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Results for “Autonomic dysfunction”

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At least 1,297 records · Page 72Linked to original sources

PubMed1993

Sympathetic skin response and R-R interval variation in rheumatoid arthritis. Two simple tests for the assessment of autonomic function.

Autonomic nervous system involvement with peripheral neuropathy is a well known complication of rheumatoid arthritis (RA). In the assessment of autonomic function of patients with rheumatoid arthritis, we performed sympathetic skin response (SSR) and R-R interval variation (RRIV) tests in 30 patients and in 30 normal controls. Of 30 patients, 5 had complaints of clinical dysautonomic symptoms. SSRs were abnormal in 6 of 30 patients, whereas 8 showed abnormal RRIVs during deep breathing. Nine of 30 patients also showed electrophysiologic evidence of peripheral neuropathy. All 5 of the patients with clinical dysautonomic symptoms showed abnormal SSR and RRIV test results. No patients with normal results on both tests had clinical dysautonomia. This study showed that there are frequent abnormalities in SSR and RRIV tests in patients with rheumatoid arthritis whether there is a clinical symptom of autonomic dysfunction or not.

Action Potentials↗

PubMed1986

Autonomic neuropathy in systemic sclerosis: a case report and evaluation of six patients.

We describe a case of systemic sclerosis with sympathetic and parasympathetic neuropathy and detail autonomic testing in six further patients. Of these six patients, three showed early parasympathetic damage. None of the patients had evidence of peripheral neuropathy, and there was no correlation between the presence of autonomic dysfunction and the severity of Raynaud's phenomenon.

Adult↗

PubMed1989

The relationship of the lock-step phenomenon and precipitous changes in mean arterial blood pressure.

The lock-step phenomenon (LSP) is the occurrence of postganglionic cardiac sympathetic discharge (PCSD) and cortical epileptiform activity (EA) in a time-locked fashion. The relationship between the LSP and precipitous changes in blood pressure (PCBP: greater than 23 mm Hg in 10 sec) was determined in 9 cats after EA was induced with pentylenetetrazol following pretreatment with phenobarbital (20 mg/kg, i.v.). Electrocorticogram (ECoG), PCSD, lead II EKG, and mean arterial blood pressure (MAP) were monitored. Since an interspike interval of 2.8 sec was frequently found to exist between ECoG spikes when the LSP was present, 4 categories of LSP were defined: LSP absent; stable LSP with 2.8 sec interval; stable LSP without 2.8 sec interval; and unstable LSP with increasing or decreasing rates of discharge. The duration of each LSP pattern and the proportion of time spent in PCBP were determined. A one-way repeated measures ANOVA and the Newman-Keuls post-hoc test showed that a higher mean proportion of time spent in PCBP was associated with the unstable LSP pattern (P less than 0.05). The LSP and associated patterns as related to precipitous changes in MAP are indicators of changes in autonomic function. Autonomic dysfunction with EA, causing cardiac arrhythmias, has been postulated as a cause of sudden unexplained death (SUD) in persons with epilepsy. Thus, an understanding of the autonomic changes, as indicated by PCBP associated with LSP, may contribute to the understanding and prevention of SUD in persons with epilepsy.

Animals↗

PubMedDate not supplied

Electrophysiologic evaluation of autonomic function in cerebral palsy.

The presence of clinical autonomic dysfunction in patients with neurologic diseases, such as multiple sclerosis, Parkinson's disease, and cerebrovascular accident, has become increasingly recognized in the past decade. Very few autonomic tests have been done on pediatric patients thus far. The purpose of this study was to investigate the autonomic function in patients with cerebral palsy using two noninvasive tests: sympathetic skin response (SSR) and R-R interval variation (RRIV). Twenty-four patients with cerebral palsy and 24 control subjects between the ages of 4 and 12 yr were enrolled in this study. There was no significant difference of mean latency, amplitude, or amplitude ratio of SSR between the two groups under electric stimulus, startling stimulus, and deep breathing conditions. No significant difference in frequency of absent response and asymmetric response was also noted. Mean heart rate under relaxed sitting condition was significantly higher in the study group. Significant negative correlation between heart rate and age was noted in the control group but was not present in the study group. Also, there was no statistical difference of mean RRIV between the two groups. No objective evidence of autonomic disturbance in patients with cerebral palsy was found in this study.

Age Factors↗

PubMedDate not supplied

Cardiovascular dysautonomia of patients with end-stage renal disease and type I or type II diabetes.

BACKGROUND: End-stage renal disease and diabetes mellitus are known to cause autonomic dysfunctions that are responsible for poor outcomes. Studies suggest that 24-hour heart rate variability with power spectral analysis is more sensitive to early changes in autonomic function than laboratory-evoked measures. OBJECTIVES: To evaluate cardiovascular autonomic function in patients (a) awaiting kidney or pancreas-kidney transplantation, (b) without diabetes (NonDM), (c) with Type I insulin dependent diabetes mellitus (IDDM), and (d) with Type II noninsulin dependent diabetes mellitus (NIDDM), and to compare the results of the laboratory-evoked cardiovascular autonomic tests with those from 24-hour heart rate variability monitoring with power spectral analysis. METHOD: This cross-sectional study examined autonomic function in prekidney transplant patients with and without diabetes (N=96), comparing laboratory-evoked measures to 24-hour measures. RESULTS: The nondiabetic group had a normal change in heart rate with deep breathing, Valsalva ratio, and change in systolic blood pressure with tilt. Both diabetic groups had poorer values for all measures of heart rate variability; demonstrated abnormal changes in heart rate with deep breathing and borderline Valsalva ratios; demonstrated a greater decrease in circadian rhythmicity; and had lower SDNNS, pNN50s, and rMSSDs than the nondiabetic group. CONCLUSIONS: Results showed that 24-hour measures are more sensitive, that patients with end-stage renal disease and diabetes regardless of type experience significantly poorer function than do patients without diabetes, and that these values approach those associated with sudden cardiac death.

Adult↗

PubMed2003

Influences of an anticholinergic antiparkinsonian drug, parkinsonism, and psychotic symptoms on cardiac autonomic function in schizophrenia.

The arguments against the use of anticholinergic antiparkinsonian drugs for neuroleptic-induced parkinsonism have been based, in part, on their autonomic side effects. Except for anecdotal case reports, there is little evidence that antiparkinsonian drugs are the main factor causing autonomic dysfunction in schizophrenic patients with parkinsonism. Therefore, in the current study, the separate influences of the anticholinergic antiparkinsonian drug (biperiden), parkinsonism, and psychotic symptoms on cardiac autonomic function were investigated in 48 patients with schizophrenia. Biperiden was discontinued in 33 patients with or without parkinsonism and commenced in 15 patients with parkinsonism. Their parkinsonism and psychotic symptoms were assessed using rating scales, and their cardiac autonomic functions were assessed using the mean R-R interval and 3 methods of analyzing heart rate variability both before and after the change in medication. Consequently, the cardiac autonomic function was not affected by biperiden or the change in parkinsonism. Cardiac vagal function decreased when psychotic symptoms were more pronounced, but cardiac sympathetic function did not show a significant change. Therefore, it appeared that psychotic symptoms played the predominant role in modifying the cardiac autonomic function, implying the existence of autonomic changes associated with cognitive processing and a possible relation between psychotic symptoms and autonomic symptoms in schizophrenia.

Adult↗

PubMed1983

Ventricular standstill despite normal electrophysiology study: a further possible indication for pacing.

Permanent pacing has usually been indicated for the treatment of organic disease of the sinus node or specific cardiac conducting tissue. We report three patients in whom profound syncope was apparently related to intense, transient autonomic dysfunction. Although ventricular standstill was documented in all three, detailed electrophysiology study, responses to graded Valsalva manoeuvres and carotid sinus massage, and repeated observations after cardiac autonomic blockade by IV atropine (0.03 mg/Kg) and propranolol (0.15 mg/Kg) were essentially normal. Permanent ventricular (VVI) pacing has controlled symptoms in all three, over follow-up period of 20 to 26 months. These observations suggest that transient autonomic imbalance may be a cause of undiagnosed cardiac syncope. This is neither excluded by normal electrophysiology study nor by normal responses to usual provocative autonomic interventions.

Adolescent↗

PubMed1985

Paraneoplastic tonic pupils.

Tonic pupils developed in two patients with malignancies outside the nervous system. Symptoms and signs of more generalized somatic and autonomic nervous system involvement were also present. Although the exact morphologic basis for autonomic dysfunction in patients with paraneoplastic neurologic deterioration is uncertain, recent studies suggest that in some cases an autoimmune mechanism is responsible and may be directed against autonomic ganglion cells.

Adenocarcinoma↗

PubMed1976

[Certain aspects of the pathogenesis and prophylactic treatment of hypertensive crises].

The paper analyses the results of a study of the clinical peculiarities of the course of essential hypertension with crises, of the changes in the functional state of the central nervous system, and of some neuro-humoral systems of the human body. In most of the patients tending to develope frequent crises distinct changes were noted in the EEG that indicate dysfunction of the hypothalamic zone and of the reticular formation of the brain stem, their clinical course being characterized by significant astheno-neurotic disorders with autonomous dysfunction and cerebral angiodistonic disturbances. For the prevention of crises it is essential to conduct a pathogenetically substantiated and highly differentiated systematic therapy, as well as special measures aimed at increasing the endurance of the central nervous system, improving the circulation and metabolic processes in the brain, decreasing tnd hypothalamic structures of the brain, and correcting the dishormonal disorders.

Adult↗

PubMed1997

Autonomic evaluation by means of standard tests and power spectral analysis in multiple sclerosis.

Standard autonomic tests [heart rate response to deep breathing (HRDB), change in systolic blood pressure due to tilt], and spectral analysis of heart rate (HR), arterial blood pressure (ABP), and the associated transfer function analysis (gains and phases) were performed in 20 patients with multiple sclerosis to determine their diagnostic value. Transfer function analysis suggested impairment of baroreflex function in 7 patients and an alteration of cardiorespiratory coupling on a brain stem level in 4 patients. In addition, sympathetic vasomotor outflow was reduced in 2 patients (spectral ABP measures in the mid frequency band) and a decrease of vagal outflow was suggested by abnormal respiratory HR parameters in another 2 patients. An abnormal HRDB was present in 5 patients and was probably due to a central alteration (cardiorespiratory coupling) in 2 patients and due to diminished respiratory effort in 1 patient. Spectral analysis of both HR and ABP oscillations and their transfer function may considerably improve the pathophysiological interpretation of cardiovascular autonomic dysfunction in patients with central nervous system disease.

Adult↗

PubMed1995

Cardiac autonomic function during sleep and wakefulness in multiple sclerosis.

Some studies in multiple sclerosis (MS) patients have shown evidence of autonomic dysfunction involving the cardiovascular system. However, the findings in these studies have not been completely consistent. The discrepancy may be related to the limits of the traditional autonomic tests during wakefulness. In our study, after the investigation of the cardiovascular reflexes during wakefulness, heart rate (HR) variations were considered during sleep in order to avoid the limits of cooperation and the emotional state of the patient. We evaluated tonic (vagal activity) HR modifications in relation to the deepening of sleep, as well as phasic (sympathetic activity) HR modifications in relation to spontaneous body movements during sleep, in 25 MS patients and 25 age-matched controls. No difference was found between the two groups in autonomic function during wakefulness. A reduced parasympathetic activity was observed in MS subjects during both rapid eye movement (REM) and non-REM sleep, while no difference was found in sympathetic function between patients and controls. No significant correlation was found between cardiac autonomic data during sleep and MRI lesion load in the infratentorial areas and, in particular, of the brain stem. The findings of our study suggest that autonomic nervous system evaluation during sleep could show impairment earlier than the traditional autonomic tests during wakefulness.

Adult↗

PubMed1992

Autonomic involvement in inherited neuropathies.

The inherited peripheral neuropathies constitute a large group of disorders, in some of which the causative metabolic defect has been identified whereas in the majority it is still unknown. Amongst the former, autonomic involvement is an important component in porphyric neuropathy, in the familial amyloid polyneuropathies, in Fabry's disease and in dopamine beta-hydroxylase deficiency. The latter group includes the hereditary sensory and autonomic neuropathies in some of which, such as the Riley-Day syndrome, autonomic disturbances are prominent, whereas in others they constitute only a minor component of the symptomatology. Autonomic dysfunction is an important component of the neurological manifestations in multiple endocrine neoplasia type IIB.

Autonomic Nervous System Diseases↗

PubMed1995

Comparison of autonomic function using Valsalva ratio and 30:15 postural ratio prior to and after haemodialysis treatment.

In published studies of chronic haemodialysis patients, the frequency of autonomic dysfunction varies widely. One reason for the variation may be the time of testing with respect to time of dialysis. The current study tests the hypothesis that autonomic function--as measured by heart rate responses to the Valsalva manoeuvre (Valsalva ratio) and 30:15 electrocardiogram (ECG) R-R interval to upright posture (postural ratio)--is different when patients are above 'dry weight' (predialysis) than when they are at or below dry weight (postdialysis). The study also reviews available literature to analyze other factors that may affect the results of autonomic testing in this population. A total of 25 chronic haemodialysis patients underwent standard Valsalva and 30:15 R-R interval postural autonomic testing prior to and after haemodialysis. In addition, pre- and postdialysis orthostatic responses were measured and compared with a control population. The 30:15 ratio increased after dialysis (p = 0.001). The Valsalva ratio did not change with dialysis. Out of 25 subjects, seven had an abnormal 30:15 ratio prior to dialysis decreasing to two out of 25 patients postdialysis (p < 0.03). Orthostatic responses predialysis did not differ from those in the control group. Review of the literature shows great variability in definition of normal Valsalva and postural (30:15 R-R interval) ratios. Diabetic patients in the current and prior studies were more likely to have abnormal responses.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1990

Comparison of panic symptom sequences and pathophysiologic models.

In an attempt to assess which of the proposed etiologic models best accounts for the symptomatology seen in panic attacks, 21 patients with panic attacks were asked to describe the symptom sequence during an attack. Using the Kolmogorov-Smirnov test, the Runs test, and Friedman's 2-way ANOVA, the degree of agreement between their attacks, and the proposed models was assessed. All three analyses suggest that, at the 0.1, 0.025, and 0.05 levels of significance respectively, the autonomic dysfunction model best accounts for the sequence of symptoms in panic attacks.

Anxiety Disorders↗

PubMed1981

Autonomic neuropathy in experimental allergic neuritis: an electrophysiological and histological study.

Electrophysiological and histological studies have been performed on the vagus and splanchnic nerves of guinea pigs with experimental allergic neuritis. Slowing of conduction and dispersion of the compound action potential were consistent with the pathological changes of demyelination. In teased single fibre preparations, axonal degeneration was found more frequently than was expected and in the splanchnic nerves, the unmyelinated fibres appeared to have been indirectly involved. These findings in experimental allergic neuritis are relevant to the pathogenesis of autonomic dysfunction in the Landry-Guillain-Barré syndrome.

Animals↗

PubMed2006

Immunology of disorders of neuromuscular transmission.

The neuromuscular junction (NMJ) is a prototype synapse and myasthenia gravis is the prototypic antibody-mediated disorder. There are now three other disorders of neuromuscular transmission caused by antibodies to other essential components of the NMJ. Antibodies to the muscle-specific kinase, MuSK, are defining a new form of myasthenia that can be associated with muscle atrophy. Antibodies to voltage-gated calcium channels are responsible for muscle weakness and autonomic dysfunction in the Lambert Eaton myasthenic syndrome. Antibodies to voltage-gated potassium channels are found in patients with a range of disorders affecting the NMJ, the autonomic system or the central nervous system. The pathogenic mechanisms probably depend on the IgG subclass of the antibodies and are only partly shared between the diseases.

Autoantibodies↗

PubMed1987

Autonomic neuropathy and vibration exposure in forestry workers.

The variation in heart rate (HRV) at rest and during deep breathing (6 cycles a minute) of 88 professional lumber jacks was studied using a computer technique. The traditional indexes of HRV (CV, CVS, MEAN) were calculated and the spectral components of the HRV were also computed. There was a significant difference (p less than 0.001) between the HRV indexes during the deep breathing test in those with the shortest (CV = 10.1 +/- 1.1) and those with the longest (CV V 6.2 +/- 0.4) exposures to vibration. The values of the HRV indexes decreased with age, but multiple regression analysis showed that the total exposure time to vibration had an independent negative association with the HRV. There were significant differences in all the frequency bands (frequency related power, FRP) of the heart rate between those with the longest and those with the shortest exposures. The HRV during a deep breathing test is associated with the activity of the parasympathetic nervous system and is decreased in autonomic neuropathies. Our results suggest that prolonged exposure to the vibration caused by a chain saw has a negative effect on the parasympathetic activity and thus causes autonomic dysfunction.

Adult↗

PubMed2005

[Application of heart rate variability in prognosis of patients with diabetes mellitus].

The ECG based heart rate variability (HRV) measurements has become an important method of assessment of the cardiac autonomic regulation. There is a large body of clinical and experimental evidences indicating that reduced HRV is a predictor of death in patients after myocardial infarction and with heart failure. Diabetic autonomic neuropathy (DAN) is a serious and common complication of diabetes. Cardiovascular autonomic neuropathy (CAN) is the most studied and clinically important form of DAN. Published data demonstrate that CAN is strongly associated with an increased risk of myocardial ischaemia, serious arrhythmias, exercise intolerance and mortality. The determination of the presence of CAN is usually based on Ewing's tests. Measurement of HRV is readily available method and serves to establish diagnosis of autonomic dysfunction. The reduction in parameters of HRV seems not only to carry negative prognostic value in patients with diabetes but also to precede the clinical expression of autonomic neuropathy HRV evaluation in diabetes can encourage physician to improve further therapy.

Arrhythmias, Cardiac↗