac autonomic activity between obese and normal weight adults and find out the highest association between the indices of HRV and obesity. The study was conducted in 30 adult obese persons (body mass index [BMI] >30 kg/m 2 ) and 29 healthy normal weight controls (BMI 18-24 kg/m 2 ). Short-term HRV variables were assessed using standard protocol. Data were compared between groups using Mann-Whitney U test. Obesity indices such as waist circumference, hip circumference, waist-hip ratio (WHR), and BMI were measured and calculated, and they were correlated with HRV indices using Spearman's correlation analysis. In the obese group, there was a significant increase in the mean heart rate, whereas the HRV parasympathetic indicators were less (eg, root mean square of differences of successive RR intervals [28.75 {16.72-38.35} vs 41.55 {30.6-56.75} ms, p =0.018], number of RR intervals that differ by >50 ms, that is, NN50 [15.5 {2-39} vs 83.5 {32.75-116.25}, p =0.010], etc) and the sympathetic indicator low frequency (LF)/high frequency (HF) ratio (1.2 [0.65-2.20] vs 0.79 [0.5-1.02], p =0.045) was more than that of the normal weight group. Spearman's correlation between HRV and obesity indices showed significant positive correlation of WHR with LF in normalized unit ( r =0.478, p <0.01) and LF/HF ratio ( r =0.479, p <0.01), whereas it had significant negative correlation with high frequency power ms 2 ( r =-0.374, p <0.05) and HF in normalized unit ( r =-0.478, p <0.01). There was a nonsignificant correlation of BMI with HRV variables in obese individuals. Increased WHR, by far an indicator of visceral adiposity, was strongly associated with reduced cardiac parasympathetic and increased sympathetic activity in obese individuals defined by BMI. However, BMI itself has a weak relationship with HRV cardiac autonomic markers. Thus, even with a slight increase in WHR in an individual, there could be a greater risk of cardiovascular morbidity and mortality brought about by cardiac autonomic alterations.

[Polyneuropathy in diabetes type 1].

PubMed

Wilczyńska, Małgorzata

2002-01-01

Diabetic neuropathy is a clinical state of nerve damage caused by hyperglicaemia, raised activation of polyol pathway, oxydative stress, changes in endoneurial arteries and myelinated fibres. Patient complains of pain and paresthesiae in hands and limbs. The feelings of pain, temperature, touch, vibration are significantly reduced. The changes may also concern cranial nerves (IIII, IV, VI, VII), intracostal nerves, hands and limbs (Garland and Tavemer syndrome). Autonomic neuropathy concerns the impairment of autonomic functions of cardio-vascular, gastro-intestinal, uro-genital and other systems. The treatment concerns the improvement of diabetes metabolic control. Antiinflammatory antisteroid drugs are widely used but their usefulness is limited. Antidepressive drugs are the most often used group. The improvement is observed after 6 months of treatment. The side effects - orthostatic hypotension, heart rhythm disturbation and obstipation are harmful for the patients with coronary heart disease. In the cases of persistent pain the oral antiepileptic drugs may be used or cream with capsaicin for skin surface.

Investigations of the Cardiovascular and Respiratory Systems on Board the International Space Station: Experiments Puls and Pneumocard

NASA Astrophysics Data System (ADS)

Baranov, V. M.; Baevsky, R. M.; Drescher, J.; Tank, J.

parameters describing the results of the function of these systems like heart rate, arterial pressure, cardiac output, or breathing frequency, concentration of O2 and CO2 , etc. Missing significant changes of these parameters during weightlessness supports the hypothesis that adaptational and compensatory mechanisms are sufficient and guarantee cardiovascular homeostasis under changing environmental conditions. characteristic changes of the vegetative balance and of the activity of different regulatory elements at the brainstem and subcortical level. This changes guaranteed the adaptation to long term weightlessness. However, it remains unclear to what extent the different levels are involved. Moreover, the criteria describing the efficacy of cardiorespiratory interaction for the different functional states are not defined yet. The investigation of this problems is highly relevant in order to improve the medical control, especially if considering that the disruption of regulatory systems mostly precedes dangerous destruction of homeostasis. cardiovascular and respiratory function on Board the International Space Station (ISS) aiming to obtain new insights into the interaction between different regulatory elements. "Puls" is measures ECG, photoplethysmogram (PPG), and the pneumotachogram (PTG). The ECG is used to measure time series of R-R intervals and to analyse HRV. PPG is used to define the pulse wave velocity, phases of the cardiac cycle, and an estimate of the filling of finger vessels. The variability of these parameters is also calculated and compared to HRV. The analysis of the PTG allows to describe the interaction of the regulatory parameters of the cardiovascular and respiratory systems. Hence, an important feature of the experiment "Puls" is the investigation of regulatory mechanisms rather than of cardiovascular homeostasis. cardiography) and left ventricular contractility (seismocardiography) will be obtained. This expansion is of major importance because, it allows us to get deeper insight into regulatory mechanisms of the cardiorespiratory system and into the state of cardiovascular homeostasis. have the same size (90 x 60 x 20 mm), identical technology, and identical interfaces with the computer. the onboard experiment and to store the obtained data; 2) "Editor": to archive and dearchive the obtained data, to edit them and to insert necessary comments and markers; 3) "Earth": to edit and analyse the data under laboratory conditions.The subprogram "Earth" is an original software package for data analysis, peak detection, calculation of a variety of parameters, time series forming and editing, statistical and spectral time series analysis. Furthermore, a specialized data base is designated for storing of the biosignals, results of analysis, information about the investigated subjects and comments of simple autonomic function tests will allow to assess different elements of the regulatory mechanisms. Special interest will be given to respiratory tests in order to evaluate the interaction between the cardiovascular system and respiration. volunteers and in patients with different cardiovascular diseases. The results were used to establish normal values and criteria for the prognosis of pathologic changes. These materials will be used at valuation the data obtained during researches on ISS. respiratory systems onboard the ISS are the following: 1) definition of the most important parameters, which can be measured simple and reliable during weightlessness; 2) development of miniaturized devices which can be kept on the astronauts body and which could be used in future as an autonomic system of operational medical control; 3) development of original software packages which allow to detect prognostic changes of the regulatory pattern preceding diseases and based on time series analysis of a large number of cardiorespiratory parameters.

Does treatment of SDB in children improve cardiovascular outcome?

PubMed

Vlahandonis, Anna; Walter, Lisa M; Horne, Rosemary S C

2013-02-01

Sleep disordered breathing (SDB) is a common disorder in both adults and children and is caused by the obstruction of the upper airway during sleep. Unlike adults, most cases of paediatric SDB are due to the presence of enlarged tonsils and adenoids, thus the main treatment option is adenotonsillectomy (T&A). It is well known that obstructive sleep apnoea in adults increases the risk for hypertension, coronary artery disease and stroke, and there is now mounting evidence that SDB also has a significant impact on the cardiovascular system in children with reports of elevated blood pressure, endothelial dysfunction and altered autonomic cardiovascular control. As there is now substantial evidence that elevated blood pressure in childhood is carried on to adulthood it is important to know if treatment of SDB improves cardiovascular outcomes. Studies in adults have shown that treatment of SDB leads to improvements in cardiovascular function, including a reduction in pulmonary artery pressure, systemic blood pressure and endothelial dysfunction. However, studies exploring the outcomes of treatment of SDB in children on the cardiovascular system are limited and varied in their methodology and outcome measures. As a number of cardiovascular disturbances are sequelae of SDB, early detection and management could result in the reduction of elevated blood pressure in children, and consequently a reduction in cardiovascular morbidity in adulthood. The aim of this review is to summarise the findings of studies to date which have investigated the cardiovascular outcomes in children treated for SDB and to make recommendations for future management of this very common disease. Crown Copyright © 2012. Published by Elsevier Ltd. All rights reserved.

Instrumentation for Non-Invasive Assessment of Cardiovascular Regulation

NASA Technical Reports Server (NTRS)

Cohen, Richard J.

1999-01-01

It is critically important to be able to assess alterations in cardiovascular regulation during and after space flight. We propose to develop an instrument for the non-invasive assessment of such alterations that can be used on the ground and potentially during space flight. This instrumentation would be used by the Cardiovascular Alterations Team at multiple sites for the study of the effects of space flight on the cardiovascular system and the evaluation of countermeasures. In particular, the Cardiovascular Alterations Team will use this instrumentation in conjunction with ground-based human bed-rest studies and during application of acute stresses e.g., tilt, lower body negative pressure, and exercise. In future studies, the Cardiovascular Alterations Team anticipates using this instrumentation to study astronauts before and after space flight and ultimately, during space flight. The instrumentation may also be used by the Bone Demineralization/Calcium Metabolism Team, the Neurovestibular Team and the Human Performance Factors, Sleep and Chronobiology Team to measure changes in autonomic nervous function. The instrumentation will be based on a powerful new technology - cardiovascular system identification (CSI) - which has been developed in our laboratory. CSI provides a non-invasive approach for the study of alterations in cardiovascular regulation. This approach involves the analysis of second-to-second fluctuations in physiologic signals such as heart rate and non-invasively measured arterial blood pressure in order to characterize quantitatively the physiologic mechanisms responsible for the couplings between these signals. Through the characterization of multiple physiologic mechanisms, CSI provides a closed-loop model of the cardiovascular regulatory state in an individual subject.

Angiotensin II in the paraventricular nucleus stimulates sympathetic outflow to the cardiovascular system and make vasopressin release in rat.

PubMed

Khanmoradi, Mehrangiz; Nasimi, Ali

2016-10-06

The hypothalamic paraventricular nucleus (PVN) plays essential roles in neuroendocrine and autonomic functions, including cardiovascular regulation. It was shown that microinjection of angiotensin II (AngII) into the PVN produced a pressor response. In this study, we explored the probable mechanisms of this pressor response. AngII was microinjected into the PVN and cardiovascular responses were recorded. Then, the responses were re-tested after systemic injection of a ganglionic blocker, Hexamethonium, or a vasopressin V1 receptor blocker. Hexamethonium pretreatment (i.v.) greatly and significantly attenuated the pressor response to AngII, with no significant effect on heart rate, indicating that the sympathetic system is involved in the cardiovascular effect of AngII in the PVN. Systemic pretreatment (i.v.) with V1 antagonist greatly and significantly attenuated the pressor response to AngII, with no significant effect on heart rate, indicating that vasopressin release is involved in the cardiovascular effect of AngII in the PVN. Overall, we found that AngII microinjected into the PVN produced a pressor response mediated by the sympathetic system and vasopressin release, indicating that other than circulating AngII, endogenous AngII of the PVN increases the vasopressin release from the PVN. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Social technology restriction alters state-anxiety but not autonomic activity in humans.

PubMed

Durocher, John J; Lufkin, Kelly M; King, Michelle E; Carter, Jason R

2011-12-01

Social technology is extensively used by young adults throughout the world, and it has been suggested that interrupting access to this technology induces anxiety. However, the influence of social technology restriction on anxiety and autonomic activity in young adults has not been formally examined. Therefore, we hypothesized that restriction of social technology would increase state-anxiety and alter neural cardiovascular regulation of arterial blood pressure. Twenty-one college students (age 18-23 yr) were examined during two consecutive weeks in which social technology use was normal or restricted (randomized crossover design). Mean arterial pressure (MAP), heart rate, and muscle sympathetic nerve activity (MSNA) were measured at rest and during several classic autonomic stressors, including isometric handgrip, postexercise muscle ischemia, cold pressor test, and mental stress. Tertile analysis revealed that restriction of social technology was associated with increases (12 ± 2 au; range 5 to 21; n = 7), decreases (-6 ± 2 au; range -2 to -11; n = 6), or no change (0 ± 0 au; range -1 to 3; n = 8) in state-anxiety. Social technology restriction did not alter MAP (74 ± 1 vs. 73 ± 1 mmHg), heart rate (62 ± 2 vs. 61 ± 2 beats/min), or MSNA (9 ± 1 vs. 9 ± 1 bursts/min) at rest, and it did not alter neural or cardiovascular responses to acute stressors. In conclusion, social technology restriction appears to have an interindividual influence on anxiety, but not autonomic activity. It remains unclear how repeated bouts, or chronic restriction of social technology, influence long-term psychological and cardiovascular health.

Linear Analysis of Autonomic Activity and Its Correlation with Creatine Kinase-MB in Overt Thyroid Dysfunctions.

PubMed

Mavai, Manisha; Singh, Yogendra Raj; Gupta, R C; Mathur, Sandeep K; Bhandari, Bharti

2018-04-01

Autonomic activity may be deranged in thyroid dysfunctions and may lead to cardiovascular morbidity and mortality. Myopathy is a common manifestation in thyroid disorders and may be associated with raised serum creatine kinase (CK). We hypothesized that cardiovascular abnormality in thyroid dysfunction may manifest as raised CK-MB. This study was designed to investigate the correlation of CK and its isoform CK-MB with thyroid profile and linear parameters of heart rate variability (HRV). The study was conducted on 35 hypothyroid and hyperthyroid patients each, and 25 age-matched healthy controls. Autonomic activity was assessed by simple short term 5-min HRV. Biochemical evaluation of serum thyroid profile, CK-NAC and CK-MB were estimated in all the subjects. Our results demonstrated low HRV in hypo- as well as hyperthyroid patients. We observed significantly higher serum CK levels in hypothyroid patients when compared to hyperthyroids and controls. However, no significant differences were observed in CK-MB levels in the three groups. Significant positive correlation of CK with TSH and negative correlation with some HRV parameters (LF power, HF power, total power, SDNN, RMSSD) was observed in hypothyroid patients. Whereas correlation of CK-MB with thyroid profile as well as HRV parameters was non-significant in all the groups. Based on the CK and CK-MB findings and their correlation, we conclude that the cardiovascular changes seen in thyroid dysfunctions may primarily be due to autonomic imbalance without apparent cardiac muscle involvement. Whereas, raised CK levels indicate predominantly skeletal muscle involvement in hypothyroid patients.

Blood flow restriction training and the exercise pressor reflex: a call for concern.

PubMed

Spranger, Marty D; Krishnan, Abhinav C; Levy, Phillip D; O'Leary, Donal S; Smith, Scott A

2015-11-01

Blood flow restriction (BFR) training (also known as Kaatsu training) is an increasingly common practice employed during resistance exercise by athletes attempting to enhance skeletal muscle mass and strength. During BFR training, blood flow to the exercising muscle is mechanically restricted by placing flexible pressurizing cuffs around the active limb proximal to the working muscle. This maneuver results in the accumulation of metabolites (e.g., protons and lactic acid) in the muscle interstitium that increase muscle force and promote muscle growth. Therefore, the premise of BFR training is to simulate and receive the benefits of high-intensity resistance exercise while merely performing low-intensity resistance exercise. This technique has also been purported to provide health benefits to the elderly, individuals recovering from joint injuries, and patients undergoing cardiac rehabilitation. Since the seminal work of Alam and Smirk in the 1930s, it has been well established that reductions in blood flow to exercising muscle engage the exercise pressor reflex (EPR), a reflex that significantly contributes to the autonomic cardiovascular response to exercise. However, the EPR and its likely contribution to the BFR-mediated cardiovascular response to exercise is glaringly missing from the scientific literature. Inasmuch as the EPR has been shown to generate exaggerated increases in sympathetic nerve activity in disease states such as hypertension (HTN), heart failure (HF), and peripheral artery disease (PAD), concerns are raised that BFR training can be used safely for the rehabilitation of patients with cardiovascular disease, as has been suggested. Abnormal BFR-induced and EPR-mediated cardiovascular complications generated during exercise could precipitate adverse cardiovascular or cerebrovascular events (e.g., cardiac arrhythmia, myocardial infarction, stroke and sudden cardiac death). Moreover, although altered EPR function in HTN, HF, and PAD underlies our concern for the widespread implementation of BFR, use of this training mechanism may also have negative consequences in the absence of disease. That is, even normal, healthy individuals performing resistance training exercise with BFR are potentially at increased risk for deleterious cardiovascular events. This review provides a brief yet detailed overview of the mechanisms underlying the autonomic cardiovascular response to exercise with BFR. A more complete understanding of the consequences of BFR training is needed before this technique is passively explored by the layman athlete or prescribed by a health care professional. Copyright © 2015 the American Physiological Society.

Baroreflex Function in Rats after Simulated Microgravity

NASA Technical Reports Server (NTRS)

Hasser, Eileen M.

1997-01-01

Prolonged exposure of humans to decreased gravitational forces during spaceflight results in a number of adverse cardiovascular consequences, often referred to as cardiovascular deconditioning. Prominent among these negative cardiovascular effects are orthostatic intolerance and decreased exercise capacity. Rat hindlimb unweighting is an animal model which simulates weightlessness, and results in similar cardiovascular consequences. Cardiovascular reflexes, including arterial and cardiopulmonary baroreflexes, are required for normal adjustment to both orthostatic challenges and exercise. Therefore, the orthostatic intolerance and decreased exercise capacity associated with exposure to microgravity may be due to cardiovascular reflex dysfunction. The proposed studies will test the general hypothesis that hindlimb unweighting in rats results in impaired autonomic reflex control of the sympathetic nervous system. Specifically, we hypothesize that the ability to reflexly increase sympathetic nerve activity in response to decreases in arterial pressure or blood volume will be blunted due to hindlimb unweighting. There are 3 specific aims: (1) To evaluate arterial and cardiopulmonary baroreflex control of renal and lumbar sympathetic nerve activity in conscious rats subjected to 14 days of hindlimb unweighting; (2) To examine the interaction between arterial and cardiopulmonary baroreflex control of sympathetic nerve activity in conscious hindlimb unweighted rats; (3) to evaluate changes in afferent and/or central nervous system mechanisms in baroreflex regulation of the sympathetic nervous system. These experiments will provide information related to potential mechanisms for orthostatic and exercise intolerance due to microgravity.

Vascular dysfunctions following spinal cord injury

PubMed Central

Popa, F; Grigorean, VT; Onose, G; Sandu, AM; Popescu, M; Burnei, G; Strambu, V; Sinescu, C

2010-01-01

The aim of this article is to analyze the vascular dysfunctions occurring after spinal cord injury (SCI). Vascular dysfunctions are common complications of SCI. Cardiovascular disturbances are the leading causes of morbidity and mortality in both acute and chronic stages of SCI. Neuroanatomy and physiology of autonomic nervous system, sympathetic and parasympathetic, is reviewed. SCI implies disruption of descendent pathways from central centers to spinal sympathetic neurons, originating in intermediolateral nuclei of T1–L2 cord segments. Loss of supraspinal control over sympathetic nervous system results in reduced overall sympathetic activity below the level of injury and unopposed parasympathetic outflow through intact vagal nerve. SCI associates significant vascular dysfunction. Spinal shock occurs during the acute phase following SCI and it is a transitory suspension of function and reflexes below the level of the injury. Neurogenic shock, part of spinal shock, consists of severe arterial hypotension and bradycardia. Autonomic dysreflexia appears during the chronic phase, after spinal shock resolution, and it is a life–threatening syndrome of massive imbalanced reflex sympathetic discharge occurring in patients with SCI above the splanchnic sympathetic outflow (T5–T6). Arterial hypotension with orthostatic hypotension occurs in both acute and chronic phases. The etiology is multifactorial. We described a few factors influencing the orthostatic hypotension occurrence in SCI: sympathetic nervous system dysfunction, low plasma catecholamine levels, rennin–angiotensin–aldosterone activity, peripheral alpha–adrenoceptor hyperresponsiveness, impaired function of baroreceptors, hyponatremia and low plasmatic volume, cardiovascular deconditioning, morphologic changes in sympathetic neurons, plasticity within spinal circuits, and motor deficit leading to loss of skeletal muscle pumping activity. Additional associated cardiovascular concerns in SCI, such as deep vein thrombosis and long–term risk for coronary heart disease and systemic atherosclerosis are also described. Proper prophylaxis, including non–pharmacologic and pharmacological strategies, diminishes the occurrence of the vascular dysfunction following SCI. Each vascular disturbance requires a specific treatment. PMID:20945818

Cardiovascular Consequences of Childhood Secondhand Tobacco Smoke Exposure: Prevailing Evidence, Burden, and Racial and Socioeconomic Disparities: A Scientific Statement From the American Heart Association.

PubMed

Raghuveer, Geetha; White, David A; Hayman, Laura L; Woo, Jessica G; Villafane, Juan; Celermajer, David; Ward, Kenneth D; de Ferranti, Sarah D; Zachariah, Justin

2016-10-18

Although public health programs have led to a substantial decrease in the prevalence of tobacco smoking, the adverse health effects of tobacco smoke exposure are by no means a thing of the past. In the United States, 4 of 10 school-aged children and 1 of 3 adolescents are involuntarily exposed to secondhand tobacco smoke (SHS), with children of minority ethnic backgrounds and those living in low-socioeconomic-status households being disproportionately affected (68% and 43%, respectively). Children are particularly vulnerable, with little control over home and social environment, and lack the understanding, agency, and ability to avoid SHS exposure on their own volition; they also have physiological or behavioral characteristics that render them especially susceptible to effects of SHS. Side-stream smoke (the smoke emanating from the burning end of the cigarette), a major component of SHS, contains a higher concentration of some toxins than mainstream smoke (inhaled by the smoker directly), making SHS potentially as dangerous as or even more dangerous than direct smoking. Compelling animal and human evidence shows that SHS exposure during childhood is detrimental to arterial function and structure, resulting in premature atherosclerosis and its cardiovascular consequences. Childhood SHS exposure is also related to impaired cardiac autonomic function and changes in heart rate variability. In addition, childhood SHS exposure is associated with clustering of cardiometabolic risk factors such as obesity, dyslipidemia, and insulin resistance. Individualized interventions to reduce childhood exposure to SHS are shown to be at least modestly effective, as are broader-based policy initiatives such as community smoking bans and increased taxation. The purpose of this statement is to summarize the available evidence on the cardiovascular health consequences of childhood SHS exposure; this will support ongoing efforts to further reduce and eliminate SHS exposure in this vulnerable population. This statement reviews relevant data from epidemiological studies, laboratory-based experiments, and controlled behavioral trials concerning SHS and cardiovascular disease risk in children. Information on the effects of SHS exposure on the cardiovascular system in animal and pediatric studies, including vascular disruption and platelet activation, oxidation and inflammation, endothelial dysfunction, increased vascular stiffness, changes in vascular structure, and autonomic dysfunction, is examined. The epidemiological, observational, and experimental evidence accumulated to date demonstrates the detrimental cardiovascular consequences of SHS exposure in children. Increased awareness of the adverse, lifetime cardiovascular consequences of childhood SHS may facilitate the development of innovative individual, family-centered, and community health interventions to reduce and ideally eliminate SHS exposure in the vulnerable pediatric population. This evidence calls for a robust public health policy that embraces zero tolerance of childhood SHS exposure. © 2016 American Heart Association, Inc.

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

PubMed

Toschi-Dias, Edgar; Trombetta, Ivani C; da Silva, Valdo José Dias; Maki-Nunes, Cristiane; Alves, Maria Janieire N N; Angelo, Luciana F; Cepeda, Felipe X; Martinez, Daniel G; Negrão, Carlos Eduardo; Rondon, Maria Urbana P B

2013-03-01

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.

Cardiovascular haemodynamics and cardiac autonomic control in patients with subclinical and overt hyperthyroidism.

PubMed

Petretta, M; Bonaduce, D; Spinelli, L; Vicario, M L; Nuzzo, V; Marciano, F; Camuso, P; De Sanctis, V; Lupoli, G

2001-12-01

To characterize cardiac structure and function and cardiac autonomic control in patients with subclinical and overt hyperthyroidism. Thirty patients with subclinical hyperthyroidism and 30 with overt disease were selected from patients never previously treated for endocrinological disease in the outpatient clinic of our institution. Twenty normal individuals were studied as control group. Left ventricular structure and function and cardiac autonomic control were evaluated, respectively, by two-dimensional Doppler echocardiography and by 24-h Holter recording with heart rate variability analysis. Patients with overt hyperthyroidism showed greater values of left ventricular end-diastolic volume (P<0.05) and left ventricular mass (P<0.05) than patients with subclinical disease. In addition, the mean velocity of left ventricular fibre shortening (P<0.05) and left ventricular ejection fraction (P<0.05) were greater in patients with overt hyperthyroidism than in patients with subclinical disease. No difference in any of these parameters was detectable between normal subjects and patients with subclinical disease. The isovolumic relaxation period was shorter in patients with subclinical hyperthyroidism than in control individuals (P<0.05) and in patients with overt hyperthyroidism (P<0.05). As regards cardiac autonomic control, all time and frequency domain measures decreased progressively from control individuals to patients with subclinical hyperthyroidism and those with overt disease (P<0.001). Thyrotoxic patients show changes in left ventricular structure and increased echocardiographic indexes of myocardial contractility, whereas the only echocardiographic feature detectable in patients with subclinical hyperthyroidism is an increased velocity of left ventricular relaxation. Cardiac parasympathetic withdrawal is evident in patients with overt hyperthyroidism and in patients with subclinical disease.

Central Neural Control of the Cardiovascular System: Current Perspectives

ERIC Educational Resources Information Center

Dampney, Roger A. L.

2016-01-01

This brief review, which is based on a lecture presented at the American Physiological Society Teaching Refresher Course on the Brain and Systems Control as part of the Experimental Biology meeting in 2015, aims to summarize current concepts of the principal mechanisms in the brain that regulate the autonomic outflow to the cardiovascular system.…

Pet ownership and cardiovascular risk reduction: supporting evidence, conflicting data and underlying mechanisms.

PubMed

Arhant-Sudhir, Kanish; Arhant-Sudhir, Rish; Sudhir, Krishnankutty

2011-11-01

1. It is widely believed that pet ownership is beneficial to humans and that some of this benefit is through favourable effects on cardiovascular risk. In the present review, we critically examine the evidence in support of this hypothesis and present the available data with respect to major cardiovascular risk factors. 2. There is evidence that dog owners are less sedentary and have lower blood pressure, plasma cholesterol and triglycerides, attenuated responses to laboratory-induced mental stress and improved survival following myocardial infarction compared with non-pet owners. However, conflicting data exist with regard to the association between pet ownership and each of these risk factors. 3. Numerous non-cardiovascular effects of pet ownership have been reported, largely in the psychosocial domain, but the relationship is complex and can vary with demographic and social factors. 4. A unifying hypothesis is presented, linking improved mood and emotional state to decreased central and regional autonomic activity, improved endothelial function and, thus, lower blood pressure and reduced cardiac arrhythmias. 5. Overall, ownership of domestic pets, particularly dogs, is associated with positive health benefits. © 2011 The Authors. Clinical and Experimental Pharmacology and Physiology © 2011 Blackwell Publishing Asia Pty Ltd.

Effect of Methamphetamine Dependence on Heart Rate Variability

PubMed Central

Henry, Brook L.; Minassian, Arpi; Perry, William

2010-01-01

Background Methamphetamine (METH) is an increasing popular and highly addictive stimulant associated with autonomic nervous system (ANS) dysfunction, cardiovascular pathology, and neurotoxicity. Heart rate variability (HRV) has been used to assess autonomic function and predict mortality in cardiac disorders and drug intoxication, but has not been characterized in METH use. We recorded HRV in a sample of currently abstinent individuals with a history of METH dependence compared to age- and gender-matched drug-free comparison subjects. Method HRV was assessed using time domain, frequency domain, and nonlinear entropic analyses in 17 previously METH-dependent and 21 drug-free comparison individuals during a 5 minute rest period. Results The METH-dependent group demonstrated significant reduction in HRV, reduced parasympathetic activity, and diminished heartbeat complexity relative to comparison participants. More recent METH use was associated with increased sympathetic tone. Conclusion Chronic METH exposure may be associated with decreased HRV, impaired vagal function, and reduction in heart rate complexity as assessed by multiple methods of analysis. We discuss and review evidence that impaired HRV may be related to the cardiotoxic or neurotoxic effects of prolonged METH use. PMID:21182570

Using the autonomic standards to assess orthostatic hypotension in persons with SCI: a case series.

PubMed

Wecht, Jill M; Wilson, James; Previnaire, Jean-Gabriel

2017-01-01

Spinal cord injury (SCI) creates a complex and unique syndrome of medical issues related to disruption of somatic and autonomic pathways. Among these impaired control of blood pressure (BP) can significantly impede patients' activities of daily living. The International Standards for the Assessment of Autonomic Function after SCI (ISAFSCI) is used to document the impact of SCI on resting BP (abnormal if below 90 mmHg) and the presence or absence of orthostatic hypotension (OH), defined as a symptomatic or asymptomatic decrease in BP (>/=20/10 mmHg) upon moving to an upright position. Case 1 documents the adverse influence of prescribed medications (antidepressants for neuropathic pain) on OH; case 2 describes the influence of bladder management on cardiovascular instability (autonomic dysreflexia and subsequent OH); case 3 describes the association between spasticity and OH; case 4 describes OH associated with a Valsalva maneuver. Impaired control of BP can stem from a combination of medical issues and autonomic dysfunction in persons with SCI. Management strategies for OH will vary depending on the stage of the SCI, the root cause of the OH and other confounding medical conditions. Non-pharmacological treatment should be considered as a first line of intervention and consideration should be given to cessation of potentially contributory medications prior to implementing pharmaceutical interventions. The systematic use of ISAFSCI by clinicians is recommended to document BP irregularities and to describe the effects of treatment strategies aimed at improving BP control in the SCI population.

Autonomic predictors of recovery following surgery: A comparative study

PubMed Central

Williamson, John B.; Lewis, Greg; Grippo, Angela J.; Lamb, Damon; Harden, Emily; Handleman, Mika; Lebow, Jocelyn; Carter, C. Sue; Porges, Stephen W.

2015-01-01

Although heart rate and temperature are continuously monitored in patients during recovery following surgery, measures that extract direct manifestations of neural regulation of autonomic circuits from the beat-to-beat heart rate may be more sensitive to outcome. We explore the relationship between features of autonomic regulation and survival in the prairie vole, a small mammal, with features of vagal regulation of the heart similar to humans. Cardiac vagal regulation is manifested in the beat-to-beat heart rate variability (HRV) pattern and can be quantified by extracting measures of the amplitude of periodic oscillations associated with spontaneous breathing. Thus, monitoring beat-to-beat heart rate patterns post-surgery in the prairie vole may provide an opportunity to dynamically assess autonomic adjustments during recovery. Surgeries to implant telemetry devices to monitor body temperature and continuous ECG in prairie voles are routinely performed in our laboratory. Ten of these implanted prairie voles died within 48 h post-surgery. To compare the post-surgery autonomic trajectories with typical surviving prairie voles, the post-surgery data from 17 surviving prairie voles were randomly selected. The data are reported hourly for 27 prairie voles between 6 and 14 h (1 h before the demise of the first subject) post-surgery. Receiver operator curves were calculated hourly for each variable to evaluate sensitivity in discriminating survival. The data illustrate that measures of HRV are the most sensitive indicators. These findings provide a foundation for investigating further neural mechanisms of cardiovascular function. PMID:20451468

Cardiovascular Deconditioning in Humans: Human Studies Core

NASA Technical Reports Server (NTRS)

Williams, Gordon

1999-01-01

Major cardiovascular problems, secondary to cardiovascular deconditioning, may occur on extended space missions. While it is generally assumed that the microgravity state is the primary cause of cardiovascular deconditioning, sleep deprivation and disruption of diurnal rhythms may also play an important role. Factors that could be modified by either or both of these perturbations include: autonomic function and short-term cardiovascular reflexes, vasoreactivity, circadian rhythm of cardiovascular hormones (specifically the renin-angiotensin system) and renal sodium handling and hormonal influences on that process, venous compliance, cardiac mass, and cardiac conduction processes. The purpose of the Human Studies Core is to provide the infrastructure to conduct human experiments which will allow for the assessment of the likely role of such factors in the space travel associated cardiovascular deconditioning process and to develop appropriate countermeasures. The Core takes advantage of a newly-created Intensive Physiologic Monitoring (IPM) Unit at the Brigham and Women's Hospital, Boston, MA, to perform these studies. The Core includes two general experimental protocols. The first protocol involves a head down tilt bed-rest study to simulate microgravity. The second protocol includes the addition of a disruption of circadian rhythms to the simulated microgravity environment. Before and after each of these environmental manipulations, the subjects will undergo acute stressors simulating changes in volume and/or stress, which could occur in space and on return to Earth. The subjects are maintained in a rigidly controlled environment with fixed light/dark cycles, activity pattern, and dietary intake of nutrients, fluids, ions and calories.

Heart-Rate Variability—More than Heart Beats?

PubMed Central

Ernst, Gernot

2017-01-01

Heart-rate variability (HRV) is frequently introduced as mirroring imbalances within the autonomous nerve system. Many investigations are based on the paradigm that increased sympathetic tone is associated with decreased parasympathetic tone and vice versa. But HRV is probably more than an indicator for probable disturbances in the autonomous system. Some perturbations trigger not reciprocal, but parallel changes of vagal and sympathetic nerve activity. HRV has also been considered as a surrogate parameter of the complex interaction between brain and cardiovascular system. Systems biology is an inter-disciplinary field of study focusing on complex interactions within biological systems like the cardiovascular system, with the help of computational models and time series analysis, beyond others. Time series are considered surrogates of the particular system, reflecting robustness or fragility. Increased variability is usually seen as associated with a good health condition, whereas lowered variability might signify pathological changes. This might explain why lower HRV parameters were related to decreased life expectancy in several studies. Newer integrating theories have been proposed. According to them, HRV reflects as much the state of the heart as the state of the brain. The polyvagal theory suggests that the physiological state dictates the range of behavior and psychological experience. Stressful events perpetuate the rhythms of autonomic states, and subsequently, behaviors. Reduced variability will according to this theory not only be a surrogate but represent a fundamental homeostasis mechanism in a pathological state. The neurovisceral integration model proposes that cardiac vagal tone, described in HRV beyond others as HF-index, can mirror the functional balance of the neural networks implicated in emotion–cognition interactions. Both recent models represent a more holistic approach to understanding the significance of HRV. PMID:28955705

Heart-Rate Variability-More than Heart Beats?

PubMed

Ernst, Gernot

2017-01-01

Heart-rate variability (HRV) is frequently introduced as mirroring imbalances within the autonomous nerve system. Many investigations are based on the paradigm that increased sympathetic tone is associated with decreased parasympathetic tone and vice versa . But HRV is probably more than an indicator for probable disturbances in the autonomous system. Some perturbations trigger not reciprocal, but parallel changes of vagal and sympathetic nerve activity. HRV has also been considered as a surrogate parameter of the complex interaction between brain and cardiovascular system. Systems biology is an inter-disciplinary field of study focusing on complex interactions within biological systems like the cardiovascular system, with the help of computational models and time series analysis, beyond others. Time series are considered surrogates of the particular system, reflecting robustness or fragility. Increased variability is usually seen as associated with a good health condition, whereas lowered variability might signify pathological changes. This might explain why lower HRV parameters were related to decreased life expectancy in several studies. Newer integrating theories have been proposed. According to them, HRV reflects as much the state of the heart as the state of the brain. The polyvagal theory suggests that the physiological state dictates the range of behavior and psychological experience. Stressful events perpetuate the rhythms of autonomic states, and subsequently, behaviors. Reduced variability will according to this theory not only be a surrogate but represent a fundamental homeostasis mechanism in a pathological state. The neurovisceral integration model proposes that cardiac vagal tone, described in HRV beyond others as HF-index, can mirror the functional balance of the neural networks implicated in emotion-cognition interactions. Both recent models represent a more holistic approach to understanding the significance of HRV.

The Association between Central Adiposity and Autonomic Dysfunction in Obesity

PubMed Central

Fidan-Yaylali, Güzin; Yaylali, Yalin Tolga; Erdogan, Çağdaş; Can, Beray; Senol, Hande; Gedik-Topçu, Bengi; Topsakal, Senay

2016-01-01

Objective To determine the relationship between central adiposity parameters and autonomic nervous system (ANS) dysfunction. Subjects and Methods The study included 114 obese individuals without any cardiovascular risk factors. Weight (in kg), height (in m), and waist circumference (WC; in cm) were measured and body mass index was calculated. Echocardiographic examination was performed to measure left ventricular mass and epicardial fat thickness (EFT). All the participants underwent an exercise test and electrophysiological evaluation using electromyography. Heart rate recovery (HRR) at 1-5 min, R-R interval variation at rest and during hyperventilation, and sympathetic skin response were measured. Pearson's correlation analysis was used. Multiple linear regression analysis was used to identify the factors associated with autonomic dysfunction. Results The HRR at 1-5 min was negatively correlated with WC and age (WC-HRR1: r = −0.32; WC-HRR2: r = −0.31; WC-HRR3: r = −0.26; WC-HRR4: r = −0.23; WC-HRR5: r = −0.21; age-HRR2: r = −0.32; age-HRR3: r = −0.28; age-HRR4: r = −0.41; age-HRR5: r = −0.42). Age was the only independent predictor of reduced HRR at 1-5 min. In addition, WC predicted a reduced HRR at 3 min. There were no significant associations between central obesity and electrophysiological parameters. EFT was not associated with ANS dysfunction. Conclusion In this study, central adiposity and aging were associated with ANS dysfunction in obese individuals. The WC could be a marker of ANS dysfunction in obese individuals without any cardiovascular risk factors. The HRR assessment at a later decay phase could be more valuable for evaluating ANS function than during early recovery. PMID:27194294

Hyperinsulinemia and Insulin Resistance in Dopamine β-Hydroxylase Deficiency

PubMed Central

Arnold, Amy C.; Garland, Emily M.; Celedonio, Jorge E.; Raj, Satish R.; Abumrad, Naji N.; Biaggioni, Italo; Robertson, David; Luther, James M.

2017-01-01

Context: Dopamine β-hydroxylase (DBH) deficiency is a rare genetic disorder characterized by failure to convert dopamine to norepinephrine. DBH-deficient patients lack sympathetic adrenergic function and are therefore predisposed to orthostatic hypotension. DBH-deficient mice exhibit hyperinsulinemia, lower plasma glucose levels, and insulin resistance due to loss of tonic sympathetic inhibition of insulin secretion. The impact of DBH deficiency on glucose homeostasis in humans is unknown. Case Description: We describe the metabolic profile of an adolescent female DBH-deficient patient. The patient underwent genetic testing, cardiovascular autonomic function testing, and evaluation of insulin secretion and sensitivity with hyperglycemic clamp under treatment-naive conditions. All procedures were repeated after 1 year of treatment with the norepinephrine prodrug droxidopa (300 mg, 3 times a day). Genetic testing showed a homozygous mutation in the DBH gene (rs74853476). Under treatment-naive conditions, she had undetectable plasma epinephrine and norepinephrine levels, resulting in sympathetic noradrenergic failure and orthostatic hypotension (−32 mm Hg supine to seated). She had high adiposity (41%) and fasting plasma insulin levels (25 μU/mL), with normal glucose (91 mg/dL). Hyperglycemic clamp revealed increased glucose-stimulated insulin secretion and insulin resistance. Droxidopa restored plasma norepinephrine and improved orthostatic tolerance, with modest effects on glucose homeostasis. Conclusions: We provide evidence for impairment in cardiovascular autonomic regulation, hyperinsulinemia, enhanced glucose-stimulated insulin secretion, and insulin resistance in a DBH-deficient patient. These metabolic derangements were not corrected by chronic droxidopa treatment. These findings provide insight into the pathophysiology and treatment of DBH deficiency and into the importance of catecholaminergic mechanisms to resting metabolism. PMID:27778639

Hyperinsulinemia and Insulin Resistance in Dopamine β-Hydroxylase Deficiency.

PubMed

Arnold, Amy C; Garland, Emily M; Celedonio, Jorge E; Raj, Satish R; Abumrad, Naji N; Biaggioni, Italo; Robertson, David; Luther, James M; Shibao, Cyndya A

2017-01-01

Dopamine β-hydroxylase (DBH) deficiency is a rare genetic disorder characterized by failure to convert dopamine to norepinephrine. DBH-deficient patients lack sympathetic adrenergic function and are therefore predisposed to orthostatic hypotension. DBH-deficient mice exhibit hyperinsulinemia, lower plasma glucose levels, and insulin resistance due to loss of tonic sympathetic inhibition of insulin secretion. The impact of DBH deficiency on glucose homeostasis in humans is unknown. We describe the metabolic profile of an adolescent female DBH-deficient patient. The patient underwent genetic testing, cardiovascular autonomic function testing, and evaluation of insulin secretion and sensitivity with hyperglycemic clamp under treatment-naive conditions. All procedures were repeated after 1 year of treatment with the norepinephrine prodrug droxidopa (300 mg, 3 times a day). Genetic testing showed a homozygous mutation in the DBH gene (rs74853476). Under treatment-naive conditions, she had undetectable plasma epinephrine and norepinephrine levels, resulting in sympathetic noradrenergic failure and orthostatic hypotension (-32 mm Hg supine to seated). She had high adiposity (41%) and fasting plasma insulin levels (25 μU/mL), with normal glucose (91 mg/dL). Hyperglycemic clamp revealed increased glucose-stimulated insulin secretion and insulin resistance. Droxidopa restored plasma norepinephrine and improved orthostatic tolerance, with modest effects on glucose homeostasis. We provide evidence for impairment in cardiovascular autonomic regulation, hyperinsulinemia, enhanced glucose-stimulated insulin secretion, and insulin resistance in a DBH-deficient patient. These metabolic derangements were not corrected by chronic droxidopa treatment. These findings provide insight into the pathophysiology and treatment of DBH deficiency and into the importance of catecholaminergic mechanisms to resting metabolism. Copyright © 2017 by the Endocrine Society

Effect of Yoga-Based Intervention in Patients with Inflammatory Bowel Disease.

PubMed

Sharma, Purnima; Poojary, Gopal; Dwivedi, Sada Nand; Deepak, Kishore Kumar

2015-01-01

Inflammatory bowel disease (IBD) is a chronic illness characterized by gross inflammation in the gastrointestinal tract that can result in symptoms such as abdominal pain, cramping, diarrhea, and bloody stools. IBD is believed to be influenced by psychological factors such as stress and anxiety. Therefore, a yoga intervention that reduces stress and anxiety may be an effective complementary treatment for these disorders. A total of 100 IBD patients [ulcerative colitis (UC) n = 60 and Crohn's disease (CD) n = 40] during the clinical remission phase of disease were included in the study. These patients were allocated randomly to either the yoga group that underwent an 8-week yoga intervention (physical postures, pranayama, and meditation) 1- hour/day in addition to standard medical therapy (UC, n = 30; CD, n = 20) or the control group (UC, n = 30; CD n = 20), which continued with standard medical therapy alone. The main outcome measures were cardiovascular autonomic functions, serum eosinophilic cationic protein, interleukin- 2 soluble receptors, Speilberger's State Trait Anxiety Inventory (STAI) scores, and clinical symptoms. Before the intervention, all the outcome measures were comparable in the two groups. After the 8-week yoga intervention, fewer UC patients reported arthralgia. The number of patients reporting intestinal colic pain in the control group was higher. State and trait anxiety levels were significantly reduced in patients with UC. However, no significant changes were observed in cardiovascular autonomic functions, eosinophilic cationic proteins, or interleukin-2 soluble receptors. A simplified yoga-based regimen is a safe and effective complementary clinical treatment modality for patients with inflammatory bowel disease during the clinical remission phase.

Eyeball pressure stimulation induces subtle sympathetic activation in patients with a history of moderate or severe traumatic brain injury.

PubMed

Wang, Ruihao; Hösl, Katharina M; Ammon, Fabian; Markus, Jörg; Koehn, Julia; Roy, Sankanika; Liu, Mao; de Rojas Leal, Carmen; Muresanu, Dafin; Flanagan, Steven R; Hilz, Max J

2018-06-01

After traumatic brain injury (TBI), there may be persistent central-autonomic-network (CAN) dysfunction causing cardiovascular-autonomic dysregulation. Eyeball-pressure-stimulation (EPS) normally induces cardiovagal activation. In patients with a history of moderate or severe TBI (post-moderate-severe-TBI), we determined whether EPS unveils cardiovascular-autonomic dysregulation. In 51 post-moderate-severe-TBI patients (32.7 ± 10.5 years old, 43.1 ± 33.4 months post-injury), and 30 controls (29.1 ± 9.8 years), we recorded respiration, RR-intervals (RRI), systolic and diastolic blood-pressure (BPsys, BPdia), before and during EPS (120 sec; 30 mmHg), using an ocular-pressure-device (Okulopressor®). We calculated spectral-powers of mainly sympathetic low (LF: 0.04-0.15 Hz) and parasympathetic high (HF: 0.15-0.5 Hz) frequency RRI-fluctuations, sympathetically mediated LF-powers of BPsys, and calculated normalized (nu) LF- and HF-powers of RRI. We compared parameters between groups before and during EPS by repeated-measurement-analysis-of-variance with post-hoc analysis (significance: p < 0.05). At rest, sympathetically mediated LF-BPsys-powers were significantly lower in the patients than the controls. During EPS, only controls significantly increased RRIs and parasympathetically mediated HFnu-RRI-powers, but decreased LF-RRI-powers, LFnu-RRI-powers, and LF-BPsys-powers; in contrast, the patients slightly though significantly increased BPsys upon EPS, without changing any other parameter. In post-moderate-severe-TBI patients, autonomic BP-modulation was already compromised at rest. During EPS, our patients failed to activate cardiovagal modulation but slightly increased BPsys, indicating persistent CAN dysregulation. Our findings unveil persistence of subtle cardiovascular-autonomic dysregulation even years after TBI. Copyright © 2018 International Federation of Clinical Neurophysiology. Published by Elsevier B.V. All rights reserved.

Alleviating Autonomic Dysreflexia after Spinal Cord Injury

DTIC Science & Technology

2016-10-01

below  the  level  of  injury,  frequently  initiated  in  the  bladder  or  bowel.  It  is   a  key  contributor  to   cardiovascular   disease ,  the...affects blood flow and arterial pressure, and contributes to an increased risk of cardiovascular disease . Potential Treatment Strategies As...LG, Brown DJ, Ungar G, Moore P, McNeil JJ, Louis WJ (1992) Risk factors for cardiovascular disease in chronic spinal cord inju- ry patients

A Disintegrin and Metalloprotease 17 in the Cardiovascular and Central Nervous Systems.

PubMed

Xu, Jiaxi; Mukerjee, Snigdha; Silva-Alves, Cristiane R A; Carvalho-Galvão, Alynne; Cruz, Josiane C; Balarini, Camille M; Braga, Valdir A; Lazartigues, Eric; França-Silva, Maria S

2016-01-01

ADAM17 is a metalloprotease and disintegrin that lodges in the plasmatic membrane of several cell types and is able to cleave a wide variety of cell surface proteins. It is somatically expressed in mammalian organisms and its proteolytic action influences several physiological and pathological processes. This review focuses on the structure of ADAM17, its signaling in the cardiovascular system and its participation in certain disorders involving the heart, blood vessels, and neural regulation of autonomic and cardiovascular modulation.

Central fat influences cardiac autonomic function in obese and overweight girls.

PubMed

Soares-Miranda, Luisa; Alves, Alberto J; Vale, Susana; Aires, Luisa; Santos, Rute; Oliveira, José; Mota, Jorge

2011-10-01

It has been suggested that upper-body fat compared with lower-body fat is more closely associated with cardiovascular abnormalities. Our objective was to analyze the relationship between central fat (CF) and cardiac autonomic (cANS) function in obese and overweight girls. Children were classified in two groups based on CF: those above (CFa(50)) and those below the 50th percentile (CFb(50)) of the entire sample. This study included 16 female children who were diagnosed as being overweight or obese (age: 14.3 ± 2.8 years; weight: 75.0 ± 15.8 kg; height: 157.1 ± 8.9 cm; body mass index: 30.1 ± 5.4; and total body fat: 40.5 ± 5.0%; Tanner stage: 4). cANS function was assessed through heart rate variability (HRV) and CF parameters by dual-energy X-ray absorptiometry. Female children with higher CF exhibited significantly higher sympathetic and lower parasympathetic modulation than those with lower CF, independently of total body fat. The data of the present study indicate that CF is associated with less favorable indexes of HRV. In addition, our findings suggest that CF might be an important measure to assess the effect of obesity on cANS function in female children.

Gender Differences in Autonomic Control of the Cardiovascular System.

PubMed

Pothineni, Naga Venkata; Shirazi, Lily F; Mehta, Jawahar L

2016-01-01

The autonomic nervous system (ANS) is a key regulator of the cardiovascular system. The two arms of the ANS, sympathetic and parasympathetic (vagal) have co-regulatory effects on cardiac homeostasis. ANS modulation and dysfunction are also believed to affect various cardiac disease states. Over the past decade, there has been increasing evidence suggesting gender differences in ANS activity. In multiple previous studies, ANS activity was primarily assessed using heart rate variability, muscle sympathetic nerve activity, coronary blood flow velocity, and plasma biomarkers. Heart rate variability is a non-invasive measure, which can be analyzed in terms of low frequency and high frequency oscillations, which indicate the sympathetic and parasympathetic tone, respectively. These measures have been studied between women and men in states of rest and stress, and in cardiac disease. Studies support the concept of a significant gender difference in ANS activity. Further studies are indicated to elucidate specific differences and mechanisms, which could guide targeted therapy of various cardiovascular disease states.

Stress, depression, and cardiovascular dysregulation: A review of neurobiological mechanisms and the integration of research from preclinical disease models

PubMed Central

Grippo, Angela J.; Johnson, Alan Kim

2008-01-01

A bidirectional association between mood disorders such as depression, and cardiovascular diseases such as myocardial infarction and congestive heart failure, has been described; however, the precise neurobiological mechanisms that underlie these associations have not been fully elucidated. This review is focused on the neurobiological processes and mediators that are common to both mood and cardiovascular disorders, with an emphasis on the role of exogenous stressors in addition to: (a) neuroendocrine and neurohumoral changes involving dysfunction of the hypothalamic-pituitary-adrenal axis and activation of the renin-angiotensin-aldosterone system, (b) immune alterations including activation of pro-inflammatory cytokines, (c) autonomic and cardiovascular dysregulation including increased sympathetic drive, withdrawal of parasympathetic tone, cardiac rate and rhythm disturbances, and altered baroreceptor reflex function, (d) central neurotransmitter system dysfunction including dopamine, norepinephrine and serotonin, and (e) behavioral changes including fatigue and physical inactivity. We also focus specifically on experimental investigations with preclinical disease models, conducted to elucidate the neurobiological mechanisms underlying the link between mood disorders and cardiovascular disease. These include: (a) the chronic mild stress model of depression, (b) a model of congestive heart failure, a model of cardiovascular deconditioning, (d) pharmacological manipulations of body fluid and sodium balance, and (e) pharmacological manipulations of the central serotonergic system. In combination with the extensive literature describing findings from human research, the investigation of mechanisms underlying mood and cardiovascular regulation using animal models will enhance our understanding of the association of depression and cardiovascular disease, and can promote the development of better treatments and interventions for individuals with these co-morbid conditions. PMID:19116888

Experimental Evidences Supporting the Benefits of Exercise Training in Heart Failure.

PubMed

Ichige, Marcelo H A; Pereira, Marcelo G; Brum, Patrícia C; Michelini, Lisete C

2017-01-01

Heart Failure (HF), a common end point for many cardiovascular diseases, is a syndrome with a very poor prognosis. Although clinical trials in HF have achieved important outcomes in reducing mortality, little is known about functional mechanisms conditioning health improvement in HF patients. In parallel with clinical studies, basic science has been providing important discoveries to understand the mechanisms underlying the pathophysiology of HF, as well as to identify potential targets for the treatment of this syndrome. In spite of being the end-point of cardiovascular derangements caused by different etiologies, autonomic dysfunction, sympathetic hyperactivity, oxidative stress, inflammation and hormonal activation are common factors involved in the progression of this syndrome. Together these causal factors create a closed link between three important organs: brain, heart and the skeletal muscle. In the past few years, we and other groups have studied the beneficial effects of aerobic exercise training as a safe therapy to avoid the progression of HF. As summarized in this chapter, exercise training, a non-pharmacological tool without side effects, corrects most of the HF-induced neurohormonal and local dysfunctions within the brain, heart and skeletal muscles. These adaptive responses reverse oxidative stress, reduce inflammation, ameliorate neurohormonal control and improve both cardiovascular and skeletal muscle function, thus increasing the quality of life and reducing patients' morbimortality.

Vestibular autonomic regulation (including motion sickness and the mechanism of vomiting)

NASA Technical Reports Server (NTRS)

Balaban, C. D.

1999-01-01

Autonomic manifestations of vestibular dysfunction and motion sickness are well established in the clinical literature. Recent studies of 'vestibular autonomic regulation' have focused predominantly on autonomic responses to stimulation of the vestibular sense organs in the inner ear. These studies have shown that autonomic responses to vestibular stimulation are regionally selective and have defined a 'vestibulosympathetic reflex' in animal experiments. Outside the realm of experimental preparations, however, the importance of vestibular inputs in autonomic regulation is unclear because controls for secondary factors, such as affective/emotional responses and cardiovascular responses elicited by muscle contraction and regional blood pooling, have been inadequate. Anatomic and physiologic evidence of an extensive convergence of vestibular and autonomic information in the brainstem suggests though that there may be an integrated representation of gravitoinertial acceleration from vestibular, somatic, and visceral receptors for somatic and visceral motor control. In the case of vestibular dysfunction or motion sickness, the unpleasant visceral manifestations (e.g. epigastric discomfort, nausea or vomiting) may contribute to conditioned situational avoidance and the development of agoraphobia.

Linear and Nonlinear Analyses of the Cardiac Autonomic Control in Children With Developmental Coordination Disorder: A Case-Control Study.

PubMed

Cavalcante Neto, Jorge L; Zamunér, Antonio R; Moreno, Bianca C; Silva, Ester; Tudella, Eloisa

2018-01-01

Children with Developmental Coordination Disorder (DCD) and children at risk for DCD (r-DCD) present motor impairments interfering in their school, leisure and daily activities. In addition, these children may have abnormalities in their cardiac autonomic control, which together with their motor impairments, restrict their health and functionality. Therefore, this study aimed to assess the cardiac autonomic control, by linear and nonlinear analysis, at supine and during an orthostatic stimulus in DCD, r-DCD and typically developed children. Thirteen DCD children (11 boys and 2 girls, aged 8.08 ± 0.79 years), 19 children at risk for DCD (13 boys and 6 girls, aged 8.10 ± 0.96 years) and 18 typically developed children, who constituted the control group (CG) (10 boys and 8 girls, aged 8.50 ± 0.96 years) underwent a heart rate variability (HRV) examination. R-R intervals were recorded in order to assess the cardiac autonomic control using a validated HR monitor. HRV was analyzed by linear and nonlinear methods and compared between r-DCD, DCD, and CG. The DCD group presented blunted cardiac autonomic adjustment to the orthostatic stimulus, which was not observed in r-DCD and CG. Regarding nonlinear analysis of HRV, the DCD group presented lower parasympathetic modulation in the supine position compared to the r-DCD and CG groups. In the within group analysis, only the DCD group did not increase HR from supine to standing posture. Symbolic analysis revealed a significant decrease in 2LV ( p < 0.0001) and 2UV ( p < 0.0001) indices from supine to orthostatic posture only in the CG. In conclusion, r-DCD and DCD children present cardiac autonomic dysfunction characterized by higher sympathetic, lower parasympathetic and lower complexity of cardiac autonomic control in the supine position, as well as a blunted autonomic adjustment to the orthostatic stimulus. Therefore, cardiovascular health improvement should be part of DCD children's management, even in cases of less severe motor impairment.

Neuropad for the detection of cardiovascular autonomic neuropathy in patients with type 2 diabetes.

PubMed

Mendivil, Carlos O; Kattah, William; Orduz, Arturo; Tique, Claudia; Cárdenas, José L; Patiño, Jorge E

2016-01-01

Cardiovascular autonomic neuropathy (CAN) is a prevalent and neglected chronic complication of diabetes, with a large impact on morbidity and mortality. Part of the reason why it is not detected and treated opportunely is because of the complexity of the tests required for its diagnosis. We evaluated the Neuropad®, a test based on sudomotor function, as a screening tool for CAN in adult patients with type 2 diabetes in Bogotá, Colombia. This was a cross-sectional evaluation of Neuropad® for the detection of CAN. Patients were 20-75years of age and did not suffer from any other type of neuropathy. CAN was diagnosed using the Ewing battery of tests for R-R variability during deep breathing, Valsalva and lying-to-standing maneuvers. Additionally, distal symmetric polyneuropathy (DSP) was diagnosed using a sign-based scale (Michigan Neuropathy Disability Score - NDS) and a symptom-based score (Total Symptom Score - TSS). The primary outcome was the sensitivity and specificity of the Neuropad® for the diagnosis of CAN, and secondary outcomes were the sensitivity and specificity of Neuropad® for DSP. We studied 154 patients (74 men and 80 women). Prevalence of CAN was extremely high (68.0% of study participants), but also DSP was prevalent, particularly according to the signs-based definition (45%). The sensitivity of the Neuropad® for any degree of CAN was 70.1%, being slightly higher for the deep breathing and Valsalva tests than for lying-to-standing. The specificity of the Neuropad® for any type of CAN was only 37.0%, as expected for a screening exam. The negative predictive value was higher for the deep breathing and Valsalva tests (69.4 and 81.6%, respectively). Neuropad showed also a good sensitivity and negative predictive value for DSP. The sensitivity and specificity of Neuropad were better among men, and among patients with diabetes duration above the group median. The Neuropad is a simple and inexpensive device that demonstrated an adequate performance as a screening tool for cardiovascular autonomic neuropathy in Latin American patients with DM2. Copyright © 2016 Elsevier Inc. All rights reserved.

Influences of Vestibular System on Sympathetic Nervous System. Implications for countermeasures.

NASA Astrophysics Data System (ADS)

Denise, Pr Pierre

As gravity is a direct and permanent stress on body fluids, muscles and bones, it is not surpris-ing that weightlessness has important effects on cardiovascular and musculo-skeletal systems. However, these harmful effects do not totally result from the removal of the direct stress of gravity on these organs, but are also partially and indirectly mediated by the vestibular sys-tem. Besides its well known crucial role in spatial orientation and postural equilibrium, it is now clear that the vestibular system is also involved in the regulation of other important physi-ological systems: respiratory and cardiovascular systems, circadian regulation, food intake and even bone mineralization. The neuroanatomical substrate for these vestibular-mediated reg-ulations is still poorly defined, but there is much evidence that vestibular system has strong impacts not only on brainstem autonomic centers but on many hypothalamic nuclei as well. As autonomic nervous system controls almost all body organs, bringing into play the vestibular system by hypergravity or microgravity could virtually affects all major physiological func-tions. There is experimental evidence that weightlessness as well as vestibular lesion induce sympathetic activation thus participating in space related physiological alterations. The fact that some effects of weightlessness on biological systems are mediated by the vestibular system has an important implication for using artificial gravity as a countermeasure: artificial gravity should load not only bones and the cardiovascular system but the vestibular system as well. In short-arm centrifuges, the g load at the head level is low because the head is near the axis of rotation. If the vestibular system is involved in cardiovascular deconditioning and bone loss during weightlessness, it would be more effective to significantly stimulate it and thus it would be necessary to place the head off-axis. Moreover, as the otolithic organs are non longer stimu-lated in term of gravity during space flight, and because of the plasticity of the brain, it might be possible that their inputs be progressively interpreted as resulting from translational move-ment with no gravity related activation. Therefore, on return to Earth the effect of the otoliths on cardiovascular regulation might be temporarily lost leading to orthostatic intolerance.

Direct and Indirect Effects of PM on the Cardiovascular System

PubMed Central

Nelin, Timothy D.; Joseph, Allan M.; Gorr, Matthew W.; Wold, Loren E.

2011-01-01

Human exposure to particulate matter (PM) elicits a variety of responses on the cardiovascular system through both direct and indirect pathways. Indirect effects of PM on the cardiovascular system are mediated through the autonomic nervous system, which controls heart rate variability, and inflammatory responses, which augment acute cardiovascular events and atherosclerosis. Recent research demonstrates that PM also affects the cardiovascular system directly by entry into the systemic circulation. This process causes myocardial dysfunction through mechanisms of reactive oxygen species production, calcium ion interference, and vascular dysfunction. In this review, we will present key evidence in both the direct and indirect pathways, suggest clinical applications of the current literature, and recommend directions for future research. PMID:22119171

[A role of the autonomic nervous system in cerebro-cardiac disorders].

PubMed

Basantsova, N Yu; Tibekina, L M; Shishkin, A N

The authors consider anatomical/physiological characteristics and a role of different autonomic CNS regions, including insula cortex, amygdala complex, anterior cingulate cortex, ventral medial prefrontal cortex, hypothalamus and epiphysis, involved in the regulation of cardiovascular activity. The damage of these structures, e.g., due to the acute disturbance of cerebral blood circulation, led to arrhythmia, including fatal arrhythmia, in previously intact myocardium; systolic and diastolic dysfunction, ischemic changes considered in the frames of cerebro-cardial syndrome. On the cellular level, the disturbance of autonomic regulation resulted in catechol amine excitotoxicity, oxidative stress and free radical myocardium injury.

Impact of escitalopram on vagally mediated cardiovascular function in healthy participants: implications for understanding differential age-related, treatment emergent effects.

PubMed

Kemp, Andrew H; Outhred, Tim; Saunders, Sasha; Brunoni, Andre R; Nathan, Pradeep J; Malhi, Gin S

2014-06-01

Black box warnings for young adults under the age of 25 years indicate that antidepressants may increase risk of suicide. While underlying mechanisms for age-related treatment effects remain unclear, vagally mediated cardiovascular function may play a key role. Decreased heart rate (HR) and an increase in its variability (HRV) improve one's capacity to adapt to environmental stress and attenuate risk for suicide. Using a double blind, randomized, placebo-controlled, crossover, experimental study, we examine whether a single dose of escitalopram (20 mg) attenuates cardiovascular responses to stress under experimental conditions and determine whether age moderates these effects. Forty-four healthy females received a single dose of escitalopram (20 mg) and placebo treatment separated by a 1-week interval (>5 half-lives). HR and high frequency HRV (HF HRV normalized units; 0.15-0.40 Hz) were measured during resting state and stress. While escitalopram attenuated the increase in HR and increased HF HRV, these moderate to large effects were only significant in participants over 25 years of age. No beneficial cardiovascular effects of escitalopram were observed in those under the age of 25. Maturational differences in the development of the prefrontal cortex--a critical region in the central network of autonomic control--may underpin these differential findings. This study provides a theoretical framework on which future research on treatment-emergent suicidality in clinical populations could be based.

Cardiac Autonomic Neuropathy as a Result of Mild Hypercaloric Challenge in Absence of Signs of Diabetes: Modulation by Antidiabetic Drugs

PubMed Central

Al-Assi, Ola; Ghali, Rana; Mroueh, Ali; Kaplan, Abdullah; Mougharbil, Nahed

2018-01-01

Cardiac autonomic neuropathy (CAN) is an early cardiovascular complication of diabetes occurring before metabolic derangement is evident. The cause of CAN remains elusive and cannot be directly linked to hyperglycemia. Recent clinical data report cardioprotective effects of some antidiabetic drugs independent of their hypoglycemic action. Here, we used a rat model receiving limited daily increase in calories from fat (HC diet) to assess whether mild metabolic challenge led to CAN in absence of interfering effects of hyperglycemia, glucose intolerance, or obesity. Rats receiving HC diet for 12 weeks showed reduction in baroreceptor sensitivity and heart rate variability despite lack of change in baseline hemodynamic and cardiovascular structural parameters. Impairment of cardiac autonomic control was accompanied with perivascular adipose inflammation observed as an increased inflammatory cytokine expression, together with increased cardiac oxidative stress, and signaling derangement characteristic of diabetic cardiomyopathy. Two-week treatment with metformin or pioglitazone rectified the autonomic derangement and corrected the molecular changes. Switching rats to normal chow but not to isocaloric amounts of HC for two weeks reversed CAN. As such, we conclude that adipose inflammation due to increased fat intake might underlie development of CAN and, hence, the beneficial effects of metformin and pioglitazone. PMID:29643979

Respiratory sinus arrhythmia: time domain characterization using autoregressive moving average analysis

NASA Technical Reports Server (NTRS)

Triedman, J. K.; Perrott, M. H.; Cohen, R. J.; Saul, J. P.

1995-01-01

Fourier-based techniques are mathematically noncausal and are therefore limited in their application to feedback-containing systems, such as the cardiovascular system. In this study, a mathematically causal time domain technique, autoregressive moving average (ARMA) analysis, was used to parameterize the relations of respiration and arterial blood pressure to heart rate in eight humans before and during total cardiac autonomic blockade. Impulse-response curves thus generated showed the relation of respiration to heart rate to be characterized by an immediate increase in heart rate of 9.1 +/- 1.8 beats.min-1.l-1, followed by a transient mild decrease in heart rate to -1.2 +/- 0.5 beats.min-1.l-1 below baseline. The relation of blood pressure to heart rate was characterized by a slower decrease in heart rate of -0.5 +/- 0.1 beats.min-1.mmHg-1, followed by a gradual return to baseline. Both of these relations nearly disappeared after autonomic blockade, indicating autonomic mediation. Maximum values obtained from the respiration to heart rate impulse responses were also well correlated with frequency domain measures of high-frequency "vagal" heart rate control (r = 0.88). ARMA analysis may be useful as a time domain representation of autonomic heart rate control for cardiovascular modeling.

Brain-derived neurotrophic factor as a regulator of systemic and brain energy metabolism and cardiovascular health

PubMed Central

Rothman, Sarah M; Griffioen, Kathleen J; Wan, Ruiqian; Mattson, Mark P

2012-01-01

Overweight sedentary individuals are at increased risk for cardiovascular disease, diabetes, and some neurological disorders. Beneficial effects of dietary energy restriction (DER) and exercise on brain structural plasticity and behaviors have been demonstrated in animal models of aging and acute (stroke and trauma) and chronic (Alzheimer's and Parkinson's diseases) neurological disorders. The findings described later, and evolutionary considerations, suggest brain-derived neurotrophic factor (BDNF) plays a critical role in the integration and optimization of behavioral and metabolic responses to environments with limited energy resources and intense competition. In particular, BDNF signaling mediates adaptive responses of the central, autonomic, and peripheral nervous systems from exercise and DER. In the hypothalamus, BDNF inhibits food intake and increases energy expenditure. By promoting synaptic plasticity and neurogenesis in the hippocampus, BDNF mediates exercise- and DER-induced improvements in cognitive function and neuroprotection. DER improves cardiovascular stress adaptation by a mechanism involving enhancement of brainstem cholinergic activity. Collectively, findings reviewed in this paper provide a rationale for targeting BDNF signaling for novel therapeutic interventions in a range of metabolic and neurological disorders. PMID:22548651

Estrogen attenuates the cardiovascular and ventilatory responses to central command in cats.

PubMed

Hayes, Shawn G; Moya Del Pino, Nicolas B; Kaufman, Marc P

2002-04-01

Static exercise is well known to increase heart rate, arterial blood pressure, and ventilation. These increases appear to be less in women than in men, a difference that has been attributed to an effect of estrogen on neuronal function. In decerebrate male cats, we examined the effect of estrogen (17beta-estradiol; 0.001, 0.01, 0.1, and 1.0 microg/kg iv) on the cardiovascular and ventilatory responses to central command and the exercise pressor reflex, the two neural mechanisms responsible for evoking the autonomic and ventilatory responses to exercise. We found that 17beta-estradiol, in each of the three doses tested, attenuated the pressor, cardioaccelerator, and phrenic nerve responses to electrical stimulation of the mesencephalic locomotor region (i.e., central command). In contrast, none of the doses of 17beta-estradiol had any effect on the pressor, cardioaccelerator, and ventilatory responses to static contraction or stretch of the triceps surae muscles. We conclude that, in decerebrate male cats, estrogen injected intravenously attenuates cardiovascular and ventilatory responses to central command but has no effect on responses to the exercise pressor reflex.

Organisational injustice and impaired cardiovascular regulation among female employees.

PubMed

Elovainio, M; Kivimäki, M; Puttonen, S; Lindholm, H; Pohjonen, T; Sinervo, T

2006-02-01

To examine the relation between perceived organisational justice and cardiovascular reactivity in women. The participants were 57 women working in long term care homes. Heart rate variability and systolic arterial pressure variability were used as markers of autonomic function. Organisational justice was measured using the scale of Moorman. Data on other risk factors were also collected. Results from logistic regression models showed that the risk for increased low frequency band systolic arterial pressure variability was 3.8-5.8 times higher in employees with low justice than in employees with high justice. Low perceived justice was also related to an 80% excess risk of reduced high frequency heart rate variability compared to high perceived justice, but this association was not statistically significant. These findings are consistent with the hypothesis that cardiac dysregulation is one stress mechanism through which a low perceived justice of decision making procedures and interpersonal treatment increases the risk of health problems in personnel.

Central command: control of cardiac sympathetic and vagal efferent nerve activity and the arterial baroreflex during spontaneous motor behaviour in animals.

PubMed

Matsukawa, Kanji

2012-01-01

Feedforward control by higher brain centres (termed central command) plays a role in the autonomic regulation of the cardiovascular system during exercise. Over the past 20 years, workers in our laboratory have used the precollicular-premammillary decerebrate animal model to identify the neural circuitry involved in the CNS control of cardiac autonomic outflow and arterial baroreflex function. Contrary to the traditional idea that vagal withdrawal at the onset of exercise causes the increase in heart rate, central command did not decrease cardiac vagal efferent nerve activity but did allow cardiac sympathetic efferent nerve activity to produce cardiac acceleration. In addition, central command-evoked inhibition of the aortic baroreceptor-heart rate reflex blunted the baroreflex-mediated bradycardia elicited by aortic nerve stimulation, further increasing the heart rate at the onset of exercise. Spontaneous motor activity and associated cardiovascular responses disappeared in animals decerebrated at the midcollicular level. These findings indicate that the brain region including the caudal diencephalon and extending to the rostral mesencephalon may play a role in generating central command. Bicuculline microinjected into the midbrain ventral tegmental area of decerebrate rats produced a long-lasting repetitive activation of renal sympathetic nerve activity that was synchronized with the motor nerve discharge. When lidocaine was microinjected into the ventral tegmental area, the spontaneous motor activity and associated cardiovascular responses ceased. From these findings, we conclude that cerebral cortical outputs trigger activation of neural circuits within the caudal brain, including the ventral tegmental area, which causes central command to augment cardiac sympathetic outflow at the onset of exercise in decerebrate animal models.

Postprandial hypotension in older adults: Can it be prevented by drinking water before the meal?

PubMed

Grobéty, Bastien; Grasser, Erik Konrad; Yepuri, Gayathri; Dulloo, Abdul G; Montani, Jean-Pierre

2015-10-01

An important consequence of ageing is a tendency for postprandial blood pressure to decline, which can lead to fainting. As a possible countermeasure, we investigated in healthy older adults the impact of drinking water before a breakfast meal on postprandial cardiovascular and autonomic functions. After a stable cardiovascular baseline recording for at least 20 min, twelve older adult (67 ± 1 y) test subjects ingested, in a crossover study design, either 100 mL or 500 mL of tap water over 4 min, which was followed by the consumption of the test breakfast meal (1708 kJ) over a period of 15 min. Then, cardiovascular recordings were resumed for 90 min after the meal. Eleven young (25 ± 1 y) and healthy subjects served as a control group. Measurements included beat-to-beat blood pressure, heart rate, impedance cardiography and autonomic variables. In older adults, systolic and diastolic blood pressure started to decline around 30 min after the meal, with the lowest values around 60 min; these effects were not observed in the young control group. Postprandial systolic blood pressure decreased between 30 and 90 min to a greater extent in response to 100 mL than to 500 mL (-6.4 vs. -3.3 mmHg, P < 0.05). Drinking 500 mL of water tended to increase stroke volume, cardiac output and vagal markers to a greater extent than 100 mL. Our data suggest that drinking a large volume (500 mL) of water before a meal may attenuate postprandial hypotension in older adults. Copyright © 2014 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.

Complex nonlinear autonomic nervous system modulation link cardiac autonomic neuropathy and peripheral vascular disease.

PubMed

Khalaf, Kinda; Jelinek, Herbert F; Robinson, Caroline; Cornforth, David J; Tarvainen, Mika P; Al-Aubaidy, Hayder

2015-01-01

Physiological interactions are abundant within, and between, body systems. These interactions may evolve into discrete states during pathophysiological processes resulting from common mechanisms. An association between arterial stenosis, identified by low ankle-brachial pressure index (ABPI) and cardiovascular disease (CVD) as been reported. Whether an association between vascular calcification-characterized by high ABPI and a different pathophysiology-is similarly associated with CVD, has not been established. The current study aims to investigate the association between ABPI, and cardiac rhythm, as an indicator of cardiovascular health and functionality, utilizing heart rate variability (HRV). Two hundred and thirty six patients underwent ABPI assessment. Standard time and frequency domain, and non-linear HRV measures were determined from 5-min electrocardiogram. ABPI data were divided into normal (n = 101), low (n = 67) and high (n = 66) and compared to HRV measures.(DFAα1 and SampEn were significantly different between the low ABPI, high ABPI and control groups (p < 0.05). A possible coupling between arterial stenosis and vascular calcification with decreased and increased HRV respectively was observed. Our results suggest a model for interpreting the relationship between vascular pathophysiology and cardiac rhythm. The cardiovascular system may be viewed as a complex system comprising a number of interacting subsystems. These cardiac and vascular subsystems/networks may be coupled and undergo transitions in response to internal or external perturbations. From a clinical perspective, the significantly increased sample entropy compared to the normal ABPI group and the decreased and increased complex correlation properties measured by DFA for the low and high ABPI groups respectively, may be useful indicators that a more holistic treatment approach in line with this more complex clinical picture is required.

Cardiovascular Responses to Sexual Activity in Able-Bodied Individuals and Those Living with Spinal Cord Injury.

PubMed

Davidson, Ross; Elliott, Stacy; Krassioukov, Andrei

2016-12-15

Sexuality is an integral part of the human experience and persists in health and disability. The cardiovascular system is crucial to sexual function and can be affected profoundly by spinal cord injury (SCI). The effects of sexual activity on the cardiovascular system in SCI have not been summarized and compared with sexual activity in able-bodied individuals. A keyword search of Embase, PubMed, and Medline was conducted. From 471 retrieved studies for able-bodied individuals, 11 were included that met the strict criteria of medically uncomplicated participants. In the SCI literature, 117 studies were screened, with 18 meeting criteria. In able-bodied persons, sexual activity resulted in modest increases in systolic blood pressure peaking at orgasm (males of 163 mm Hg and females of 142 mm Hg) and returning to baseline shortly afterward. In persons with SCI, results varied from minimal changes to significant elevations in systolic blood pressure because of episodes of autonomic dysreflexia, especially in those with high thoracic and cervical lesions. Peak systolic blood pressure in these individuals was measured to be as high as 325 mm Hg. In the SCI population, more intense stimuli (including penile vibrostimulation and electroejaculation) tended to result in a greater increase in systolic blood pressure compared with self-stimulation. Studies that used continuous versus intermittent monitoring were more likely to report greater changes in systolic blood pressure. In able-bodied persons, sexual activity results in modest increases in blood pressure. In those with SCI, intense stimulation and higher injury levels result in a higher likelihood of autonomic dysreflexia and elevated blood pressure. Because of rapid changes in blood pressure, continuous monitoring is more advantageous than intermittent measurement, because the latter may miss peak values.

Thermoregulatory disorders and illness related to heat and cold stress.

PubMed

Cheshire, William P

2016-04-01

Thermoregulation is a vital function of the autonomic nervous system in response to cold and heat stress. Thermoregulatory physiology sustains health by keeping body core temperature within a degree or two of 37°C, which enables normal cellular function. Heat production and dissipation are dependent on a coordinated set of autonomic responses. The clinical detection of thermoregulatory impairment provides important diagnostic and localizing information in the evaluation of disorders that impair thermoregulatory pathways, including autonomic neuropathies and ganglionopathies. Failure of neural thermoregulatory mechanisms or exposure to extreme or sustained temperatures that overwhelm the body's thermoregulatory capacity can also result in potentially life-threatening departures from normothermia. Hypothermia, defined as a core temperature of <35.0°C, may present with shivering, respiratory depression, cardiac dysrhythmias, impaired mental function, mydriasis, hypotension, and muscle dysfunction, which can progress to cardiac arrest or coma. Management includes warming measures, hydration, and cardiovascular support. Deaths from hypothermia are twice as frequent as deaths from hyperthermia. Hyperthermia, defined as a core temperature of >40.5°C, may present with sweating, flushing, tachycardia, fatigue, lightheadedness, headache, and paresthesia, progressing to weakness, muscle cramps, oliguria, nausea, agitation, hypotension, syncope, confusion, delirium, seizures, and coma. Mental status changes and core temperature distinguish potentially fatal heat stroke from heat exhaustion. Management requires the immediate reduction of core temperature. Ice water immersion has been shown to be superior to alternative cooling measures. Avoidance of thermal risk and early recognition of cold or heat stress are the cornerstones of preventive therapy. Copyright © 2016 The Author. Published by Elsevier B.V. All rights reserved.

Gastric emptying, postprandial blood pressure, glycaemia and splanchnic flow in Parkinson's disease.

PubMed

Trahair, Laurence G; Kimber, Thomas E; Flabouris, Katerina; Horowitz, Michael; Jones, Karen L

2016-05-28

To determine gastric emptying, blood pressure, mesenteric artery blood flow, and blood glucose responses to oral glucose in Parkinson's disease. Twenty-one subjects (13 M, 8 F; age 64.2 ± 1.6 years) with mild to moderate Parkinson's disease (Hoehn and Yahr score 1.4 ± 0.1, duration of known disease 6.3 ± 0.9 years) consumed a 75 g glucose drink, labelled with 20 MBq (99m)Tc-calcium phytate. Gastric emptying was quantified with scintigraphy, blood pressure and heart rate with an automated device, superior mesenteric artery blood flow by Doppler ultrasonography and blood glucose by glucometer for 180 min. Autonomic nerve function was evaluated with cardiovascular reflex tests and upper gastrointestinal symptoms by questionnaire. The mean gastric half-emptying time was 106 ± 9.1 min, gastric emptying was abnormally delayed in 3 subjects (14%). Systolic and diastolic blood pressure fell (P < 0.001) and mesenteric blood flow and blood glucose (P < 0.001 for both) increased, following the drink. Three subjects (14%) had definite autonomic neuropathy and 8 (38%) had postprandial hypotension. There were no significant relationships between changes in blood pressure, heart rate or mesenteric artery blood flow with gastric emptying. Gastric emptying was related to the score for autonomic nerve function (R = 0.55, P < 0.01). There was an inverse relationship between the blood glucose at t = 30 min (R = -0.52, P < 0.05), while the blood glucose at t = 180 min was related directly (R = 0.49, P < 0.05), with gastric emptying. In mild to moderate Parkinson's disease, gastric emptying is related to autonomic dysfunction and a determinant of the glycaemic response to oral glucose.

Is vaspin related to cardio-metabolic status and autonomic function in early stages of glucose intolerance and in metabolic syndrome?

PubMed

Dimova, Rumyana; Tankova, Tsvetalina; Kirilov, Georgi; Chakarova, Nevena; Dakovska, Lilia; Grozeva, Greta

2016-01-01

This study aims to assess serum vaspin in early stages of glucose intolerance and in the presence of metabolic syndrome (MetS); and to evaluate vaspin correlation to different cardio-metabolic parameters and autonomic tone in these subjects. 185 subjects (80 males and 105 females) of mean age 45.8 ± 11.6 years and mean BMI 31.2 ± 6.3 kg/m(2), divided into groups according to: glucose tolerance, presence of MetS and cardio-vascular autonomic dysfunction (CAD), were enrolled. Glucose tolerance was studied during OGTT. Anthropometric indices, blood pressure, HbA1c, serum lipids, hsCRP, fasting immunoreactive insulin and serum vaspin were measured. Body composition was estimated by impedance analysis. AGEs were assessed by skin fluorescence. CAD was assessed by ANX-3.0. There was no difference in vaspin levels between the groups according to glucose tolerance, presence of MetS, and CAD. Regression analysis revealed independent association between serum vaspin and total body fat in newly diagnosed type 2 diabetes (NDT2D) group, and between serum vaspin and age and total body fat in MetS group. Vaspin negatively correlated with both sympathetic and parasympathetic activity in normal glucose tolerance (NGT) and just with parasympathetic tone in NGT without MetS. Our results demonstrate no overt fluctuations in vaspin levels in the early stages of glucose intolerance and in MetS. Total body fat seems to be related to vaspin levels in MetS and NDT2D. Our data show negative correlation between vaspin and autonomic function in NGT, as vaspin is associated with parasympathetic activity even in the absence of MetS.

Preserved functional autonomic phenotype in adult mice overexpressing moderate levels of human alpha‐synuclein in oligodendrocytes

PubMed Central

Tank, Jens; da Costa‐Goncalves, Andrey C.; Kamer, Ilona; Qadri, Fatimunnisa; Ubhi, Kiren; Rockenstein, Edward; Diedrich, André; Masliah, Eliezer; Gross, Volkmar; Jordan, Jens

2014-01-01

Abstract Mice overexpressing human alpha‐synuclein in oligodendrocytes (MBP1‐α‐syn) recapitulate some key functional and neuropathological features of multiple system atrophy (MSA). Whether or not these mice develop severe autonomic failure, which is a key feature of human MSA, remains unknown. We explored cardiovascular autonomic regulation using long‐term blood pressure (BP) radiotelemetry and pharmacological testing. We instrumented 12 MBP1‐α‐syn mice and 11 wild‐type mice aged 9 months for radiotelemetry. Animals were tested with atropine, metoprolol, clonidine, and trimethaphan at 9 and 12 months age. We applied spectral and cross‐spectral analysis to assess heart rate (HR) and BP variability. At 9 months of age daytime BP (transgenic: 101 ± 2 vs. wild type: 99 ± 2 mmHg) and HR (497 ± 11 vs. 505 ± 16 beats/min) were similar. Circadian BP and HR rhythms were maintained. Nighttime BP (109 ± 2 vs. 108 ± 2 mmHg) and HR (575 ± 15 vs. 569 ± 14 beats/min), mean arterial BP responses to trimethaphan (−21 ± 8 vs. −10 ± 5 mmHg, P = 0.240) and to clonidine (−8 ± 3 vs. −5 ± 2 mmHg, P = 0.314) were similar. HR responses to atropine (+159 ± 24 vs. +146 ± 22 beats/min), and to clonidine (−188 ± 21 vs. −163 ± 33 beats/min) did not differ between strains. Baroreflex sensitivity (4 ± 1 vs. 4 ± 1 msec/mmHg) and HR variability (total power, 84 ± 17 vs. 65 ± 21 msec²) were similar under resting conditions and during pharmacological testing. Repeated measurements at 12 months of age provided similar results. In mice, moderate overexpression of human alpha‐synuclein in oligodendrocytes is not sufficient to induce overt autonomic failure. Additional mechanisms may be required to express the autonomic failure phenotype including higher levels of expression or more advanced age. PMID:25428949

[The use of sodium chloride baths in children with a heart lesion subjected to long-term exposure to low radiation doses].

PubMed

Poberskaia, V A; Dement'eva, O I

1997-01-01

Children exposed to low-dose radiation are often treated in sanatoria with mineral baths. Of the latter balneoprocedures widely practiced are sodium chloride (SC) baths with mineralization 20-30 g/l. Mineralization 40 g/l is less frequently used. To specify changes in the function of cardiovascular system induced by SC baths of different concentration (40 versus 20 g/l) 131 senior schoolchildren exposed to low-dose radiation or other environmental pollutants were examined both after a single balneological procedure and after the course treatment (maximum 10 procedures). The baths lasted 8-15 min at water temperature 36-38 OC in a day intervals. The response was assessed by ECG, tetrapolar chest rheography, bicycle exercise. All the children had cardiovascular disorders of non-rheumatic origin. Therapeutic effect was more pronounced after baths with SC concentration 40 g/l. These baths are recommended for improvement of vegetative regulation of the heart, correction of hemodynamic defects. Baths with mineralization 20 g/l are better in upgrading function of the autonomic nervous system.

Mind-body relationships in elite apnea divers during breath holding: a study of autonomic responses to acute hypoxemia

PubMed Central

Laurino, Marco; Menicucci, Danilo; Mastorci, Francesca; Allegrini, Paolo; Piarulli, Andrea; Scilingo, Enzo P.; Bedini, Remo; Pingitore, Alessandro; Passera, Mirko; L'Abbate, Antonio; Gemignani, Angelo

2011-01-01

The mental control of ventilation with all associated phenomena, from relaxation to modulation of emotions, from cardiovascular to metabolic adaptations, constitutes a psychophysiological condition characterizing voluntary breath-holding (BH). BH induces several autonomic responses, involving both autonomic cardiovascular and cutaneous pathways, whose characterization is the main aim of this study. Electrocardiogram and skin conductance (SC) recordings were collected from 14 elite divers during three conditions: free breathing (FB), normoxic phase of BH (NPBH) and hypoxic phase of BH (HPBH). Thus, we compared a set of features describing signal dynamics between the three experimental conditions: from heart rate variability (HRV) features (in time and frequency-domains and by using nonlinear methods) to rate and shape of spontaneous SC responses (SCRs). The main result of the study rises by applying a Factor Analysis to the subset of features significantly changed in the two BH phases. Indeed, the Factor Analysis allowed to uncover the structure of latent factors which modeled the autonomic response: a factor describing the autonomic balance (AB), one the information increase rate (IIR), and a latter the central nervous system driver (CNSD). The BH did not disrupt the FB factorial structure, and only few features moved among factors. Factor Analysis indicates that during BH (1) only the SC described the emotional output, (2) the sympathetic tone on heart did not change, (3) the dynamics of interbeats intervals showed an increase of long-range correlation that anticipates the HPBH, followed by a drop to a random behavior. In conclusion, data show that the autonomic control on heart rate and SC are differentially modulated during BH, which could be related to a more pronounced effect on emotional control induced by the mental training to BH. PMID:22461774

Heart Rate Responses to Autonomic Challenges in Obstructive Sleep Apnea

PubMed Central

Macey, Paul M.; Kumar, Rajesh; Woo, Mary A.; Yan-Go, Frisca L.; Harper, Ronald M.

2013-01-01

Obstructive sleep apnea (OSA) is accompanied by structural alterations and dysfunction in central autonomic regulatory regions, which may impair dynamic and static cardiovascular regulation, and contribute to other syndrome pathologies. Characterizing cardiovascular responses to autonomic challenges may provide insights into central nervous system impairments, including contributions by sex, since structural alterations are enhanced in OSA females over males. The objective was to assess heart rate responses in OSA versus healthy control subjects to autonomic challenges, and, separately, characterize female and male patterns. We studied 94 subjects, including 37 newly-diagnosed, untreated OSA patients (6 female, age mean±std: 52.1±8.1 years; 31 male aged 54.3±8.4 years), and 57 healthy control subjects (20 female, 50.5±8.1 years; 37 male, 45.6±9.2 years). We measured instantaneous heart rate with pulse oximetry during cold pressor, hand grip, and Valsalva maneuver challenges. All challenges elicited significant heart rate differences between OSA and control groups during and after challenges (repeated measures ANOVA, p<0.05). In post-hoc analyses, OSA females showed greater impairments than OSA males, which included: for cold pressor, lower initial increase (OSA vs. control: 9.5 vs. 7.3 bpm in females, 7.6 vs. 3.7 bpm in males), OSA delay to initial peak (2.5 s females/0.9 s males), slower mid-challenge rate-of-increase (OSA vs. control: −0.11 vs. 0.09 bpm/s in females, 0.03 vs. 0.06 bpm/s in males); for hand grip, lower initial peak (OSA vs. control: 2.6 vs. 4.6 bpm in females, 5.3 vs. 6.0 bpm in males); for Valsalva maneuver, lower Valsalva ratio (OSA vs. control: 1.14 vs. 1.30 in females, 1.29 vs. 1.34 in males), and OSA delay during phase II (0.68 s females/1.31 s males). Heart rate responses showed lower amplitude, delayed onset, and slower rate changes in OSA patients over healthy controls, and impairments may be more pronounced in females. The dysfunctions may reflect central injury in the syndrome, and suggest autonomic deficiencies that may contribute to further tissue and functional pathologies. PMID:24194842

Age Effect on Autonomic Cardiovascular Control in Pilots

DTIC Science & Technology

2000-08-01

Nantcheva**, M. Vukov *** *National Center of Hygiene, Medical Ecology and Nutrition 15 Dimitar Nestorov Blvd. 1431 Sofia, Bulgaria "**Military Medical...values and critique. Inter. Physiol. Behav. Sci. 1997, 3, of health risk compared with referents. 202-219. 14. Fluckiger L., Boivin J ., Quilliot D...during flight. Aviat. Space Chapman and Hall. 1991, 590 pp. Environ Med. 1998,4, 360-367. 4. Berntson G., Cacioppo J ., Quigley K. Autonomic 18. Hellman J

Impact of aging on cardiac function in a female rat model of menopause: role of autonomic control, inflammation, and oxidative stress.

PubMed

Machi, Jacqueline Freire; Dias, Danielle da Silva; Freitas, Sarah Cristina; de Moraes, Oscar Albuquerque; da Silva, Maikon Barbosa; Cruz, Paula Lázara; Mostarda, Cristiano; Salemi, Vera M C; Morris, Mariana; De Angelis, Kátia; Irigoyen, Maria-Cláudia

2016-01-01

The aim of this study was to evaluate the effects of aging on metabolic, cardiovascular, autonomic, inflammatory, and oxidative stress parameters after ovarian hormone deprivation (OVX). Female Wistar rats (3 or 22 months old) were divided into: young controls, young ovariectomized, old controls, and old ovariectomized (bilateral ovaries removal). After a 9-week follow-up, physical capacity, metabolic parameters, and morphometric and cardiac functions were assessed. Subsequently, arterial pressure was recorded and cardiac autonomic control was evaluated. Oxidative stress was measured on the cardiac tissue, while inflammatory profile was assessed in the plasma. Aging or OVX caused an increase in body and fat weight and triglyceride concentration and a decrease in both insulin sensitivity and aerobic exercise capacity. Left ventricular diastolic dysfunction and increased cardiac overload (myocardial performance index) were reported in old groups when compared with young groups. Aging and OVX led to an increased sympathetic tonus, and vagal tonus was lower only for the old groups. Tumor necrosis factor-α and interleukin-6 were increased in old groups when compared with young groups. Glutathione redox balance (GSH/GSSG) was reduced in young ovariectomized, old controls, and old ovariectomized groups when compared with young controls, indicating an increased oxidative stress. A negative correlation was found between GSH/GSSG and tumor necrosis factor-α (r=-0.6, P<0.003). Correlations were found between interleukin-6 with adipose tissue (r=0.5, P<0.009) and vagal tonus (r=-0.7, P<0.0002); and among myocardial performance index with interleukin-6 (r=0.65, P<0.0002), sympathetic tonus (r=0.55, P<0.006), and physical capacity (r=-0.55, P<0.003). The findings in this trial showed that ovariectomy aggravated the impairment of cardiac and functional effects of aging in female rats, probably associated with exacerbated autonomic dysfunction, inflammation, and oxidative stress.

Two anomalous cardiovascular responses to active standing in essential hypertension.

PubMed

Bettencourt, M Joaquina; Pinto, Basílio Gomes; de Oliveira, E Infante; Silva-Carvalho, L

2008-05-01

In a previous work we studied, non-invasively, autonomic nervous system control of circulation in healthy subjects, observing the hemodynamic reaction to active standing. We now propose to extend this analysis to essential hypertension (EH), investigating possible autonomic dysfunction. The cardiovascular response to postural change from the supine position to active standing of 48 EH patients, of both sexes, with and without medication, was compared with that obtained for healthy subjects. We evaluated arterial systolic (SBP) and diastolic (DBP) blood pressure, stroke volume (SV), inotropic index (INOI), total vascular resistance (TVR), cardiac work (W), stroke work (SW), arterial compliance (AC) and heart rate (HR), using the entirely non-invasive BoMed NCCOM3 thoracic electrical bioimpedance monitor and sphygmomanometry. We found two patient groups characterized by different linear relationships between values of cardiovascular variables in active standing and in supine positions. Except for HR, in both groups these regression lines differed from normal. Compared to the supine position, in active standing, one group (EH-I) presented increased TVR, diminished SV, INOI, W, SW, and AC, and normal HR; the other group (EH-II) presented diminished TVR and HR and increased SV, INOI, W, SW and AC. The two patient groups could be separated on the basis of their age, but not on the basis of their systolic, diastolic and mean arterial blood pressures, gender or medication. The younger patient group (EH-I) included 28 subjects aged 24 to 69 years (50+/-10), of whom 11 were unmedicated, and the older patient group (EH-II) included 20 subjects aged 35 to 75 years (62+/-11), of whom 7 were unmedicated. Our results show a depressed response in postural change for older patients, which in the autonomic control of circulation expresses carotid baroreflex impairment, and conversely an enhanced response for younger patients, which can be caused by a maladjustment of the influence of cardiopulmonary mechanoreflexes in the alance with arterial baroreflexes. This work suggests the existence of two different levels of dysautonomia in EH, according to age. The deterministic changes in cardiovascular variables after postural change show that, regarding autonomic nervous system control to maintain homeostasis, certain circulatory statuses are favored.

Abnormal cardiac autonomic control in sickle cell disease following transient hypoxia.

PubMed

Sangkatumvong, Suvimol; Khoo, Michael C K; Coates, Thomas D

2008-01-01

Abnormalities in autonomic control in sickle cell anemia (SCA) patients have been reported by multiple researchers. However their potential causal association with sickle cell crisis remains unknown. We employed hypoxia, a known trigger to sickle cell crisis, to perturb the autonomic systems of the subjects. Cardiac autonomic control was non-invasively assessed by tracking the changes in heart rate variability (HRV) that occur following brief exposure to a hypoxia stimulus. Time varying spectral analysis of HRV was applied to estimate the cardiac autonomic response to the transient episode of hypoxia. The results demonstrate that cardiovascular autonomic response to hypoxia is substantially more sensitive in SCA than in normal controls. We also developed a model to compensate for the confounding effects of respiration on the HRV spectral indices by using the corresponding respiration signal to compensate for the respiratory correlated part of the HRV. This technique improved the resolution with which the effect of hypoxia on changes in HRV could be measured.

Effects of nitric oxide synthesis inhibitor or fluoxetine treatment on depression-like state and cardiovascular changes induced by chronic variable stress in rats.

PubMed

Almeida, Jeferson; Duarte, Josiane O; Oliveira, Leandro A; Crestani, Carlos C

2015-01-01

Comorbidity between mood disorders and cardiovascular disease has been described extensively. However, available antidepressants can have cardiovascular side effects. Treatment with selective inhibitors of neuronal nitric oxide synthase (nNOS) induces antidepressant effects, but whether the antidepressant-like effects of these drugs are followed by cardiovascular changes has not been previously investigated. Here, we tested in male rats exposed to chronic variable stress (CVS) the hypothesis that nNOS blockers are advantageous compared with conventional antidepressants in terms of cardiovascular side effects. We compared the effects of chronic treatment with the preferential nNOS inhibitor 7-nitroindazole (7-NI) with those evoked by the conventional antidepressant fluoxetine on alterations that are considered as markers of depression (immobility in the forced swimming test, FST, decreased body weight gain and increased plasma corticosterone concentration) and cardiovascular changes caused by CVS. Rats were exposed to a 14-day CVS protocol, while being concurrently treated daily with either 7-NI (30 mg/kg) or fluoxetine (10 mg/kg). Fluoxetine and 7-NI prevented the increase in immobility in the FST induced by CVS and reduced plasma corticosterone concentration in stressed rats. Both these treatments also prevented the CVS-evoked reduction of the depressor response to vasodilator agents and baroreflex changes. Fluoxetine and 7-NI-induced cardiovascular changes independent of stress exposure, including cardiac autonomic imbalance, increased intrinsic heart rate and vascular sympathetic modulation, a reduction of the pressor response to vasoconstrictor agents, and impairment of baroreflex activity. Altogether, these findings provide evidence that fluoxetine and 7-NI have similar effects on the depression-like state induced by CVS and on cardiovascular function.

Autonomic status and pain profile in patients of chronic low back pain and following electro acupuncture therapy: a randomized control trial.

PubMed

Shankar, Nilima; Thakur, Manisha; Tandon, Om Prakash; Saxena, Ashok Kumar; Arora, Shobha; Bhattacharya, Neena

2011-01-01

Pain is a syndrome characterized by several neurophysiological changes including that of the autonomic nervous system. Chronic low back pain (LBP) is a major health problem and is a frequent reason for using unconventional therapies especially acupuncture. This study was conducted to evaluate the autonomic status and pain profile in chronic LBP patients and to observe the effect of electro acupuncture therapy. Chronic LBP patients (n=60) were recruited from the Department of Orthopaedics, GTB Hospital, Delhi. Age and sex matched healthy volunteers were selected as controls (n=30). Following a written consent, LBP patients were randomly allocated into two study groups - Group A received 10 sittings of electro acupuncture, on alternate days, at GB and UB points selected for back pain, while the Group B received a conventional drug therapy in the form of oral Valdecoxib together with supervised physiotherapy. Controls were assessed once while the patients were assessed twice, before and after completion of the treatment program (3 weeks). The autonomic status was studied with non-invasive cardiovascular autonomic function tests which included E: I ratio, 30:15 ratio, postural challenge test and sustained handgrip test. Pain intensity was measured with the visual analogue scale (VAS) and the global perceived effect (GPE). Statistical analysis was performed using repeated measure's ANOVA with Tukey's test. Pain patients showed a significantly reduced vagal tone and increased sympathetic activity as compared to the controls (P<0.05 to P<0.001 in different variables). Following treatment, both the study groups showed a reduction in vagal tone together with a decrease in the sympathetic activity. There was also a considerable relief of pain in both groups, however, the acupuncture group showed a better response (P<0.01). We conclude that there is autonomic dysfunction in chronic LBP patients. Acupuncture effectively relieves the pain and improves the autonomic status and hence can be used as an alternative/additive treatment modality in these cases.

Association of glucose homeostasis measures with heart rate variability among Hispanic/Latino adults without diabetes: the Hispanic Community Health Study/Study of Latinos (HCHS/SOL).

PubMed

Meyer, Michelle L; Gotman, Nathan M; Soliman, Elsayed Z; Whitsel, Eric A; Arens, Raanan; Cai, Jianwen; Daviglus, Martha L; Denes, Pablo; González, Hector M; Moreiras, Juan; Talavera, Gregory A; Heiss, Gerardo

2016-03-16

Reduced heart rate variability (HRV), a measure of cardiac autonomic function, is associated with an increased risk of cardiovascular disease (CVD) and mortality. Glucose homeostasis measures are associated with reduced cardiac autonomic function among those with diabetes, but inconsistent associations have been reported among those without diabetes. This study aimed to examine the association of glucose homeostasis measures with cardiac autonomic function among diverse Hispanic/Latino adults without diabetes. The Hispanic community Health Study/Study of Latinos (HCHS/SOL; 2008-2011) used two-stage area probability sampling of households to enroll 16,415 self-identified Hispanics/Latinos aged 18-74 years from four USA communities. Resting, standard 12-lead electrocardiogram recordings were used to estimate the following ultrashort-term measures of HRV: RR interval (RR), standard deviation of all normal to normal RR (SDNN) and root mean square of successive differences in RR intervals (RMSSD). Multivariable regression analysis was used to estimate associations between glucose homeostasis measures with HRV using data from 11,994 adults without diabetes (mean age 39 years; 52 % women). Higher fasting glucose was associated with lower RR, SDNN, and RMSSD. Fasting insulin and the homeostasis model assessment of insulin resistance was negatively associated with RR, SDNN, and RMSSD, and the association was stronger among men compared with women. RMSSD was, on average, 26 % lower in men with higher fasting insulin and 29 % lower in men with lower insulin resistance; for women, the corresponding estimates were smaller at 4 and 9 %, respectively. Higher glycated hemoglobin was associated with lower RR, SDNN, and RMSSD in those with abdominal adiposity, defined by sex-specific cut-points for waist circumference, after adjusting for demographics and medication use. There were no associations between glycated hemoglobin and HRV measures among those without abdominal adiposity. Impairment in glucose homeostasis was associated with lower HRV in Hispanic/Latino adults without diabetes, most prominently in men and individuals with abdominal adiposity. These results suggest that reduced cardiac autonomic function is associated with metabolic impairments before onset of overt diabetes in certain subgroups, offering clues for the pathophysiologic processes involved as well as opportunity for identification of those at high risk before autonomic control is manifestly impaired.

Are glucose levels, glucose variability and autonomic control influenced by inspiratory muscle exercise in patients with type 2 diabetes? Study protocol for a randomized controlled trial.

PubMed

Schein, Aso; Correa, Aps; Casali, Karina Rabello; Schaan, Beatriz D

2016-01-20

Physical exercise reduces glucose levels and glucose variability in patients with type 2 diabetes. Acute inspiratory muscle exercise has been shown to reduce these parameters in a small group of patients with type 2 diabetes, but these results have yet to be confirmed in a well-designed study. The aim of this study is to investigate the effect of acute inspiratory muscle exercise on glucose levels, glucose variability, and cardiovascular autonomic function in patients with type 2 diabetes. This study will use a randomized clinical trial crossover design. A total of 14 subjects will be recruited and randomly allocated to two groups to perform acute inspiratory muscle loading at 2 % of maximal inspiratory pressure (PImax, placebo load) or 60 % of PImax (experimental load). Inspiratory muscle training could be a novel exercise modality to be used to decrease glucose levels and glucose variability. ClinicalTrials.gov NCT02292810 .

Heart rate complexity: A novel approach to assessing cardiac stress reactivity.

PubMed

Brindle, Ryan C; Ginty, Annie T; Phillips, Anna C; Fisher, James P; McIntyre, David; Carroll, Douglas

2016-04-01

Correlation dimension (D2), a measure of heart rate (HR) complexity, has been shown to decrease in response to acute mental stress and relate to adverse cardiovascular health. However, the relationship between stress-induced changes in D2 and HR has yet to be established. The present studies aimed to assess this relationship systematically while controlling for changes in respiration and autonomic activity. In Study 1 (N = 25) D2 decreased during stress and predicted HR reactivity even after adjusting for changes in respiration rate, and cardiac vagal tone. This result was replicated in Study 2 (N = 162) and extended by including a measure of cardiac sympathetic activity; correlation dimension remained an independent predictor of HR reactivity in a hierarchical linear model containing measures of cardiac parasympathetic and sympathetic activity and their interaction. These results suggest that correlation dimension may provide additional information regarding cardiac stress reactivity above that provided by traditional measures of cardiac autonomic function. © 2015 Society for Psychophysiological Research.

Predicting seizures in untreated temporal lobe epilepsy using point-process nonlinear models of heartbeat dynamics.

PubMed

Valenza, G; Romigi, A; Citi, L; Placidi, F; Izzi, F; Albanese, M; Scilingo, E P; Marciani, M G; Duggento, A; Guerrisi, M; Toschi, N; Barbieri, R

2016-08-01

Symptoms of temporal lobe epilepsy (TLE) are frequently associated with autonomic dysregulation, whose underlying biological processes are thought to strongly contribute to sudden unexpected death in epilepsy (SUDEP). While abnormal cardiovascular patterns commonly occur during ictal events, putative patterns of autonomic cardiac effects during pre-ictal (PRE) periods (i.e. periods preceding seizures) are still unknown. In this study, we investigated TLE-related heart rate variability (HRV) through instantaneous, nonlinear estimates of cardiovascular oscillations during inter-ictal (INT) and PRE periods. ECG recordings from 12 patients with TLE were processed to extract standard HRV indices, as well as indices of instantaneous HRV complexity (dominant Lyapunov exponent and entropy) and higher-order statistics (bispectra) obtained through definition of inhomogeneous point-process nonlinear models, employing Volterra-Laguerre expansions of linear, quadratic, and cubic kernels. Experimental results demonstrate that the best INT vs. PRE classification performance (balanced accuracy: 73.91%) was achieved only when retaining the time-varying, nonlinear, and non-stationary structure of heartbeat dynamical features. The proposed approach opens novel important avenues in predicting ictal events using information gathered from cardiovascular signals exclusively.

Regulation of circadian blood pressure: from mice to astronauts.

PubMed

Agarwal, Rajiv

2010-01-01

Circadian variation is commonly seen in healthy people; aberration in these biological rhythms is an early sign of disease. Impaired circadian variation of blood pressure (BP) has been shown to be associated with greater target organ damage and with an elevated risk of cardiovascular events independent of the BP load. The purpose of this review is to examine the physiology of circadian BP variation and propose a tripartite model that explains the regulation of circadian BP. The time-keeper in mammals resides centrally in the suprachiasmatic nucleus. Apart from this central clock, molecular clocks exist in most peripheral tissues including vascular tissue and the kidney. These molecular clocks regulate sodium balance, sympathetic function and vascular tone. A physiological model is proposed that integrates our understanding of molecular clocks in mice with the circadian BP variation among humans. The master regulator in this proposed model is the sleep-activity cycle. The equivalents of peripheral clocks are endothelial and adrenergic functions. Thus, in the proposed model, the variation in circadian BP is dependent upon three major factors: physical activity, autonomic function, and sodium sensitivity. The integrated consideration of physical activity, autonomic function, and sodium sensitivity appears to explain the physiology of circadian BP variation and the pathophysiology of disrupted BP rhythms in various conditions and disease states. Our understanding of molecular clocks in mice may help to explain the provenance of blunted circadian BP variation even among astronauts.

Prediction of autonomic dysreflexia during urodynamics: a prospective cohort study.

PubMed

Walter, Matthias; Knüpfer, Stephanie C; Cragg, Jacquelyn J; Leitner, Lorenz; Schneider, Marc P; Mehnert, Ulrich; Krassioukov, Andrei V; Schubert, Martin; Curt, Armin; Kessler, Thomas M

2018-04-13

Autonomic dysreflexia is a severe and potentially life-threatening condition in patients with spinal cord injury, as it can lead to myocardial ischemia, brain hemorrhage, or even death. Urodynamic investigation is the gold standard to assess neurogenic lower urinary tract dysfunction due to spinal cord injury and reveal crucial pathological findings, such as neurogenic detrusor overactivity. However, neurogenic detrusor overactivity and urodynamic investigation are known to be leading triggers of autonomic dysreflexia. Therefore, we aimed to determine predictors of autonomic dysreflexia in individuals with spinal cord injury during urodynamic investigation. This prospective cohort study included 300 patients with spinal cord injuries and complete datasets of continuous non-invasive cardiovascular monitoring, recorded during same session repeat urodynamic investigation. We used logistic regression to reveal predictors of autonomic dysreflexia during urodynamic investigation. We found that level of injury and presence of neurogenic detrusor overactivity were the only two independent significant predictors for autonomic dysreflexia during urodynamic investigation. A lesion at spinal segment T6 or above (odds ratio (OR) 5.5, 95% CI 3.2-9.4) compared to one at T7 or below, and presence of neurogenic detrusor overactivity (OR 2.7, 95% confidence interval (CI) 1.4-4.9) were associated with a significant increased odds of autonomic dysreflexia during urodynamic investigation. Both odds persisted after adjustment for age, sex, and completeness and stage of injury (adjusted OR (AOR) 6.6, 95% CI 3.8-11.7, and AOR 2.2, 95% CI 1.1-4.5, respectively). Further stratification by lesion level showed level-dependent significantly increased adjusted odds of autonomic dysreflexia, i.e., from C1-C4 (AOR 16.2, 95% CI 5.9-57.9) to T4-T6 (AOR 2.6, 95% CI 1.3-5.2), compared to lesions at T7 or below. In patients with neurogenic lower urinary tract dysfunction due to spinal cord injury, autonomic dysreflexia is independently predicted by lesion level and presence of neurogenic detrusor overactivity. Considering the health risks associated with autonomic dysreflexia, such as seizures, stroke, retinal bleeding, or even death, we recommend both continuous cardiovascular monitoring during urodynamic investigation in all spinal cord-injured patients with emphasis on those with cervical lesions, and appropriate neurogenic detrusor overactivity treatment to reduce the probability of potentially life-threatening complications. ClinicalTrials.gov, NCT01293110 .

Neural autonomic control in orthostatic intolerance.

PubMed

Furlan, Raffaello; Barbic, Franca; Casella, Francesco; Severgnini, Giorgio; Zenoni, Luca; Mercieri, Angelo; Mangili, Ruggero; Costantino, Giorgio; Porta, Alberto

2009-10-01

Inability to maintain the upright position is manifested by a number of symptoms shared by either human pathophysiology and conditions following weightlessness or bed rest. Alterations of the neural sympathetic cardiovascular control have been suggested to be one of the potential underlying etiopathogenetic mechanisms in these conditions. We hypothesize that the study of the autonomic profile of human orthostatic intolerance syndromes may furnish a valuable insight into the complexity of the sympathetic alterations leading to a reduced gravitational tolerance. In the present paper we describe abnormalities both in the magnitude and in the pattern of the sympathetic neural firing observed in patients affected by orthostatic intolerance, attending the upright position. Also, we discuss similarity and differences in the neural sympathetic mechanisms regulating the cardiovascular system during the gravitational stimulus both in clinical syndromes and in subjects returning from space.

The Impact of Early Life Stress on Growth and Cardiovascular Risk: A Possible Example for Autonomic Imprinting?

PubMed

Buchhorn, Reiner; Meint, Sebastian; Willaschek, Christian

2016-01-01

Early life stress is imprinting regulatory properties with life-long consequences. We investigated heart rate variability in a group of small children with height below the third percentile, who experienced an episode of early life stress due to heart failure or intra uterine growth retardation. These children appear to develop autonomic dysfunction in later life. Compared to the healthy control group heart rate variability (HRV) is reduced on average in a group of 101 children with short stature. Low HRV correlates to groups of children born small for gestational age (SGA), children with cardiac growth failure and children with congenital syndromes, but not to those with constitutional growth delay (CGD), who had normal HRV. Reduced HRV indicated by lower RMSSD and High Frequency (HF)-Power is indicating reduced vagal activity as a sign of autonomic imbalance. It is not short stature itself, but rather the underlying diseases that are the cause for reduced HRV in children with height below the third percentile. These high risk children-allocated in the groups with an adverse autonomic imprinting in utero or infancy (SGA, congenital heart disease and congenital syndromes)-have the highest risk for 'stress diseases' such as cardiovascular disease in later life. The incidence of attention deficit disorder is remarkably high in our group of short children.

The Impact of Early Life Stress on Growth and Cardiovascular Risk: A Possible Example for Autonomic Imprinting?

PubMed Central

Buchhorn, Reiner; Meint, Sebastian

2016-01-01

Introduction Early life stress is imprinting regulatory properties with life-long consequences. We investigated heart rate variability in a group of small children with height below the third percentile, who experienced an episode of early life stress due to heart failure or intra uterine growth retardation. These children appear to develop autonomic dysfunction in later life. Results Compared to the healthy control group heart rate variability (HRV) is reduced on average in a group of 101 children with short stature. Low HRV correlates to groups of children born small for gestational age (SGA), children with cardiac growth failure and children with congenital syndromes, but not to those with constitutional growth delay (CGD), who had normal HRV. Reduced HRV indicated by lower RMSSD and High Frequency (HF)-Power is indicating reduced vagal activity as a sign of autonomic imbalance. Conclusion It is not short stature itself, but rather the underlying diseases that are the cause for reduced HRV in children with height below the third percentile. These high risk children—allocated in the groups with an adverse autonomic imprinting in utero or infancy (SGA, congenital heart disease and congenital syndromes)—have the highest risk for ‘stress diseases’ such as cardiovascular disease in later life. The incidence of attention deficit disorder is remarkably high in our group of short children. PMID:27861527

Dietary Sodium and Health: More Than Just Blood Pressure

PubMed Central

Farquhar, William B.; Edwards, David G.; Jurkovitz, Claudine T.; Weintraub, William S.

2016-01-01

Sodium is essential for cellular homeostasis and physiological function. Excess dietary sodium has been linked to elevations in blood pressure (BP). Salt-sensitivity of BP varies widely, but certain subgroups tend to be more salt-sensitive. The mechanisms underlying sodium-induced increases in BP are not completely understood, but may involve alterations in renal function, fluid volume, fluid regulatory hormones, the vasculature, cardiac function, and the autonomic nervous system. Recent pre-clinical and clinical data support that even in the absence of an increase in BP, excess dietary sodium can adversely affect target organs, including the blood vessels, heart, kidneys, and brain. In this review, we address these issues and the epidemiological literature relating dietary sodium to BP and cardiovascular health outcomes, addressing recent controversies. We also provide information and strategies for reducing dietary sodium. PMID:25766952

Association of heart rate variability in taxi drivers with marked changes in particulate air pollution in Beijing in 2008.

PubMed

Wu, Shaowei; Deng, Furong; Niu, Jie; Huang, Qinsheng; Liu, Youcheng; Guo, Xinbiao

2010-01-01

Heart rate variability (HRV), a marker of cardiac autonomic function, has been -associated with particulate matter (PM) air pollution, especially in older patients and those with cardio-vascular diseases. However, the effect of PM exposure on cardiac autonomic function in young, healthy adults has received less attention. We evaluated the relationship between exposure to traffic-related PM with an aerodynamic diameter

The sympathetic/parasympathetic imbalance in heart failure with reduced ejection fraction

PubMed Central

Floras, John S.; Ponikowski, Piotr

2015-01-01

Cardiovascular autonomic imbalance, a cardinal phenotype of human heart failure, has adverse implications for symptoms during wakefulness and sleep; for cardiac, renal, and immune function; for exercise capacity; and for lifespan and mode of death. The objectives of this Clinical Review are to summarize current knowledge concerning mechanisms for disturbed parasympathetic and sympathetic circulatory control in heart failure with reduced ejection fraction and its clinical and prognostic implications; to demonstrate the patient-specific nature of abnormalities underlying this common phenotype; and to illustrate how such variation provides opportunities to improve or restore normal sympathetic/parasympathetic balance through personalized drug or device therapy. PMID:25975657

Synergistic effects of low-intensity exercise conditioning and β-blockade on cardiovascular and autonomic adaptation in pre- and postmenopausal women with hypertension.

PubMed

Goldie, Catherine L; Brown, C Ann; Hains, Sylvia M J; Parlow, Joel L; Birtwhistle, Richard

2013-10-01

The effects of a 12-week low-intensity exercise conditioning program (walking) on blood pressure (BP), heart rate (HR), rate-pressure product (RPP), and cardiac autonomic function were measured in 40 sedentary women with hypertension. Women were assigned to either an exercise group (n = 20) or a control group (n = 20), matched for β-blockade treatment. They underwent testing at the beginning and at the end of the 12-week study period in three conditions: supine rest, standing, and low-intensity steady state exercise. The exercise group participated in a 12-week, low-intensity walking program, while the control group continued with usual sedentary activity. Compared with the control group, women in the exercise group showed reductions in systolic and diastolic BP and RPP (i.e., the estimated cardiac workload). β-Blockers increased baroreflex sensitivity and lowered BP and HR in all participants; however, those in the exercise group showed the effects of both treatments: a greater reduction in HR and RPP. The combination of exercise training and β-blockade produces cardiac and autonomic adaptations that are not observed with either treatment alone, suggesting that β-blockade enhances the conditioning effects of low-intensity exercise in women with hypertension.

Orthostatic intolerance: potential pathophysiology and therapy.

PubMed

Lu, Chih-Cherng; Tseng, Ching-Jiunn; Tang, Hung-Shang; Tung, Che-Se

2004-09-30

Orthostatic intolerance affects an estimated 1 in 500 persons and causes a wide range of disabilities. After essential hypertension, it is the most frequently encountered dysautonomia, accounting for the majority of patients referred to centers specializing in autonomic disorders. Patients are typically young females with symptoms such as dizziness, visual changes, head and neck discomfort, poor concentration, fatigue, palpitations, tremulousness, anxiety, and, in some cases, syncope. Syncope is the most hazardous symptom of orthostatic intolerance, presumably occurring because of impaired cerebral perfusion and in part to compensatory autonomic mechanisms. The etiology of this syndrome is still unclear but is heterogeneous. Orthostatic intolerance used to be characterized by an overall enhancement of noradrenergic tone at rest in some patients and by a patchy dysautonomia of postganglionic sympathetic fibers with a compensatory cardiac sympathetic activation in others. However, recent advances in molecular genetics are improving our understanding of orthostatic intolerance, such as several genetic diseases (such as Ehler-Danlos syndrome and norepinephrine transporter deficiency) presenting with symptoms typical of orthostatic intolerance. Future work will include investigation of genetic functional mutations underlying interindividual differences in autonomic cardiovascular control, body fluid regulation, and vascular regulation in orthostatic intolerance patients. The goal of this review article is to describe recent advances in understanding the pathophysiological mechanisms of orthostatic intolerance and their clinical significance.

Dose-response study of N,N-dimethyltryptamine in humans. I. Neuroendocrine, autonomic, and cardiovascular effects.

PubMed

Strassman, R J; Qualls, C R

1994-02-01

To begin applying basic neuropharmacological hypotheses of hallucinogenic drug actions to humans, we generated dose-response data for intravenously administered dimethyltryptamine fumarate's (DMT) neuroendocrine, cardiovascular, autonomic, and subjective effects in a group of experienced hallucinogen users. Dimethyltryptamine, an endogenous mammalian hallucinogen and drug of abuse, was administered intravenously at 0.05, 0.1, 0.2, and 0.4 mg/kg to 11 experienced hallucinogen users, in a double-blind, saline placebo-controlled, randomized design. Treatments were separated by at least 1 week. Peak DMT blood levels and subjective effects were seen within 2 minutes after drug administration, and were negligible at 30 minutes. Dimethyltryptamine dose dependently elevated blood pressure, heart rate, pupil diameter, and rectal temperature, in addition to elevating blood concentrations of beta-endorphin, corticotropin, cortisol, and prolactin. Growth hormone blood levels rose equally in response to all doses of DMT, and melatonin levels were unaffected. Threshold doses for significant effects relative to placebo were also hallucinogenic (0.2 mg/kg and higher). Subjects with five or more exposures to 3,4-methylenedioxymethamphetamine demonstrated less robust pupil diameter effects than those with two or fewer exposures. Dimethyltryptamine can be administered safely to experienced hallucinogen users and dose-response data generated for several measures hypothesized under serotonergic modulatory control. Additional studies characterizing the specific mechanisms mediating DMT's biological effects may prove useful in psychopharmacological investigations of drug-induced and endogenous alterations in brain function.

A minor wound with a fatal course

PubMed Central

Loeffler, Christoph; Mols, Georg; Hecksteden, Kai; Pfeiffer, Jens; Ridder, Gerd J

2011-01-01

The authors report on a fatal case of severe tetanus in a 74-year old woman. Despite comprehensive intensive care management they could not achieve a satisfying control of the autonomic dysfunction caused by tetanus. By now there is no established therapy for the treatment of the autonomic dysfunction. This report demonstrates the dismal prognosis of severe tetanus in the older people, which is often complicated by cardiovascular comorbidity and underlines the importance of tetanus prevention by sufficient vaccination. PMID:22693194

Stress, autonomic imbalance, and the prediction of metabolic risk: A model and a proposal for research.

PubMed

Wulsin, Lawson; Herman, James; Thayer, Julian F

2018-03-01

Devising novel prevention strategies for metabolic disorders will depend in part on the careful elucidation of the common pathways for developing metabolic risks. The neurovisceral integration model has proposed that autonomic imbalance plays an important role in the pathway from acute and chronic stress to cardiovascular disease. Though generally overlooked by clinicians, autonomic imbalance (sympathetic overactivity and/or parasympathetic underactivity) can be measured and modified by methods that are available in primary care. This review applies the neurovisceral integration concept to the clinical setting by proposing that autonomic imbalance plays a primary role in the development of metabolic risks. We present a testable model, a systematic review of the evidence in support of autonomic imbalance as a predictor for metabolic risks, and specific approaches to test this model as a guide to future research on the role of stress in metabolic disorders. We propose that autonomic imbalance deserves consideration by researchers, clinicians, and policymakers as a target for early interventions to prevent metabolic disorders. Published by Elsevier Ltd.

Twenty-Four Hour Non-Invasive Ambulatory Blood Pressure and Heart Rate Monitoring in Parkinson’s Disease

PubMed Central

Stuebner, Eva; Vichayanrat, Ekawat; Low, David A.; Mathias, Christopher J.; Isenmann, Stefan; Haensch, Carl-Albrecht

2013-01-01

Non-motor symptoms are now commonly recognized in Parkinson’s disease (PD) and can include dysautonomia. Impairment of cardiovascular autonomic function can occur at any stage of PD but is typically prevalent in advanced stages or related to (anti-Parkinsonian) drugs and can result in atypical blood pressure (BP) readings and related symptoms such as orthostatic hypotension (OH) and supine hypertension. OH is usually diagnosed with a head-up-tilt test (HUT) or an (active) standing test (also known as Schellong test) in the laboratory, but 24 h ambulatory blood pressure monitoring (ABPM) in a home setting may have several advantages, such as providing an overview of symptoms in daily life alongside pathophysiology as well as assessment of treatment interventions. This, however, is only possible if ABPM is administrated correctly and an autonomic protocol (including a diary) is followed which will be discussed in this review. A 24-h ABPM does not only allow the detection of OH, if it is present, but also the assessment of cardiovascular autonomic dysfunction during and after various daily stimuli, such as postprandial and alcohol dependent hypotension, as well as exercise and drug induced hypotension. Furthermore, information about the circadian rhythm of BP and heart rate (HR) can be obtained and establish whether or not a patient has a fall of BP at night (i.e., “dipper” vs. non-“dipper”). The information about nocturnal BP may also allow the investigation or detection of disorders such as sleep dysfunction, nocturnal movement disorders, and obstructive sleep apnea, which are common in PD. Additionally, a 24-h ABPM should be conducted to examine the effectiveness of OH therapy. This review will outline the methodology of 24 h ABPM in PD, summarize findings of such studies in PD, and briefly consider common daily stimuli that might affect 24 h ABPM. PMID:23720648

Exercise training improves hemodynamic recovery to isometric exercise in obese men with type 2 diabetes but not in obese women.

PubMed

Kanaley, Jill A; Goulopoulou, Styliani; Franklin, Ruth; Baynard, Tracy; Carhart, Robert L; Weinstock, Ruth S; Fernhall, Bo

2012-12-01

Women with type 2 diabetes (T2D) show greater rates of mortality due to ischemic heart disease than men with T2D. We aimed to examine cardiovascular and autonomic function responses to isometric handgrip (IHG) exercise between men and women with T2D, before and after an exercise training program. Hemodynamic responses were measured in 22 men and women with T2D during and following a 3-min IHG test, and before and after 16 wks of aerobic exercise training. Women had a smaller decrease in mean arterial pressure (MAP) and systolic blood pressure (BP) during recovery from IHG (ΔMAP(REC)) than men pre- and post-training (P<0.05). Men showed a greater reduction in diastolic BP during recovery from IHG (P<0.05), and exercise training improved this response in men but not in women (men, pre-training: -13.9±1.8, post-training: -20.5±5.3 mmHg vs. women, pre-training: -10.7±1.7, post-training: -4.1±4.9 mmHg; P<0.05). Men had a greater reduction in sympathetic modulation of vasomotor tone (P<0.05), as estimated by blood pressure variability, following IHG. This response was accentuated after training, while this training effect was not seen in women. Post-training ΔMAP(REC) was correlated with recovery of low frequency component of the BP spectrum (ΔLF(SBPrec), r=0.52, P<0.05). Differences in BP recovery immediately following IHG may be attributed to gender differences in cardiovascular autonomic modulation. An improvement in these responses occurs following aerobic exercise training in obese men, but not in obese women with T2D which reflects a better adaptive autonomic response to exercise training. Copyright © 2012 Elsevier Inc. All rights reserved.

Passive hind-limb cycling improves cardiac function and reduces cardiovascular disease risk in experimental spinal cord injury.

PubMed

West, Christopher R; Crawford, Mark A; Poormasjedi-Meibod, Malihe-Sadat; Currie, Katharine D; Fallavollita, Andre; Yuen, Violet; McNeill, John H; Krassioukov, Andrei V

2014-04-15

Spinal cord injury (SCI) causes altered autonomic control and severe physical deconditioning that converge to drive maladaptive cardiac remodelling. We used a clinically relevant experimental model to investigate the cardio-metabolic responses to SCI and to establish whether passive hind-limb cycling elicits a cardio-protective effect. Initially, 21 male Wistar rats were evenly assigned to three groups: uninjured control (CON), T3 complete SCI (SCI) or T3 complete SCI plus passive hind-limb cycling (SCI-EX; 2 × 30 min day(-1), 5 days week(-1) for 4 weeks beginning 6 days post-SCI). On day 32, cardio-metabolic function was assessed using in vivo echocardiography, ex vivo working heart assessments, cardiac histology/molecular biology and blood lipid profiles. Twelve additional rats (n = 6 SCI and n = 6 SCI-EX) underwent in vivo echocardiography and basal haemodynamic assessments pre-SCI and at days 7, 14 and 32 post-SCI to track temporal cardiovascular changes. Compared with CON, SCI exhibited a rapid and sustained reduction in left ventricular dimensions and function that ultimately manifested as reduced contractility, increased myocardial collagen deposition and an up-regulation of transforming growth factor beta-1 (TGFβ1) and mothers against decapentaplegic homolog 3 (Smad3) mRNA. For SCI-EX, the initial reduction in left ventricular dimensions and function at day 7 post-SCI was completely reversed by day 32 post-SCI, and there were no differences in myocardial contractility between SCI-EX and CON. Collagen deposition was similar between SCI-EX and CON. TGFβ1 and Smad3 were down-regulated in SCI-EX. Blood lipid profiles were improved in SCI-EX versus SCI. We provide compelling novel evidence that passive hind-limb cycling prevents cardiac dysfunction and reduces cardiovascular disease risk in experimental SCI.

Changes in systolic arterial pressure variability are associated with the decreased aerobic performance of rats subjected to physical exercise in the heat.

PubMed

Müller-Ribeiro, Flávia C; Wanner, Samuel P; Santos, Weslley H M; Malheiros-Lima, Milene R; Fonseca, Ivana A T; Coimbra, Cândido C; Pires, Washington

2017-01-01

Enhanced cardiovascular strain is one of the factors that explains degraded aerobic capacity in hot environments. The cardiovascular system is regulated by the autonomic nervous system, whose activity can be indirectly evaluated by analyzing heart rate variability (HRV) and systolic arterial pressure (SAP) variability. However, no study has addressed whether HRV or SAP variability can predict aerobic performance during a single bout of exercise. Therefore, this study aimed to investigate whether there is an association between cardiovascular variability and performance in rats subjected to treadmill running at two ambient temperatures. In addition, this study investigated whether the heat-induced changes in cardiovascular variability and reductions in performance are associated with each other. Male Wistar rats were implanted with a catheter into their carotid artery for pulsatile blood pressure recordings. After recovery from surgery, the animals were subjected to incremental-speed exercise until they were fatigued under temperate (25°C) and hot (35°C) conditions. Impaired performance and exaggerated cardiovascular responses were observed in the hot relative to the temperate environment. Significant and negative correlations between most of the SAP variability components (standard deviation, variance, very low frequency [VLF], and low frequency [LF]) at the earlier stages of exercise and total exercise time were observed in both environmental conditions. Furthermore, the heat-induced changes in the sympathetic components of SAP variability (VLF and LF) were associated with heat-induced impairments in performance. Overall, the results indicate that SAP variability at the beginning of exercise predicts the acute performance of rats. Our findings also suggest that heat impairments in aerobic performance are associated with changes in cardiovascular autonomic control. Copyright © 2016 Elsevier Ltd. All rights reserved.

Endogenous subclinical hyperthyroidism and cardiovascular system: time to reconsider?

PubMed

Patanè, Salvatore; Marte, Filippo; Sturiale, Mauro

2011-05-19

Subclinical hyperthyroidism is an increasingly recognized entity that is defined as a normal serum free thyroxine and free triiodothyronine levels with a thyroid-stimulating hormone level suppressed below the normal range and usually undetectable. Exogenous sublinical hyperthyroidism is a thyroid metabolic state caused by L-thyroxine administration. Endogenous subclinical hyperthyroidism is a thyroid metabolic state in patients with autonomously functioning thyroid nodule or multinodular goiter, various forms of thyroiditis, in areas with endemic goiter and particularly in elderly subjects. Endogenous subclinical hyperthyroidism is currently the subject of numerous studies and it yet remains controversial particularly as it relates to its treatment and to cardiovascular impact nevertheless established effects have been demonstrated. Recently, acute myocardial infarction without significant coronary stenoses and recurrent acute pulmonary embolism have been reported associated with subclinical hyperthyroidism without L-thyroxine administration. So, it is very important to recognize and to treat promptly also endogenous subclinical hyperthyroidism. Copyright © 2009 Elsevier Ireland Ltd. All rights reserved.

Organisational injustice and impaired cardiovascular regulation among female employees

PubMed Central

Elovainio, M; Kivimäki, M; Puttonen, S; Lindholm, H; Pohjonen, T; Sinervo, T

2006-01-01

Objectives To examine the relation between perceived organisational justice and cardiovascular reactivity in women. Methods The participants were 57 women working in long term care homes. Heart rate variability and systolic arterial pressure variability were used as markers of autonomic function. Organisational justice was measured using the scale of Moorman. Data on other risk factors were also collected. Results Results from logistic regression models showed that the risk for increased low frequency band systolic arterial pressure variability was 3.8–5.8 times higher in employees with low justice than in employees with high justice. Low perceived justice was also related to an 80% excess risk of reduced high frequency heart rate variability compared to high perceived justice, but this association was not statistically significant. Conclusions These findings are consistent with the hypothesis that cardiac dysregulation is one stress mechanism through which a low perceived justice of decision making procedures and interpersonal treatment increases the risk of health problems in personnel. PMID:16421394

Influences of prostanoids and nitric oxide on post-suspension hypotension in female Sprague-Dawley rats

NASA Technical Reports Server (NTRS)

Eatman, D.; Listhrop, R. A.; Beasley, A. S.; Socci, R. R.; Abukhalaf, I.; Bayorh, M. A.

2003-01-01

Impairment in cardiovascular functions sometimes manifested in astronauts during standing postflight, may be related to the diminished autonomic function and/or excessive production of endothelium-dependent relaxing factors. In the present study, using the 30 degrees head-down tilt (HDT) model, we compared the cardiovascular and biochemical effects of 7 days of suspension and a subsequent 6-h post-suspension period between suspended and non-suspended conscious female Sprague-Dawley rats. Mean arterial pressure (MAP) and heart rate were measured prior to suspension (basal), daily thereafter, and every 2h post-suspension. Following 7 days of suspension, MAP was not different from their basal values, however, upon release from suspension, MAP was significantly reduced compared to the non-suspended rats. Nitric oxide levels were elevated while thromboxane A(2) levels declined significantly in both plasma and tissue samples following post-suspension. The levels of prostacyclin following post-suspension remained unaltered in plasma and aortic rings but was significantly elevated in carotid arterial rings. Therefore, the post-suspension reduction in mean arterial pressure is due mostly to overproduction of nitric oxide and to a lesser extent prostacyclin.

The effect of orthostatic stress on multiscale entropy of heart rate and blood pressure.

PubMed

Turianikova, Zuzana; Javorka, Kamil; Baumert, Mathias; Calkovska, Andrea; Javorka, Michal

2011-09-01

Cardiovascular control acts over multiple time scales, which introduces a significant amount of complexity to heart rate and blood pressure time series. Multiscale entropy (MSE) analysis has been developed to quantify the complexity of a time series over multiple time scales. In previous studies, MSE analyses identified impaired cardiovascular control and increased cardiovascular risk in various pathological conditions. Despite the increasing acceptance of the MSE technique in clinical research, information underpinning the involvement of the autonomic nervous system in the MSE of heart rate and blood pressure is lacking. The objective of this study is to investigate the effect of orthostatic challenge on the MSE of heart rate and blood pressure variability (HRV, BPV) and the correlation between MSE (complexity measures) and traditional linear (time and frequency domain) measures. MSE analysis of HRV and BPV was performed in 28 healthy young subjects on 1000 consecutive heart beats in the supine and standing positions. Sample entropy values were assessed on scales of 1-10. We found that MSE of heart rate and blood pressure signals is sensitive to changes in autonomic balance caused by postural change from the supine to the standing position. The effect of orthostatic challenge on heart rate and blood pressure complexity depended on the time scale under investigation. Entropy values did not correlate with the mean values of heart rate and blood pressure and showed only weak correlations with linear HRV and BPV measures. In conclusion, the MSE analysis of heart rate and blood pressure provides a sensitive tool to detect changes in autonomic balance as induced by postural change.

Heart rate variability interventions for concussion and rehabilitation

PubMed Central

Conder, Robert L.; Conder, Alanna A.

2014-01-01

The study of heart rate variability (HRV) has emerged as an essential component of cardiovascular health, as well as a physiological mechanism by which one can increase the interactive communication between the cardiac and the neurocognitive systems (i.e., the body and the brain). It is well-established that lack of HRV implies cardiopathology, morbidity, reduced quality-of-life, and precipitous mortality. On the positive, optimal HRV has been associated with good cardiovascular health, autonomic nervous system (ANS) control, emotional regulation, and enhanced neurocognitive processing. In addition to health benefits, optimal HRV has been shown to improve neurocognitive performance by enhancing focus, visual acuity and readiness, and by promoting emotional regulation needed for peak performance. In concussed athletes and soldiers, concussions not only alter brain connectivity, but also alter cardiac functioning and impair cardiovascular performance upon exertion. Altered sympathetic and parasympathetic balance in the ANS has been postulated as a critical factor in refractory post concussive syndrome (PCS). This article will review both the pathological aspects of reduced HRV on athletic performance, as well as the cardiovascular and cerebrovascular components of concussion and PCS. Additionally, this article will review interventions with HRV biofeedback (HRV BFB) training as a promising and underutilized treatment for sports and military-related concussion. Finally, this article will review research and promising case studies pertaining to use of HRV BFB for enhancement of cognition and performance, with applicability to concussion rehabilitation. PMID:25165461

Heart rate variability interventions for concussion and rehabilitation.

PubMed

Conder, Robert L; Conder, Alanna A

2014-01-01

The study of heart rate variability (HRV) has emerged as an essential component of cardiovascular health, as well as a physiological mechanism by which one can increase the interactive communication between the cardiac and the neurocognitive systems (i.e., the body and the brain). It is well-established that lack of HRV implies cardiopathology, morbidity, reduced quality-of-life, and precipitous mortality. On the positive, optimal HRV has been associated with good cardiovascular health, autonomic nervous system (ANS) control, emotional regulation, and enhanced neurocognitive processing. In addition to health benefits, optimal HRV has been shown to improve neurocognitive performance by enhancing focus, visual acuity and readiness, and by promoting emotional regulation needed for peak performance. In concussed athletes and soldiers, concussions not only alter brain connectivity, but also alter cardiac functioning and impair cardiovascular performance upon exertion. Altered sympathetic and parasympathetic balance in the ANS has been postulated as a critical factor in refractory post concussive syndrome (PCS). This article will review both the pathological aspects of reduced HRV on athletic performance, as well as the cardiovascular and cerebrovascular components of concussion and PCS. Additionally, this article will review interventions with HRV biofeedback (HRV BFB) training as a promising and underutilized treatment for sports and military-related concussion. Finally, this article will review research and promising case studies pertaining to use of HRV BFB for enhancement of cognition and performance, with applicability to concussion rehabilitation.

Cardiovascular regulation during sleep quantified by symbolic coupling traces

NASA Astrophysics Data System (ADS)

Suhrbier, A.; Riedl, M.; Malberg, H.; Penzel, T.; Bretthauer, G.; Kurths, J.; Wessel, N.

2010-12-01

Sleep is a complex regulated process with short periods of wakefulness and different sleep stages. These sleep stages modulate autonomous functions such as blood pressure and heart rate. The method of symbolic coupling traces (SCT) is used to analyze and quantify time-delayed coupling of these measurements during different sleep stages. The symbolic coupling traces, defined as the symmetric and diametric traces of the bivariate word distribution matrix, allow the quantification of time-delayed coupling. In this paper, the method is applied to heart rate and systolic blood pressure time series during different sleep stages for healthy controls as well as for normotensive and hypertensive patients with sleep apneas. Using the SCT, significant different cardiovascular mechanisms not only between the deep sleep and the other sleep stages but also between healthy subjects and patients can be revealed. The SCT method is applied to model systems, compared with established methods, such as cross correlation, mutual information, and cross recurrence analysis and demonstrates its advantages especially for nonstationary physiological data. As a result, SCT proves to be more specific in detecting delays of directional interactions than standard coupling analysis methods and yields additional information which cannot be measured by standard parameters of heart rate and blood pressure variability. The proposed method may help to indicate the pathological changes in cardiovascular regulation and also the effects of continuous positive airway pressure therapy on the cardiovascular system.

Cardiac autonomic modulation and sleepiness: physiological consequences of sleep deprivation due to 40 h of prolonged wakefulness.

PubMed

Glos, Martin; Fietze, Ingo; Blau, Alexander; Baumann, Gert; Penzel, Thomas

2014-02-10

The autonomic nervous system (ANS) is modulated by sleep and wakefulness. Noninvasive assessment of cardiac ANS with heart rate variability (HRV) analysis is a window for monitoring malfunctioning of cardiovascular autonomic modulation due to sleep deprivation. This study represents the first investigation of dynamic ANS effects and of electrophysiological and subjective sleepiness, in parallel, during 40 h of prolonged wakefulness under constant routine (CR) conditions. In eleven young male healthy subjects, ECG, EEG, EOG, and EMG chin recordings were performed during baseline sleep, during 40 h of sleep deprivation, and during recovery sleep. After sleep deprivation, slow-wave sleep and sleep efficiency increased, whereas HRV - global variability and HRV sympathovagal balance - was reduced (all p<0.05). Sleep-stage-dependent analysis revealed reductions in the sympathovagal balance only for NREM sleep stages (all p<0.05). Comparison of the daytime pattern of CR day one (CR baseline) with that of CR day two (CR sleep deprivation) disclosed an increase in subjective sleepiness, in the amount of unintended sleep, and in HRV sympathovagal balance, with accompaniment by increased EEG alpha attenuation (all p<0.05). Circadian rhythm analysis revealed the strongest influence on heart rate, with less influence on HRV sympathovagal balance. Hour-by-hour analysis disclosed the difference between CR sleep deprivation and CR baseline for subjective sleepiness at almost every single hour and for unintended sleep particularly in the morning and afternoon (both p<0.05). These findings indicate that 40 h of prolonged wakefulness lead in the following night to sleep-stage-dependent reduction in cardiac autonomic modulation. During daytime, an increased occurrence of behavioral and physiological signs of sleepiness was accompanied by diminished cardiac autonomic modulation. The observed changes are an indicator of autonomic stress due to sleep deprivation - which, if chronic, could potentially increase cardiovascular risk. Copyright © 2013 Elsevier Inc. All rights reserved.

Autonomic markers associated with generalized social phobia symptoms: heart rate variability and salivary alpha-amylase.

PubMed

García-Rubio, María J; Espín, Laura; Hidalgo, Vanesa; Salvador, Alicia; Gómez-Amor, Jesús

2017-01-01

The study of autonomic nervous system changes associated with generalized social phobia (GSP) disorder has increased in recent years, showing contradictory results. The present study aimed to evaluate how young people with GSP reacted before, during, and after exposure to the Trier Stress Social Test (TSST), focusing on their autonomic changes (heart rate variability (HRV) and salivary alpha-amylase (sAA)) compared to a control group (non-GSP). Some psychological variables were also considered. Sex was specifically studied as a possible modulator of autonomic fluctuations and psychological state. Eighty young people were randomly distributed into two counterbalanced situations: stress condition (N = 18 and 21 for GSP and non-GSP, respectively) and control condition (N = 21 and 20 for GSP and non-GSP, respectively), where cardiovascular variables were continuously recorded. Psychological questionnaires about mood and perceived stress were filled out, and five saliva samples were collected to analyze sAA. GSP participants showed higher values on low- and high-frequency ratios (HR domains), compared to non-GSP people, during exposure to the TSST, but no differences were observed after the stressor. Furthermore, the two groups did not differ in sAA. Importantly, positive affect in GSP participants was modulated by sex. The present study suggests that the balance between high- and low-frequency domains of HRV is a key cardiovascular marker reflecting the stress response of GSP people, as well the importance of sex in positive affect when facing a stressful situation.

An experimental design for quantification of cardiovascular responses to music stimuli in humans.

PubMed

Chang, S-H; Luo, C-H; Yeh, T-L

2004-01-01

There have been several researches on the relationship between music and human physiological or psychological responses. However, there are cardiovascular index factors that have not been explored quantitatively due to the qualitative nature of acoustic stimuli. This study proposes and demonstrates an experimental design for quantification of cardiovascular responses to music stimuli in humans. The system comprises two components: a unit for generating and monitoring quantitative acoustic stimuli and a portable autonomic nervous system (ANS) analysis unit for quantitative recording and analysis of the cardiovascular responses. The experimental results indicate that the proposed system can exactly achieve the goal of full control and measurement for the music stimuli, and also effectively support many quantitative indices of cardiovascular response in humans. In addition, the analysis results are discussed and predicted in the future clinical research.

Long-Duration Space Flight Provokes Pathologic Q-Tc Interval Prolongation

NASA Technical Reports Server (NTRS)

D'Aunno, DOminick S.; Dougherty, Anne H.; DeBlock, Heidi F.; Meck, Janice V.

2002-01-01

Space flight has a profound influence on the cardiovascular and autonomic nervous systems. Alterations in baroreflex function, plasma catecholamine concentrations, and arterial pressure regulation have been observed. Changes in autonomic regulation of cardiac function may lead to serious rhythm disturbances. In fact, ventricular tachycardia has been reported during long-duration space flight. The study aim was to determine the effects of space flight on cardiac conduction. Methods and Results: Electrocardiograms (ECGs) and serum electrolytes were obtained before and after short-duration (SD) (4-16 days) and long-duration (LD) (4-6 months) missions. Holter recordings were obtained from 3 different subjects before, during and after a 4-month mission. P-R, R-R, and Q-T intervals were measured manually in a random, blinded fashion and Bazzet's formula used to correct the Q-T interval (Q-Tc). Space flight had no clinically significant effect on electrolyte concentrations. P-R and RR intervals were decreased after SD flight (p<0.05) and recovered 3 days after landing. In the same subjects, P-R and Q-Tc intervals were prolonged after LD flight (p<0.01). Clinically significant Q-Tc prolongation (>0.44 sec) occurred during the first month of flight and persisted until 3 days after landing (p<0.01). Conclusions - Space flight alters cardiac conduction with more ominous changes seen with LD missions. Alterations in autonomic tone may explain ECG changes associated with space flight. Primary cardiac changes may also contribute to the conduction changes with LD flight. Q-Tc prolongation may predispose astronauts to ventricular arrhythmias during and after long-duration space flight.

Dietary sodium and health: more than just blood pressure.

PubMed

Farquhar, William B; Edwards, David G; Jurkovitz, Claudine T; Weintraub, William S

2015-03-17

Sodium is essential for cellular homeostasis and physiological function. Excess dietary sodium has been linked to elevations in blood pressure (BP). Salt sensitivity of BP varies widely, but certain subgroups tend to be more salt sensitive. The mechanisms underlying sodium-induced increases in BP are not completely understood but may involve alterations in renal function, fluid volume, fluid-regulatory hormones, the vasculature, cardiac function, and the autonomic nervous system. Recent pre-clinical and clinical data support that even in the absence of an increase in BP, excess dietary sodium can adversely affect target organs, including the blood vessels, heart, kidneys, and brain. In this review, the investigators review these issues and the epidemiological research relating dietary sodium to BP and cardiovascular health outcomes, addressing recent controversies. They also provide information and strategies for reducing dietary sodium. Copyright © 2015 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

Bisphenol A Alters Autonomic Tone and Extracellular Matrix Structure and Induces Sex-Specific Effects on Cardiovascular Function in Male and Female CD-1 Mice

PubMed Central

Gear, Robin B.; Kendig, Eric L.

2015-01-01

The aim of this study was to determine whether bisphenol A (BPA) has adverse effects on cardiovascular functions in CD-1 mice and define sex-specific modes of BPA action in the heart. Dams and analyzed progeny were maintained on a defined diet containing BPA (0.03, 0.3, 3, 30, or 300 ppm) that resulted in BPA exposures from 4–5 to approximately 5000 μg/kg · d or a diet containing 17α-ethinyl estradiol (EE; ∼0.02, 0.2, and 0.15 μg/kg · d) as an oral bioavailable estrogen control. Assessment of electrocardiogram parameters using noninvasive methods found that ventricular functions in both male and female mice were not altered by either BPA or EE. However, exposure-related changes in the rates of ventricular contraction, suggestive of a shift in sympathovagal balance of heart rate control toward increased parasympathetic activity, were detected in males. Decreased systolic blood pressure was observed in males exposed to BPA above 5 μg/kg · d and in females from the highest BPA exposure group. Morphometric histological measures revealed sexually dimorphic changes in the composition of the cardiac collagen extracellular matrix, increases in fibrosis, and evidence of modest exposure-related remodeling. Experiments using the α-selective adrenergic agonist phenylephrine found that BPA enhanced reflex bradycardia in females, but not males, revealed that BPA and EE exposure sex specifically altered the sympathetic regulation of the baroreflex circuits. Increased sensitivity to the cardiotoxic effects of the β-adrenergic agonist isoproterenol was observed in BPA- and EE-exposed females. This effect was not observed in males, in which BPA or EE exposures were protective of isoproterenol-induced ischemic damage and hypertrophy. The results of RNA sequence analysis identified significant sex-specific changes in gene expression in response to BPA that were consistent with the observed exposure-related phenotypic changes in the collagenous and noncollagenous extracellular matrix, cardiac remodeling, altered autonomic responses, changes in ion channel and transporter functions, and altered glycolytic and lipid metabolism. PMID:25594700

[Endurance training and cardial adaptation (athlete's heart)].

PubMed

Dickhuth, Hans-Hermann; Röcker, Kai; Mayer, Frank; König, Daniel; Korsten-Reck, Ulrike

2004-06-01

One essential function of the cardiovascular system is to provide an adequate blood supply to all organs, including the skeletal muscles at rest and during exercise. Adaptation to chronic exercise proceeds mainly via the autonomic nervous system. On the one hand, peripheral muscles influence the autonomic reactions through "feedback" control via ergoreceptors, in particular, mechano- and chemoreceptors. On the other hand, there is central control in the sense of a "feed forward" regulation, e. g., the reaction of an athlete before competition. Along with other influential factors, such as circulatory presso-, chemo-, and volume receptors, the incoming impulses are processed in vegetative centers.A cardiovascular reaction, then, is the result of nerval and humoral sympathetic and parasympathetic activity. At rest, the parasympathetic tone dominates. It reduces heart frequency and conduction velocity. The high vagal tone is initially reduced with increasing physical exertion and switches at higher intensity to increasingly sympathetic activation. This mechanism of reaction to exercise is supported by inverse central and peripheral transmissions.Chronic endurance training leads to an improved local aerobic capacity of the exercised musculature. At rest, it augments parasympathetic activity when the muscle mass is sufficiently large, i. e., 20-30% of the skeletal musculature. The extent of the adaptation depends on individual factors, such as scope, intensity of training, and type of muscle fiber. A higher vagal tone delays the increase in the sympathetic tone during physical exertion. The regulatory range of heart rate, contractility, diastolic function, and blood pressure is increased. In addition, adaptation results in functional and structural changes in the vascular system. Cardiocirculatory work is economized, and maximum performance and oxygen uptake are improved. Endurance training exceeding an individual limit causes harmonic enlargement and hypertrophy of the heart. The thickness of both, the septum and posterior wall increases to the same extent as the interior volume. The mass/volume ratio, and therefore the maximum systolic wall stress, remains constant in contrast to pathologic forms of hypertrophy. Adaptations, including function and size of the heart, show a regression in healthy inactive persons without any structural heart disease.

Cardiovascular response to acute stress in freely moving rats: time-frequency analysis.

PubMed

Loncar-Turukalo, Tatjana; Bajic, Dragana; Japundzic-Zigon, Nina

2008-01-01

Spectral analysis of cardiovascular series is an important tool for assessing the features of the autonomic control of the cardiovascular system. In this experiment Wistar rats ecquiped with intraarterial catheter for blood pressure (BP) recording were exposed to stress induced by blowing air. The problem of non stationary data was overcomed applying the Smoothed Pseudo Wigner Villle (SPWV) time-frequency distribution. Spectral analysis was done before stress, during stress, immediately after stress and later in recovery. The spectral indices were calculated for both systolic blood pressure (SBP) and pulse interval (PI) series. The time evolution of spectral indices showed perturbed sympathovagal balance.

[Effect of lead on the cardiovascular system].

PubMed

Zyśko, Dorota; Chlebda, Ewa; Gajek, Jacek

2004-11-01

Lead is a metal widely spread in the natural environment. It is strongly toxic, particularly to the peripheral and central nervous systems. The toxic influence on the cardiovascular system is most pronounced in case of higher exposures, where myocardium and the renal circulation are affected, in consequence of which secondary arterial hypertension can develop. It seems that lead affects the cardiovascular system mainly by changing the peripheral autonomic nervous system and leading to chronic neuropathy. Chronic exposure, even to low doses of lead, can impair conduction in myocardium. In order to assess those changes thoroughly prospective studies involving newly employed workers with occupational exposure to toxic activity of lead will be necessary.

Preserved functional autonomic phenotype in adult mice overexpressing moderate levels of human alpha-synuclein in oligodendrocytes.

PubMed

Tank, Jens; da Costa-Goncalves, Andrey C; Kamer, Ilona; Qadri, Fatimunnisa; Ubhi, Kiren; Rockenstein, Edward; Diedrich, André; Masliah, Eliezer; Gross, Volkmar; Jordan, Jens

2014-11-01

Mice overexpressing human alpha-synuclein in oligodendrocytes (MBP1-α-syn) recapitulate some key functional and neuropathological features of multiple system atrophy (MSA). Whether or not these mice develop severe autonomic failure, which is a key feature of human MSA, remains unknown. We explored cardiovascular autonomic regulation using long-term blood pressure (BP) radiotelemetry and pharmacological testing. We instrumented 12 MBP1-α-syn mice and 11 wild-type mice aged 9 months for radiotelemetry. Animals were tested with atropine, metoprolol, clonidine, and trimethaphan at 9 and 12 months age. We applied spectral and cross-spectral analysis to assess heart rate (HR) and BP variability. At 9 months of age daytime BP (transgenic: 101 ± 2 vs. wild type: 99 ± 2 mmHg) and HR (497 ± 11 vs. 505 ± 16 beats/min) were similar. Circadian BP and HR rhythms were maintained. Nighttime BP (109 ± 2 vs. 108 ± 2 mmHg) and HR (575 ± 15 vs. 569 ± 14 beats/min), mean arterial BP responses to trimethaphan (-21 ± 8 vs. -10 ± 5 mmHg, P = 0.240) and to clonidine (-8 ± 3 vs. -5 ± 2 mmHg, P = 0.314) were similar. HR responses to atropine (+159 ± 24 vs. +146 ± 22 beats/min), and to clonidine (-188 ± 21 vs. -163 ± 33 beats/min) did not differ between strains. Baroreflex sensitivity (4 ± 1 vs. 4 ± 1 msec/mmHg) and HR variability (total power, 84 ± 17 vs. 65 ± 21 msec²) were similar under resting conditions and during pharmacological testing. Repeated measurements at 12 months of age provided similar results. In mice, moderate overexpression of human alpha-synuclein in oligodendrocytes is not sufficient to induce overt autonomic failure. Additional mechanisms may be required to express the autonomic failure phenotype including higher levels of expression or more advanced age. © 2014 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of the American Physiological Society and The Physiological Society.

Effects of acute and chronic systemic methamphetamine on respiratory, cardiovascular and metabolic function, and cardiorespiratory reflexes

PubMed Central

Hassan, Sarah F.; Wearne, Travis A.; Cornish, Jennifer L.

2016-01-01

Key points Methamphetamine (METH) abuse is escalating worldwide, with the most common cause of death resulting from cardiovascular failure and hyperthermia; however, the underlying physiological mechanisms are poorly understood.Systemic administration of METH in anaesthetised rats reduced the effectiveness of some protective cardiorespiratory reflexes, increased central respiratory activity independently of metabolic function, and increased heart rate, metabolism and respiration in a pattern indicating that non‐shivering thermogenesis contributes to the well‐described hyperthermia.In animals that showed METH‐induced behavioural sensitisation following chronic METH treatment, no changes were evident in baseline cardiovascular, respiratory and metabolic measures and the METH‐evoked effects in these parameters were similar to those seen in saline‐treated or drug naïve animals.Physiological effects evoked by METH were retained but were neither facilitated nor depressed following chronic treatment with METH.These data highlight and identify potential mechanisms for targeted intervention in patients vulnerable to METH overdose. Abstract Methamphetamine (METH) is known to promote cardiovascular failure or life‐threatening hyperthermia; however, there is still limited understanding of the mechanisms responsible for evoking the physiological changes. In this study, we systematically determined the effects on both autonomic and respiratory outflows, as well as reflex function, following acute and repeated administration of METH, which enhances behavioural responses. Arterial pressure, heart rate, phrenic nerve discharge amplitude and frequency, lumbar and splanchnic sympathetic nerve discharge, interscapular brown adipose tissue and core temperatures, and expired CO2 were measured in urethane‐anaesthetised male Sprague‐Dawley rats. Novel findings include potent increases in central inspiratory drive and frequency that are not dependent on METH‐evoked increases in expired CO2 levels. Increases in non‐shivering thermogenesis correlate with well‐described increases in body temperature and heart rate. Unexpectedly, METH evoked minor effects on both sympathetic outflows and mean arterial pressure. METH modified cardiorespiratory reflex function in response to hypoxia, hypercapnia and baroreceptor unloading. Chronically METH‐treated rats failed to exhibit changes in baseline sympathetic, cardiovascular, respiratory and metabolic parameters. The tonic and reflex cardiovascular, respiratory and metabolic responses to METH challenge were similar to those seen in saline‐treated and drug naive animals. Overall, these findings describe independent and compound associations between physiological systems evoked by METH and serve to highlight that a single dose of METH can significantly impact basic homeostatic systems and protective functions. These effects of METH persist even following chronic METH treatment. PMID:26584821

Fetal body weight and the development of the control of the cardiovascular system in fetal sheep.

PubMed

Frasch, M G; Müller, T; Wicher, C; Weiss, C; Löhle, M; Schwab, K; Schubert, H; Nathanielsz, P W; Witte, O W; Schwab, M

2007-03-15

Reduced birth weight predisposes to cardiovascular diseases in later life. We examined in fetal sheep at 0.76 (n = 18) and 0.87 (n = 17) gestation whether spontaneously occurring variations in fetal weight affect maturation of autonomic control of cardiovascular function. Fetal weights at both gestational ages were grouped statistically in low (LW) and normal weights (NW) (P < 0.01). LW fetuses were within the normal weight span showing minor growth dysproportionality at 0.76 gestation favouring heart and brain, with a primary growth of carcass between 0.76 and 0.87 gestation (P < 0.05). While twins largely contributed to LW fetuses, weight differences between singletons and twins were absent at 0.76 and modest at 0.87 gestation, underscoring the fact that twins belong to normality in fetal sheep not constituting a major malnutritive condition. Mean fetal blood pressure (FBP) of all fetuses was negatively correlated to fetal weight at 0.76 but not 0.87 gestation (P < 0.05). At this age, FBP and baroreceptor reflex sensitivity were increased in LW fetuses (P < 0.05), suggesting increased sympathetic activity and immaturity of circulatory control. Development of vagal modulation of fetal heart rate depended on fetal weight (P < 0.01). These functional associations were largely independent of twin pregnancies. We conclude, low fetal weight within the normal weight span is accompanied by a different trajectory of development of sympathetic blood pressure and vagal heart rate control. This may contribute to the development of elevated blood pressure in later life. Examination of the underlying mechanisms and consequences may contribute to the understanding of programming of cardiovascular diseases.

Respiratory modulation of cardiovascular rhythms before and after short-duration human spaceflight.

PubMed

Verheyden, B; Beckers, F; Couckuyt, K; Liu, J; Aubert, A E

2007-12-01

Astronauts commonly return from space with altered short-term cardiovascular dynamics and blunted baroreflex sensitivity. Although many studies have addressed this issue, post-flight effects on the dynamic circulatory control remain incompletely understood. It is not clear how long the cardiovascular system needs to recover from spaceflight as most post-flight investigations only extended between a few days and 2 weeks. In this study, we examined the effect of short-duration spaceflight (1-2 weeks) on respiratory-mediated cardiovascular rhythms in five cosmonauts. Two paced-breathing protocols at 6 and 12 breaths min(-1) were performed in the standing and supine positions before spaceflight, and after 1 and 25 days upon return. Dynamic baroreflex function was evaluated by transfer function analysis between systolic pressure and the RR intervals. Post-flight orthostatic blood pressure control was preserved in all cosmonauts. In the standing position after spaceflight there was an increase in heart rate (HR) of approx. 20 beats min(-1) or more. Averaged for all five cosmonauts, respiratory sinus dysrhythmia and transfer gain reduced to 40% the day after landing, and had returned to pre-flight levels after 25 days. Low-frequency gain decreased from 6.6 (3.4) [mean (SD)] pre-flight to 3.9 (1.6) post-flight and returned to 5.7 (1.3) ms mmHg(-1) after 25 days upon return to Earth. Unlike alterations in the modulation of HR, blood pressure dynamics were not significantly different between pre- and post-flight sessions. Our results indicate that short-duration spaceflight reduces respiratory modulation of HR and decreases cardiac baroreflex gain without affecting post-flight arterial blood pressure dynamics. Altered respiratory modulation of human autonomic rhythms does not persist until 25 days upon return to Earth.

[Heart rate variability as a method of assessing the autonomic nervous system in polycystic ovary syndrome].

PubMed

de Sá, Joceline Cássia Ferezini; Costa, Eduardo Caldas; da Silva, Ester; Azevedo, George Dantas

2013-09-01

Polycystic ovary syndrome (PCOS) is an endocrine disorder associated with several cardiometabolic risk factors, such as central obesity, insulin resistance, type 2 diabetes, metabolic syndrome, and hypertension. These factors are associated with adrenergic overactivity, which is an important prognostic factor for the development of cardiovascular disorders. Given the common cardiometabolic disturbances occurring in PCOS women, over the last years studies have investigated the cardiac autonomic control of these patients, mainly based on heart rate variability (HRV). Thus, in this review, we will discuss the recent findings of the studies that investigated the HRV of women with PCOS, as well as noninvasive methods of analysis of autonomic control starting from basic indexes related to this methodology.

Instantaneous Transfer Entropy for the Study of Cardiovascular and Cardiorespiratory Nonstationary Dynamics.

PubMed

Valenza, Gaetano; Faes, Luca; Citi, Luca; Orini, Michele; Barbieri, Riccardo

2018-05-01

Measures of transfer entropy (TE) quantify the direction and strength of coupling between two complex systems. Standard approaches assume stationarity of the observations, and therefore are unable to track time-varying changes in nonlinear information transfer with high temporal resolution. In this study, we aim to define and validate novel instantaneous measures of TE to provide an improved assessment of complex nonstationary cardiorespiratory interactions. We here propose a novel instantaneous point-process TE (ipTE) and validate its assessment as applied to cardiovascular and cardiorespiratory dynamics. In particular, heartbeat and respiratory dynamics are characterized through discrete time series, and modeled with probability density functions predicting the time of the next physiological event as a function of the past history. Likewise, nonstationary interactions between heartbeat and blood pressure dynamics are characterized as well. Furthermore, we propose a new measure of information transfer, the instantaneous point-process information transfer (ipInfTr), which is directly derived from point-process-based definitions of the Kolmogorov-Smirnov distance. Analysis on synthetic data, as well as on experimental data gathered from healthy subjects undergoing postural changes confirms that ipTE, as well as ipInfTr measures are able to dynamically track changes in physiological systems coupling. This novel approach opens new avenues in the study of hidden, transient, nonstationary physiological states involving multivariate autonomic dynamics in cardiovascular health and disease. The proposed method can also be tailored for the study of complex multisystem physiology (e.g., brain-heart or, more in general, brain-body interactions).

Cardioprotective Properties of Aerobic and Resistance Training Against Myocardial Infarction.

PubMed

Barboza, C A; Souza, G I H; Oliveira, J C M F; Silva, L M; Mostarda, C T; Dourado, P M M; Oyama, L M; Lira, F S; Irigoyen, M C; Rodrigues, B

2016-06-01

We evaluated the effects of aerobic and resistance exercise training on ventricular morphometry and function, physical capacity, autonomic function, as well as on ventricular inflammatory status in trained rats prior to myocardial infarction. Male Wistar rats were divided into the following groups: sedentary+Sham, sedentary+myocardial infarction, aerobic trained+myocardial infarction, and resistance trained+myocardial infarction. Sham and myocardial infarction were performed after training periods. In the days following the surgeries, evaluations were performed. Aerobic training prevents aerobic (to a greater extent) and resistance capacity impairments, ventricular dysfunction, baroreflex sensitivity and autonomic disorders (vagal tonus decrease and sympathetic tonus increase) triggered by myocardial infarction. Resistance training was able to prevent negative changes to aerobic and resistance capacity (to a greater extent) but not to ventricular dysfunction, and it prevented cardiovascular sympathetic increments. Additionally, both types of training reduced left ventricle inflammatory cytokine concentration. Our results suggest that aerobic and, for the first time, dynamic resistance training were able to reduce sympathetic tonus to the heart and vessels, as well as preventing the increase in pro-inflammatory cytokine concentrations in the left ventricle of trained groups. These data emphasizes the positive effects of aerobic and dynamic resistance training on the prevention of the negative changes triggered by myocardial infarction. © Georg Thieme Verlag KG Stuttgart · New York.

Decreased baroreflex sensitivity is linked to the atherogenic index, retrograde inflammation, and oxidative stress in subclinical hypothyroidism.

PubMed

Syamsunder, Avupati Naga; Pal, Pravati; Pal, Gopal Krushna; Kamalanathan, Chandrakasan Sadishkumar; Parija, Subhash Chandra; Nanda, Nivedita; Sirisha, Allampalli

2017-02-01

Purpose/aim of the study: The present study investigated the link of hyperlipidemia, inflammation and oxidative stress (OS) to cardiovascular (CV) risks in subclinical hypothyroidism (SCH). We enrolled 81 subclinical hypothyroid patients and 80 healthy subjects as control. Their CV and autonomic functions were assessed by spectral analysis of heart rate variability (HRV), continuous blood pressure variability (BPV) measurement and conventional autonomic function testing. Thyroid profile, lipid profile, immunological, inflammatory and OS markers were estimated and correlated with the baro-reflex sensitivity (BRS), the marker of sympathovagal imbalance (SVI) & CV risk. Mean arterial pressure (MAP, P<0.0001), total peripheral resistance (TPR, P<0.0001), ratio of low-frequency to high-frequency power of HRV (LF-HF ratio) (P<0.0001) were significantly higher and BRS (P<0.0001) was significantly lower in SCH group than the control group. BRS significantly correlated with heart rate, MAP, LF-HF ratio, lipid risk factors, anti-thyroperoxidase antibody, thyroid-stimulating hormone, high-sensitive C-reactive protein (hsCRP), malondialdehyde (MDA) and SCH. It was concluded that SVI is associated with SCH. Though dyslipidemia, inflammation and OS contributed to decreased BRS, SCH per se contributed maximally to it. Decreased BRS could be a physiological basis of increased CV risks in patients with SCH.

Depletion of catecholaminergic neurons of the rostral ventrolateral medulla in multiple systems atrophy with autonomic failure

NASA Technical Reports Server (NTRS)

Benarroch, E. E.; Smithson, I. L.; Low, P. A.; Parisi, J. E.

1998-01-01

The ventrolateral portion of the intermediate reticular formation of the medulla (ventrolateral medulla, VLM), including the C1/A1 groups of catecholaminergic neurons, is thought to be involved in control of sympathetic cardiovascular outflow, cardiorespiratory interactions, and reflex control of vasopressin release. As all these functions are affected in patients with multiple systems atrophy (MSA) with autonomic failure, we sought to test the hypothesis that catecholaminergic (tyrosine hydroxylase [TH]-positive) neurons of the VLM are depleted in these patients. Medullas were obtained at autopsy from 4 patients with MSA with prominent autonomic failure and 5 patients with no neurological disease. Patients with MSA had laboratory evidence of severe adrenergic sudomotor and cardiovagal failure. Tissue was immersion fixed in 2% paraformaldehyde at 4 degrees C for 24 hours and cut into 1-cm blocks in the coronal plane from throughout the medulla. Serial 50-microm sections were collected and one section every 300 microm was stained for TH. There was a pronounced depletion of TH neurons in the rostral VLM in all cases of MSA. There was also significant reduction of TH neurons in the caudal VLM in 3 MSA patients compared with 3 control subjects. In 2 MSA cases and in 2 control subjects, the thoracic spinal cord was available for study. There was also depletion of TH fibers and sympathetic preganglionic neurons (SPNs) in the 2 MSA cases examined. Thus, depletion of catecholaminergic neurons in the VLM may provide a substrate for some of the autonomic and endocrine manifestations of MSA.

Increased interarm blood pressure difference is associated with autonomic dysfunction and atherosclerosis in patients with chest pain and no history of coronary artery disease.

PubMed

Hwang, Hui-Jeong; Sohn, Il Suk; Kim, Dong-Hee; Park, Chang-Bum; Cho, Jin-Man; Kim, Chong-Jin

2017-08-15

Interarm blood pressure (BP) difference has been reported to be associated with atherosclerosis and increased cardiovascular death. We were to investigate associations of interarm systolic blood pressure (SBP) difference with heart rate recovery (HRR) after exercise, an index of autonomic function, and carotid atherosclerotic markers, and to evaluate the association of interarm SBP difference with concurrent coronary artery disease (CAD). A total of 995 consecutive patients who underwent treadmill stress echocardiography with chest pain but no history of CAD were enrolled. Interarm SBP difference, carotid intima-media thickness (IMT) and plaque were measured before exercise, and HRR 2min following exercise was assessed. Suspected CAD was defined as newly developed wall motion abnormalities after treadmill exercise. Patients with an interarm SBP difference≥10mmHg had higher prevalence of hypertension, increased right and left SBP, right diastolic BP, mean arterial pressure, body mass index and carotid IMT, existent carotid plaque, lower metabolic equivalents and slower HRR. Interarm SBP difference≥10mmHg was independently associated with slower HRR and existent carotid plaque. Suspected CAD was associated with existent carotid plaque or slower HRR, but not with an interarm SBP difference≥10mmHg. Increased interarm SBP difference was associated with lower autonomic modulation and carotid atherosclerosis in patients with chest pain and no history of CAD, but not with suspected CAD. Observed adverse prognosis in patients with increased interarm BP difference might result from long-term persistent autonomic dysfunction and atherosclerosis. Copyright © 2017 Elsevier B.V. All rights reserved.

Exercise training starting at weaning age preserves cardiac pacemaker function in adulthood of diet-induced obese rats.

PubMed

Carvalho de Lima, Daniel; Guimarães, Juliana Bohnen; Rodovalho, Gisele Vieira; Silveira, Simonton Andrade; Haibara, Andrea Siqueira; Coimbra, Cândido Celso

2014-08-01

Peripheral sympathetic overdrive in young obese subjects contributes to further aggravation of insulin resistance, diabetes, and hypertension, thus inducing worsening clinical conditions in adulthood. Exercise training has been considered a strategy to repair obesity autonomic dysfunction, thereby reducing the cardiometabolic risk. Therefore, the aim of this study was to assess the effect of early exercise training, starting immediately after weaning, on cardiac autonomic control in diet-induced obese rats. Male Wistar rats (weaning) were divided into four groups: (i) a control group (n = 6); (ii) an exercise-trained control group (n = 6); (iii) a diet-induced obesity group (n = 6); and (iv) an exercise-trained diet-induced obesity group (n = 6). The development of obesity was induced by 9 weeks of palatable diet intake, and the training program was implemented in a motor-driven treadmill (5 times per week) during the same period. After this period, animals were submitted to vein and artery catheter implantation to assess cardiac autonomic balance by methylatropine (3 mg/kg) and propranolol (4 mg/kg) administration. Exercise training increased running performance in both groups (p < 0.05). Exercise training also prevented the increased resting heart rate in obese rats, which seemed to be related to cardiac pacemaker activity preservation (p < 0.05). Additionally, the training program preserved the pressure and bradycardia responses to autonomic blockade in obese rats (p < 0.05). An exercise program beginning at weaning age prevents cardiovascular dysfunction in obese rats, indicating that exercise training may be used as a nonpharmacological therapeutic strategy for the treatment of cardiometabolic diseases.

Spaceflight-Induced Cardiovascular Changes and Recovery During NASA's Functional Task Test

NASA Technical Reports Server (NTRS)

Arzeno, N. M.; Stenger, M. B.; Bloomberg, J. J.; Platts, S. H.

2010-01-01

Microgravity-induced physiological changes could impair a crewmember s performance upon return to a gravity environment. The Functional Task Test (FTT) is designed to correlate these physiological changes to performance in mission-critical tasks. The Recovery from Fall/Stand Test (RFST) simulates one such task, measuring the ability to recover from a prone position and the cardiovascular response to orthostasis. The purpose of this study was to evaluate spaceflight-induced cardiovascular changes during the FTT. METHODS: Five astronauts participated in the FTT before 10-15 day missions, on landing day (R+0), and one (R+1), six (R+6) and thirty (R+30) days after landing. The RFST consisted of a 2-minute prone rest followed by a 3-minute stand during which heart rate (HR, Holter) and continuous blood pressure (BP, Finometer) were measured. Spectral heart rate variability (HRV) was calculated during the RFST to approximate autonomic function. Statistical analysis was performed with two-factor repeated measures ANOVA. RESULTS: During RFST, HR was higher on R+0 than preflight (p<0.004). This increase in HR persisted on R+1 and R+6 during the stand portion of RFST (p<0.026). BP was well-regulated on all test days. Parasympathetic activity was diminished on R+0 (p=0.035). Sympathovagal balance tended to be affected by spaceflight (main effect, p=0.072), appearing to be slightly elevated during postflight RFST except on R+30. Additionally, analysis of HR during the functional tasks yielded a higher HR on R+0 than preflight during 8 of 11 tasks analyzed, where all tasks had HR return to preflight values by R+30 (p<0.05). CONCLUSION: Spaceflight causes an increase in HR, decrease in parasympathetic activity, and increase in sympathovagal balance, which we confirmed during RFST. These spaceflight-induced changes seen in the RFST, along with the increased postflight HR in most functional tasks, can be used to assess functional performance after short-duration spaceflight.

Cardiovascular Complications of Marijuana and Related Substances: A Review.

PubMed

Singh, Amitoj; Saluja, Sajeev; Kumar, Akshat; Agrawal, Sahil; Thind, Munveer; Nanda, Sudip; Shirani, Jamshid

2018-06-01

The recreational use of cannabis has sharply increased in recent years in parallel with its legalization and decriminalization in several countries. Commonly, the traditional cannabis has been replaced by potent synthetic cannabinoids and cannabimimetics in various forms. Despite overwhelming public perception of the safety of these substances, an increasing number of serious cardiovascular adverse events have been reported in temporal relation to recreational cannabis use. These have included sudden cardiac death, vascular (coronary, cerebral and peripheral) events, arrhythmias and stress cardiomyopathy among others. Many of the victims of these events are relatively young men with few if any cardiovascular risk factors. However, there are reasons to believe that older individuals and those with risk factors for or established cardiovascular disease are at even higher danger of such events following exposure to cannabis. The pathophysiological basis of these events is not fully understood and likely encompasses a complex interaction between the active ingredients (particularly the major cannabinoid, Δ 9 -tetrahydrocannabinol), and the endo-cannabinoid system, autonomic nervous system, as well as other receptor and non-receptor mediated pathways. Other complicating factors include opposing physiologic effects of other cannabinoids (predominantly cannabidiol), presence of regulatory proteins that act as metabolizing enzymes, binding molecules, or ligands, as well as functional polymorphisms of target receptors. Tolerance to the effects of cannabis may also develop on repeated exposures at least in part due to receptor downregulation or desensitization. Moreover, effects of cannabis may be enhanced or altered by concomitant use of other illicit drugs or medications used for treatment of established cardiovascular diseases. Regardless of these considerations, it is expected that the current cannabis epidemic would add significantly to the universal burden of cardiovascular diseases.

Cardiac autonomic neuropathy in patients with diabetes mellitus: current perspectives

PubMed Central

Fisher, Victoria L; Tahrani, Abd A

2017-01-01

Cardiac autonomic neuropathy (CAN) is a common and often-underdiagnosed complication of diabetes mellitus (DM). CAN is associated with increased mortality, cardiovascular disease, chronic kidney disease, and morbidity in patients with DM, but despite these significant consequences CAN often remains undiagnosed for a prolonged period. This is commonly due to the disease being asymptomatic until the later stages, as well as a lack of easily available screening strategies. In this article, we review the latest developments in the epidemiology, pathogenesis, diagnosis, consequences, and treatments of CAN in patients with DM. PMID:29062239

Numerical modeling of dynamics of heart rate and arterial pressure during passive orthostatic test

NASA Astrophysics Data System (ADS)

Ishbulatov, Yu. M.; Kiselev, A. R.; Karavaev, A. S.

2018-04-01

A model of human cardiovascular system is proposed to describe the main heart rhythm, influence of autonomous regulation on frequency and strength of heart contractions and resistance of arterial vessels; process of formation of arterial pressure during systolic and diastolic phases; influence of respiration; synchronization between loops of autonomous regulation. The proposed model is used to simulate the dynamics of heart rate and arterial pressure during passive transition from supine to upright position. Results of mathematical modeling are compared to original experimental data.

Investigating the neurodevelopmental mediators of aggression in children with a history of child maltreatment:An exploratory field study.

PubMed

Dileo, J F; Brewer, W; Northam, E; Yucel, M; Anderson, V

2017-08-01

Maltreatment of children is a chronic community problem that increases the risk of future aggression. Despite several decades of research highlighting this relationship, few studies have explored the potential neuropsychological deficits that are likely to mediate it. This exploratory study aimed to examine how child maltreatment may be associated with aggression via impairment in the developing prefrontal-limbic-autonomic pathways that are implicated in neuropsychological models of aggression. Furthermore, it aimed to investigate the relationship between child maltreatment and both reactive and proactive aggression subtypes. To investigate this non-invasively in an at-risk population, children with a documented protective care history (n = 20) and a community control group (n = 30), aged between 6 and 12 years, were compared on measures of cardiovascular functioning, affect regulation and cognitive functioning aligned with this neuropsychological model. Whilst no group differences were found on cardiovascular functioning (i.e., resting heart rate, heart rate reactivity, heart rate variability), the protective care group performed significantly worse on measures of affect regulation and cognitive functioning (i.e., global intelligence, executive functioning, smell identification and social cognition). The relationship between child maltreatment and aggression was mediated by executive dysfunction and affect dysregulation but not global IQ, social cognition or olfactory identification. The results suggest that interventions targeting aggression in maltreated children will benefit from clinical assessment and psychological strategies that address the executive dysfunction and affect dysregulation that has been associated with this clinical outcome.

Overt and Latent Cardiac Effects of Ozone Inhalation in Rats: Evidence for Autonomic Modulation and Increased Myocardial Vulnerability

EPA Science Inventory

Background: Ozone (03) is a well-documented respiratory oxidant, but increasing epidemiologic evidence points to extra-pulmonary effects including positive associations between ambient 03 concentrations and cardiovascular morbidity/mortality. Objectives: With preliminary reports ...

Diagnosis of multiple system atrophy

PubMed Central

Palma, Jose-Alberto; Norcliffe-Kaufmann, Lucy; Kaufmann, Horacio

2017-01-01

Multiple system atrophy (MSA) may be difficult to distinguish clinically from other disorders, particularly in the early stages of the disease. An autonomic-only presentation can be indistinguishable from pure autonomic failure. Patients presenting with parkinsonism may be misdiagnosed as having Parkinson disease. Patients presenting with the cerebellar phenotype of MSA can mimic other adult-onset ataxias due to alcohol, chemotherapeutic agents, lead, lithium, and toluene, or vitamin E deficiency, as well as paraneoplastic, autoimmune, or genetic ataxias. A careful medical history and meticulous neurological examination remain the cornerstone for the accurate diagnosis of MSA. Ancillary investigations are helpful to support the diagnosis, rule out potential mimics, and define therapeutic strategies. This review summarizes diagnostic investigations useful in the differential diagnosis of patients with suspected MSA. Currently used techniques include structural and functional brain imaging, cardiac sympathetic imaging, cardiovascular autonomic testing, olfactory testing, sleep study, urological evaluation, and dysphagia and cognitive assessments. Despite advances in the diagnostic tools for MSA in recent years and the availability of consensus criteria for clinical diagnosis, the diagnostic accuracy of MSA remains sub-optimal. As other diagnostic tools emerge, including skin biopsy, retinal biomarkers, blood and cerebrospinal fluid biomarkers, and advanced genetic testing, a more accurate and earlier recognition of MSA should be possible, even in the prodromal stages. This has important implications as misdiagnosis can result in inappropriate treatment, patient and family distress, and erroneous eligibility for clinical trials of disease-modifying drugs. PMID:29111419

Cardiorespiratory and autonomic interactions during snoring related resistive breathing.

PubMed

Mateika, J H; Mitru, G

2001-03-15

We hypothesized that blood pressure (BP) is less during snoring as compared to periods of non-snoring in non-apneic individuals. Furthermore, we hypothesized that this reduction may be accompanied by a simultaneous decrease in sympathetic (SNSA) and parasympathetic (PNSA) nervous system activity and an increase in heart rate (HR). N/A. N/A. N/A. The variables mentioned above in addition to breathing frequency were measured in 9 subjects during NREM sleep. In addition, the lowest systolic (SBP) and diastolic blood pressure (DBP) during inspiration and the highest SBP and DBP during expiration was determined breath-by-breath from segments selected from each NREM cycle. Heart rate variability was used as a marker of autonomic nervous system activity. Our results showed that BP during snoring decreased compared to non-snoring and the breath-by-breath BP analysis suggested that this difference may have been mediated by changes in intrathoracic pressure. In conjunction with the decrease in BP, SNSA decreased and HR increased however PNSA remained constant. Thus, a decrease in PNSA was likely not the primary mechanism responsible for the HR response. We conclude that BP responses and SNSA during snoring are similar to that reported previously in non-snoring individuals. However, the causal mechanisms maybe different and manifested in other measures such as HR. Thus, nocturnal cardiovascular and autonomic function maybe uniquely different in non-apneic snoring individuals.

Cardiac Autonomic Regulation and Repolarization During Acute Experimental Hypoglycemia in Type 2 Diabetes

PubMed Central

Chow, Elaine; Bernjak, Alan; Walkinshaw, Emma; Lubina-Solomon, Alexandra; Freeman, Jenny; Macdonald, Ian A.; Sheridan, Paul J.

2017-01-01

Hypoglycemia is associated with increased cardiovascular mortality in trials of intensive therapy in type 2 diabetes mellitus (T2DM). We previously observed an increase in arrhythmias during spontaneous prolonged hypoglycemia in patients with T2DM. We examined changes in cardiac autonomic function and repolarization during sustained experimental hypoglycemia. Twelve adults with T2DM and 11 age- and BMI-matched control participants without diabetes underwent paired hyperinsulinemic clamps separated by 4 weeks. Glucose was maintained at euglycemia (6.0 mmol/L) or hypoglycemia (2.5 mmol/L) for 1 h. Heart rate, blood pressure, and heart rate variability were assessed every 30 min and corrected QT intervals and T-wave morphology every 60 min. Heart rate initially increased in participants with T2DM but then fell toward baseline despite maintained hypoglycemia at 1 h accompanied by reactivation of vagal tone. In control participants, vagal tone remained depressed during sustained hypoglycemia. Participants with T2DM exhibited greater heterogeneity of repolarization during hypoglycemia as demonstrated by T-wave symmetry and principal component analysis ratio compared with control participants. Epinephrine levels during hypoglycemia were similar between groups. Cardiac autonomic regulation during hypoglycemia appears to be time dependent. Individuals with T2DM demonstrate greater repolarization abnormalities for a given hypoglycemic stimulus despite comparable sympathoadrenal responses. These mechanisms could contribute to arrhythmias during clinical hypoglycemic episodes. PMID:28137792

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

PubMed

Toschi-Dias, Edgar; Tobaldini, Eleonora; Solbiati, Monica; Costantino, Giorgio; Sanlorenzo, Roberto; Doria, Stefania; Irtelli, Floriana; Mencacci, Claudio; Montano, Nicola

2017-05-01

Several 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. Forty-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. After 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. Intensive 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. Copyright © 2017 Elsevier B.V. All rights reserved.

Permutation entropy analysis of heart rate variability for the assessment of cardiovascular autonomic neuropathy in type 1 diabetes mellitus.

PubMed

Carricarte Naranjo, Claudia; Sanchez-Rodriguez, Lazaro M; Brown Martínez, Marta; Estévez Báez, Mario; Machado García, Andrés

2017-07-01

Heart rate variability (HRV) analysis is a relevant tool for the diagnosis of cardiovascular autonomic neuropathy (CAN). To our knowledge, no previous investigation on CAN has assessed the complexity of HRV from an ordinal perspective. Therefore, the aim of this work is to explore the potential of permutation entropy (PE) analysis of HRV complexity for the assessment of CAN. For this purpose, we performed a short-term PE analysis of HRV in healthy subjects and type 1 diabetes mellitus patients, including patients with CAN. Standard HRV indicators were also calculated in the control group. A discriminant analysis was used to select the variables combination with best discriminative power between control and CAN patients groups, as well as for classifying cases. We found that for some specific temporal scales, PE indicators were significantly lower in CAN patients than those calculated for controls. In such cases, there were ordinal patterns with high probabilities of occurrence, while others were hardly found. We posit this behavior occurs due to a decrease of HRV complexity in the diseased system. Discriminant functions based on PE measures or probabilities of occurrence of ordinal patterns provided an average of 75% and 96% classification accuracy. Correlations of PE and HRV measures showed to depend only on temporal scale, regardless of pattern length. PE analysis at some specific temporal scales, seem to provide additional information to that obtained with traditional HRV methods. We concluded that PE analysis of HRV is a promising method for the assessment of CAN. Copyright © 2017 Elsevier Ltd. All rights reserved.

Heart rate variability indexes as a marker of chronic adaptation in athletes: a systematic review.

PubMed

da Silva, Vanessa Pereira; de Oliveira, Natacha Alves; Silveira, Heitor; Mello, Roger Gomes Tavares; Deslandes, Andrea Camaz

2015-03-01

Regular exercise promotes functional and structural changes in the central and peripheral mechanisms of the cardiovascular system. Heart rate variability (HRV) measurement provides a sensitive indicator of the autonomic balance. However, because of the diversity of methods and variables used, the results are difficult to compare in the sports sciences. Since the protocol (supine, sitting, or standing position) and measure (time or frequency domain) are not well defined, the aim of this study is to investigate the HRV measures that better indicates the chronic adaptations of physical exercise in athletes. PubMed (MEDLINE), Web of Science, SciELO (Scientific Electronic Library), and Scopus databases were consulted. Original complete articles in English with short-term signals evaluating young and adult athletes, between 17 and 40 years old, with a control group, published up to 2013 were included. Selected 19 of 1369 studies, for a total sample pool of 333 male and female athletes who practice different sports. The main protocols observed were the supine or standing positions in free or controlled breathing conditions. The main statistical results found in this study were the higher mean RR, standard deviation of RR intervals, and high frequency in athletes group. In addition, the analyses of Cohen's effect size showed that factors as modality of sport, protocol used and unit of measure selected could influence this expected results. Our findings indicate that time domain measures are more consistent than frequency domain to describe the chronic cardiovascular autonomic adaptations in athletes. © 2014 Wiley Periodicals, Inc.

Post-exercise hypotension and heart rate variability response after water- and land-ergometry exercise in hypertensive patients.

PubMed

Bocalini, Danilo Sales; Bergamin, Marco; Evangelista, Alexandre Lopes; Rica, Roberta Luksevicius; Pontes, Francisco Luciano; Figueira, Aylton; Serra, Andrey Jorge; Rossi, Emilly Martinelli; Tucci, Paulo José Ferreira; Dos Santos, Leonardo

2017-01-01

systemic arterial hypertension is the most prevalent cardiovascular disease; physical activity for hypertensive patients is related to several beneficial cardiovascular adaptations. This paper evaluated the effect of water- and land-ergometry exercise sessions on post-exercise hypotension (PEH) of healthy normotensive subjects versus treated or untreated hypertensive patients. Forty-five older women composed three experimental groups: normotensive (N, n = 10), treated hypertensive (TH, n = 15) and untreated hypertensive (UH, n = 20). The physical exercise acute session protocol was performed at 75% of maximum oxygen consumption (VO2max) for 45 minutes; systolic (SBP), diastolic (DBP) and mean (MBP) blood pressure were evaluated at rest, peak and at 15, 30, 45, 60, 75 and 90 minutes after exercise cessation. Additionally, the heart rate variability (HRV) was analyzed by R-R intervals in the frequency domain for the assessment of cardiac autonomic function. In both exercise modalities, equivalent increases in SBP were observed from rest to peak exercise for all groups, and during recovery, significant PEH was noted. At 90 minutes after the exercise session, the prevalence of hypotension was significantly higher in water- than in the land-based protocol. Moreover, more pronounced reductions in SBP and DBP were observed in the UH patients compared to TH and N subjects. Finally, exercise in the water was more effective in restoring HRV during recovery, with greater effects in the untreated hypertensive group. Our data demonstrated that water-ergometry exercise was able to induce expressive PEH and improve cardiac autonomic modulation in older normotensive, hypertensive treated or hypertensive untreated subjects when compared to conventional land-ergometry.

Generalised smooth-muscle disease with defective muscarinic-receptor function.

PubMed

Bannister, R; Hoyes, A D

1981-03-28

A patient with widespread smooth-muscle disease presented with chronic intestinal pseudo-obstruction but had in addition defects of the bladder, pupils, sweating, and cardiovascular function. There was no evidence of a primary neural lesion, and minor changes in the muscle did not resemble those of a myopathy. In each organ affected muscarinic cholinergic function was at fault, but instead of supersensitivity to cholinergic drugs, which occurs in postganglionic autonomic neuropathies, there was a lack of response to cholinergic drugs and anticholinesterases. It was therefore concluded that the patient had a new type of defect of muscarinic-receptor function. The cause was unknown, but it may have been an autoimmune disease resembling myasthenia, in which there is a postjunctional defect of muscarinic receptors. In similar cases binding of muscarinic agonists and antagonists should be tested. When antibodies to purified human muscarinic receptors become available different patterns of smooth-muscle defect may be identifiable, enabling the lesion to be defined more precisely.

Effects of autonomic ganglion blockade on fractal and spectral components of blood pressure and heart rate variability in free-moving rats.

PubMed

Castiglioni, Paolo; Di Rienzo, Marco; Radaelli, Alberto

2013-11-01

Fractal analysis is a promising tool for assessing autonomic influences on heart rate (HR) and blood pressure (BP) variability. The temporal spectrum of scale coefficients, α(t), was recently proposed to describe the cardiovascular fractal dynamics. Aim of our work is to evaluate sympathetic influences on cardiovascular variability analyzing α(t) and spectral powers of HR and BP after ganglionic blockade. BP was recorded in 11 rats before and after autonomic blockade by hexamethonium infusion (HEX). Systolic and diastolic BP, pulse pressure and pulse interval were derived beat-by-beat. Segments longer than 5 min were selected at baseline and HEX to estimate power spectra and α(t). Comparisons were made by paired t-test. HEX reduced all spectral components of systolic and diastolic BP, the reduction being particularly significant around the frequency of Mayer waves; it induced a reduction on α(t) coefficients at t<2s and an increase on coefficients at t>8s. HEX reduced only slower components of pulse interval power spectrum, but decreased significantly faster scale coefficients (t<8s). HEX only marginally affected pulse pressure variability. Results indicate that the sympathetic outflow contributes to BP fractal dynamics with fractional Gaussian noise (α<1) at longer scales and fractional Brownian motion (α>1) at shorter scales. Ganglionic blockade also removes a fractional Brownian motion component at shorter scales from HR dynamics. Results may be explained by the characteristic time constants between sympathetic efferent activity and cardiovascular effectors. Therefore fractal analysis may complete spectral analysis with information on the correlation structure of the data. Copyright © 2013 Elsevier B.V. All rights reserved.

Implication of altered autonomic control for orthostatic tolerance in SCI.

PubMed

Wecht, Jill Maria; Bauman, William A

2018-01-01

Neural output from the sympathetic and parasympathetic branches of the autonomic nervous system (ANS) are integrated to appropriately control cardiovascular responses during routine activities of daily living including orthostatic positioning. Sympathetic control of the upper extremity vasculature and the heart arises from the thoracic cord between T1 and T5, whereas splanchnic bed and lower extremity vasculature receive sympathetic neural input from the lower cord between segments T5 and L2. Although the vasculature is not directly innervated by the parasympathetic nervous system, the SA node is innervated by post-ganglionic vagal nerve fibers via cranial nerve X. Segmental differences in sympathetic cardiovascular innervation highlight the effect of lesion level on orthostatic cardiovascular control following spinal cord injury (SCI). Due to impaired sympathetic cardiovascular control, many individuals with SCI, particularly those with lesions above T6, are prone to orthostatic hypotension (OH) and orthostatic intolerance (OI). Symptomatic OH, which may result in OI, is a consequence of episodic reductions in cerebral perfusion pressure and the symptoms may include: dizziness, lightheadedness, nausea, blurred vision, ringing in the ears, headache and syncope. However, many, if not most, individuals with SCI who experience persistent and episodic hypotension and OH do not report symptoms of cerebral hypoperfusion and therefore do not raise clinical concern. This review will discuss the mechanism underlying OH and OI following SCI, and will review our knowledge to date regarding the prevalence, consequences and possible treatment options for these conditions in the SCI population. Published by Elsevier B.V.

Behavioral and autonomic responses to acute restraint stress are segregated within the lateral septal area of rats.

PubMed

Reis, Daniel G; Scopinho, América A; Guimarães, Francisco S; Corrêa, Fernando M A; Resstel, Leonardo B M

2011-01-01

The Lateral Septal Area (LSA) is involved with autonomic and behavior responses associated to stress. In rats, acute restraint (RS) is an unavoidable stress situation that causes autonomic (body temperature, mean arterial pressure (MAP) and heart rate (HR) increases) and behavioral (increased anxiety-like behavior) changes in rats. The LSA is one of several brain regions that have been involved in stress responses. The aim of the present study was to investigate if the neurotransmission blockade in the LSA would interfere in the autonomic and behavioral changes induced by RS. Male Wistar rats with bilateral cannulae aimed at the LSA, an intra-abdominal datalogger (for recording internal body temperature), and an implanted catheter into the femoral artery (for recording and cardiovascular parameters) were used. They received bilateral microinjections of the non-selective synapse blocker cobalt chloride (CoCl(2), 1 mM/ 100 nL) or vehicle 10 min before RS session. The tail temperature was measured by an infrared thermal imager during the session. Twenty-four h after the RS session the rats were tested in the elevated plus maze (EPM). Inhibition of LSA neurotransmission reduced the MAP and HR increases observed during RS. However, no changes were observed in the decrease in skin temperature and increase in internal body temperature observed during this period. Also, LSA inhibition did not change the anxiogenic effect induced by RS observed 24 h later in the EPM. The present results suggest that LSA neurotransmission is involved in the cardiovascular but not the temperature and behavioral changes induced by restraint stress.

Analysis of cardiovascular regulation.

PubMed

Wilhelm, F H; Grossman, P; Roth, W T

1999-01-01

Adequate characterization of hemodynamic and autonomic responses to physical and mental stress can elucidate underlying mechanisms of cardiovascular disease or anxiety disorders. We developed a physiological signal processing system for analysis of continuously recorded ECG, arterial blood pressure (BP), and respiratory signals using the programming language Matlab. Data collection devices are a 16-channel digital, physiological recorder (Vitaport), a finger arterial pressure transducer (Finapres), and a respiratory inductance plethysmograph (Respitrace). Besides the conventional analysis of the physiological channels, power spectral density and transfer functions of respiration, heart rate, and blood pressure variability are used to characterize respiratory sinus arrhythmia (RSA), 0.10-Hz BP oscillatory activity (Mayer-waves), and baroreflex sensitivity. The arterial pressure transducer waveforms permit noninvasive estimation of stroke volume, cardiac output, and systemic vascular resistance. Time trends in spectral composition of indices are assessed using complex demodulation. Transient dynamic changes of cardiovascular parameters at the onset of stress and recovery periods are quantified using a regression breakpoint model that optimizes piecewise linear curve fitting. Approximate entropy (ApEn) is computed to quantify the degree of chaos in heartbeat dynamics. Using our signal processing system we found distinct response patterns in subgroups of patients with coronary artery disease or anxiety disorders, which were related to specific pharmacological and behavioral factors.

Naturally Occurring Variations in the Human Cholinesterase Genes: Heritability and Association with Cardiovascular and Metabolic Traits

PubMed Central

Valle, Anne M.; Radić, Zoran; Rana, Brinda K.; Mahboubi, Vafa; Wessel, Jennifer; Shih, Pei-an Betty; Rao, Fangwen; O'Connor, Daniel T.

2011-01-01

Cholinergic neurotransmission in the central and autonomic nervous systems regulates immediate variations in and longer-term maintenance of cardiovascular function with acetylcholinesterase (AChE) activity that is critical to temporal responsiveness. Butyrylcholinesterase (BChE), largely confined to the liver and plasma, subserves metabolic functions. AChE and BChE are found in hematopoietic cells and plasma, enabling one to correlate enzyme levels in whole blood with hereditary traits in twins. Using both twin and unrelated subjects, we found certain single nucleotide polymorphisms (SNPs) in the ACHE gene correlated with catalytic properties and general cardiovascular functions. SNP discovery from ACHE resequencing identified 19 SNPs: 7 coding SNPs (cSNPs), of which 4 are nonsynonymous, and 12 SNPs in untranslated regions, of which 3 are in a conserved sequence of an upstream intron. Both AChE and BChE activity traits in blood were heritable: AChE at 48.8 ± 6.1% and BChE at 81.4 ± 2.8%. Allelic and haplotype variations in the ACHE and BCHE genes were associated with changes in blood AChE and BChE activities. AChE activity was associated with BP status and SBP, whereas BChE activity was associated with features of the metabolic syndrome (especially body weight and BMI). Gene products from cDNAs with nonsynonymous cSNPs were expressed and purified. Protein expression of ACHE nonsynonymous variant D134H (SNP6) is impaired: this variant shows compromised stability and altered rates of organophosphate inhibition and oxime-assisted reactivation. A substantial fraction of the D134H instability could be reversed in the D134H/R136Q mutant. Hence, common genetic variations at ACHE and BCHE loci were associated with changes in corresponding enzymatic activities in blood. PMID:21493754

The autonomic laboratory

NASA Technical Reports Server (NTRS)

Low, P. A.; Opfer-Gehrking, T. L.

1999-01-01

The autonomic nervous system can now be studied quantitatively, noninvasively, and reproducibly in a clinical autonomic laboratory. The approach at the Mayo Clinic is to study the postganglionic sympathetic nerve fibers of peripheral nerve (using the quantitative sudomotor axon reflex test [QSART]), the parasympathetic nerves to the heart (cardiovagal tests), and the regulation of blood pressure by the baroreflexes (adrenergic tests). Patient preparation is extremely important, since the state of the patient influences the results of autonomic function tests. The autonomic technologist in this evolving field needs to have a solid core of knowledge of autonomic physiology and autonomic function tests, followed by training in the performance of these tests in a standardized fashion. The range and utilization of tests of autonomic function will likely continue to evolve.

Sex Differences in Insular Cortex Gyri Responses to the Valsalva Maneuver.

PubMed

Macey, Paul M; Rieken, Nicholas S; Kumar, Rajesh; Ogren, Jennifer A; Middlekauff, Holly R; Wu, Paula; Woo, Mary A; Harper, Ronald M

2016-01-01

Sex differences in autonomic regulation may underlie cardiovascular disease variations between females and males. One key autonomic brain region is the insular cortex, which typically consists of five main gyri in each hemisphere, and shows a topographical organization of autonomic function across those gyri. The present study aims to identify possible sex differences in organization of autonomic function in the insula. We studied brain functional magnetic resonance imaging (fMRI) responses to a series of four 18-s Valsalva maneuvers in 22 healthy females (age ± SD: 50.0 ± 7.9 years) and 36 healthy males (45.3 ± 9.2 years). Comparisons of heart rate (HR) and fMRI signals were performed with repeated measures ANOVA (threshold P < 0.05 for all findings). All subjects achieved the target 30 mmHg expiratory pressure for all challenges. Typical HR responses were elicited by the maneuver, including HR increases from ~4 s into the strain period (Phase II) and rapid declines to below baseline 5-10 s, following strain release (Phase IV). Small, but significant, sex differences in HR percent change occurred during the sympathetic-dominant Phase II (female < male) and parasympathetic-dominant Phase IV (female > male, i.e., greater undershoot in males). The insular cortices showed similar patterns in all gyri, with greater signal decreases in males than females. Both sexes exhibited an anterior-posterior topographical organization of insular responses during Phase II, with anterior gyri showing higher responses than more posterior gyri. The exception was the right anterior-most gyrus in females, which had lower responses than the four other right gyri. Responses were lateralized, with right-sided dominance during Phase II in both sexes, except the right anterior-most gyrus in females, which showed lower responses than the left. The findings confirm the anterior and right-sided sympathetic dominance of the insula. Although sex differences were prominent in response magnitude, organization differences between males and females were limited to the right anterior-most gyrus, which showed a lower fMRI response in females vs. males (and vs. other gyri in females). The sex differences suggest a possible differing baseline state of brain physiology or tonic functional activity between females and males, especially in the right anterior-most gyrus.

Concurrent relations among cigarette smoking status, resting heart rate variability, and erectile response.

PubMed

Harte, Christopher B

2014-05-01

Heart rate variability (HRV) is a marker of sympathovagal balance; it has been implicated in erectile function and is also altered by tobacco use. Furthermore, smoking and erectile health are strongly related, given that smokers are at increased risk for erectile dysfunction. Few studies have explored the interrelationships between smoking, HRV, and erectile function concurrently. The aim of this study was to examine potential mechanisms underlying tobacco's effects on penile hemodynamics by exploring the mediating role of HRV. The sample comprised 119 men (smokers = 64; nonsmokers = 55) (mean age 28.90 years; standard deviation (SD) 11.68; range 18-58) selected from the control conditions of three previously published experiments. Participants were free from a history of cardiovascular disease, myocardial infarct, and/or cardiac/cardiovascular medication use. During a laboratory visit, self-report, anthropometric, cardiovascular, and electrocardiographic data were assessed, as well as sexual arousal responses elicited from viewing an erotic film. Objective sexual arousal indices (circumferential change via penile plethysmography), self-reported erectile function (per the erectile function domain score of the International Index of Erectile Function [IIEF-EF]), and time- (SD of beat-to-beat intervals) and frequency-domain parameters of HRV (ratio of low-frequency [LF] power to high-frequency [HF] power [LF/HF ratio]) were assessed. Being a current long-term cigarette smoker was associated with dysregulated sympathovagal balance (higher LF/HF ratios, indicative of sympathetic nervous system dominance), which in turn showed inverse relations with magnitude of erectile tumescence. HRV did not mediate relations between tobacco use and either IIEF-EF scores or resting penile circumference. Findings suggest that dysfunctional cardiac autonomic tone may be an underlying mechanism by which tobacco exerts its deleterious effects on erectile health. Further research is necessary to determine whether this relationship is mechanistic in nature, or whether it is better explained by other health factors. © 2014 International Society for Sexual Medicine.

TRPA1 mediates changes in heart rate variability and cardiac ...

EPA Pesticide Factsheets

Short-term exposure to ambient air pollution is linked with adverse cardiovascular effects. While previous research focused primarily on particulate matter-induced responses, gaseous air pollutants also contribute to cause short-term cardiovascular effects. Mechanisms underlying such effects have not been adequately described; however, the immediate nature of the response suggests involvement of irritant neural activation and downstream autonomic dysfunction. Thus, this study examines the role of TRPA1, an irritant sensory receptor found in the airways, in the cardiac response of mice to acrolein and ozone. Conscious unrestrained wild-type C57BL/6 (WT) and TRPA1 knockout (KO) mice implanted with radiotelemeters were exposed once to 3ppm acrolein, 0.3ppm ozone, or filtered air. Heart rate (HR) and electrocardiogram (ECG) were recorded continuously before, during and after exposure. Analysis of ECG morphology, incidence of arrhythmia and heart rate variability (HRV) were performed. Cardiac mechanical function was assessed using a Langendorff perfusion preparation 24h post-exposure. Acrolein exposure increased HRV independent of HR, as well as incidence of arrhythmia. Acrolein also increased left ventricular developed pressure in WT mice at 24h post-exposure. Ozone did not produce any changes in cardiac function. Neither gas produced ECG effects, changes in HRV, arrhythmogenesis, or mechanical function in KO mice. These data demonstrate that a single exposure to ac

Early life persistent vitamin D deficiency exacerbates ...

EPA Pesticide Factsheets

Epidemiological and animal data have conclusively linked adverse cardiovascular outcomes to air pollution exposure. As such, cardiovascular function is maintained by adequate levels of certain essential micronutrients like vitamin D. Unfortunately, vitamin D deficiency (VDD) has become highly prevalent in the United States, as well as in the world, even affecting otherwise healthy individuals. My initial studies showed that VDD alters cardiac function, increases cardiac arrhythmia and HRV (i.e. indirect measure of autonomic tone) in mice; this response is further exacerbated after smog exposure. VDD has been shown to alter the responsiveness of transient receptor potential A1 (TRPA1) channels, which we have previously shown to be involved in cardiopulmonary dysfunction to acrolein, which is a ubiquitous air pollutant and potent TRPA1 agonist. The effect of VDD on TRPA1-induced air pollution responses is not known and is the purpose of this study. 3-week old mice were placed on a VDD or normal diet (ND) for 19 weeks and then implanted with radiotelemeters for the measurement of heart rate, electrocardiogram and HRV. Mice were exposed to filtered air then acrolein for 3 hours each on separate days. During exposure, ventilatory function and ECG were simultaneously recorded. Acrolein increased parasympathetic tone in ND mice, but not VDD mice during exposure. However, acrolein caused cardiac arrhythmias only in VDD mice during exposure. Similar to previous studies,

Validation of Cardiovascular Parameters during NASA's Functional Task Test

NASA Technical Reports Server (NTRS)

Arzeno, N. M.; Stenger, M. B.; Bloomberg, J. J.; Platts, S. H.

2009-01-01

Microgravity exposure causes physiological deconditioning and impairs crewmember task performance. The Functional Task Test (FTT) is designed to correlate these physiological changes to performance in a series of operationally-relevant tasks. One of these, the Recovery from Fall/Stand Test (RFST), tests both the ability to recover from a prone position and cardiovascular responses to orthostasis. PURPOSE: Three minutes were chosen for the duration of this test, yet it is unknown if this is long enough to induce cardiovascular responses similar to the operational 5 min stand test. The purpose of this study was to determine the validity and reliability of heart rate variability (HRV) analysis of a 3 min stand and to examine the effect of spaceflight on these measures. METHODS: To determine the validity of using 3 vs. 5 min of standing to assess HRV, ECG was collected from 7 healthy subjects who participated in a 6 min RFST. Mean R-R interval (RR) and spectral HRV were measured in minutes 0-3 and 0-5 following the heart rate transient due to standing. Significant differences between the segments were determined by a paired t-test. To determine the reliability of the 3-min stand test, 13 healthy subjects completed 3 trials of the FTT on separate days, including the RFST with a 3 min stand. Analysis of variance (ANOVA) was performed on the HRV measures. One crewmember completed the FTT before a 14-day mission, on landing day (R+0) and one (R+1) day after returning to Earth. RESULTS VALIDITY: HRV measures reflecting autonomic activity were not significantly different during the 0-3 and 0-5 min segments. RELIABILITY: The average coefficient of variation for RR, systolic (SBP) and diastolic blood pressures during the RFST were less than 8% for the 3 sessions. ANOVA results yielded a greater inter-subject variability (p<0.006) than inter-session variability (p>0.05) for HRV in the RFST. SPACEFLIGHT: Lower RR and higher SBP were observed on R+0 in rest and stand. On R+1, both RR and SBP trended towards preflight rest and stand values. Postflight HRV showed higher LF/HF for rest and stand and lower HFnu during rest. CONCLUSION: These studies show that a 3 min stand delivers repeatable HRV data in the context of this larger series of FTT tests. Spaceflight-induced changes in blood pressure, RR and autonomic function (HRV) are evident from the RFST.

Measuring Cardiac Autonomic Nervous System (ANS) Activity in Toddlers - Resting and Developmental Challenges.

PubMed

Bush, Nicole R; Caron, Zoe K; Blackburn, Katherine S; Alkon, Abbey

2016-02-25

The autonomic nervous system (ANS) consists of two branches, the parasympathetic and sympathetic nervous systems, and controls the function of internal organs (e.g., heart rate, respiration, digestion) and responds to everyday and adverse experiences (1). ANS measures in children have been found to be related to behavior problems, emotion regulation, and health (2-7). Therefore, understanding the factors that affect ANS development during early childhood is important. Both branches of the ANS affect young children's cardiovascular responses to stimuli and have been measured noninvasively, via external monitoring equipment, using valid and reliable measures of physiological change (8-11). However, there are few studies of very young children with simultaneous measures of the parasympathetic and sympathetic nervous systems, which limits understanding of the integrated functioning of the two systems. In addition, the majority of existing studies of young children report on infants' resting ANS measures or their reactivity to commonly used mother-child interaction paradigms, and less is known about ANS reactivity to other challenging conditions. We present a study design and standardized protocol for a non-invasive and rapid assessment of cardiac autonomic control in 18 month old children. We describe methods for continuous monitoring of the parasympathetic and sympathetic branches of the ANS under resting and challenge conditions during a home or laboratory visit and provide descriptive findings from our sample of 140 ethnically diverse toddlers using validated equipment and scoring software. Results revealed that this protocol can produce a range of physiological responses to both resting and developmentally challenging conditions, as indicated by changes in heart rate and indices of parasympathetic and sympathetic activity. Individuals demonstrated variability in resting levels, responses to challenges, and challenge reactivity, which provides additional evidence that this protocol is useful for the examination of ANS individual differences for toddlers.

Recovery of the cardiac autonomic nervous and vascular system after maximal cardiopulmonary exercise testing in recreational athletes.

PubMed

Weberruss, Heidi; Maucher, Johannes; Oberhoffer, Renate; Müller, Jan

2018-01-01

The body's adaptation to physical exercise is modulated by sympathetic and parasympathetic (vagal) branches of the autonomic nervous system (ANS). Heart rate variability (HRV), the beat-to-beat variation of the heart, is a proxy measure for ANS activity, whereas blood pressure (BP) is an indicator for cardiovascular function. Impaired vagal activity and lower BP is already described after exercise. However, inconsistent results exist about how long vagal recovery takes and how long post-exercise hypotension persists. Therefore, the aim of this study was to assess HRV and BP 1 h after maximal cardiopulmonary exercise testing (CPET). HRV (Polar RS800CX), peripheral and central BP (Mobil-O-Graph ® ) were prospectively studied in 107 healthy volunteers (47 female, median age 29.0 years) in supine position, before and 60 min after maximal CPET. One hour after terminating CPET measures of HRV were still impaired and post-exercise BP was significantly reduced suggesting an improved vascular function compared to pre levels. HRV parameters post-exercise were 34.7% (RMSSD), 67.2% (pNN50), 57.2% (HF), and 42.7% (LF) lower compared to pre-exercise levels (for all p < 0.001). Median reduction in BP was 5 mmHg for systolic BP (p < 0.001), and 4 mmHg for diastolic BP (p = 0.016) and central systolic post-exercise (p = 0.005). One hour after terminating strenuous exercise, autonomic nervous regulation seems to be postponed which is reflected in reduced HRV, whereas the early recovery of the vasculature, post-exercise hypotension, is still preserved over the recovery period of 1 h.

Autonomic nervous system function assessed by conventional and spectral analysis might be useful in terms of predicting retinal deterioration in persons with type 1 diabetes mellitus.

PubMed

Duvnjak, L; Tomić, M; Blaslov, K; Vučković Rebrina, S

2016-06-01

To determine whether cardiac autonomic dysfunction represents a risk factor for diabetic retinopathy (DR) development and progression in persons with type 1 diabetes mellitus (T1DM). The study comprised 154 normoalbuminuric persons with T1DM divided into two groups according to the DR presence: with and without DR. Cardiovascular autonomic functioning was measured at baseline using conventional and spectral analysis. Participants were re-examined for the DR presence 18months after. The group with DR had longer disease duration compared to the group without DR (20 vrs 11.5years, p<0.001), heart rate coefficient of variation (HRV-CV) at rest and during deep breathing were lower in participants with DR (p=0.001 and 0.004), as well did spectral indices of HRV: low frequency (LF) band, high frequency (HF) band (p=0.003 and 0.022) while LF/HF ratio indicating sympathovagal balance was higher (p=0.037). No difference in glycaemic control or blood pressure value were observed. Twenty-one (13.36%) participants developed non proliferative DR or progressed to proliferative DR. Cox proportional regression showed that the 18months risk from retinal deterioration was reduced by 33.4% by each increase in the HRV-CV of 1%, 12.7% for the same HRV-CV increase during deep breathing while LF band of 1ms(2) results in 8.6% risk reduction. This study provides evidence that DR should not be considered merely a metabolic control manifestation and that HRV-CV as well as spectral indices of HRV might serve as a practical tool to identify a subgroup of T1DM patients with higher risk of retinal deterioration. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Circadian blood pressure variability in type 1 diabetes subjects and their nondiabetic siblings - influence of erythrocyte electron transfer.

PubMed

Matteucci, Elena; Consani, Cristina; Masoni, Maria Chiara; Giampietro, Ottavio

2010-10-05

Normotensive non-diabetic relatives of type 1 diabetes (T1D) patients have an abnormal blood pressure response to exercise testing that is associated with indices of metabolic syndrome and increased oxidative stress. The primary aim of this study was to investigate the circadian variability of blood pressure and the ambulatory arterial stiffness index (AASI) in healthy siblings of T1D patients vs healthy control subjects who had no first-degree relative with T1D. Secondary aims of the study were to explore the influence of both cardiovascular autonomic function and erythrocyte electron transfer activity as oxidative marker on the ambulatory blood pressure profile. Twenty-four hour ambulatory blood pressure monitoring (ABPM) was undertaken in 25 controls, 20 T1D patients and 20 siblings. In addition to laboratory examination (including homeostasis model assessment of insulin sensitivity) and clinical testing of autonomic function, we measured the rate of oxidant-induced erythrocyte electron transfer to extracellular ferricyanide (RBC vfcy). Systolic blood pressure (SBP) midline-estimating statistic of rhythm and pulse pressure were higher in T1D patients and correlated positively with diabetes duration and RBC vfcy; autonomic dysfunction was associated with diastolic BP ecphasia and increased AASI. Siblings had higher BMI, lower insulin sensitivity, larger SBP amplitude, and higher AASI than controls. Daytime SBP was positively, independently associated with BMI and RBC vfcy. Among non-diabetic people, there was a significant correlation between AASI and fasting plasma glucose. Siblings of T1D patients exhibited a cluster of sub-clinical metabolic abnormalities associated with consensual perturbations in BP variability. Moreover, our findings support, in a clinical setting, the proposed role of transplasma membrane electron transport systems in vascular pathobiology.

Independent validation of the scales for outcomes in Parkinson's disease-autonomic (SCOPA-AUT).

PubMed

Rodriguez-Blazquez, C; Forjaz, M J; Frades-Payo, B; de Pedro-Cuesta, J; Martinez-Martin, P

2010-02-01

Autonomic dysfunction is common in Parkinson's disease (PD) and causes a great impact in health-related quality of life (HRQL) and functional status of patients. This study is the first independent validation of the Scales for Outcomes in PD-Autonomic (SCOPA-AUT). In an observational, cross-sectional study (ELEP Study), 387 PD patients were assessed using, in addition to the SCOPA-AUT, the Hoehn and Yahr staging, SCOPA-Motor, SCOPA-Cognition, Cumulative Illness Rating Scale-Geriatrics, modified Parkinson Psychosis Rating Scale, Clinical Impression of Severity Index for PD, Hospital Anxiety and Depression Scale, SCOPA-Sleep, SCOPA-Psychosocial, pain and fatigue visual analogue scales, and EQ-5D. SCOPA-AUT acceptability, internal consistency, construct validity, and precision were explored. Data quality was satisfactory (97%). SCOPA-AUT total score did not show floor or ceiling effect, and skewness was 0.40. Cronbach's alpha coefficients ranged from 0.64 (Cardiovascular and Thermorregulatory subscales) to 0.95 (Sexual dysfunction, women). Item homogeneity index was low (0.24) for Gastrointestinal subscale. Factor analysis identified eight factors for men (68% of the variance) and seven factors for women (65% of the variance). SCOPA-AUT correlated at a high level with specific HRQL and functional measures (r(S) = 0.52-0.56). SCOPA-AUT scores were higher for older patients, for more advanced disease, and for patients treated only with levodopa (Kruskal-Wallis test, P < 0.01). Standard error of measurement for SCOPA-AUT subscales was 0.81 (sexual, men) - 2.26 (gastrointestinal). Despite its heterogeneous content, which determines some weaknesses in the psychometric attributes of its subscales, SCOPA-AUT is an acceptable, consistent, valid and precise scale.

Heart rate variability changes during stroop color and word test among genders.

PubMed

Satish, Priyanka; Muralikrishnan, Krishnan; Balasubramanian, Kabali; Shanmugapriya

2015-01-01

Stress is the reaction of the body to a change that requires physical, mental or emotional adjustments. Individual differences in stress reactivity are a potentially important risk factor for gender-specific health problems in men and women. The Autonomic regulation of the cardiovascular system is most commonly affected by stress and is assessed by means of short term heart rate variability (HRV).The present study was undertaken to investigate the difference in the cardiovascular Autonomic Nervous System response to mental stress between the genders using HRV as tool. We compared the mean RR interval, Blood pressure and indices of HRV during the StroopColor Word Test (SCWT).Twenty five male (Age 19.52±0.714, BMI 22.73±2 kg/m2) and twenty five female subjects (Age 19.80±0.65, BMI 22.39±1.9) performed SCWT for five minutes. Blood Pressure (SBP p<0.01, DBP p<0.042) & Mean HR (p<0.010) values showed statistically significant difference among the genders. HRV indices like LFms2 (p<0.051), HF nu (p<0.029) and LF/HF ratio (p<0.025, p<0.052) show statistically significant difference among the genders. The response by the cardiovascular system to a simple mental stressor exhibits difference among the genders.

Subfornical organ neurons integrate cardiovascular and metabolic signals.

PubMed

Cancelliere, Nicole M; Ferguson, Alastair V

2017-02-01

The subfornical organ (SFO) is a critical circumventricular organ involved in the control of cardiovascular and metabolic homeostasis. Despite the plethora of circulating signals continuously sensed by the SFO, studies investigating how these signals are integrated are lacking. In this study, we use patch-clamp techniques to investigate how the traditionally classified "cardiovascular" hormone ANG II, "metabolic" hormone CCK and "metabolic" signal glucose interact and are integrated in the SFO. Sequential bath application of CCK (10 nM) and ANG (10 nM) onto dissociated SFO neurons revealed that 63% of responsive SFO neurons depolarized to both CCK and ANG; 25% depolarized to ANG only; and 12% hyperpolarized to CCK only. We next investigated the effects of glucose by incubating and recording neurons in either hypoglycemic, normoglycemic, or hyperglycemic conditions and comparing the proportions of responses to ANG ( n = 55) or CCK ( n = 83) application in each condition. A hyperglycemic environment was associated with a larger proportion of depolarizing responses to ANG ( χ 2 , P < 0.05), and a smaller proportion of depolarizing responses along with a larger proportion of hyperpolarizing responses to CCK ( χ 2 , P < 0.01). Our data demonstrate that SFO neurons excited by CCK are also excited by ANG and that glucose environment affects the responsiveness of neurons to both of these hormones, highlighting the ability of SFO neurons to integrate multiple metabolic and cardiovascular signals. These findings have important implications for this structure's role in the control of various autonomic functions during hyperglycemia. Copyright © 2017 the American Physiological Society.

Role of oxidative stress in cardiovascular disease outcomes following exposure to ambient air pollution.

PubMed

Kelly, Frank J; Fussell, Julia C

2017-09-01

Exposure to ambient air pollution is associated with adverse cardiovascular outcomes. These are manifested through several, likely overlapping, pathways including at the functional level, endothelial dysfunction, atherosclerosis, pro-coagulation and alterations in autonomic nervous system balance and blood pressure. At numerous points within each of these pathways, there is potential for cellular oxidative imbalances to occur. The current review examines epidemiological, occupational and controlled exposure studies and research employing healthy and diseased animal models, isolated organs and cell cultures in assessing the importance of the pro-oxidant potential of air pollution in the development of cardiovascular disease outcomes. The collective body of data provides evidence that oxidative stress (OS) is not only central to eliciting specific cardiac endpoints, but is also implicated in modulating the risk of succumbing to cardiovascular disease, sensitivity to ischemia/reperfusion injury and the onset and progression of metabolic disease following ambient pollution exposure. To add to this large research effort conducted to date, further work is required to provide greater insight into areas such as (a) whether an oxidative imbalance triggers and/or worsens the effect and/or is representative of the consequence of disease progression, (b) OS pathways and cardiac outcomes caused by individual pollutants within air pollution mixtures, or as a consequence of inter-pollutant interactions and (c) potential protection provided by nutritional supplements and/or pharmacological agents with antioxidant properties, in susceptible populations residing in polluted urban cities. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

[Atmospheric pollution and cardiovascular damage].

PubMed

Román, Oscar; Prieto, María José; Mancilla, Pedro

2004-06-01

The damaging effect of atmospheric pollution with particulate matter and toxic gases on the respiratory system and its effect in the incidence and severity of respiratory diseases, is well known. A similar effect on the cardiovascular system is currently under investigation. Epidemiological studies have demonstrated that the inhalation of particulate matter can increase cardiovascular disease incidence and mortality, specially ischemic heart disease. The damage would be mediated by alterations in the autonomic nervous system, inflammation, infections and free radicals. In human studies, environmental pollution is associated with alterations in cardiac frequency variability and blood pressure and with changes in ventricular repolarization. Experimentally, an enhancement of ischemia, due to coronary obstruction, has been demonstrated. The study of the toxic effects of environmental pollution over the cardiovascular system, is an open field, specially in Chile, were the big cities have serious contamination problems.

Insular Alzheimer disease pathology and the psychometric correlates of mortality.

PubMed

Royall, Donald R

2008-03-01

Right hemisphere dysfunction is associated with mortality in Alzheimer's disease (AD) and other neurologic conditions. These associations may be mediated by insular pathology, as insular lesions result in demonstrable changes in cardiovascular and autonomic control. AD affects the insulae at a preclinical stage, and insular AD pathology may be present in up to 40% of nondemented septuagenarians and octogenarians. This pathology can affect in vivo cardiac conduction and thereby dispose to cardiac arrhythmias and sudden death. Thus, AD pathology should be considered as a possible explanation for autonomic morbidity and mortality in nondemented elderly persons.

The Phantom in our opera - or the hidden ways of the autonomic nervous system in cardiac patients

PubMed Central

van Tellingen, C.

2004-01-01

The role of the autonomic nervous system in the understanding of pathophysiological mechanisms in a variety of cardiovascular clinico-pathological conditions is highlighted from a clinician's point of view with the focus on coronary mimicry, enhanced sympathetic tone and syndrome X. A unique case is presented where sinus node dysfunction in pandysautonomia seemed to be an early sign of hypothalamic glioblastoma. In addition, relevant literature on this topic is addressed to put distinct clinical patterns into a broader perspective. ImagesFigure 1Figure 2Figure 3Figure 4Figure 5Figure 6 PMID:25696275

Comparative Electrocardiographic, Autonomic, and Systemic Inflammatory Responses to Soy Biodiesel and Petroleum Diesel Emissions in Rats

EPA Science Inventory

CONTEXT: 8iodiesel fuel represents an alternative to high particulate matter (PM)-emitting petroleum-based diesel fuels, yet uncertainty remains regarding potential biodiesel combustion emission health impacts.OBJECTIVE: The purpose of this study was to compare cardiovascular res...

Particles Alter Diesel Exhaust Gases-Induced Hypotension, Cardiac Arrhythmia,Conduction Disturbance, and Autonomic Imbalance in Heart Failure-Prone Rats

EPA Science Inventory

Epidemiologic studies indicate that acute exposures to vehicular traffic and particulate matter (PM) air pollution are key causes of fatal cardiac arrhythmia, especially in those with preexisting cardiovascular disease. Researchers point to electrophysiologic dysfunction and auto...

[Circadian blood pressure variation under several pathophysiological conditions including secondary hypertension].

PubMed

Imai, Yutaka; Hosaka, Miki; Satoh, Michihiro

2014-08-01

Abnormality of circadian blood pressure (BP) variation, i.e. non-dipper, riser, nocturnal hypertension etc, is brought by several pathophysiological conditions especially by secondary hypertension. These pathophysiological conditions are classified into several categories, i.e. disturbance of autonomic nervous system, metabolic disorder, endocrine disorder, disorder of Na and water excretion (e.g. sodium sensitivity), severe target organ damage and ischemia, cardiovascular complications and drug induced hypertension. Each pathophysiological condition which brings disturbance of circadian BP variation is included in several categories, e.g. diabetes mellitus is included in metabolic disorder, autonomic imbalance, sodium sensitivity and endocrine disorder. However, it seems that unified principle of the genesis of disturbance of circadian BP variation in many pathophysiological conditions is autonomic imbalance. Thus, it is concluded that disturbance of circadian BP variation is not purposive biological behavior but the result of autonomic imbalance which looks as if compensatory reaction such as exaggerated Na-water excretion during night in patient with Na-water retention who reveals disturbed circadian BP variation.

Autonomic responses to cold face stimulation in sickle cell disease: a time-varying model analysis.

PubMed

Chalacheva, Patjanaporn; Kato, Roberta M; Sangkatumvong, Suvimol; Detterich, Jon; Bush, Adam; Wood, John C; Meiselman, Herbert; Coates, Thomas D; Khoo, Michael C K

2015-07-14

Sickle cell disease (SCD) is characterized by sudden onset of painful vaso-occlusive crises (VOC), which occur on top of the underlying chronic blood disorder. The mechanisms that trigger VOC remain elusive, but recent work suggests that autonomic dysfunction may be an important predisposing factor. Heart-rate variability has been employed in previous studies, but the derived indices have provided only limited univariate information about autonomic cardiovascular control in SCD. To circumvent this limitation, a time-varying modeling approach was applied to investigate the functional mechanisms relating blood pressure (BP) and respiration to heart rate and peripheral vascular resistance in healthy controls, untreated SCD subjects and SCD subjects undergoing chronic transfusion therapy. Measurements of respiration, heart rate, continuous noninvasive BP and peripheral vascular resistance were made before, during and after the application of cold face stimulation (CFS), which perturbs both the parasympathetic and sympathetic nervous systems. Cardiac baroreflex sensitivity estimated from the model was found to be impaired in nontransfused SCD subjects, but partially restored in SCD subjects undergoing transfusion therapy. Respiratory-cardiac coupling gain was decreased in SCD and remained unchanged by chronic transfusion. These results are consistent with autonomic dysfunction in the form of impaired parasympathetic control and sympathetic overactivity. As well, CFS led to a significant reduction in vascular resistance baroreflex sensitivity in the nontransfused SCD subjects but not in the other groups. This blunting of the baroreflex control of peripheral vascular resistance during elevated sympathetic drive could be a potential factor contributing to the triggering of VOC in SCD. © 2015 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of the American Physiological Society and The Physiological Society.

Cardiac dysfunctions following spinal cord injury

PubMed Central

Sandu, AM; Popescu, M; Iacobini, MA; Stoian, R; Neascu, C; Popa, F

2009-01-01

The aim of this article is to analyze cardiac dysfunctions occurring after spinal cord injury (SCI). Cardiac dysfunctions are common complications following SCI. Cardiovascular disturbances are the leading causes of morbidity and mortality in both acute and chronic stages of SCI. We reviewed epidemiology of cardiac disturbances after SCI, and neuroanatomy and pathophysiology of autonomic nervous system, sympathetic and parasympathetic. SCI causes disruption of descendent pathways from central control centers to spinal sympathetic neurons, originating into intermediolateral nuclei of T1–L2 spinal cord segments. Loss of supraspinal control over sympathetic nervous system results in reduced overall sympathetic activity below the level of injury and unopposed parasympathetic outflow through intact vagal nerve. SCI associates significant cardiac dysfunction. Impairment of autonomic nervous control system, mostly in patients with cervical or high thoracic SCI, causes cardiac dysrrhythmias, especially bradycardia and, rarely, cardiac arrest, or tachyarrhytmias and hypotension. Specific complication dependent on the period of time after trauma like spinal shock and autonomic dysreflexia are also reviewed. Spinal shock occurs during the acute phase following SCI and is a transitory suspension of function and reflexes below the level of the injury. Neurogenic shock, part of spinal shock, consists of severe bradycardia and hypotension. Autonomic dysreflexia appears during the chronic phase, after spinal shock resolution, and it is a life–threatening syndrome of massive imbalanced reflex sympathetic discharge occurring in patients with SCI above the splanchnic sympathetic outflow (T5–T6). Besides all this, additional cardiac complications, such as cardiac deconditioning and coronary heart disease may also occur. Proper prophylaxis, including nonpharmacologic and pharmacological strategies and cardiac rehabilitation diminish occurrence of the cardiac dysfunction following SCI. Each type of cardiac disturbance requires specific treatment. PMID:20108532

Association of Heart Rate Variability in Taxi Drivers with Marked Changes in Particulate Air Pollution in Beijing in 2008

PubMed Central

Wu, Shaowei; Deng, Furong; Niu, Jie; Huang, Qinsheng; Liu, Youcheng; Guo, Xinbiao

2010-01-01

Background Heart rate variability (HRV), a marker of cardiac autonomic function, has been associated with particulate matter (PM) air pollution, especially in older patients and those with cardiovascular diseases. However, the effect of PM exposure on cardiac autonomic function in young, healthy adults has received less attention. Objectives We evaluated the relationship between exposure to traffic-related PM with an aerodynamic diameter ≤ 2.5 μm (PM2.5) and HRV in a highly exposed panel of taxi drivers. Methods Continuous measurements of personal exposure to PM2.5 and ambulatory electrocardiogram monitoring were conducted on 11 young healthy taxi drivers for a 12-hr work shift during their work time (0900–2100 hr) before, during, and after the Beijing 2008 Olympic Games. Mixed-effects regression models were used to estimate associations between PM2.5 exposure and percent changes in 5-min HRV indices after combining data from the three time periods and controlling for potentially confounding variables. Results Personal exposures of taxi drivers to PM2.5 changed markedly across the three time periods. The standard deviation of normal-to-normal (SDNN) intervals decreased by 2.2% [95% confidence interval (CI), −3.8% to −0.6%] with an interquartile range (IQR; 69.5 μg/m3) increase in the 30-min PM2.5 moving average, whereas the low-frequency and high-frequency powers decreased by 4.2% (95% CI, −9.0% to 0.8%) and 6.2% (95% CI, −10.7% to −1.5%), respectively, in association with an IQR increase in the 2-hr PM2.5 moving average. Conclusions Marked changes in traffic-related PM2.5 exposure were associated with altered cardiac autonomic function in young healthy adults. PMID:20056565

Cardiorespiratory responses and reduced apneic time to cold-water face immersion after high intensity exercise.

PubMed

Konstantinidou, Sylvia; Soultanakis, Helen

2016-01-01

Apnea after exercise may evoke a neurally mediated conflict that may affect apneic time and create a cardiovascular strain. The physiological responses, induced by apnea with face immersion in cold water (10 °C), after a 3-min exercise bout, at 85% of VO2max,were examined in 10 swimmers. A pre-selected 40-s apnea, completed after rest (AAR), could not be met after exercise (AAE), and was terminated with an agonal gasp reflex, and a reduction of apneic time, by 75%. Bradycardia was evident with immersion after both, 40-s of AAR and after AAE (P<0.05). The dramatic elevation of, systolic pressure and pulse pressure, after AAE, were indicative of cardiovascular stress. Blood pressure after exercise without apnea was not equally elevated. The activation of neurally opposing functions as those elicited by the diving reflex after high intensity exercise may create an autonomic conflict possibly related to oxygen-conserving reflexes stimulated by the trigeminal nerve, and those elicited by exercise. Copyright © 2015. Published by Elsevier B.V.

Utility of Autonomic Function Tests to Differentiate Dementia with Lewy Bodies and Parkinson Disease with Dementia from Alzheimer Disease.

PubMed

Toru, Shuta; Kanouchi, Tadashi; Yokota, Takanori; Yagi, Yosuke; Machida, Akira; Kobayashi, Takayoshi

2018-01-01

We studied autonomic disturbance in patients with dementia with Lewy bodies (DLB), Parkinson disease with dementia (PDD), Alzheimer disease (AD), to determine whether autonomic function tests can be used to distinguish these disorders. Autonomic function was tested in 56 patients with DLB, 37 patients with PDD, and 59 patients with AD by using the sympathetic skin response, coefficient of variation in R-R interval, the head-up tilt test, serum norepinephrine concentration, and 123I-meta-iodobenzylguanidine cardiac scintigraphy. Symptoms of autonomic dysfunction, such as constipation, urinary symptoms, and orthostatic hypotension, were also noted. The groups did not differ on baseline characteristics other than those associated with Parkinsonism and dementia. All patients with DLB and PDD had some dysautonomia, whereas rates were much lower for patients with AD (19%). Significantly more DLB and PDD patients than AD patients showed abnormalities on autonomic function tests. Autonomic function tests might be quite useful to distinguish DLB and PDD from AD. © 2017 S. Karger AG, Basel.

Pupillary Light Reflexes are Associated with Autonomic Dysfunction in Bolivian Diabetics But Not Chagas Disease Patients.

PubMed

Halperin, Anthony; Pajuelo, Monica; Tornheim, Jeffrey A; Vu, Nancy; Carnero, Andrés M; Galdos-Cardenas, Gerson; Ferrufino, Lisbeth; Camacho, Marilyn; Justiniano, Juan; Colanzi, Rony; Bowman, Natalie M; Morris, Tiffany; MacDougall, Hamish; Bern, Caryn; Moore, Steven T; Gilman, Robert H

2016-06-01

Autonomic dysfunction is common in Chagas disease and diabetes. Patients with either condition complicated by cardiac autonomic dysfunction face increased mortality, but no clinical predictors of autonomic dysfunction exist. Pupillary light reflexes (PLRs) may identify such patients early, allowing for intensified treatment. To evaluate the significance of PLRs, adults were recruited from the outpatient endocrine, cardiology, and surgical clinics at a Bolivian teaching hospital. After testing for Chagas disease and diabetes, participants completed conventional autonomic testing (CAT) evaluating their cardiovascular responses to Valsalva, deep breathing, and orthostatic changes. PLRs were measured using specially designed goggles, then CAT and PLRs were compared as measures of autonomic dysfunction. This study analyzed 163 adults, including 96 with Chagas disease, 35 patients with diabetes, and 32 controls. PLRs were not significantly different between Chagas disease patients and controls. Patients with diabetes had longer latency to onset of pupil constriction, slower maximum constriction velocities, and smaller orthostatic ratios than nonpatients with diabetes. PLRs correlated poorly with CAT results. A PLR-based clinical risk score demonstrated a 2.27-fold increased likelihood of diabetes complicated by autonomic dysfunction compared with the combination of blood tests, CAT, and PLRs (sensitivity 87.9%, specificity 61.3%). PLRs represent a promising tool for evaluating subclinical neuropathy in patients with diabetes without symptomatic autonomic dysfunction. Pupillometry does not have a role in the evaluation of Chagas disease patients. © The American Society of Tropical Medicine and Hygiene.

Relationship between cardiac autonomic function and cognitive function in Alzheimer's disease.

PubMed

Nonogaki, Zen; Umegaki, Hiroyuki; Makino, Taeko; Suzuki, Yusuke; Kuzuya, Masafumi

2017-01-01

Alzheimer's disease (AD) affects many central nervous structures and neurotransmitter systems. These changes affect not only cognitive function, but also cardiac autonomic function. However, the functional relationship between cardiac autonomic function and cognition in AD has not yet been investigated. The objective of the present study was to evaluate the association between cardiac autonomic function measured by heart rate variability and cognitive function in AD. A total of 78 AD patients were recruited for this study. Cardiac autonomic function was evaluated using heart rate variability analysis. Multiple linear regression analysis was used to model the association between heart rate variability and cognitive function (global cognitive function, memory, executive function and processing speed), after adjustment for covariates. Global cognitive function was negatively associated with sympathetic modulation (low-to-high frequency power ratio). Memory performance was positively associated with parasympathetic modulation (high frequency power) and negatively associated with sympathetic modulation (low-to-high frequency power ratio). These associations were independent of age, sex, educational years, diabetes, hypertension and cholinesterase inhibitor use. Cognitive function, especially in the areas of memory, is associated with cardiac autonomic function in AD. Specifically, lower cognitive performance was found to be associated with significantly higher cardiac sympathetic and lower parasympathetic function in AD. Geriatr Gerontol Int 2017; 17: 92-98. © 2015 Japan Geriatrics Society.

76 FR 82310 - Cardiovascular and Renal Drugs Advisory Committee; Notice of Meeting

Federal Register 2010, 2011, 2012, 2013, 2014

2011-12-30

... (Parkinson's Disease, Multiple System Atrophy, and Pure Autonomic Failure), Dopamine Beta-Hydroxylase... recommendations to the Agency on FDA's regulatory issues. Date and Time: The meeting will be held on February 23... Colesville Rd., Silver Spring, MD 20910. The hotel's telephone number is (301) 589-5200. Contact Person...

Syncope: what is the trigger?

PubMed

Hainsworth, R

2003-02-01

Although a syncopal attack is frequently preceded by prodromal symptoms, sometimes the onset can be so abrupt that there is no warning at all. The switch in autonomic responses responsible for such an attack is quite rapid and dramatic, but the trigger for this remains one of the unresolved mysteries in cardiovascular physiology.

Tolerance to Central Hypovolemia: The Influence of Oscillations in Arterial Pressure and Cerebral Blood Velocity

DTIC Science & Technology

2011-10-01

specific details about whether they were taking oral contraceptive medications, both of which can impact cardiovascular responses to hypovo- lemia (4, 20...Gerontology 49: 279–286, 2003. 59. Stewart JM. Autonomic nervous system dysfunction in adolescents with postural orthostatic tachycardia syndrome and

The Beauty and the Beast: Aspects of the Autonomic Nervous System.

PubMed

Corti, Roberto; Binggeli, Christian; Sudano, Isabella; Spieker, Lukas E.; Wenzel, René R.; Lüscher, Thomas F.; Noll, Georg

2000-06-01

Sympathetic nerve activity is altered and is a prognostic factor for many cardiovascular diseases such as hypertension, coronary syndromes, and congestive heart failure. Therefore, the selection of vasoactive drugs for the treatment of these diseases should also take into consideration their effects on the sympathetic nervous system.

Overt and Latent Cardiac Effects of Ozone Inhalation in Rats: Evidence for Autonomic Modulation and Increased Myocardial Vulnerability*

EPA Science Inventory

Ozone (O3) is a well-documented respiratory oxidant, but increasing epidemiologic evidence points to extra-pulmonary effects including positive associations between ambient O3 concentrations and cardiovascular morbidity/mortality. With preliminary reports linking O3 exposure wit...

Particulate inhalation in rats causes concentration-dependent electrocardiographic, autonomic, and cardiac microRNA expression changes

EPA Science Inventory

Recently, investigators in key epidemiologic studies have demonstrated associations between fine particulate matter (PM)-associated metals and increased hospital admissions (Ni and V; Bell et al. 2009) and cardiovascular mortality (Ni and Fe; Ostro et a1. 2007). Residual oil fly ...

Electrocardiographic and autonomic effects of acute particulate matter (PM) exposure in a rat model of cardiomyopathy

EPA Science Inventory

Human exposure to ambient PM from fossil-fuel emissions is linked to cardiovascular disease and death. This association strengthens in people with preexisting cardiac disease--especially heart failure (HF). Cardiomyopathy is the most common cause of heart failure. The mechanisms ...

The prognostic value of heart rate variability in the elderly, changing the perspective: from sympathovagal balance to chaos theory.

PubMed

Nicolini, Paola; Ciulla, Michele M; De Asmundis, Carlo; Magrini, Fabio; Brugada, Pedro

2012-05-01

Heart rate variability (HRV) is the temporal beat-to-beat variation in successive RR intervals on an electrocardiographic (ECG) recording and it reflects the regulation of the heart rate (HR) by the autonomic nervous system (ANS). HRV analysis is a noninvasive tool for the assessment of autonomic function that gained momentum in the late 1980s when its clinical relevance as a predictor of mortality was established by a milestone study by Kleiger et al. in patients with postacute myocardial infarction. In the last few decades, the increasing availability of commercial ECG devices offering HRV analysis has made HRV a favorite marker for risk stratification in the setting of cardiovascular disease. The rapid aging of the world population and the growing popularity of HRV have also fueled interest for the prognostic value of HRV in the elderly, outside a specific cardiological context. However, the discussion of HRV measures in the elderly is still very much centered on the rather reductionistic model of sympathovagal balance, with the orthosympathetic and parasympathetic limbs of the ANS exercising opposing effects on the heart via autonomic tone. The expanding application of nonlinear dynamics to medicine has brought to the forefront the notion of system complexity, embedded in the mathematical concepts of chaos theory and fractals, and provides an opportunity to suggest a broader interpretation for the prognostic significance of HRV, especially in the elderly. Although the use of novel indices of HRV may be hampered by practical issues, a more holistic approach to HRV may still be safeguarded if traditional time- and frequency-domain measures are viewed in terms of autonomic modulation. This review focuses on HRV in geriatric populations. It considers studies on the prognostic value of HRV in elderly subjects, discussing the potential confounding effect of erratic rhythm, and concentrates on the conceptual distinction between autonomic tone and autonomic modulation. It also briefly addresses the question of the practicality of ECG recordings and identifies a promising area for future research in the effects of common noncardioactive drugs on HRV. ©2012, The Authors. Journal compilation ©2012 Wiley Periodicals, Inc.

Assessment of cardiac sympathetic neuronal function using PET imaging.

PubMed

Bengel, Frank M; Schwaiger, Markus

2004-01-01

The autonomic nervous system plays a key role for regulation of cardiac performance, and the importance of alterations of innervation in the pathophysiology of various heart diseases has been increasingly emphasized. Nuclear imaging techniques have been established that allow for global and regional investigation of the myocardial nervous system. The guanethidine analog iodine 123 metaiodobenzylguanidine (MIBG) has been introduced for scintigraphic mapping of presynaptic sympathetic innervation and is available today for imaging on a broad clinical basis. Not much later than MIBG, positron emission tomography (PET) has also been established for characterizing the cardiac autonomic nervous system. Although PET is methodologically demanding and less widely available, it provides substantial advantages. High spatial and temporal resolution along with routinely available attenuation correction allows for detailed definition of tracer kinetics and makes noninvasive absolute quantification a reality. Furthermore, a series of different radiolabeled catecholamines, catecholamine analogs, and receptor ligands are available. Those are often more physiologic than MIBG and well understood with regard to their tracer physiologic properties. PET imaging of sympathetic neuronal function has been successfully applied to gain mechanistic insights into myocardial biology and pathology. Available tracers allow dissection of processes of presynaptic and postsynaptic innervation contributing to cardiovascular disease. This review summarizes characteristics of currently available PET tracers for cardiac neuroimaging along with the major findings derived from their application in health and disease.

Endocrine and Hypertensive Disorders of Potassium Regulation: Primary Aldosteronism

PubMed Central

Weiner, I. David

2013-01-01

The identification that primary aldosteronism is a common cause of resistant hypertension is a significant advance in our ability to care for patients with hypertension. Primary aldosteronism is common, and when unrecognized is associated with increased incidence of adverse cardiovascular outcomes. Identification of primary aldosteronism is based upon use of the plasma aldosterone level, plasma renin activity and the aldosterone:renin ratio (ARR). Differentiation between unilateral and bilateral autonomous adrenal aldosterone production then guides further therapy, with use of mineralocorticoid receptor blockers for those with bilateral autonomous adrenal aldosterone production and laparoscopic adrenalectomy for those with unilateral autonomous aldosterone production. In this review, we discuss in detail the pathogenesis of primary aldosteronism-induced hypertension and potassium disorders, the evaluation of the patient with suspected primary aldosteronism and the management of primary aldosteronism, both through medications and through surgery. PMID:23953804

Stress management at the worksite: reversal of symptoms profile and cardiovascular dysregulation.

PubMed

Lucini, Daniela; Riva, Silvano; Pizzinelli, Paolo; Pagani, Massimo

2007-02-01

Work stress may increase cardiovascular risk either indirectly, by inducing unhealthy life styles, or directly, by affecting the autonomic nervous system and arterial pressure. We hypothesized that, before any apparent sign of disease, work-related stress is already accompanied by alterations of RR variability profile and that a simple onsite stress management program based on cognitive restructuring and relaxation training could reduce the level of stress symptoms, revert stress-related autonomic nervous system dysregulation, and lower arterial pressure. We compared 91 white-collar workers, enrolled at a time of work downsizing (hence, in a stress condition), with 79 healthy control subjects. Psychological profiles were assessed by questionnaires and autonomic nervous system regulation by spectral analysis of RR variability. We also tested a simple onsite stress management program (cognitive restructuring and relaxation training) in a subgroup of workers compared with a sham subgroup (sham program). Workers presented an elevated level of stress-related symptoms and an altered variability profile as compared with control subjects (low-frequency component of RR variability was, respectively, 65.2+/-2 versus 55.3+/-2 normalized units; P<0.001; opposite changes were observed for the high-frequency component). These alterations were largely reverted (low-frequency component of RR variability from 63.6+/-3.9 to 49.3+/-3 normalized units; P<0.001) by the stress management program, which also slightly lowered systolic arterial pressure. No changes were observed in the sham program group. This noninvasive study indicates that work stress is associated with unpleasant symptoms and with an altered autonomic profile and suggests that a stress management program could be implemented at the worksite, with possible preventive advantages for hypertension.

Autonomic Dysfunction Predicts Clinical Outcomes After Acute Ischemic Stroke: A Prospective Observational Study.

PubMed

Xiong, Li; Tian, Ge; Leung, Howan; Soo, Yannie O Y; Chen, Xiangyan; Ip, Vincent H L; Mok, Vincent C T; Chu, Winnie C W; Wong, Ka Sing; Leung, Thomas W H

2018-01-01

Central autonomic dysfunction increases stroke morbidity and mortality. We aimed to investigate whether poststroke autonomic dysfunction graded by Ewing battery can predict clinical outcome. In this prospective observational study, we assessed autonomic function of ischemic stroke patients within 7 days from symptom onset by Ewing battery. On the basis of the magnitude of autonomic dysfunction, we stratified patients into significant (definite, severe, or atypical) or minor (normal or early) autonomic function impairment groups and correlated the impairment with the 3-month modified Rankin Scale score (good outcome: modified Rankin Scale score 0≈2; poor outcome: modified Rankin Scale score 3≈6). Among the 150 patients enrolled (mean age, 66.4±9.9 years; 70.7% males), minor autonomic dysfunction was identified in 36 patients (24.0%), and significant autonomic dysfunction was identified in 114 patients (76.0%) based on Ewing battery. In 3 months, a poor functional outcome was found in 32.5% of significant group patients compared with 13.9% in the minor group ( P =0.031). Crude odds ratios of the magnitude of autonomic dysfunction and 3-month unfavorable functional outcome after acute ischemic stroke were 2.979 (95% confidence interval, 1.071-8.284; P =0.036). After adjusting for confounding variables with statistical significance between the 2 functional outcome subgroups identified in univariate analysis (including sex and National Institutes of Health Stroke Scale score on admission), the magnitude of autonomic dysfunction still independently predicted an unfavorable outcome, with an odds ratio of 3.263 (95% confidence interval, 1.141-9.335; P =0.027). Autonomic dysfunction gauged by Ewing battery predicts poor functional outcome after acute ischemic stroke. © 2017 American Heart Association, Inc.

The immediate and short-term chemosensory impacts of coffee and caffeine on cardiovascular activity.

PubMed

McMullen, Michael K; Whitehouse, Julie M; Shine, Gillian; Whitton, Peter A; Towell, Anthony

2011-09-01

The immediate and short-term chemosensory impacts of coffee and caffeine on cardiovascular activity. Caffeine is detected by 5 of the 25 gustatory bitter taste receptors (hTAS2Rs) as well as by intestinal STC-1 cell lines. Thus there is a possibility that caffeine may elicit reflex autonomic responses via chemosensory stimulation. The cardiovascular impacts of double-espresso coffee, regular (130 mg caffeine) and decaffeinated, and encapsulated caffeine (134 mg) were compared with a placebo-control capsule. Measures of four post-ingestion phases were extracted from a continuous recording of cardiovascular parameters and contrasted with pre-ingestion measures. Participants (12 women) were seated in all but the last phase when they were standing. Both coffees increased heart rate immediately after ingestion by decreasing both the diastolic interval and ejection time. The increases in heart rate following the ingestion of regular coffee extended for 30 min. Encapsulated caffeine decreased arterial compliance and increased diastolic pressure when present in the gut and later in the standing posture. These divergent findings indicate that during ingestion the caffeine in coffee can elicit autonomic arousal via the chemosensory stimulation of the gustatory receptors which extends for at least 30 min. In contrast, encapsulated caffeine can stimulate gastrointestinal receptors and elicit vascular responses involving digestion. Research findings on caffeine are not directly applicable to coffee and vice versa. The increase of heart rate resulting from coffee drinking is a plausible pharmacological explanation for the observation that coffee increases risk for coronary heart disease in the hour after ingestion. This journal is © The Royal Society of Chemistry 2011

Passive hind-limb cycling improves cardiac function and reduces cardiovascular disease risk in experimental spinal cord injury

PubMed Central

West, Christopher R; Crawford, Mark A; Poormasjedi-Meibod, Malihe-Sadat; Currie, Katharine D; Fallavollita, Andre; Yuen, Violet; McNeill, John H; Krassioukov, Andrei V

2014-01-01

Spinal cord injury (SCI) causes altered autonomic control and severe physical deconditioning that converge to drive maladaptive cardiac remodelling. We used a clinically relevant experimental model to investigate the cardio-metabolic responses to SCI and to establish whether passive hind-limb cycling elicits a cardio-protective effect. Initially, 21 male Wistar rats were evenly assigned to three groups: uninjured control (CON), T3 complete SCI (SCI) or T3 complete SCI plus passive hind-limb cycling (SCI-EX; 2 × 30 min day−1, 5 days week−1 for 4 weeks beginning 6 days post-SCI). On day 32, cardio-metabolic function was assessed using in vivo echocardiography, ex vivo working heart assessments, cardiac histology/molecular biology and blood lipid profiles. Twelve additional rats (n = 6 SCI and n = 6 SCI-EX) underwent in vivo echocardiography and basal haemodynamic assessments pre-SCI and at days 7, 14 and 32 post-SCI to track temporal cardiovascular changes. Compared with CON, SCI exhibited a rapid and sustained reduction in left ventricular dimensions and function that ultimately manifested as reduced contractility, increased myocardial collagen deposition and an up-regulation of transforming growth factor beta-1 (TGFβ1) and mothers against decapentaplegic homolog 3 (Smad3) mRNA. For SCI-EX, the initial reduction in left ventricular dimensions and function at day 7 post-SCI was completely reversed by day 32 post-SCI, and there were no differences in myocardial contractility between SCI-EX and CON. Collagen deposition was similar between SCI-EX and CON. TGFβ1 and Smad3 were down-regulated in SCI-EX. Blood lipid profiles were improved in SCI-EX versus SCI. We provide compelling novel evidence that passive hind-limb cycling prevents cardiac dysfunction and reduces cardiovascular disease risk in experimental SCI. PMID:24535438

Role of inflammation in cardiopulmonary health effects of PM

DOE Office of Scientific and Technical Information (OSTI.GOV)

Donaldson, Ken; Mills, Nicholas; MacNee, William

2005-09-01

The relationship between increased exposure to PM and adverse cardiovascular effects is well documented in epidemiological studies. Inflammation in the lungs, caused by deposited particles, can be seen as a key process that could mediate adverse effects on the cardiovascular system. There are at least three potential pathways that could lead from pulmonary inflammation to adverse cardiovascular effects. Firstly, inflammation in the lung could lead to systemic inflammation, which is well known to be linked to sudden death from cardiovascular causes. Systemic inflammation can lead to destabilization by activation of inflammatory processes in atheromatous plaques. Secondly, inflammation can cause anmore » imbalance in coagulation factors that favor propagation of thrombi if thrombosis is initiated. Thirdly, inflammation could affect the autonomic nervous system activity in ways that could lead to alterations in the control of heart rhythm which could culminate in fatal dysrhythmia.« less

A tale of two mechanisms: a meta-analytic approach toward understanding the autonomic basis of cardiovascular reactivity to acute psychological stress.

PubMed

Brindle, Ryan C; Ginty, Annie T; Phillips, Anna C; Carroll, Douglas

2014-10-01

A series of meta-analyses was undertaken to determine the contributions of sympathetic and parasympathetic activation to cardiovascular stress reactivity. A literature search yielded 186 studies of sufficient quality that measured indices of sympathetic (n = 113) and/or parasympathetic activity (n = 73). A range of psychological stressors perturbed blood pressure and heart rate. There were comparable aggregate effects for sympathetic activation, as indexed by increased plasma epinephrine and norepinephrine, and shortened pre-ejection period and parasympathetic deactivation, as indexed by heart rate variability measures. Effect sizes varied with stress task, sex, and age. In contrast to alpha-adrenergic blockade, beta-blockade attenuated cardiovascular reactivity. Cardiovascular reactivity to acute psychological stress would appear to reflect both beta-adrenergic activation and vagal withdrawal to a largely equal extent. Copyright © 2014 Society for Psychophysiological Research.

Abnormal norepinephrine clearance and adrenergic receptor sensitivity in idiopathic orthostatic intolerance

NASA Technical Reports Server (NTRS)

Jacob, G.; Shannon, J. R.; Costa, F.; Furlan, R.; Biaggioni, I.; Mosqueda-Garcia, R.; Robertson, R. M.; Robertson, D.

1999-01-01

BACKGROUND: Chronic orthostatic intolerance (OI) is characterized by symptoms of inadequate cerebral perfusion with standing, in the absence of significant orthostatic hypotension. A heart rate increase of >/=30 bpm is typical. Possible underlying pathophysiologies include hypovolemia, partial dysautonomia, or a primary hyperadrenergic state. We tested the hypothesis that patients with OI have functional abnormalities in autonomic neurons regulating cardiovascular responses. METHODS AND RESULTS: Thirteen patients with chronic OI and 10 control subjects underwent a battery of autonomic tests. Systemic norepinephrine (NE) kinetics were determined with the patients supine and standing before and after tyramine administration. In addition, baroreflex sensitivity, hemodynamic responses to bolus injections of adrenergic agonists, and intrinsic heart rate were determined. Resting supine NE spillover and clearance were similar in both groups. With standing, patients had a greater decrease in NE clearance than control subjects (55+/-5% versus 30+/-7%, P<0.02). After tyramine, NE spillover did not change significantly in patients but increased 50+/-10% in control subjects (P<0.001). The dose of isoproterenol required to increase heart rate 25 bpm was lower in patients than in control subjects (0.5+/-0.05 versus 1.0+/-0.1 microg, P<0.005), and the dose of phenylephrine required to increase systolic blood pressure 25 mm Hg was lower in patients than control subjects (105+/-11 versus 210+/-12 microg, P<0.001). Baroreflex sensitivity was lower in patients (12+/-1 versus 18+/-2 ms/mm Hg, P<0.02), but the intrinsic heart rate was similar in both groups. CONCLUSIONS: The decreased NE clearance with standing, resistance to the NE-releasing effect of tyramine, and increased sensitivity to adrenergic agonists demonstrate dramatically disordered sympathetic cardiovascular regulation in patients with chronic OI.

Autonomic modulation of arterial pressure and heart rate variability in hypertensive diabetic rats.

PubMed

Farah, Vera de Moura Azevedo; De Angelis, Kátia; Joaquim, Luis Fernando; Candido, Georgia O; Bernardes, Nathalia; Fazan, Rubens; Schaan, Beatriz D'Agord; Irigoyen, Maria-Claudia

2007-08-01

The aim of the present study was to evaluate the autonomic modulation of the cardiovascular system in streptozotocin (STZ)-induced diabetic spontaneously hypertensive rats (SHR), evaluating baroreflex sensitivity and arterial pressure and heart rate variability. Male SHR were divided in control (SHR) and diabetic (SHR+DM, 5 days after STZ) groups. Arterial pressure (AP) and baroreflex sensitivity (evaluated by tachycardic and bradycardic responses to changes in AP) were monitored. Autoregressive spectral estimation was performed for systolic AP (SAP) and pulse interval (PI) with oscillatory components quantified as low (LF:0.2-0.6Hz) and high (HF:0.6-3.0Hz) frequency ranges. Mean AP and heart rate in SHR+DM (131+/-3 mmHg and 276+/-6 bpm) were lower than in SHR (160+/-7 mmHg and 330+/-8 bpm). Baroreflex bradycardia was lower in SHR+DM as compared to SHR (0.55+/-0.1 vs. 0.97+/-0.1 bpm/mmHg). Overall SAP variability in the time domain (standard deviation of beat-by-beat time series of SAP) was lower in SHR+DM (3.1+/-0.2 mmHg) than in SHR (5.7+/-0.6 mmHg). The standard deviation of the PI was similar between groups. Diabetes reduced the LF of SAP (3.3+/-0.8 vs. 28.7+/-7.6 mmHg2 in SHR), while HF of SAP were unchanged. The power of oscillatory components of PI did not differ between groups. These results show that the association of hypertension and diabetes causes an impairment of the peripheral cardiovascular sympathetic modulation that could be, at least in part, responsible for the reduction in AP levels. Moreover, this study demonstrates that diabetes might actually impair the reduced buffer function of the baroreceptors while reducing blood pressure.

Positron emission tomography in cardiovascular disease.

PubMed

Beanlands, R

1996-10-01

Positron emission tomography (PET) represents an advanced form of nuclear imaging technology. The use of positron emitting isotopes, such as C-11, O-15, N-13, and F-18 permit radiolabelling of naturally occurring compounds in the body or close analogues. This, combined with technical advantages of PET imaging, allow quantification of physiological processes in humans. PET has become established as the most accurate noninvasive means for the diagnosis of coronary artery disease using myocardial perfusion radiotracers, which include rubidium-82, N-13-amonia, and O-15-water. These approaches have also been applied for long term evaluation of the effects of therapy and for the quantification of myocardial bloodflow. Radiolabelling of metabolic substrates, including C-11 palmitate, C-11 acetate and F-18 flurodeoxyglucose (FDG) have permitted evaluation of myocardial metabolism. F-18 FDG PET imaging has been established as the best means for defining viable myocardium in patients with reduced ventricular function being considered for revascularization. FDG PET can also identify patients being considered for cardiac transplant, who may be candidates for revascularization. In this review, other applications for metabolic, autonomic nervous system and receptor imaging are also discussed. The availability of cardiac PET in Canada is currently limited. However, with the reducing costs of capital and more cost effectiveness data, PET may become more widely available. Cardiac PET imaging is established as a tremendous diagnostic tool for defining viable myocardium, assessment of perfusion and long term evaluation of therapy without invasive procedures. PET is also a vital research tool capable of evaluating flow, metabolism, myocardial receptors, autonomic nervous system and potentially radiolabelled drugs. Cardiac PET imaging will continue to provide important insight, expanding our understanding and treatment of patients with cardiovascular disease.

Sex and family history of cardiovascular disease influence heart rate variability during stress among healthy adults.

PubMed

Emery, Charles F; Stoney, Catherine M; Thayer, Julian F; Williams, DeWayne; Bodine, Andrew

2018-07-01

Studies of sex differences in heart rate variability (HRV) typically have not accounted for the influence of family history (FH) of cardiovascular disease (CVD). This study evaluated sex differences in HRV response to speech stress among men and women (age range 30-49 years) with and without a documented FH of CVD. Participants were 77 adults (mean age = 39.8 ± 6.2 years; range: 30-49 years; 52% female) with positive FH (FH+, n = 32) and negative FH (FH-, n = 45) of CVD, verified with relatives of participants. Cardiac activity for all participants was recorded via electrocardiogram during a standardized speech stress task with three phases: 5-minute rest, 5-minute speech, and 5-minute recovery. Outcomes included time domain and frequency domain indicators of HRV and heart rate (HR) at rest and during stress. Data were analyzed with repeated measures analysis of variance, with sex and FH as between subject variables and time/phase as a within subject variable. Women exhibited higher HR than did men and greater HR reactivity in response to the speech stress. However, women also exhibited greater HRV in both the time and frequency domains. FH+ women generally exhibited elevated HRV, despite the elevated risk of CVD associated with FH+. Although women participants exhibited higher HR at rest and during stress, women (both FH+ and FH-) also exhibited elevated HRV reactivity, reflecting greater autonomic control. Thus, enhanced autonomic function observed in prior studies of HRV among women is also evident among FH+ women during a standardized stress task. Copyright © 2018 Elsevier Inc. All rights reserved.

Post-exercise hypotension and heart rate variability response after water- and land-ergometry exercise in hypertensive patients

PubMed Central

Bocalini, Danilo Sales; Bergamin, Marco; Evangelista, Alexandre Lopes; Rica, Roberta Luksevicius; Pontes, Francisco Luciano; Figueira, Aylton; Serra, Andrey Jorge; Rossi, Emilly Martinelli; Tucci, Paulo José Ferreira

2017-01-01

Background systemic arterial hypertension is the most prevalent cardiovascular disease; physical activity for hypertensive patients is related to several beneficial cardiovascular adaptations. This paper evaluated the effect of water- and land-ergometry exercise sessions on post-exercise hypotension (PEH) of healthy normotensive subjects versus treated or untreated hypertensive patients. Methods Forty-five older women composed three experimental groups: normotensive (N, n = 10), treated hypertensive (TH, n = 15) and untreated hypertensive (UH, n = 20). The physical exercise acute session protocol was performed at 75% of maximum oxygen consumption (VO2max) for 45 minutes; systolic (SBP), diastolic (DBP) and mean (MBP) blood pressure were evaluated at rest, peak and at 15, 30, 45, 60, 75 and 90 minutes after exercise cessation. Additionally, the heart rate variability (HRV) was analyzed by R-R intervals in the frequency domain for the assessment of cardiac autonomic function. Results In both exercise modalities, equivalent increases in SBP were observed from rest to peak exercise for all groups, and during recovery, significant PEH was noted. At 90 minutes after the exercise session, the prevalence of hypotension was significantly higher in water- than in the land-based protocol. Moreover, more pronounced reductions in SBP and DBP were observed in the UH patients compared to TH and N subjects. Finally, exercise in the water was more effective in restoring HRV during recovery, with greater effects in the untreated hypertensive group. Conclusion Our data demonstrated that water-ergometry exercise was able to induce expressive PEH and improve cardiac autonomic modulation in older normotensive, hypertensive treated or hypertensive untreated subjects when compared to conventional land-ergometry. PMID:28658266

Effects of acute administration of selective serotonin reuptake inhibitors on sympathetic nerve activity

PubMed Central

Tiradentes, R.V.; Pires, J.G.P.; Silva, N.F.; Ramage, A.G.; Santuzzi, C.H.; Futuro, H.A.

2014-01-01

Serotonergic mechanisms have an important function in the central control of circulation. Here, the acute effects of three selective serotonin (5-HT) reuptake inhibitors (SSRIs) on autonomic and cardiorespiratory variables were measured in rats. Although SSRIs require 2-3 weeks to achieve their full antidepressant effects, it has been shown that they cause an immediate inhibition of 5-HT reuptake. Seventy male Wistar rats were anesthetized with urethane and instrumented to record blood pressure, heart rate, renal sympathetic nerve activity (RSNA), and respiratory frequency. At lower doses, the acute cardiovascular effects of fluoxetine, paroxetine and sertraline administered intravenously were insignificant and variable. At middle and higher doses, a general pattern was observed, with significant reductions in sympathetic nerve activity. At 10 min, fluoxetine (3 and 10 mg/kg) reduced RSNA by -33±4.7 and -31±5.4%, respectively, without changes in blood pressure; 3 and 10 mg/kg paroxetine reduced RSNA by -35±5.4 and -31±5.5%, respectively, with an increase in blood pressure +26.3±2.5; 3 mg/kg sertraline reduced RSNA by -59.4±8.6%, without changes in blood pressure. Sympathoinhibition began 5 min after injection and lasted approximately 30 min. For fluoxetine and sertraline, but not paroxetine, there was a reduction in heart rate that was nearly parallel to the sympathoinhibition. The effect of these drugs on the other variables was insignificant. In conclusion, acute peripheral administration of SSRIs caused early autonomic cardiovascular effects, particularly sympathoinhibition, as measured by RSNA. Although a peripheral action cannot be ruled out, such effects are presumably mostly central. PMID:25003632

Detection of cardiovascular autonomic neuropathy using exercise testing in patients with type 2 diabetes mellitus.

PubMed

Banthia, Smriti; Bergner, Daniel W; Chicos, Alexandru B; Ng, Jason; Pelchovitz, Daniel J; Subacius, Haris; Kadish, Alan H; Goldberger, Jeffrey J

2013-01-01

This study investigated autonomic nervous system function in subjects with diabetes during exercise and recovery. Eighteen type 2 diabetics (age 55±2 years) and twenty healthy controls (age 51±1 years) underwent two 16-min bicycle submaximal ECG stress tests followed by 45 min of recovery. During session #2, atropine (0.04 mg/kg) was administered at peak exercise, and the final two minutes of exercise and entire recovery occurred under parasympathetic blockade. Plasma catecholamines were measured throughout. Parasympathetic effect was defined as the difference between a measured parameter at baseline and after parasympathetic blockade. The parasympathetic effect on the RR interval was blunted (P=.004) in diabetic subjects during recovery. Parasympathetic effect on QT-RR slope during early recovery was diminished in the diabetes group (diabetes 0.13±0.02, control 0.21±0.02, P=.03). Subjects with diabetes had a lower heart rate recovery at 1 min (diabetes 18.5±1.9 bpm, control 27.6±1.5 bpm, P<.001). In subjects with well-controlled type 2 diabetes, even with minimal evidence of CAN using current methodology, altered cardiac autonomic balance is present and can be detected through an exercise-based assessment for CAN. The early post-exercise recovery period in diabetes was characterized by enhanced sympathoexcitation, diminished parasympathetic reactivation and delay in heart rate recovery. Copyright © 2013 Elsevier Inc. All rights reserved.

Diagnosis of multiple system atrophy.

PubMed

Palma, Jose-Alberto; Norcliffe-Kaufmann, Lucy; Kaufmann, Horacio

2018-05-01

Multiple system atrophy (MSA) may be difficult to distinguish clinically from other disorders, particularly in the early stages of the disease. An autonomic-only presentation can be indistinguishable from pure autonomic failure. Patients presenting with parkinsonism may be misdiagnosed as having Parkinson disease. Patients presenting with the cerebellar phenotype of MSA can mimic other adult-onset ataxias due to alcohol, chemotherapeutic agents, lead, lithium, and toluene, or vitamin E deficiency, as well as paraneoplastic, autoimmune, or genetic ataxias. A careful medical history and meticulous neurological examination remain the cornerstone for the accurate diagnosis of MSA. Ancillary investigations are helpful to support the diagnosis, rule out potential mimics, and define therapeutic strategies. This review summarizes diagnostic investigations useful in the differential diagnosis of patients with suspected MSA. Currently used techniques include structural and functional brain imaging, cardiac sympathetic imaging, cardiovascular autonomic testing, olfactory testing, sleep study, urological evaluation, and dysphagia and cognitive assessments. Despite advances in the diagnostic tools for MSA in recent years and the availability of consensus criteria for clinical diagnosis, the diagnostic accuracy of MSA remains sub-optimal. As other diagnostic tools emerge, including skin biopsy, retinal biomarkers, blood and cerebrospinal fluid biomarkers, and advanced genetic testing, a more accurate and earlier recognition of MSA should be possible, even in the prodromal stages. This has important implications as misdiagnosis can result in inappropriate treatment, patient and family distress, and erroneous eligibility for clinical trials of disease-modifying drugs. Copyright © 2017 Elsevier B.V. All rights reserved.

Low heart rate variability in unemployed men: The possible mediating effects of life satisfaction.

PubMed

Jandackova, V K; Jackowska, M

2015-01-01

Unemployment has consistently been associated with increased risk of cardiovascular disease and premature mortality, and impaired autonomic modulation of the heart might be one mechanism partly explaining this. This study examined whether the possible effect of unemployment on cardiac autonomic modulation is in part mediated by lower psychological well-being. The sample comprised of 15 job-seeking men aged 30-49 years matched with 15 employed men on age, type of job, smoking habits, alcohol intake, frequency of physical activity, and body mass index. Heart rate variability (HRV) during a modified orthostatic test was the measure of cardiac autonomic modulation, and life satisfaction was the measure of psychological well-being. Unemployed men had significantly lower overall HRV (p = .040) than controls. This association was partially mediated through lower general life satisfaction, and in particular, by low financial satisfaction, independently of demographic and/or behavioral factors that influence HRV. These findings suggest that seeking a job is a potential stressor that may reduce overall HRV and contribute towards disturbance of cardiac autonomic modulation in men. Financial difficulties could be one mechanism through which the effects of unemployment are translated into impaired autonomic modulation.

Neurocardiology: Structure-Based Function.

PubMed

Ardell, Jeffrey L; Armour, John Andrew

2016-09-15

Cardiac control is mediated via a series of reflex control networks involving somata in the (i) intrinsic cardiac ganglia (heart), (ii) intrathoracic extracardiac ganglia (stellate, middle cervical), (iii) superior cervical ganglia, (iv) spinal cord, (v) brainstem, and (vi) higher centers. Each of these processing centers contains afferent, efferent, and local circuit neurons, which interact locally and in an interdependent fashion with the other levels to coordinate regional cardiac electrical and mechanical indices on a beat-to-beat basis. This control system is optimized to respond to normal physiological stressors (standing, exercise, and temperature); however, it can be catastrophically disrupted by pathological events such as myocardial ischemia. In fact, it is now recognized that autonomic dysregulation is central to the evolution of heart failure and arrhythmias. Autonomic regulation therapy is an emerging modality in the management of acute and chronic cardiac pathologies. Neuromodulation-based approaches that target select nexus points of this hierarchy for cardiac control offer unique opportunities to positively affect therapeutic outcomes via improved efficacy of cardiovascular reflex control. As such, understanding the anatomical and physiological basis for such control is necessary to implement effectively novel neuromodulation therapies. © 2016 American Physiological Society. Compr Physiol 6:1635-1653, 2016. Copyright © 2016 John Wiley & Sons, Inc.

Clinical and electrophysiologic attributes as predictors of results of autonomic function tests

NASA Technical Reports Server (NTRS)

Wu, C. L.; Denq, J. C.; Harper, C. M.; O'Brien, P. C.; Low, P. A.

1998-01-01

Autonomic dysfunction is a feature of some neuropathies and not others. It has been suggested that some clinical and electrophysiologic attributes are predictable of autonomic impairment detected using laboratory testing; however, dear guidelines are unavailable. We evaluated 138 relatively unselected patients with peripheral neuropathy who underwent neurologic evaluation, electromyography (EMG), nerve conduction studies, and autonomic function tests to determine which variables were predictive of laboratory findings of autonomic failure. The variables evaluated were 1) clinical somatic neuropathic findings, 2) clinical autonomic symptoms, and 3) electrophysiologic findings. Autonomic symptoms were strongly predictive (Rs = 0.40, p < 0.001) of autonomic failure. Among the non-autonomic indices, absent ankle reflexes were mildly predictive (Rs = 0.19, p = 0.022) of autonomic impairment, but all others were not (duration, clinical pattern, severity, weakness, sensory loss). Electrophysiologic changes of an axonal neuropathy predicted autonomic impairment while demyelinating neuropathy did not. We conclude that autonomic studies will most likely be abnormal in patients who have symptoms of autonomic involvement and those who have an axonal neuropathy.

Terrain Navigation Concepts for Autonomous Vehicles,

DTIC Science & Technology

1984-06-01

AD-fi144 994 TERRAIN NAVIGATION CONCEPTS FOR AUTONOMOUS VEHICLES (U) i/i I ARMY ENGINEER OPOGRAPHIC LABS FORT BELVOIR VA R D LEIGHTY JUN 84 ETL-R@65...FUNCTIONS The pacing problem for developing autonomous vehicles that can efficiently move to designated locations in the real world in the perfor- mance...autonomous functions can serve as general terrain navigation requirements for our discussion of autonomous vehicles . LEIGHTY Can we build a vehicular system

Cardiovascular indicators of disgust.

PubMed

Rohrmann, Sonja; Hopp, Henrik

2008-06-01

A bradycardia and an increasing parasympathetic activity are often recommended as characteristic physiological disgust reactions. However, findings concerning the influence of disgust on heart rate and autonomic control are heterogenous. Apart from this, only a few studies examined cardiovascular reactions to disgust, besides heart rate. The aim of this study is a differentiated description of cardiovascular reactions going along with disgust using impedance cardiography. Moreover, it will be surveyed if different cardiovascular responses are associated with content-specific disgust-inductions. One-hundred subjects watched three films: A neutral film (screensaver), a filmclip showing an amputation of the upper extremity and a filmclip displaying a person who is vomiting. The latter films are regarded as disease- and food-related disgust stimuli respectively, representing two superior disgust domains. Subjective, electrodermal and cardiovascular reactions to these films were compared using Repeated Measures ANOVAs. Strong subjective, electrodermal and cardiovascular reactions towards the filmclips with disgusting content were observed. The cardiovascular reactions of the disease- and food-related disgust stimuli differed in subjective and physiological parameters. Thus, a decrease in heart rate could only be observed as a response to disease-related disgust-induction. The observed differences are discussed as an endorsement for a domain-specific organisation of disgust reactions.

Heart rate variability biofeedback in patients with alcohol dependence: a randomized controlled study

PubMed Central

Penzlin, Ana Isabel; Siepmann, Timo; Illigens, Ben Min-Woo; Weidner, Kerstin; Siepmann, Martin

2015-01-01

Background and objective In patients with alcohol dependence, ethyl-toxic damage of vasomotor and cardiac autonomic nerve fibers leads to autonomic imbalance with neurovascular and cardiac dysfunction, the latter resulting in reduced heart rate variability (HRV). Autonomic imbalance is linked to increased craving and cardiovascular mortality. In this study, we sought to assess the effects of HRV biofeedback training on HRV, vasomotor function, craving, and anxiety. Methods We conducted a randomized controlled study in 48 patients (14 females, ages 25–59 years) undergoing inpatient rehabilitation treatment. In the treatment group, patients (n=24) attended six sessions of HRV biofeedback over 2 weeks in addition to standard rehabilitative care, whereas, in the control group, subjects received standard care only. Psychometric testing for craving (Obsessive Compulsive Drinking Scale), anxiety (Symptom Checklist-90-Revised), HRV assessment using coefficient of variation of R-R intervals (CVNN) analysis, and vasomotor function assessment using laser Doppler flowmetry were performed at baseline, immediately after completion of treatment or control period, and 3 and 6 weeks afterward (follow-ups 1 and 2). Results Psychometric testing showed decreased craving in the biofeedback group immediately postintervention (OCDS scores: 8.6±7.9 post-biofeedback versus 13.7±11.0 baseline [mean ± standard deviation], P<0.05), whereas craving was unchanged at this time point in the control group. Anxiety was reduced at follow-ups 1 and 2 post-biofeedback, but was unchanged in the control group (P<0.05). Following biofeedback, CVNN tended to be increased (10.3%±2.8% post-biofeedback, 10.1%±3.5% follow-up 1, 10.1%±2.9% follow-up 2 versus 9.7%±3.6% baseline; P=not significant). There was no such trend in the control group. Vasomotor function assessed using the mean duration to 50% vasoconstriction of cutaneous vessels after deep inspiration was improved following biofeedback immediately postintervention and was unchanged in the control group (P<0.05). Conclusion Our data indicate that HRV biofeedback might be useful to decrease anxiety, increase HRV, and improve vasomotor function in patients with alcohol dependence when complementing standard rehabilitative inpatient care. PMID:26557753

Cardiovascular reactivity to a marital conflict version of the Trier social stress test in intimate partner violence perpetrators.

PubMed

Romero-Martínez, Angel; Nunes-Costa, Rui; Lila, Marisol; González-Bono, Esperanza; Moya-Albiol, Luis

2014-07-01

Intimate partner violence (IPV) perpetrators have been categorized into two groups based on their heart rate (HR) reactivity to stress following Gottman's studies. Overall, type I perpetrators tend to show autonomic underarousal, whereas type II or reactive perpetrators present a hyper-reactivity in anticipation of stress. In this study, changes in HR, pre-ejection period (PEP), vagal ratio as well as psychological state variables (anxiety and anger) in response to stress were assessed, comparing a group of type II IPV perpetrators (based on violence reports and psychological assessment; n = 17; mean age = 37) with non-violent controls (n = 17; mean age = 35) using modified version of the Trier Social Stress Test. IPV perpetrators had higher HRs and lower vagal ratios than controls, particularly during the recovery period. Moreover, the former presented shorter PEPs than controls. There were no differences between groups in the magnitude of response of the HR, PEP or vagal ratio. High baseline anxiety and anger were associated with an HR increase during the preparation time in IPV perpetrators but not in controls. These findings indicate a different cardiovascular pattern of response to psychosocial stress in IPV perpetrators, especially during recovery. Thus, they contribute to understanding the biological functioning of violence sub-types, supporting the validity of cardiovascular measures as diagnostic indicators for IPV classification.

Isolated heart models: cardiovascular system studies and technological advances.

PubMed

Olejnickova, Veronika; Novakova, Marie; Provaznik, Ivo

2015-07-01

Isolated heart model is a relevant tool for cardiovascular system studies. It represents a highly reproducible model for studying broad spectrum of biochemical, physiological, morphological, and pharmaceutical parameters, including analysis of intrinsic heart mechanics, metabolism, and coronary vascular response. Results obtained in this model are under no influence of other organ systems, plasma concentration of hormones or ions and influence of autonomic nervous system. The review describes various isolated heart models, the modes of heart perfusion, and advantages and limitations of various experimental setups. It reports the improvements of perfusion setup according to Langendorff introduced by the authors.

Conditions for Fully Autonomous Anticipation

NASA Astrophysics Data System (ADS)

Collier, John

2006-06-01

Anticipation allows a system to adapt to conditions that have not yet come to be, either externally to the system or internally. Autonomous systems actively control the conditions of their own existence so as to increase their overall viability. This paper will first give minimal necessary and sufficient conditions for autonomous anticipation, followed by a taxonomy of autonomous anticipation. In more complex systems, there can be semi-autonomous subsystems that can anticipate and adapt on their own. Such subsystems can be integrated into a system's overall autonomy, typically with greater efficiency due to modularity and specialization of function. However, it is also possible that semi-autonomous subsystems can act against the viability of the overall system, and have their own functions that conflict with overall system functions.

Cardiovascular risk and mortality in end-stage renal disease patients undergoing dialysis: sleep study, pulmonary function, respiratory mechanics, upper airway collapsibility, autonomic nervous activity, depression, anxiety, stress and quality of life: a prospective, double blind, randomized controlled clinical trial.

PubMed

dos Reis Santos, Israel; Danaga, Aline Roberta; de Carvalho Aguiar, Isabella; Oliveira, Ezequiel Fernandes; Dias, Ismael Souza; Urbano, Jessica Julioti; Martins, Aline Almeida; Ferraz, Leonardo Macario; Fonsêca, Nina Teixeira; Fernandes, Virgilio; Fernandes, Vinicius Alves Thomaz; Lopes, Viviane Cristina Delgado; Leitão Filho, Fernando Sérgio Studart; Nacif, Sérgio Roberto; de Carvalho, Paulo de Tarso Camillo; Sampaio, Luciana Maria Malosá; Giannasi, Lílian Christiane; Romano, Salvatore; Insalaco, Giuseppe; Araujo, Ana Karina Fachini; Dellê, Humberto; Souza, Nadia Karina Guimarães; Giannella-Neto, Daniel; Oliveira, Luis Vicente Franco

2013-10-08

Chronic kidney disease (CKD) is one of the most serious public health problems. The increasing prevalence of CKD in developed and developing countries has led to a global epidemic. The hypothesis proposed is that patients undergoing dialysis would experience a marked negative influence on physiological variables of sleep and autonomic nervous system activity, compromising quality of life. A prospective, consecutive, double blind, randomized controlled clinical trial is proposed to address the effect of dialysis on sleep, pulmonary function, respiratory mechanics, upper airway collapsibility, autonomic nervous activity, depression, anxiety, stress and quality of life in patients with CKD. The measurement protocol will include body weight (kg); height (cm); body mass index calculated as weight/height(2); circumferences (cm) of the neck, waist, and hip; heart and respiratory rates; blood pressures; Mallampati index; tonsil index; heart rate variability; maximum ventilatory pressures; negative expiratory pressure test, and polysomnography (sleep study), as well as the administration of specific questionnaires addressing sleep apnea, excessive daytime sleepiness, depression, anxiety, stress, and quality of life. CKD is a major public health problem worldwide, and its incidence has increased in part by the increased life expectancy and increasing number of cases of diabetes mellitus and hypertension. Sleep disorders are common in patients with renal insufficiency. Our hypothesis is that the weather weight gain due to volume overload observed during interdialytic period will influence the degree of collapsibility of the upper airway due to narrowing and predispose to upper airway occlusion during sleep, and to investigate the negative influences of haemodialysis in the physiological variables of sleep, and autonomic nervous system, and respiratory mechanics and thereby compromise the quality of life of patients. The protocol for this study is registered with the Brazilian Registry of Clinical Trials (ReBEC RBR-7yhr4w and World Health Organization under Universal Trial Number UTN: U1111-1127-9390 [http://www.ensaiosclinicos.gov.br/rg/RBR-7yhr4w/]).

Cardiac and Vascular Function in Bedrested Volunteers: Effects of Artificial Gravity Training

NASA Technical Reports Server (NTRS)

Meng, M.; Platts, S.; Stenger, M.; Diedrich, A.; Schlegel, T.; Natapoff, A.; Knapp, C.; Evans, J.

2007-01-01

Cardiovascular effects of an artificial gravity (AG) countermeasure on deconditioned male volunteers were studied. In two groups of men we measured cardiovascular parameters at rest and in response to 30 minutes of 80 deg. head up tilt (HUT) before, at the end of, and four days following 21 days of 6 deg. head down bed rest (HDBR). One group (N=7) underwent no countermeasure while the other (N=8) received a daily, one hour, dose (2.5 gz at the foot, decreasing to 1.0 gz at the heart) of AG training on the Johnson Space Center short radius centrifuge. Cardiovascular parameters measured included heart rate, blood pressure, stroke volume, cardiac output, peripheral vascular resistance, plasma volume shifts, and vasoactive hormones. Untrained subjects exhibited shorter tilt survival (on average 8 minutes shorter) compared to trained subjects. By the end of bed rest, mean heart rate (MHR) was elevated in both groups (both supine and during tilt). In addition, treated subjects demonstrated lower, tilt-induced, increases in MHR four days following HDBR, indicating a more rapid return to pre bed rest conditions. Results from an index of autonomic balance (percentage of MHR spectral power in the respiratory frequency range) in control of heart rate are consistent with the interpretation that parasympathetic nervous system withdrawal was responsible for both tilt- and bed rest-induced increases in MHR. Our data support our pre-study hypothesis that AG treatment would lessen cardiovascular effects of deconditioning in bed rested men and suggest that AG should be further pursued as a space flight countermeasure.

78 FR 76308 - Cardiovascular and Renal Drugs Advisory Committee; Notice of Meeting

Federal Register 2010, 2011, 2012, 2013, 2014

2013-12-17

... neurogenic orthostatic hypotension in patients with primary autonomic failure (Parkinson's disease, multiple... recommendations to the Agency on FDA's regulatory issues. Date and Time: The meeting will be held on January 14... Agency's Web site at http://www.fda.gov/AdvisoryCommittees/default.htm and scroll down to the appropriate...

Autonomic Regulation on the Stroop Predicts Reading Achievement in School Age Children

ERIC Educational Resources Information Center

Becker, Derek R.; Carrere, Sybil; Siler, Chelsea; Jones, Stephanie; Bowie, Bonnie; Cooke, Cheryl

2012-01-01

In this study we examined high frequency heart rate variability (HF-HRV, a parasympathetic index) both at rest and during challenge, to assess if variations in cardiovascular activity measured during a Stroop task could be used to predict reading achievement in typically developing children. Reading achievement was examined using the Peabody…

Psychopathic Traits and Physiological Responses to Aversive Stimuli in Children Aged 9-11 Years

ERIC Educational Resources Information Center

Wang, Pan; Baker, Laura A.; Gao, Yu; Raine, Adrian; Lozano, Dora Isabel

2012-01-01

Atypical electrodermal and cardiovascular response patterns in psychopathic individuals are thought to be biological indicators of fearless and disinhibition. This study investigated the relationship between psychopathic traits and these autonomic response patterns using a countdown task in 843 children (aged 9-10 years). Heart rate (HR) and…

Overview of the Autonomic Nervous System

MedlinePlus

... be reversible or progressive. Anatomy of the autonomic nervous system The autonomic nervous system is the part of ... organs they connect with. Function of the autonomic nervous system The autonomic nervous system controls internal body processes ...

Threat Sensitivity in Bipolar Disorder

PubMed Central

Muhtadie, Luma; Johnson, Sheri L.

2015-01-01

Life stress is a major predictor of the course of bipolar disorder. Few studies have used laboratory paradigms to examine stress reactivity in bipolar disorder, and none have assessed autonomic reactivity to laboratory stressors. In the present investigation we sought to address this gap in the literature. Participants, 27 diagnosed with bipolar I disorder and 24 controls with no history of mood disorder, were asked to complete a complex working memory task presented as “a test of general intelligence.” Self-reported emotions were assessed at baseline and after participants were given task instructions; autonomic physiology was assessed at baseline and continuously during the stressor task. Compared to controls, individuals with bipolar disorder reported greater increases in pretask anxiety from baseline and showed greater cardiovascular threat reactivity during the task. Group differences in cardiovascular threat reactivity were significantly correlated with comorbid anxiety in the bipolar group. Our results suggest that a multimethod approach to assessing stress reactivity—including the use of physiological parameters that differentiate between maladaptive and adaptive profiles of stress responding— can yield valuable information regarding stress sensitivity and its associations with negative affectivity in bipolar disorder. PMID:25688436

Artificial neural network models for prediction of cardiovascular autonomic dysfunction in general Chinese population

PubMed Central

2013-01-01

Background The present study aimed to develop an artificial neural network (ANN) based prediction model for cardiovascular autonomic (CA) dysfunction in the general population. Methods We analyzed a previous dataset based on a population sample consisted of 2,092 individuals aged 30–80 years. The prediction models were derived from an exploratory set using ANN analysis. Performances of these prediction models were evaluated in the validation set. Results Univariate analysis indicated that 14 risk factors showed statistically significant association with CA dysfunction (P < 0.05). The mean area under the receiver-operating curve was 0.762 (95% CI 0.732–0.793) for prediction model developed using ANN analysis. The mean sensitivity, specificity, positive and negative predictive values were similar in the prediction models was 0.751, 0.665, 0.330 and 0.924, respectively. All HL statistics were less than 15.0. Conclusion ANN is an effective tool for developing prediction models with high value for predicting CA dysfunction among the general population. PMID:23902963

Cardiovascular dysfunction following spinal cord injury

PubMed Central

Partida, Elizabeth; Mironets, Eugene; Hou, Shaoping; Tom, Veronica J.

2016-01-01

Both sensorimotor and autonomic dysfunctions often occur after spinal cord injury (SCI). Particularly, a high thoracic or cervical SCI interrupts supraspinal vasomotor pathways and results in disordered hemodynamics due to deregulated sympathetic outflow. As a result of the reduced sympathetic activity, patients with SCI may experience hypotension, cardiac dysrhythmias, and hypothermia post-injury. In the chronic phase, changes within the CNS and blood vessels lead to orthostatic hypotension and life-threatening autonomic dysreflexia (AD). AD is characterized by an episodic, massive sympathetic discharge that causes severe hypertension associated with bradycardia. The syndrome is often triggered by unpleasant visceral or sensory stimuli below the injury level. Currently the only treatments are palliative – once a stimulus elicits AD, pharmacological vasodilators are administered to help reduce the spike in arterial blood pressure. However, a more effective means would be to mitigate AD development by attenuating contributing mechanisms, such as the reorganization of intraspinal circuits below the level of injury. A better understanding of the neuropathophysiology underlying cardiovascular dysfunction after SCI is essential to better develop novel therapeutic approaches to restore hemodynamic performance. PMID:27073353

Patients With Fibromyalgia Have Significant Autonomic Symptoms But Modest Autonomic Dysfunction.

PubMed

Vincent, Ann; Whipple, Mary O; Low, Phillip A; Joyner, Michael; Hoskin, Tanya L

2016-05-01

Research suggests that disordered autonomic function may be one contributor to deconditioning reported in fibromyalgia; however, no study to date has assessed these variables simultaneously with comprehensive measures. To characterize physical fitness and autonomic function with the use of clinically validated measures and subjective questionnaires between patients with fibromyalgia and healthy controls. Cross-sectional, observational, controlled study. Community sample of patients with fibromyalgia and healthy controls. Thirty patients with fibromyalgia and 30 pain and fatigue-free controls. Participants completed a battery of self-report questionnaires and physiological measures, including clinically validated measures of physical fitness and autonomic function. Six-Minute Walk Test total distance, maximal oxygen consumption as assessed by cardiopulmonary exercise testing, total steps using activity monitor, Composite Autonomic Scoring Scale as assessed by Autonomic Reflex Screen, total metabolic equivalents per week using the International Physical Activity Questionnaire, and self-reported autonomic symptoms via the 31-item Composite Autonomic Symptom Score questionnaire. Autonomic function, as assessed by self-report, was significantly different between patients and controls (P < .0001); in contrast, the only difference between patients and controls on the Autonomic Reflex Screen was in the adrenergic domain (P = .022), and these abnormalities were mild. Self-reported physical activity was not significantly different between patients and controls (P = .99), but levels of moderate and vigorous physical activity as measured by actigraphy were significantly lower in patients (P = .012 and P = .047, respectively). Exercise capacity (6-Minute Walk) was poorer in patients (P = .0006), but there was no significant difference in maximal volume of oxygen consumption (P = .07). Patients with fibromyalgia report more severe symptoms across all domains, including physical activity and autonomic symptoms, compared with controls, but the objective assessments only showed modest differences. Our results suggest that patients with widespread subjective impairment of function have only modest objective measures of autonomic dysfunction. We recommend that the primary treatment goal should be focused on restoration of function, which may also ameliorate symptoms. Copyright © 2016 American Academy of Physical Medicine and Rehabilitation. Published by Elsevier Inc. All rights reserved.

Patients with Fibromyalgia Have Significant Autonomic Symptoms but Modest Autonomic Dysfunction

PubMed Central

Vincent, Ann; Whipple, Mary O.; Low, Phillip A.; Joyner, Michael; Hoskin, Tanya L.

2015-01-01

Background Research suggests that disordered autonomic function may be one contributor to deconditioning reported in fibromyalgia, however no study to date has simultaneously assessed these variables utilizing comprehensive measures. Objective To characterize physical fitness and autonomic function using clinically validated measures and subjective questionnaires between patients with fibromyalgia and healthy controls. Design Cross-sectional, observational, controlled study Setting Community sample of patients with fibromyalgia and healthy controls Participants 30 patients with fibromyalgia and 30 pain and fatigue-free controls Methods: Participants completed a battery of self-report questionnaires and physiological measures including clinically validated measures of physical fitness and autonomic function. Main Outcome Measurements 6 Minute Walk Test total distance, VO2 max as assessed by cardiopulmonary exercise testing, total steps using activity monitor, Composite Autonomic Scoring Scale as assessed by Autonomic Reflex Screen, total metabolic equivalents per week using the International Physical Activity Questionnaire and self-reported autonomic symptoms using the 31-item Composite Autonomic Symptom Score questionnaire. Results Autonomic function, as assessed by self-report, was significantly different between patients and controls (p<.0001); in contrast, the only difference between patients and controls on the Autonomic Reflex Screen was in the adrenergic domain (p=.022), and these abnormalities were mild. Self-reported physical activity was not significantly different between patients and controls (p=.99), but levels of moderate and vigorous physical activity as measured by actigraphy, were significantly lower in patients (p=.012 and p=.047, respectively). Exercise capacity (6 Minute Walk) was poorer in patients (p=.0006), but there was no significant difference in maximal volume of oxygen consumption (p=.07). Conclusions Patients with fibromyalgia report more severe symptoms across all domains including physical activity and autonomic symptoms when compared to controls, but the objective assessments only showed modest differences. Our results suggest that patients with widespread subjective impairment of function have only modest objective measures of autonomic dysfunction. We recommend that the primary treatment goal should be focused on restoration of function which may also ameliorate symptoms. PMID:26314231

The sympathetic nervous system and the physiologic consequences of spaceflight: a hypothesis

NASA Technical Reports Server (NTRS)

Robertson, D.; Convertino, V. A.; Vernikos, J.

1994-01-01

Many of the physiologic consequences of weightlessness and the cardiovascular abnormalities on return from space could be due, at least in part, to alterations in the regulation of the autonomic nervous system. In this article, the authors review the rationale and evidence for an autonomic mediation of diverse changes that occur with spaceflight, including the anemia and hypovolemia of weightlessness and the tachycardia and orthostatic intolerance on return from space. This hypothesis is supported by studies of two groups of persons known to have low catecholamine levels: persons subjected to prolonged bedrest and persons with syndromes characterized by low circulating catecholamines (Bradbury-Eggleston syndrome and dopamine beta-hydroxylase deficiency). Both groups exhibit the symptoms mentioned. The increasing evidence that autonomic mechanisms underlie many of the physiologic consequences of weightlessness suggests that new pharmacologic approaches (such as administration of beta-blockers and/or sympathomimetic amines) based on these findings may attenuate these unwanted effects.

Different nutritional states and autonomic imbalance in childhood.

PubMed

Dippacher, S; Willaschek, C; Buchhorn, R

2014-11-01

Autonomic imbalance, measured as heart rate variability (HRV), and an increased cardiovascular risk are described for overweight children, as well as for patients with anorexia nervosa. We investigate whether body mass index or actual caloric intake influences HRV. In our cross-sectional study, we compared HRV parameters for a healthy control group (n=52), anorexia nervosa patients (n=17), thin (n=18) and overweight children (n=19). Anorexia nervosa patients showed significantly lower heart rates at night (P<0.001) and significantly higher SDNN (standard deviation of all RR-intervals) (P<0.001 ), whereas overweight children showed an opposing pattern. SDNN and heart rate at night are highly correlated (r=0.89, R(2)=0.79, P<0.001). We conclude that not current body mass index but caloric intake determines HRV. Obesity and anorexia nervosa are characterized by a specific pattern of autonomic imbalance.

The cardiovascular system in the ageing patient

PubMed Central

Moore, A; Mangoni, A A; Lyons, D; Jackson, S H D

2003-01-01

The ageing process is associated with important changes in the responses of the cardiovascular system to pharmacological stimuli. They are not limited to the arterial system, involved in the modulation of cardiac afterload and vascular resistance, but they also involve the low-resistance capacitance venous system and the heart. The main changes include loss of large artery compliance, dysfunction of some of the systems modulating resistance vessel tone, increased activity of the sympathetic nervous system, and reduced haemodynamic responses to inotropic agents. This review focuses on the effects of ageing on arterial and venous reactivity to drugs and hormones, the autonomic nervous system, and the cardiovascular responses to inotropic agents. Some of the age-related changes might be at least partially reversible. This may have important therapeutic implications. PMID:12919173

Neural Regulation of Cardiovascular Response to Exercise: Role of Central Command and Peripheral Afferents

PubMed Central

Nobrega, Antonio C. L.; O'Leary, Donal; Silva, Bruno Moreira; Piepoli, Massimo F.; Crisafulli, Antonio

2014-01-01

During dynamic exercise, mechanisms controlling the cardiovascular apparatus operate to provide adequate oxygen to fulfill metabolic demand of exercising muscles and to guarantee metabolic end-products washout. Moreover, arterial blood pressure is regulated to maintain adequate perfusion of the vital organs without excessive pressure variations. The autonomic nervous system adjustments are characterized by a parasympathetic withdrawal and a sympathetic activation. In this review, we briefly summarize neural reflexes operating during dynamic exercise. The main focus of the present review will be on the central command, the arterial baroreflex and chemoreflex, and the exercise pressure reflex. The regulation and integration of these reflexes operating during dynamic exercise and their possible role in the pathophysiology of some cardiovascular diseases are also discussed. PMID:24818143

Noninvasive beat-to-beat finger arterial pressure monitoring during orthostasis: a comprehensive review of normal and abnormal responses at different ages.

PubMed

van Wijnen, V K; Finucane, C; Harms, M P M; Nolan, H; Freeman, R L; Westerhof, B E; Kenny, R A; Ter Maaten, J C; Wieling, W

2017-12-01

Over the past 30 years, noninvasive beat-to-beat blood pressure (BP) monitoring has provided great insight into cardiovascular autonomic regulation during standing. Although traditional sphygmomanometric measurement of BP may be sufficient for detection of sustained orthostatic hypotension, it fails to capture the complexity of the underlying dynamic BP and heart rate responses. With the emerging use of noninvasive beat-to-beat BP monitoring for the assessment of orthostatic BP control in clinical and population studies, various definitions for abnormal orthostatic BP patterns have been used. Here, age-related changes in cardiovascular control in healthy subjects will be reviewed to define the spectrum of the most important abnormal orthostatic BP patterns within the first 180 s of standing. Abnormal orthostatic BP responses can be defined as initial orthostatic hypotension (a transient systolic BP fall of >40 mmHg within 15 s of standing), delayed BP recovery (an inability of systolic BP to recover to a value of >20 mmHg below baseline at 30 s after standing) and sustained orthostatic hypotension (a sustained decline in systolic BP of ≥20 mmHg occurring 60-180 s after standing). In the evaluation of patients with light-headedness, pre(syncope), (unexplained) falls or suspected autonomic dysfunction, it is essential to distinguish between normal cardiovascular autonomic regulation and these abnormal orthostatic BP responses. The prevalence, clinical relevance and underlying pathophysiological mechanisms of these patterns differ significantly across the lifespan. Initial orthostatic hypotension is important for identifying causes of syncope in younger adults, whereas delayed BP recovery and sustained orthostatic hypotension are essential for evaluating the risk of falls in older adults. © 2017 The Authors Journal of Internal Medicine published by John Wiley & Sons Ltd on behalf of Association for Publication of The Journal of Internal Medicine.

Systems, methods and apparatus for quiesence of autonomic safety devices with self action

NASA Technical Reports Server (NTRS)

Hinchey, Michael G. (Inventor); Sterritt, Roy (Inventor)

2011-01-01

Systems, methods and apparatus are provided through which in some embodiments an autonomic environmental safety device may be quiesced. In at least one embodiment, a method for managing an autonomic safety device, such as a smoke detector, based on functioning state and operating status of the autonomic safety device includes processing received signals from the autonomic safety device to obtain an analysis of the condition of the autonomic safety device, generating one or more stay-awake signals based on the functioning status and the operating state of the autonomic safety device, transmitting the stay-awake signal, transmitting self health/urgency data, and transmitting environment health/urgency data. A quiesce component of an autonomic safety device can render the autonomic safety device inactive for a specific amount of time or until a challenging situation has passed.

Obstructive sleep apnea and insight into mechanisms of sympathetic overactivity.

PubMed

Abboud, François; Kumar, Ravinder

2014-04-01

Nearly two decades ago, we evaluated ten patients with obstructive sleep apnea (OSA). We determined that alarming nocturnal oscillations in arterial pressure and sympathetic nerve activity (SNA) were caused by regulatory coupling and neural interactions among SNA, apnea, and ventilation. Patients with OSA exhibited high levels of SNA when awake, during normal ventilation, and during normoxia, which contributed to hypertension and organ damage. Additionally, we achieved a beneficial and potentially lifesaving reduction in SNA through the application of continuous positive airway pressure (CPAP), which remains a primary therapeutic approach for patients with OSA. With these results in hindsight, we herein discuss three concepts with functional and therapeutic relevance to the integrative neurobiology of autonomic cardiovascular control and to the mechanisms involved in excessive sympathoexcitation in OSA.

[Arrhythmias and heart blocks in flying personnel with mitral valve prolapses].

PubMed

Zakharov, V P; Karlov, V N; Bondareva, S V; Vlasov, V D

1999-01-01

Investigated were 76 pilots with ECG-verified mitral valve prolapses (MVP) of the 1st and 2nd degree (w/o profound regurgitation). There were various heart blocks and ECG repolarization changes in 35 cases. Comparison of results of the cardiovascular functional investigations of flyers with MVP displayed non-specific cardiac rhythm and conductance disturbances that were registered more often during ECG-monitoring or test loading. According to the data of this study, bicycle and treadmill ergometry revealed "pseudoischemic" shifts in ECG. Literary indications of a significant loss in human endurance of physical loads due to MVP combined with the strain-induced arrhythmia received the experimental confirmation. Probably, arrhythmias in flyers with diagnosed MVP are predominantly associated with electric instability of the myocardium against the autonomous dysfunction with prevailing adrenergic effects.

Autonomous multifunctional nanobrushes-autonomous materials

NASA Astrophysics Data System (ADS)

Ghasemi-Nejhad, Mehrdad N.; Tius, Marcus A.

2007-04-01

In this work, taking advantage of carbon nanotubes' small size, and exceptional mechanical, chemical and electrical properties, we report on a series of nano-synthesis procedures that combine conventional chemical vapor deposition and selective substrate area growth followed by chemical functionalizations to fabricate functionalized nano-brushes from aligned carbon nanotube arrays and chemically selective functional groups. The high aspect ratio and small dimension, mechanical stability and flexibility, surface chemical and adhesive characteristics of carbon nanotubes provide opportunities to create nano-brushes with selected chemical functionalities. The nano-brushes are made from aligned multi-walled carbon nanotube bristles grafted onto long SiC fiber handles in various configurations and functionalized with various chemical functional groups. These nano-brushes can easily be manipulated physically, either manually or with the aid of motors. Here, we explain the autonomous characteristics of the functionalized nano-brushes employing functional chemical groups such that the nano-brush can potentially collect various metal particles, ions, and contaminants from liquid solutions and the air environment, autonomously. These functionalized multiwalled carbon nanotube based nano-brushes can work swiftly in both liquid and air environments. With surface modification and functionalization, the nanotube nano-brushes can potentially become a versatile nano-devices in many chemical and biological applications, where they can autonomously pick up the particles they encounter since they can be chemically programmed to function as Autonomous Chemical Nano Robots (ACNR).

Increased heart rate variability during nondirective meditation.

PubMed

Nesvold, Anders; Fagerland, Morten W; Davanger, Svend; Ellingsen, Øyvind; Solberg, Erik E; Holen, Are; Sevre, Knut; Atar, Dan

2012-08-01

Meditation practices are in use for relaxation and stress reduction. Some studies indicate beneficial cardiovascular health effects of meditation. The effects on the autonomous nervous system seem to vary among techniques. The purpose of the present study was to identify autonomic nerve activity changes during nondirective meditation. Heart rate variability (HRV), blood pressure variability (BPV), and baroreflex sensitivity (BRS) were monitored in 27 middle-aged healthy participants of both genders, first during 20 min regular rest with eyes closed, thereafter practising Acem meditation for 20 min. Haemodynamic and autonomic data were collected continuously (beat-to-beat) and non-invasively. HRV and BPV parameters were estimated by power spectral analyses, computed by an autoregressive model. Spontaneous activity of baroreceptors were determined by the sequence method. Primary outcomes were changes in HRV, BPV, and BRS between rest and meditation. HRV increased in the low-frequency (LF) and high-frequency (HF) bands during meditation, compared with rest (p = 0.014, 0.013, respectively). Power spectral density of the RR-intervals increased as well (p = 0.012). LF/HF ratio decreased non-significantly, and a reduction of LF-BPV power was observed during meditation (p < 0.001). There was no significant difference in BRS. Respiration and heart rates remained unchanged. Blood pressure increased slightly during meditation. There is an increased parasympathetic and reduced sympathetic nerve activity and increased overall HRV, while practising the technique. Hence, nondirective meditation by the middle aged may contribute towards a reduction of cardiovascular risk.

Central gene expression changes associated with enhanced neuroendocrine and autonomic response habituation to repeated noise stress after voluntary wheel running in rats

PubMed Central

Sasse, Sarah K.; Nyhuis, Tara J.; Masini, Cher V.; Day, Heidi E. W.; Campeau, Serge

2013-01-01

Accumulating evidence indicates that regular physical exercise benefits health in part by counteracting some of the negative physiological impacts of stress. While some studies identified reductions in some measures of acute stress responses with prior exercise, limited data were available concerning effects on cardiovascular function, and reported effects on hypothalamic-pituitary-adrenocortical (HPA) axis responses were largely inconsistent. Given that exposure to repeated or prolonged stress is strongly implicated in the precipitation and exacerbation of illness, we proposed the novel hypothesis that physical exercise might facilitate adaptation to repeated stress, and subsequently demonstrated significant enhancement of both HPA axis (glucocorticoid) and cardiovascular (tachycardia) response habituation to repeated noise stress in rats with long-term access to running wheels compared to sedentary controls. Stress habituation has been attributed to modifications of brain circuits, but the specific sites of adaptation and the molecular changes driving its expression remain unclear. Here, in situ hybridization histochemistry was used to examine regulation of select stress-associated signaling systems in brain regions representing likely candidates to underlie exercise-enhanced stress habituation. Analyzed brains were collected from active (6 weeks of wheel running) and sedentary rats following control, acute, or repeated noise exposures that induced a significantly faster rate of glucocorticoid response habituation in active animals but preserved acute noise responsiveness. Nearly identical experimental manipulations also induce a faster rate of cardiovascular response habituation in exercised, repeatedly stressed rats. The observed regulation of the corticotropin-releasing factor and brain-derived neurotrophic factor systems across several brain regions suggests widespread effects of voluntary exercise on central functions and related adaptations to stress across multiple response modalities. PMID:24324441

Exposure to medium and high ambient levels of ozone causes adverse systemic inflammatory and cardiac autonomic effects

PubMed Central

Wong, Hofer; Donde, Aneesh; Frelinger, Jessica; Dalton, Sarah; Ching, Wendy; Power, Karron; Balmes, John R.

2015-01-01

Epidemiological evidence suggests that exposure to ozone increases cardiovascular morbidity. However, the specific biological mechanisms mediating ozone-associated cardiovascular effects are unknown. To determine whether short-term exposure to ambient levels of ozone causes changes in biomarkers of cardiovascular disease including heart rate variability (HRV), systemic inflammation, and coagulability, 26 subjects were exposed to 0, 100, and 200 ppb ozone in random order for 4 h with intermittent exercise. HRV was measured and blood samples were obtained immediately before (0 h), immediately after (4 h), and 20 h after (24 h) each exposure. Bronchoscopy with bronchoalveolar lavage (BAL) was performed 20 h after exposure. Regression modeling was used to examine dose-response trends between the endpoints and ozone exposure. Inhalation of ozone induced dose-dependent adverse changes in the frequency domains of HRV across exposures consistent with increased sympathetic tone [increase of (parameter estimate ± SE) 0.4 ± 0.2 and 0.3 ± 0.1 in low- to high-frequency domain HRV ratio per 100 ppb increase in ozone at 4 h and 24 h, respectively (P = 0.02 and P = 0.01)] and a dose-dependent increase in serum C-reactive protein (CRP) across exposures at 24 h [increase of 0.61 ± 0.24 mg/l in CRP per 100 ppb increase in ozone (P = 0.01)]. Changes in HRV and CRP did not correlate with ozone-induced local lung inflammatory responses (BAL granulocytes, IL-6, or IL-8), but changes in HRV and CRP were associated with each other after adjustment for age and ozone level. Inhalation of ozone causes adverse systemic inflammatory and cardiac autonomic effects that may contribute to the cardiovascular mortality associated with short-term exposure. PMID:25862833

Air Pollution and Autonomic and Vascular Dysfunction in Patients With Cardiovascular Disease: Interactions of Systemic Inflammation, Overweight, and Gender

PubMed Central

Huang, Wei; Zhu, Tong; Pan, Xiaochuan; Hu, Min; Lu, Shou-En; Lin, Yong; Wang, Tong; Zhang, Yuanhang; Tang, Xiaoyan

2012-01-01

The authors conducted a 2-year follow-up of 40 cardiovascular disease patients (mean age = 65.6 years (standard deviation, 5.8)) who underwent repeated measurements of cardiovascular response before and during the 2008 Beijing Olympics (Beijing, China), when air pollution was strictly controlled. Ambient levels of particulate matter with an aerodynamic diameter less than 2.5 µm (PM2.5), black carbon, nitrogen dioxide, sulfur dioxide, ozone, and carbon monoxide were measured continuously, with validation of concurrent real-time measurements of personal exposure to PM2.5 and carbon monoxide. Linear mixed-effects models were used with adjustment for individual risk factors, time-varying factors, and meteorologic effects. Significant heart rate variability reduction and blood pressure elevation were observed in association with exposure to air pollution. Specifically, interquartile-range increases of 51.8 µg/m3, 2.02 µg/m3, and 13.7 ppb in prior 4-hour exposure to PM2.5, black carbon, and nitrogen dioxide were associated with significant reductions in the standard deviation of the normal-to-normal intervals of 4.2% (95% confidence interval (CI): 1.9, 6.4), 4.2% (95% CI: 1.8, 6.6), and 3.9% (95% CI: 2.2, 5.7), respectively. Greater heart rate variability declines were observed among subjects with C-reactive protein values above the 90th percentile, subjects with a body mass index greater than 25, and females. The authors conclude that autonomic and vascular dysfunction may be one of the mechanisms through which air pollution exposure can increase cardiovascular disease risk, especially among persons with systemic inflammation and overweight. PMID:22763390

Effects of water drinking on cardiovascular responses to supine exercise and on orthostatic hypotension after exercise in pure autonomic failure.

PubMed

Humm, A M; Mason, L M; Mathias, C J

2008-10-01

Patients with pure autonomic failure (PAF) have an abnormal fall in blood pressure (BP) with supine exercise and exacerbation of orthostatic hypotension (OH) after exercise. This study assessed the pressor effect of water on the cardiovascular responses to supine exercise and on OH after exercise. 8 patients with PAF underwent a test protocol consisting of standing for 5 min, supine rest for 10 min, supine exercise by pedalling a cycle ergometer at workloads of 25, 50 and 75 W (each for 3 min), supine rest for 10 min and standing for 5 min. The test protocol was performed without water ingestion and on a separate occasion after 480 ml of distilled water immediately after pre-exercise standing. Beat to beat cardiovascular indices were measured with the Portapres II device with subsequent Modelflow analysis. All patients had severe OH pre-exercise (BP fall systolic 65.0 (26.1) mm Hg, diastolic 22.7 (13.5) mm Hg), with prompt recovery of BP in the supine position. 5 min after water drinking, there was a significant rise in BP in the supine position. With exercise, there was a clear fall in BP (systolic 42.1 (24.4) mm Hg, diastolic 25.9 (10.0) mm Hg) with a modest rise in heart rate; this occurred even after water ingestion (BP fall systolic 49.8 (18.9) mm Hg, diastolic 26.0 (9.1) mm Hg). BP remained low after exercise but was significantly higher after water intake, resulting in better tolerance of post-exercise standing. Water drinking did not change the abnormal cardiovascular responses to supine exercise. However, water drinking improved orthostatic tolerance post-exercise.

AT1 and AT2 Receptors in the Prelimbic Cortex Modulate the Cardiovascular Response Evoked by Acute Exposure to Restraint Stress in Rats.

PubMed

Brasil, Taíz F S; Fassini, Aline; Corrêa, Fernando M

2018-01-01

The prelimbic cortex (PL) is an important structure in the neural pathway integrating stress responses. Brain angiotensin is involved in cardiovascular control and modulation of stress responses. Blockade of angiotensin receptors has been reported to reduce stress responses. Acute restraint stress (ARS) is a stress model, which evokes sustained blood pressure increase, tachycardia, and reduction in tail temperature. We therefore hypothesized that PL locally generated angiotensin and angiotensin receptors modulate stress autonomic responses. To test this hypothesis, we microinjected an angiotensin-converting enzyme (ACE) inhibitor or angiotensin antagonists into the PL, prior to ARS. Male Wistar rats were used; guide cannulas were bilaterally implanted in the PL for microinjection of vehicle or drugs. A polyethylene catheter was introduced into the femoral artery to record cardiovascular parameters. Tail temperature was measured using a thermal camera. ARS was started 10 min after PL treatment with drugs. Pretreatment with ACE inhibitor lisinopril (0.5 nmol/100 nL) reduced the pressor response, but did not affect ARS-evoked tachycardia. At a dose of 1 nmol/100 nL, it reduced both ARS pressor and tachycardic responses. Pretreatment with candesartan, AT1 receptor antagonist reduced ARS-evoked pressor response, but not tachycardia. Pretreatment with PD123177, AT2 receptor antagonist, reduced tachycardia, but did not affect ARS pressor response. No treatment affected ARS fall in tail temperature. Results suggest involvement of PL angiotensin in the mediation of ARS cardiovascular responses, with participation of both AT1 and AT2 receptors. In conclusion, results indicate that PL AT1-receptors modulate the ARS-evoked pressor response, while AT2-receptors modulate the tachycardic component of the autonomic response.

Autonomic nervous system dysfunction in psychiatric disorders and the impact of psychotropic medications: a systematic review and meta-analysis

PubMed Central

Alvares, Gail A.; Quintana, Daniel S.; Hickie, Ian B.; Guastella, Adam J.

2016-01-01

Background Autonomic nervous system (ANS) dysfunction is a putative underlying mechanism for increased cardiovascular disease risk in individuals with psychiatric disorders. Previous studies suggest that this risk may be related to psychotropic medication use. In the present study we systematically reviewed and analyzed published studies of heart rate variability (HRV), measuring ANS output, to determine the effect of psychiatric illness and medication use. Methods We searched for studies comparing HRV in physically healthy adults with a diagnosed psychiatric disorder to controls and comparing HRV pre- and post-treatment with a psychotropic medication. Results In total, 140 case–control (mood, anxiety, psychosis, dependent disorders, k = 151) and 30 treatment (antidepressants, antipsychotics; k = 43) studies were included. We found that HRV was reduced in all patient groups compared to controls (Hedges g = −0.583) with a large effect for psychotic disorders (Hedges g = −0.948). Effect sizes remained highly significant for medication-free patients compared to controls across all disorders. Smaller and significant reductions in HRV were observed for specific antidepressants and antipsychotics. Limitations Study quality significantly moderated effect sizes in case–control analyses, underscoring the importance of assessing methodological quality when interpreting HRV findings. Conclusion Combined findings confirm substantial reductions in HRV across psychiatric disorders, and these effects remained significant even in medication-free individuals. Reductions in HRV may therefore represent a significant mechanism contributing to elevated cardiovascular risk in individuals with psychiatric disorders. The negative impact of specific medications on HRV suggest increased risk for cardiovascular disease in these groups, highlighting a need for treatment providers to consider modifiable cardiovascular risk factors to attenuate this risk. PMID:26447819