Introduction: Muscle sympathetic nerve activity (MSNA) and forearm blood flow (FBF) are markers of mortality in Systolic Heart Failure (S-HF). Endomyocardial Fibrosis (EMF) is a Heart Failure (HF) with Preserved Ejection Fraction (PEF-HF). Although mortality in PEF-HF can be similar to S-HF, it is still unknown if neurovascular control is impaired in PEF-HF.. Hypothesis: Our hypothesis is that even though PEF-HF show normal ejection fraction, they have the same autonomic dysfunction as S-HF. The aim was to evaluate MSNA, FBF and spontaneous baroreflex sensitivity (SBS) in PEF-HF compared to S-HF and healthy subjects (HS).. Methods: Nineteen females HF, NYHA class II and III, were divided in two groups: PEF-HF (n=10) and S-HF (n=9), and were compared to HS (n=7). Left Ventricular Ejection Fraction (LVEF), by echocardiography (Simpson); MSNA, by microneurography; FBF, by venous occlusion plethysmography; mean blood pressure (MBP) and heart rate (HR) by Finometer; SBS, by sequence method, were ...
An aspect of the present subject matter relates to a system for providing baroreflex stimulation. An embodiment of the system comprises an adverse event detector to sense an adverse event and provide a signal indicative of the adverse event, and a baroreflex stimulator. The stimulator includes a pulse generator to provide a baroreflex stimulation signal adapted to provide a baroreflex therapy, and a modulator to receive the signal indicative of the adverse event and modulate the baroreflex stimulation signal based on the signal indicative of the adverse event to change the baroreflex therapy from a first baroreflex therapy to a second baroreflex therapy. Other aspects are provided herein.
Systems and methods provide baroreflex activation to treat or reduce pain and/or to cause or enhance sedation or sleep. Methods involve activating the baroreflex system to provide pain reduction, sedation, improved sleep or some combination thereof. Systems include at least one baroreflex activation device, at least one sensor for sensing physiological activity of the patient, and a processor coupled with the baroreflex activation device(s) and the sensor(s) for processing sensed data received from the sensor and for activating the baroreflex activation device. In some embodiments, the system is fully implantable within a patient, such as in an intravascular, extravascular or intramural location.
Baroreflex sensitivity can be enhanced significantly by slow breathing, both in health and in the presence of CHF. This seems to occur through a relative increase in vagal activity and a reduction in sympathetic activity, as could be argued by the small reduction in heart rate observed during slow breathing and by the reduction in both systolic and diastolic blood pressures. The increase in tidal volume, which compensates for the reduced breathing rate in order to maintain minute ventilation,6,8 could be responsible for these autonomic changes through a reduction in sympathetic activity8 or via the Hering-Breuer reflex. In fact, sympathetic activity was found to increase with faster breathing rates and to decrease with higher tidal volumes in CHF.8,10 The increase in baroreflex sensitivity depended on the slow breathing rate and not on the regularization obtained by controlling the breathing, inasmuch as this effect was not evident when breathing was controlled at a frequency (15 breaths/min) ...
Arterial baroreflex and cardiac autonomic control play important roles in hemodynamic instability after carotid artery stenting (CAS). Spontaneous baroreflex sensitivity (BRS), heart rate variability (HRV) and blood pressure variability (BPV) are established tools for the assessment of arterial baroreflex and cardiac autonomic activity. Aim of the study was to evaluate cardiac autonomic activity (by means of HRV, BPV and BRS) after CAS and to explore the impact of internal carotid artery stenosis on BRS changes after CAS. 37 patients (68±10.45 years) with internal carotid stenosis underwent CAS. HRV, BPV and BRS were measured in all subjects before and at 1 and 72h after CAS. ANOVA was performed to compare BRS, HRV and BPV parameters before and after CAS. Spearman analysis was performed to determine a possible correlation between carotid stenosis degree (or carotid plaque diameter) and BRS changes (ΔBRS). LF/HF (index of sympatho-vagal balance) decreased during postoperative period, in ...
BACKGROUND--Disturbances of autonomic function are recognised in both the acute and convalescent phases of myocardial infarction. Recent studies have suggested that disordered autonomic function, particularly the loss of protective vagal reflexes, is associated with an increased incidence of arrhythmic deaths. The purpose of this study was to compare the value of differing prognostic indicators with measures of autonomic function and to assess the safety of arterial baroreflex testing early after infarction. METHODS--As part of a prospective trial of risk stratification in post-infarction patients arterial baroreflex sensitivity, heart rate variability, long term electrocardiographic recordings, exercise stress testing, and ejection fraction were recorded between days 7 and 10 in 122 patients with acute myocardial infarction. RESULTS--During a one year follow up period there were 10 arrhythmic events. Baroreflex sensitivity was appreciably reduced in these patients suffering arrhythmic events ...
Salt-sensitive hypertension is known to be associated with dysfunction of the baroreflex control system in the Dahl salt-sensitive (SS) rat. However, neither the physiological mechanisms nor the genomic regions underlying the baroreflex dysfunction seen in this rat model are definitively known. Here, we have adopted a mathematical modeling approach to investigate the physiological and genetic origins of baroreflex dysfunction in the Dahl SS rat. We have developed a computational model of the overall baroreflex heart rate control system based on known physiological mechanisms to analyze telemetry-based blood pressure and heart rate data from two genetic strains of rat, the SS and consomic SS.13BN, on low- and high-salt diets. With this approach, physiological parameters are estimated, unmeasured physiological variables related to the baroreflex control system are predicted, and differences in these quantities between the two strains of rat on low- and high-salt diets are detected. Specific ...
Naloxone, an opioid antagonist, augments baroreflex mechanisms in animals; this occurrence suggests that endogenous opioids blunt baroreflex responses. Limited human studies suggest an inhibitory action of endogenous opioids on baroreflex-mediated vagal responses during arterial baroreceptor deactivation. To evaluate the potential effect of endogenous opioids on cardiopulmonary baroreflex mechanisms in humans, we measured arterial and central venous pressures, heart rate, and efferent muscle sympathetic nerve activity (MSNA, by peroneal microneurography) during unloading of cardiopulmonary baroreceptors with incremental lower body negative pressure (LBNP, from 0 to -15 mm Hg) and during the cold pressor test in 21 normal subjects (aged 24 +/- 1 [mean +/- SEM] years). In 14 subjects, we performed LBNP before and after naloxone (0.15 mg/kg i.v.) and placebo (n = 11) on separate days. In six of these 14 subjects and an additional seven subjects (n = 13), studies were also performed before and after ...
Carotid baroreflex activation has been demonstrated to provide enduring reductions in arterial blood pressure. The aim of this study was to investigate the effect of long-term therapy on renal function. A total of 322 patients were enrolled in the Rheos Pivotal Trial. Group 1 consisted of 236 patients who started baroreflex activation therapy 1 month after device implantation, whereas in the 86 patients from group 2 the device was activated 6 months later. Serum creatinine and urine albumin/creatinine ratio were collected at screening (before device activation), and at months 6 and 12. Multilevel statistical analyses were adjusted for various covariables. Serum creatinine increased from 78 to 84 μmol/L, and glomerular filtration rate decreased from 92 to 87 mL/min per 1.73 m2 in group 1 at month 6 (P,0.05). These values did not change any further after 12 months of therapy. Patients with highest glomerular filtration rate showed the greatest decrease in glomerular filtration. Group 2 showed the ...
The baroreflex or baroreceptor reflex is one of the bodys homeostatic mechanisms that helps to maintain blood pressure at nearly constant levels. The baroreflex provides a rapid negative feedback loop in which an elevated blood pressure reflexively causes the heart rate to decrease and also causes blood pressure to decrease. Decreased blood pressure decreases baroreflex activation and causes heart rate to increase and to restore blood pressure levels. The baroreflex can begin to act in less than the duration of a cardiac cycle (fractions of a second) and thus baroreflex adjustments are key factors in dealing with postural hypotension, the tendency for blood pressure to decrease on standing due to gravity. The system relies on specialized neurons, known as baroreceptors, in the aortic arch, carotid sinuses, and elsewhere to monitor changes in blood pressure and relay them to the Medulla. Baroreceptors are stretch receptors and respond to the pressure induced stretching of the blood vessel in ...
TY - JOUR. T1 - Cellular and Molecular Mechanisms Underlying Arterial Baroreceptor Remodeling in Cardiovascular Diseases and Diabetes. AU - Tu, Huiyin. AU - Zhang, Dongze. AU - Li, Yu Long. PY - 2019/2/1. Y1 - 2019/2/1. N2 - Clinical trials and animal experimental studies have demonstrated an association of arterial baroreflex impairment with the prognosis and mortality of cardiovascular diseases and diabetes. As a primary part of the arterial baroreflex arc, the pressure sensitivity of arterial baroreceptors is blunted and involved in arterial baroreflex dysfunction in cardiovascular diseases and diabetes. Changes in the arterial vascular walls, mechanosensitive ion channels, and voltage-gated ion channels contribute to the attenuation of arterial baroreceptor sensitivity. Some endogenous substances (such as angiotensin II and superoxide anion) can modulate these morphological and functional alterations through intracellular signaling pathways in impaired arterial baroreceptors. Arterial ...
Evidence suggests differences between African Americans (AA) and Caucasian Americans (CA) in cardiovascular responsiveness to physiological stressors. This study tested the hypothesis that carotid baroreflex (CBR) control of heart rate (HR) and blood pressure is reduced in AAs compared to CAs during exercise. Mean arterial pressure (MAP) and HR were continuously recorded at rest and during leg cycling in 23 nonhypertensive male subjects (12 AA; 11 CA; age 19-26 yr). CBR control of HR and MAP was assessed with 5-sec pulses of neck pressure (NP, simulated hypotension) and neck suction (NS, simulated hypertension) ranging from +45 to -80 Torr. Across all NS stimuli (-20, -40, -60, -80 Torr) at rest, the AA group demonstrated attenuated CBR-mediated reductions in HR (AA, -8.9 ± 1.9 vs. CA, -14.1 ± 2.3 bpm; P
The reflex responses of fH against changes in blood pressure in tegus were accessed by pharmacological manipulation of arterial pressure, which is a common method of studying baroreflex in vertebrates (Bagshaw, 1985; Altimiras et al., 1998; Crossley et al., 2003; Hagensen et al., 2010). Although this closed-loop study tends to overestimate the reflex sensitivity, it offers the advantages of both being performed with minimal instrumentation on unanaesthetized animals and providing an integrated response caused by activation of all relevant receptors (Altimiras et al., 1998; Crossley et al., 2003; Hagensen et al., 2010). This was an appropriate study to be performed in tegus because the baroreceptor locations as well as their characterization have not previously been demonstrated in these animals.. Even at reduced metabolic rate, suggested by smaller resting fH in our winter tegus, fH baroreflex sensitivity appeared to be preserved. In semi-natural conditions, the abandonment of thermoregulatory ...
TY - JOUR. T1 - Intracoronary epinephrine attenuates baroreflex control of heart rate in the conscious dog. AU - Holmberg, M. J.. AU - Gorman, A. J.. AU - Cornish, K. G.. AU - Zucker, I. H.. PY - 1984. Y1 - 1984. N2 - In the present study, the reflex effects of low-dose (12.5-50 ng·kg-1·min-1) intracoronary epinephrine infusion on the arterial baroreflex control of heart rate were studied. Mean arterial blood pressure-heart rate curves were constructed by changing mean arterial blood pressure with graded occlusions of the descending aorta and inferior vena cava. Intracoronary epinephrine increased left ventricular dP/dt(max) by an average of 309 ± 67.0 mmHg/s but did not alter resting mean arterial blood pressure or heart rate. Peak sensitivity, the maximum absolute slope along the mean arterial blood pressure-heart rate curve, and heart rate range were 32.7 ± 3.2 and 26.7 ± 2.5% less during intracoronary epinephrine compared with control, respectively. Intracoronary epinephrine did not ...
The present study differs from previous reports in several important aspects. In contrast to all previously published studies on idiopathic dilated cardiomyopathy, we investigated the correlation between both baroreflex sensitivity and heart rate variability and several parameters of left ventricular function, including left ventricular ejection fraction and left ventricular end diastolic diameter. Our finding that heart rate variability, baroreflex sensitivity, and left ventricular ejection fraction had only a weak to moderate correlation with each other suggests that they may be of independent prognostic value in patients suffering from idiopathic dilated cardiomyopathy. In contrast to many previous studies, our study investigated a relatively homogeneous group of patients with this disease, all of whom had previously undergone left and right heart catheterisation, including endomyocardial biopsy in 90%. It should be noted that patients on antiarrhythmic drug treatment that could not be ...
The present invention provides systems, devices, and methods for using the same for activating (stimulating) the baroreflex system of a patient using a baroreflex activation system with incrementally changing therapy intensity by sensing/monitoring/interpreting sensed data.
At present, there are insufficient information about baroreflex sensitivity (BRS) and factors that determine BRS in premature newborns. The objective of this study was to determine the relationship between BRS and the characteristics that reflecting the intrauterine development (gestational age and birth weight), as well as postnatal development (postconception age and the actual weight of the child at the time of measurement). We examined 57 premature infants, who were divided into groups according to gestational age and postconception age as well as birth weight, and weight at the time of measurement. Continuous and noninvasive registration of peripheral blood pressure (BP) was performed in every child within 2-5 min under standard conditions using a Portapres (FMS) device. The results showed a close correlation of baroreflex sensitivity, heart rate and respiratory rate with gestational age, postconception age, birth weight and actual weight at the time of measurement premature newborns. An ...
Systems and methods provide baroreflex activation to treat or reduce pain and/or to cause or enhance sedation or sleep. Methods involve activating the baroreflex system to provide pain reduction, sedation, improved sleep or some combination thereof. Systems include at least one baroreflex activation device, at least one sensor for sensing physiological activity of the patient, and a processor coupled with the baroreflex activation device(s) and the sensor(s) for processing sensed data received from the sensor and for activating the baroreflex activation device. In some embodiments, the system is fully implantable within a patient, such as in an intravascular, extravascular or intramural location.
The important findings of the present study were 1) resting supine MSNA increased after 60 and 120 days of HDBR, 2) the baroreflex slopes for MSNA were augmented after HDBR, in contrast to the attenuated baroreflex control of heart rate, and 3) MSNA increments in response to HUT after HDBR were similar to those before HDBR, but mean blood pressure in 60° HUT decreased after HDBR. The attenuation of baroreflex control of R-R interval after simulated microgravity was consistent with earlier studies (10, 15-17, 19). We emphasize that it may be difficult to manage and reproduce the present experiments due to the long HDBR duration.. In relation to orthostatic hypotension, alterations in peripheral vascular regulation were demonstrated after spaceflight (6, 18, 34). We hypothesized that the baroreflex modulation of vasomotor sympathetic nerve activity, which controls peripheral vascular resistance, may be impaired, and may thus cause a reduction in vasomotor sympathoexcitation, contributing to ...
A method involves implantably detecting changes in posture of a patients body. Baroreflex responses to the posture changes are determined. An autonomic tone of the patient is determined based on the baroreflex responses. Based on the autonomic tone, various patient susceptibilities to disease may be determined, including susceptibilities to heart disease, arrhythmia, and/or sudden cardiac death.
We observed earlier that central alpha-2 adrenoceptor stimulation in mice greatly augments parasympathetic tone. To test the effects in humans, we assessed autonomic vasomotor tone and baroreflex regulation in 9 normal young adults on 2 occasions, on
It is well known that the sensitivity of the reflex control of HR in response to vasoactive agents is altered independently by hypertension and by aging in both animal models (27), and in human subjects (22, 26, 49). A consequence of both hypertension and aging is a reduction in vascular distensibility, although the mechanisms are not identical. The demonstration that reduced baroreceptor sensitivity could be accounted for by reduced aortic compliance observed in both aged normotensive rats (5) and hypertensive rats (51), as discussed in the previous section, may provide an explanation for the decreased baroreflex control of HR in hypertensive subjects and aged normotensive humans.. For example, Monahan et al. (43) measured baroreflex control of HR and carotid compliance in 47 healthy sedentary men ranging from 19 to 76 years of age. Monahan and colleagues reported a progressive decline in baroreflex sensitivity with increasing age. The decline in baroreflex sensitivity correlated significantly ...
Bernardi, L., Spadacini, G., Bellwon, J., Hajric, R., Roskamm, H., & Frey, a W. (1998). Effect of breathing rate on oxygen saturation and exercise performance in chronic heart failure. Lancet. S0140-6736(97)10341-5 One month of .1 Hz respiratory training reduces breathing effort and improves both resting pulmonary gas exchange, including enhanced 02 saturation, and exercise performance in patients with chronic heart failure.. Bernardi, L., Porta, C., Spicuzza, L., Bellwon, J., Spadacini, G., Frey, A. W., … Tramarin, R. (2002). Slow breathing increases arterial baroreflex sensitivity in patients with chronic heart failure. Circulation, 105(2), 143-5.. .1 Hz breathing induced highly significant increases in baroreflex sensitivity, beneficial adaptive regulation of blood pressure, both in controls and in chronic heart failure (CHF) patients. In addition to improving oxygen saturation and exercise tolerance, study also demonstrates that spontaneous respiratory rate can be trained with slow ...
We tested whether 6-week vagal stimulation (VS) treatment improved open-loop baroreflex function in rats after myocardial infarction (MI). The following three groups of Sprague-Dawley rats were examined: normal control (NC, n = 9), MI with no treatme
TY - JOUR. T1 - Effect of propranolol on baroreflex arc function essential hypertension. AU - Preston, R. A.. AU - OConnor, D. T.. AU - Mitas, J. A.. AU - Stone, R. A.. PY - 1978/1/1. Y1 - 1978/1/1. UR - http://www.scopus.com/inward/record.url?scp=17944391586&partnerID=8YFLogxK. UR - http://www.scopus.com/inward/citedby.url?scp=17944391586&partnerID=8YFLogxK. M3 - Article. AN - SCOPUS:17944391586. VL - 26. SP - 101A. JO - Journal of Investigative Medicine. JF - Journal of Investigative Medicine. SN - 1081-5589. IS - 2. ER - ...
The purpose of this review is to delineate the general features of endocrine regulation of the baroreceptor reflex as well as specific contributions during pregnancy. the range of sympathetic nerve activity that can be elicited by changes AR-C155858 in arterial pressure. In contrast reductions in the levels or actions of insulin in the brain blunt baroreflex efferent responses to increments or decrements in arterial pressure. Although plasma levels of angiotensin II are increased in pregnancy this is not responsible for the reduction in baroreflex gain although it may contribute to the increased level of sympathetic nerve activity in this condition. How these different hormonal effects are integrated within the Goat polyclonal to IgG (H+L). brain as well as possible interactions with additional potential neuromodulators that influence baroreflex function during pregnancy and other physiological and pathophysiological states remains to be clearly delineated. method that there is much less ...
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Yang Liu, Jia-Ying Zhou, Yu-Hong Zhou, Di Wu, Jian-Li He, Li-Min Han, Xiao-Bo Liang, Lu-Qi Wang, Xiao-Long Lu, Hanying Chen, Guo-Fen Qiao, Weinian Shou and Bai-Yan Li ...
Naturally occurring mutations involving the nervous system have provided virtually all of our current understanding of the genetic regulation of neural development (Caviness and Rakic, 1978). The difficulty of isolating the corresponding genes, however, has precluded a molecular analysis of these mutants. Insertional mutagenesis, induced by microinjection of DNA into fertilized ova to produce transgenic animals, provides a molecular tag that marks the site of the mutational event. In this article, we describe a transgenic neurological mutation, designated wocko (Wo), which disrupts the development of the inner ear. These mutant mice display a dominant behavioral phenotype that consists of circling, hyperactivity, and head tossing, reminiscent of the shaker/waltzer class of mutants, and they display a recessive homozygous sublethal phenotype. Anatomical analyses showed that both structural and neural components of the vestibular system were disrupted, while analyses of mutant fetuses showed that ...
Cardiovagal innervation is evaluated by testing heart rate variability. for more information visit www.ldteck.com or call us 305 915 1399
Synthetic constructs in biotechnology, bio-computing, and proposed gene therapy interventions are often based on plasmids or transfected circuits which implement some form of on-off (toggle or flip-flop) switch. For example, the expression of a protein used for therapeutic purposes might be triggered by the recognition of a specific combination of inducers (e.g., antigens), and memory of this event should be maintained across a cell population until a specific stimulus commands a coordinated shut-off. The robustness of such a design is hampered by molecular (intrinsic) or environmental (extrinsic) noise, which may lead to spontaneous changes of state in a subset of the population and is reflected in the bimodality of protein expression, as measured for example using flow cytometry. In this context, a majority-vote correction circuit, which brings deviant cells back into the required state, is highly desirable. To address this concrete challenge, we have developed a new theoretical design for ...
TY - JOUR. T1 - Aortic depressor nerve stimulation does not impede the dynamic characteristics of the carotid sinus baroreflex in normotensive or spontaneously hypertensive rats. AU - Kawada, Toru. AU - Turner, Michael J.. AU - Shimizu, Shuji. AU - Fukumitsu, Masafumi. AU - Kamiya, Atsunori. AU - Sugimachi, Masaru. PY - 2017/5/30. Y1 - 2017/5/30. N2 - Recent clinical trials in patients with drug-resistant hypertension indicate that electrical activation of the carotid sinus baroreflex (baroreflex activation therapy) can reduce arterial pressure (AP) for more than a year. To examine whether the electrical stimulation from one baroreflex system impedes normal short-term AP regulation via another unstimulated baroreflex system, we electrically stimulated the left aortic depressor nerve (ADN) while estimating the dynamic characteristics of the carotid sinus baroreflex in anesthetized normotensive Wistar-Kyoto (WKY, n=8) rats and spontaneously hypertensive rats (SHR, n=7). Isolated carotid sinus ...
The use of baroreflex stimulation devices (also known as baroreflex activation therapy) is a potential alternative treatment for resistant hypertension and heart failure. Both hypertension and heart failure are relatively common conditions and are initially treated with medications and lifestyle changes. A substantial portion of patients are unresponsive to conventional therapy and treating these patients is often challenging and can lead to high costs and adverse effects. As a result, there is a large unmet need for additional treatments.. New treatment options are being explored to treat drug-resistant hypertension. One such approach is the electrical activation of the carotid sinus baroreflex. Baroreceptors are pressure sensors contained within the walls of the carotid arteries. They are part of the autonomic nervous system that regulates basic physiologic functions such as heart rate and blood pressure (BP). When these receptors are stretched, as occurs with increases in BP, the baroreflex ...
After acute stroke, baroreflex sensitivity (BRS) is impaired. This impaired acute stage BRS has been reported to be predictive of worsen outcome years after stroke in general. However, it is not very clear if the impaired acute stroke BRS would actually persist months after the acute stage. It is also not clear that such change, if any, would correlate with the functional outcome or prognosis after stroke.. The trial is to investigate the longitudinal time course of BRS after ischemic stroke up to the 6th month post stroke and to see if there is any correlation of the changes in BRS with the functional outcome parameters using NIHSS and mRS scores throughout this period. ...
The complete arterial baroreceptor reflex pathway is a control system made up of two distinct portions as shown in Figure E-1: (1) an effector portion, including the heart and peripheral blood vessels, and (2) a neural portion, including the arterial baroreceptors, their afferent nerve fibers, the medullary cardiovascular centers, and the efferent sympathetic and parasympathetic fibers. Mean arterial pressure is the output of the effector portion and simultaneously the input to the neural portion. Similarly, the activity of the sympathetic (and parasympathetic) cardiovascular nerves is the output of the neural portion of the arterial baroreceptor control system and, at the same time, the input to the effector portion. For convenience, we omit continual reference to parasympathetic nerve activity in the following discussion. Throughout, however, an indicated change in sympathetic nerve activity should usually be taken to imply a reciprocal change in the activity of the cardiac parasympathetic ...
Previous studies have provided both direct and indirect evidence for a functional role of α7-containing receptors in autonomic function at the cellular level. Studies in α7-deficient mice have indicated that baroreflex stimulation of the parasympathetic limb does not display altered parasympathetic function but that stimulation of the sympathetic limb demonstrates abnormal sympathetic responses (7). The possibility has remained, however, that α7-subunits play a role in resting autonomic tone rather than in stimulated activity, and the possibility of some modulatory role on autonomic function has remained. In this study, we have shown that the α7-nAChR subunit is not required for parasympathetic modulation of HR in the resting state or under artificial controlled stimulation of vagal pathways to the heart throughout a wide stimulation range.. Resting HR and PSD profiles were not significantly different between the groups of mice, suggesting that either the α7-subunit does not play a role in ...
My name is Dale and I was recently diagnosed with POTS by Dr. Julian Stewart at the center for hypotension in New York. I participated in his CFS/POTS study because I was diagnosed with Chronic Fatigue Syndrome when I was 19 at The Mayo Clinic flollowing a one year Chronic EBV infection.Ill be 26 this year. He said I had some very unusual findings and some of the most peculiar data seen so far in such patients. I have a normal BMI but appear thin. During H.U.T. I had a 30 percent reduction of cerebral blood flow to my brain which was associated with a large degree of hypocapnia. Hr increased to over 130bmp. Heart rate variability was abnormal with increased low frequency peaks suggesting sympathhetic activation even supine.Blood pressure variability was also increased suggesting accentuated supine sympathetic baroreflex. Arm blood flows were high but leg blood flows measured by venous occlusion plethysmography were reduced and I may have the lowest blood pressure in my legs that hes ever seen. ...
Overview Todays lecture is 50 minutes long. http://www.youtube.com/watch?v=srjNMMtPATo Details The direction of spontaneous change is related to G. 2nd law dS|dq/T for spontaneous change 1st law dU = dq + dW The basic thermodynamic quantities are H, A, G and U. There are the fundamental equations. Everything is in terms of state variables. Path doesnt…
Low rates of Absorb BRS thrombosis beyond 12 months in patients treated with aggressive pre- and post-dilatation using highly non-compliant ...
α 1. Vagus Nerve. Baroreflex. M2(-). B1(+). ANP. ATII. B1. Renin. Constrict. ADH. Aldosterone. Slideshow 6856107 by henry-bernard
金 秀吉 , 河南 洋 , 林田 嘉朗 , 中村 正 , 東野 英明 , 山下 博 産業医科大学雑誌 11, 361-370, 1989 医中誌Web 被引用文献1件 ...
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34 healthy college male volunteers, 18-29yrs, performed an actual VO2max test and 2, one-mile walks for time. Each Ss age, wt (lbs), gender, HR responses, and time during a one-mile walk were obtained to calculate VO2max ...
We investigated the hemodynamic effect of synthetic atrial natriuretic factor Auriculin A (ANF) and its influence on arterial baroreflex control of heart rate, systemic blood pressure, and perfusion pressure in the hind limb (perfused at constant flow) in rabbits anesthetized with alpha-chloralose and urethane. The neural mechanisms underlying these effects were also studied. In the intact animal, a 45-minute constant infusion of ANF (2 micrograms/kg prime, 0.2 microgram/kg/min) significantly reduced mean blood pressure and increased mean perfusion pressure, while heart rate did not change. Comparable data were obtained with lower (0.5 microgram/kg + 0.05 microgram/kg/min; 1 microgram/kg + 0.1 microgram/kg/min) or higher (4 micrograms/kg + 0.4 microgram/kg/min; 8 micrograms/kg + 0.8 microgram/kg/min) doses of ANF. In addition, ANF enhanced bradycardic reflex responses to phenylephrine i.v. bolus administration, while it did not change baroreflex-mediated responses to nitroglycerin i.v. bolus ...
TY - JOUR. T1 - Chronic exercise reduces sympathetic nerve activity in rabbits with pacing-induced heart failure. T2 - A role for angiotensin II. AU - Liu, Jun Li. AU - Irvine, Scott. AU - Reid, Ian A.. AU - Patel, Kaushik P. AU - Zucker, Irving H. PY - 2000/10/10. Y1 - 2000/10/10. N2 - Background - Chronic exercise (EX) improves the quality of life and increases the survival of patients with chronic heart failure (CHF). Because sympathetic nerve activity is elevated in the CHF state, it is possible that EX is beneficial in this disease due to a decrease in sympathetic outflow. Methods and Results - We evaluated arterial baroreflex function and resting renal sympathetic nerve activity (RSNA) in EX normal and CHF rabbits before and after angiotensin II type 1 (AT1) receptor blockade. Four groups of rabbits were studied: a normal non-EX group, a normal EX group, a CHF non-EX group, and a CHF EX group. EX lowered resting RSNA in rabbits with CHF but not in normal rabbits. In addition, EX increased ...
Title:The Future of Interventional Management of Hypertension: Threats and Opportunities. VOLUME: 12 ISSUE: 1. Author(s):Alexandros Briasoulis and George Bakris. Affiliation:5841 S. Maryland Ave MC 1027, Chicago, IL 60637, USA.. Keywords:Resistant hypertension, baroreflex activation therapy, renal sympathetic denervation.. Abstract:In about 48% hypertensive patients in the United States, blood pressure remains higher than accepted treatment targets despite broad availability of effective pharmaceutical agents. Of these 48%, recent estimates define about 10-11% have treatment-resistant hypertension (TR-HTN). Compensatory changes in sympathetic nervous system function are an important component of HTN. Recent technical advances targeting the sympathetic activity of the carotid sinuses (Baroreflex Activation Therapy-BAT) and the renal sympathetic nerves (Renal Denervation Therapy-RDT) have renewed interest in invasive therapy for the treatment of drug-resistant hypertension. Encouraging results ...
In hypertension baroreceptor-mediated modulation of heart rate is impaired, resulting in a decreased vagal control. Reactive oxygen species produced locally in the vasculature decrease baroreceptor sensitivity. Folic acid has antioxidant properties. Therefore, the aim of this study was to test whether folic acid improves baroreceptor function in hypertension. Twenty-one male patients with hypertension not taking any drugs for 2 weeks participated in the study and were randomized to folic acid 5 mg or matching placebo. Cardiac and vascular sympathetic baroreceptor functions were tested before and after a single dose of folic acid or placebo with two different methods: the alpha-coefficient method and the phenylephrine (PE) and sodium nitroprusside (SNP) bolus method. In the folic acid group both methods showed significantly improved cardiac and vascular sympathetic baroreceptor sensitivity compared with placebo. This study provides evidence that folic acid improves cardiac and vascular ...
Diabetes mellitus (DM) is a disease of increasing incidence and prevalence. Arterial baroreceptors are stretch-sensitive receptors, which in a reflex manner are involved in the homeostatic control of arterial blood pressure. Diabetic subjects have depressed baroreflex sensitivity (BRS), although the exact pathomechanisms are unclear. In this review, we discuss the features, clinicaland prognostic implications of reduced BRS for diabetic patients and the potential involvement of cardiovascular autonomic neuropathy and atherosclerosis. Finally, we demonstrate evidence on interventions (e.g. pioglitazone, alpha-lipoic acid, leptin, fluvastatin, physicaltraining etc.) which could improve BRS and ameliorate cardiovascular autonomic dysfunction in diabetic patients ...