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At least 1,207 records · Page 67Linked to original sources

PubMed1995

Heart rate and blood pressure variability: implications for psychiatric research.

Symptoms of anxiety suggest autonomic dysfunction and most of the psychotropic agents used to treat anxiety and affective disorders have strong autonomic effects. This article describes the utility and importance of analysis of heart rate and blood pressure time series to study cardiac autonomic function in psychiatric research. The variability of heart rate between 0.15 and 0.5 Hz is related to respiratory sinus arrhythmia, and is modulated by cholinergic activity in both supine and standing postures, while the variability between 0.04 and 0.15 Hz is dually influenced by cholinergic and adrenergic mechanisms which can be used as a relative measure of sympathetic activity in standing posture. Analysis of beat-to-beat control of heart rate and blood pressure gives important information about cardiac sympathetic and parasympathetic interaction, which could be used to study the possible link between anxiety and depressive disorders and increased cardiovascular morbidity.

Autonomic Nervous System↗

PubMed2006

Cardiac autonomic control in individuals with Down syndrome.

Our goal in this study was to compare cardiac autonomic control at rest between 50 individuals with Down syndrome and 24 control participants without disabilities. Resting autonomic function was assessed using analysis of heart rate variability. Participants with Down syndrome had reduced total heart rate variability, which indicates possible autonomic dysfunction in this population. Their VO2 peak and BMI were not significantly correlated with resting cardiac autonomic control. This may suggest that fitness level and obesity differentially affect cardiac autonomic control in persons with Down syndrome compared to their healthy, nondisabled peers.

Adult↗

PubMed1992

Risk for cardiovascular autonomic neuropathy is associated with the HLA-DR3/4 phenotype in type I diabetes mellitus.

OBJECTIVE: To identify risk factors for the development of cardiovascular autonomic neuropathy in patients with juvenile-onset type I diabetes mellitus. DESIGN: Cross-sectional examination of an inception cohort 15 to 21 years after the onset of diabetes. SETTING: Outpatient diabetes clinic. PATIENTS: Seventy-nine patients with type I diabetes who experienced onset of disease before 21 years of age and who were followed for 15 to 21 years. MEASUREMENTS: Autonomic nerve function was evaluated in all patients using deep breathing and tilt tests. On the basis of these tests, an index of cardiovascular autonomic neuropathy was derived and patients were classified as having intact, mildly impaired, or significantly impaired autonomic function. RESULTS: The group with significantly impaired function had a higher mean hemoglobin A1 at the time of examination than the group without impairment, yet the groups did not differ regarding glycemic control during the first decade of diabetes. The HLA-DR3/4 phenotype was present in more than 50% of the patients with significant autonomic dysfunction and conferred relative odds of 6.2 (95% CI, 1.7 to 23.3) for the development of autonomic neuropathy when compared with other HLA-DR phenotypes. Sex, percent ideal body weight, and smoking did not have a statistically significant effect on the development of autonomic neuropathy. CONCLUSIONS: The development of cardiovascular autonomic neuropathy in type I diabetes mellitus is strongly associated with the HLA-DR3/4 phenotype. Thus, genetic predisposition may play an important role in the development of this complication.

Adult↗

PubMedDate not supplied

Intrathecal baclofen: a useful agent in the treatment of well-established complex regional pain syndrome.

BACKGROUND AND OBJECTIVES: We present 2 case reports that illustrate that chronic intrathecal (IT) baclofen administration may be efficacious in treating patients with long-standing complex regional pain syndrome, type I (CRPS I) who have failed treatment with multiple drugs and procedures. CASE REPORTS: Both cases presented were women who developed CRPS I following multiple lower extremity surgeries. One patient had had symptoms for 5 years and had continued symptoms despite multiple sympathetic blocks, sympathectomy, spinal cord stimulation, and various medication trials. The other patient had had chronic lower extremity pain for 30 years and symptoms of CRPS for about 5 years. Her symptoms continued despite multiple sympathetic blocks, sympathectomy, and many medications. Neither patient had motor dysfunction (dystonia, tremors, spasticity) associated with their painful disorder. One patient experienced good control of pain, allodynia, and autonomic dysfunction with a combination of IT baclofen and clonidine after failing treatment with IT morphine. Baclofen alone produced intolerable side effects at the doses required to produce adequate analgesia. The other patient experienced long-term control of pain, allodynia, and autonomic symptoms with IT baclofen alone. CONCLUSIONS: IT baclofen appears to be an option for patients with intractable CRPS who have failed other modalities, including IT morphine.

Adult↗

PubMed1989

Autonomic denervation hypersensitivity in the primary glaucomas.

Autonomic denervation hypersensitivity of the iris was assessed in 44 patients with primary closed-angle glaucoma, 20 patients with primary open-angle glaucoma, and 40 age- and sex-matched control subjects. Significantly increased pupillary constriction in response to 2.5% methacholine chloride, indicating parasympathetic denervation hypersensitivity, was present in both closed-angle (p less than 0.02) and open-angle glaucoma patients (p less than 0.001), compared with the control group. Significantly increased pupillary dilatation in response to 0.5 per cent phenylephrine hydrochloride, indicating sympathetic denervation hypersensitivity of the iris, was also present in both closed-angle glaucoma (p less than 0.01) and open-angle glaucoma patients (p less than 0.05). The association between autonomic neuropathy and the primary glaucomas is discussed, with particular reference to the potential effects of autonomic dysfunction on aqueous dynamics.

Aged↗

PubMed2000

Spectral analysis of heart variability in the newborn infant.

We investigated the relationship between spectral power and both mean heart rate (HR) and heart rate variability (HRV). Spectral power was calculated using digital heart rate recordings from term infants. Regression analysis revealed a positive correlation between low-frequency (LF) sympathetic power and HR, and a negative correlation between high-frequency (HF) parasympathetic power and HR. HRV correlated positively in all regions of the power spectrum. In awake infants, the contribution of HF power to total power (HF/TP) was significantly decreased. LF power tended to be greater, however, this trend was not statistically significant. By following expected autonomic patterns, the findings of this study confirm that spectral analysis provides a noninvasive method for the assessment of autonomic activity influencing the newborn heart. The correlation between spectral power and HRV can serve as an additional tool in the study of autonomic dysfunction.

Autonomic Nervous System↗

PubMed2000

Severe hypertension induced by the long-acting somatostatin analogue sandostatin LAR in a patient with diabetic autonomic neuropathy.

A 26-yr-old woman with type 1 diabetes and severe symptomatic autonomic neuropathy was treated with the long-acting somatostatin analogue Sandostatin LAR for intractable diarrhea. Her diarrhea had previously been successfully managed with three daily injections of octreotide without adverse consequences. She was given a single dose of Sandostatin LAR and within 2 weeks reported the development of increasingly frequent and severe headaches. Three weeks after the injection, she was admitted to hospital with severe hypertension, which eventually resolved with the administration of antihypertensive agents. No other underlying cause of the hypertension was discovered. Rechallenge of the patient with octreotide resulted in a transient hypertensive episode, which lasted 3 h. Severe hypertension, therefore, seems to be a possible adverse effect of treatment of diabetic diarrhea with somatostatin analogues, which should be used with great caution in subjects with severe autonomic dysfunction.

Adult↗

PubMed1995

Clinical/metabolic correlations in multiple system atrophy. A fludeoxyglucose F 18 positron emission tomographic study.

OBJECTIVE: To evaluate the regional cerebral metabolic involvement; the relationships among regional brain metabolism, clinical features, and quantitative measures of disease severity; and the patterns of brain involvement that can be related to the different types of onset: striatonigral degeneration vs olivopontocerebellar atrophy. DESIGN: Fludeoxyglucose F 18 positron emission tomography (PET) studies performed in patients with multiple system atrophy (MSA) were evaluated for their clinical features at the onset of the disease and at the time of the PET study. CASES: Seventeen patients diagnosed as having probable MSA and 10 age-matched controls. RESULTS: The hypometabolism in the putamen-pallidum complex and in the cerebellum was the best discriminant for disease classification. The efficacy of levodopa treatment was positively correlated with the metabolic activity of the putamen-pallidum complex. The patients with olivopontocerebellar atrophy type (N = 8) had a prevalent hypometabolism in the cerebellum, while the patients with striatonigral degeneration type (N = 9) had a prevalent impairment in the pallidum-putamen complex. We demonstrated a negative correlation between (1) severity of parkinsonism and metabolic values of putamen and caudate; (2) severity of cerebellar signs and metabolism in the cerebellum; and (3) autonomic dysfunction and metabolic activity in the thalamus, frontal, and temporal regions, bilaterally. CONCLUSIONS: These findings support the selective metabolic reduction in the putamen and cerebellum as a marker of MSA. The clinical/metabolic correlations, demonstrating the expected dependence of extrapyramidal and cerebellar signs by dysfunction of basal ganglia and cerebellum, also support a possible involvement of central nervous system structures in autonomic control.

Atrophy↗

PubMed1995

Transfer function analysis of respiratory sinus arrhythmia: a measure of autonomic function in diabetic neuropathy.

Standard techniques measuring heart rate (HR) variability do not account for its dependence on the rate and depth of respiration or measure the time relationship between changes in lung volume and HR. We used transfer function analysis to determine the magnitude and time relationship of the HR response to a known change in lung volume in controls and diabetics. This technique demonstrated significant differences between controls and diabetics with varying degrees of autonomic dysfunction. Specifically, reduced supine vagal and increased supine sympathetic HR modulation was found with progression of the autonomic neuropathy. In response to postural change the normal diabetics displayed impaired sympathetic HR modulation. Transfer function analysis yields new insight into the sequence of changes that occur with diabetic autonomic neuropathy and provides an accurate, easily comprehensible measurement of respiratory induced HR variability.

Adult↗

PubMed2005

Reproducibility of heart rate variability and blood pressure variability in individuals with spinal cord injury.

Individuals with spinal cord injury (SCI) are prone to orthostatic intolerance and an increased risk of cardiovascular disease. The use of heart rate variability (HRV) and blood pressure variability (BPV) as indices of cardiovascular regulation would be valuable in this population; however, their reproducibility has yet to be tested in those with SCI. The purpose of this study was to examine the day-to-day reproducibility of resting HRV and BPV in individuals with SCI. Ten individuals (age 35.9 +/- 13.2 yrs) with chronic (5.4 +/- 7.7 years post injury) SCI (C4-T12; ASIA A-C) participated. On two occasions within a two-week period, 10-minute supine electrocardiogram and Finapres blood pressure recordings were obtained during spontaneous breathing. Computer software calculated frequency domain measures of HRV and BPV (Low frequency (LF) power, High frequency (HF) power, and LF:HF ratio). Intraclass correlations coefficients (R) were used as an index of day-to-day reproducibility, and analyses were conducted on all participants and only those with tetraplegia. For HRV, measures of heart rate, LF, and LF:HF were found to be highly reproducible (R = 0.82-0.88); however, the reproducibility of HF was found to be poor (all participants: R = 0.53, tetraplegia: R = 0.66). Measures of blood pressure as well as systolic BPV also showed high reproducibility (R = 0.72-0.93). Measures of diastolic BPV were less reproducible but still acceptable (R = 0.71-0.89) with the exception of LF:HF(DBP) (R = 0.51). In conclusion, despite the autonomic dysfunction associated with SCI, measures of HRV and BPV may still be used as reproducible indices of autonomic cardiovascular regulation in this population.

Adult↗

PubMed2005

Are cardiac syndrome X, irritable bowel syndrome and reflex sympathetic dystrophy examples of lateral medullary ischaemic syndromes?

Altered pain appreciation and autonomic function are hallmarks of Cardiac syndrome X, Irritable bowel syndrome and Reflex sympathetic dystrophy. Both pain appreciation and autonomic function are controlled by the lateral medulla. This hypothesis proposes that lateral medullary ischaemia at a microvascular level is responsible for these syndromes and could also be linked to other conditions where autonomic dysfunction is a major feature such as late-onset asthma, type 2 diabetes and essential hypertension. Autonomic function is controlled by the nucleus tractus solitarius, which acts as the main viscero-afferent nucleus in the brain stem regulating vagal tone. It is particularly susceptible to ischaemia since it is highly metabolically active and lies in a medullary arterial watershed zone. The anatomical route of the vertebral artery through cervical vertebra makes it vulnerable to injury from whiplash with or without any genetic predisposition to atheroma formation. This could make microvascular occlusion commonplace and a plausible explanation for the above syndromes. Ischaemia rather than infarction occurs because of the excellent collateral blood supply in the brainstem. In support of this hypothesis, a new Transcranial doppler ultrasonography arterial signal has been described called small vessel knock, the ultrasound signal of small vessel occlusion. Recent evidence has shown that ultrasound targeting of this signal in the vertebral artery improves clinical symptoms in these syndromes which supports this hypothesis. Two such cases are discussed.

Arterial Occlusive Diseases↗

PubMed1999

Sympathetic skin response in diabetic children: do diabetic children have diabetic neuropathy?

BACKGROUND: Abnormal sympathetic skin response (SSR) has been reported in adult patients with diabetic neuropathy. In addition, other studies have revealed abnormal SSR in diabetic patients not having autonomic symptoms and autonomic dysfunctions. These findings have been only obtained from adult patients. There have been few reports on the autonomic functions in diabetic children. Accordingly, it is not clear whether the autonomic neuropathy occurs in diabetic children. The aim of the present study is to clear autonomic function in children with insulin-dependent diabetes mellitus by SSR. METHODS: The SSR was measured in 28 normal healthy children and in eight patients with IDDM not having symptoms of dysautonomia. The SSR was elicited using 10 stimuli on programmed Nihonkoden Neuropack Sigma model machine. Following a single electrical stimulation, four SSR were recorded in both the palms and the soles simultaneously. RESULTS: The SSR were simultaneously obtained in 100% of the two groups. The amplitudes in the palms and soles were not significantly different between the two groups. The mean and shortest latency in the soles were significantly longer in the IDDM group than in the control group (P < 0.01). None of the measurements of SSR revealed correlation with duration of diabetes and onset of illness. CONCLUSIONS: Diabetic neuropathy may not have occurred in young patients having shorter duration of illness. Conversely, assuming that prolonged latency is abnormal, it may even have occurred in them. Follow up on these patients with prolonged latencies would be required.

Adolescent↗

PubMed1995

Impaired left ventricular diastolic function and vascular postischemic vasodilation associated with microalbuminuria in IDDM patients.

OBJECTIVE: Microalbuminuria is considered an important predictor of cardiovascular events in diabetic patients. In this study, a possible association of microalbuminuria with significant changes in left ventricular (LV) morphology and function and generalized vascular dysfunction was analyzed in insulin-dependent diabetes mellitus (IDDM) patients without hypertension, coronary artery disease, or autonomic dysfunction. RESEARCH DESIGN AND METHODS: Thirty-four young long-term IDDM patients, 16 with and 18 without microalbuminuria, and 20 control subjects were studied. LV systolic function and wall thickness were evaluated by M-mode echocardiography. LV diastolic function was studied using a combined echo-Doppler and phonocardiographic technique. The hyperemic response to forearm ischemia was measured by strain-gauge plethysmography. All patients underwent 24-h ambulatory blood pressure monitoring. RESULTS: LV mass index and wall thickness:radius ratio were significantly higher in microalbuminuric patients. LV relaxation was significantly impaired in both diabetic groups compared with control subjects; moreover, this impairment was significantly greater in microalbuminuric than in normoalbuminuric patients. In microalbuminuric patients, forearm postischemic vasodilation was also significantly lower and mean awake diastolic blood pressure (dBP) was significantly higher than in the other two groups. CONCLUSIONS: Our data suggest that microalbuminuria is associated with significant changes in LV morphology, a more severe impairment of cardiac diastolic function, altered vascular dilatory capacity, and higher daytime dBP. Therefore, microalbuminuric patients should be considered to have a higher risk of cardiovascular complications and be kept under closer surveillance.

Adult↗

PubMed1996

Impact of disease duration on cardiovascular and pupillary autonomic nervous function in IDDM and NIDDM patients.

OBJECTIVE: To determine the age-independent impact of disease duration on autonomic nervous function in diabetic patients and to compare it with other disease-related complications. RESEARCH DESIGN AND METHODS: Of the patients with diabetes, 166 (66 IDDM, 100 NIDDM) were investigated using standardized cardiovascular and pupillary test procedures, which provide 10 age-independent percentile values for each patient. Sensorimotor neuropathy was assessed using a standardized clinical examination, retinopathy by fundoscopy, and nephropathy using daily urinary protein excretion and creatinine clearance. RESULTS: The duration of the disease did not correlate with the results of any one of six standard cardiovascular tests (P > 0.15). Pupillary parameters showed a weak negative correlation with disease duration (P < 0.04). Prevalence of cardiovascular autonomic dysfunction was not different in five different subgroups subdivided according to disease duration (0-6, 7-12, 13-18, 19-24, and > or = 25 years), whereas prevalence of pupillary dysfunction changed significantly with disease duration (P = 0.016). In contrast, the prevalence of sensorimotor neuropathy (P = 0.006), retinopathy (P < 0.001), and proteinuria (P = 0.010) was significantly higher in patients with long-standing disease. Disease duration was not significantly different in patients without overall cardiovascular dysfunction, as compared with patients with dysfunction (15.6 +/- 1.0 vs. 16.5 +/- 1.5 years, P = 0.626). This was also found when considering overall pupillary dysfunction (14.5 +/- 1.4 vs. 17.2 +/- 1.0 years, P = 0.125). CONCLUSIONS: Disease duration was not correlated with cardiovascular autonomic nervous function, whereas a correlation was observed with pupillary autonomic nervous function, sensorimotor neuropathy, retinopathy, and proteinuria. This may indicate that cardiovascular autonomic nervous function does not markedly change during the course of the disease. The question arises whether cardiovascular autonomic neuropathy may be more a functional abnormality than a structural lesion of the autonomic nervous system, which may be already present at the beginning, or even before, the manifestation of diabetes.

Adolescent↗

PubMed1987

Autonomic neuropathy after rubella infection.

A woman with autonomic neuropathy after rubella infection is described. She had features of both sympathetic and parasympathetic impairment, the major problems being postural hypotension, abdominal and parotid pain, and fatigue. Autonomic dysfunction persisted 38 months after the rubella infection with minimal response to treatment. The literature relating to autonomic neuropathy is reviewed, and the similarities of this patient's condition to the Guillain-Barré syndrome are discussed.

Abdomen↗

PubMed1994

[Abnormalities of cardiovascular baroreflex control in renal failure and cardiac insufficiency. Experimental study and brief critical review of the literature].

We attempted to determine the relevance and relative prevalence of autonomic dysfunction in 7 patients with end-stage renal disease (ESRD) but no heart disease, 8 patients with left ventricular dysfunction (LVD) with no renal disease and 8 patients with ESRD + LVD. In each group, the assessment of autonomic function and location of the lesion was performed by using the baroreflex sensitivity tests, based upon heart rate (ie Valsalva, deep breathing, lying to standing) to study the parasympathetic system as well as based upon blood arterial pressure (ie standing and sustained handgrip) to evaluate the sympathetic system. The same tests were performed in 7 healthy volunteers enrolled as control group. Separate studies were performed on the efferent parasympathetic arc (atropine test) and the efferent sympathetic arc (cold pressor test). There was evidence of parasympathetic damage in 100% of ESRD patients, in 87.5% of ESRD + LVD patients, and in 62.5% of LVD. Only 1 of ESRD patients showed defective response to atropine whereas the remaining had a normal response, suggesting an afferent lesion alone. No abnormalities were found in the response to cold pressor test, thereby suggesting a lack of involvement of the efferent sympathetic arc. The response to handgrip was higher in LVD patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗

PubMed1986

Diabetic autonomic neuropathy.

The incidence of autonomic dysfunction as a complication of diabetes mellitus is reported to be as high as 20% to 40%. Symptoms of diabetic autonomic neuropathy (DAN) are often vague, and signs difficult to detect on routine physical examination. The early diagnosis of DAN is possible by utilizing several simple noninvasive tests, which may also be helpful in localizing the lesion(s) to specific autonomic pathways. DAN may affect multiple organ systems, to include cardiovascular, gastrointestinal, genitourinary and/or neuroendocrine, and may, in fact, be life-threatening. The same metabolic disturbances of somatic peripheral nerve may also be responsible for DAN. Like somatosensory neuropathy, definitive therapy for DAN is not yet satisfactory, although multiple chemotherapeutic agents have been tried and warrant further investigation.

Autonomic Nervous System Diseases↗

PubMed1982

Involvement of autonomic nervous system in experimental allergic neuritis. A light- and electron-microscopic study.

The affection of the sympathetic and parasympathetic structures of the peripheral nervous system in rabbits with experimental allergic neuritis (EAN) was demonstrated light- and electron-microscopically. The general characteristics of the microscopic findings were qualitatively similar to those previously established in the somatic nervous system, but they were less extensive. The neuronal perikarya and the axons in the autonomic nervous system (ANS) were mostly normal. Occasionally, cytoplasmic vacuoles in a few nodose ganglion neurons and some degenerating axons were seen. Other than myelin derived antigens could be operating in whole-nerve induced EAN, since inflammatory cells also infiltrated target tissue areas devoid of myelinated nerve fibers. The presence of numerous plasma cells in the target tissue suggests that local antibody formation may contribute to the destructive process. Our results establish that the ANS is frequently affected in EAN, especially in the more severe forms. Thus EAN was proved to be also in this respect a useful model for the human disease Guillain-Barré syndrome, which likewise is often complicated by autonomic dysfunctions.

Animals↗