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At least 271 records · Page 15Linked to original sources
PubMed1995

Does abnormal QT interval prolongation reflect autonomic dysfunction in diabetic patients? QTc interval measure versus standardized tests in diabetic autonomic neuropathy.

The question as to whether the QTc interval correlates with five cardiovascular tests (deep breathing test, 30/15 ratio test, lying to standing test, cough test, and postural blood pressure test) for the diagnosis of diabetic autonomic neuropathy (DAN) was investigated in 168 (38 Type 1, 130 Type 2) consecutive outpatients (mean age 54.9 +/- 11.2 years). QT interval was measured on an ECG recorded at rest and QTc calculated according to Bazett's formula. The percentage of patients with a QTc greater than 0.440 s was: absent DAN = 11% (n = 7), probable DAN = 7% (n = 4), definite DAN = 23% (n = 12) (p < 0.05), and the mean (+/- SD) QTc values were 0.403 +/- 0.028 s, 0.405 +/- 0.023 s, and 0.421 +/- 0.026 s, respectively. A significant correlation between QTc duration and DAN score of autonomic cardiovascular test results (r = 0.34, p < 0.0001) was observed. The calculated specificity, sensitivity, positive and negative predictive values were 89%, 15%, 70% and 37%, respectively. In conclusion, QTc can be considered as an additional specific test in the assessment of diabetic autonomic neuropathy, but cannot replace the standard battery of cardiovascular tests.

Analysis of Variance↗
PubMed1986

Autonomic dysfunction in Parkinson's disease.

We studied autonomic functions in 31 chronically treated patients with Parkinson's disease. They were tested twice: before a dose of medication and after medication. Before a dose of medication, when motor disability was maximal ("off"), patients had higher resting pulse rate, greater orthostatic fall in blood pressure, and decreased responses to Valsalva and cold pressor stimuli than their spouse-controls. To a heat stimulus, sweating was increased in the head and neck, and skin temperatures were cooler. After medication when function was optimal ("on"), the cardiovascular reflex abnormalities remained but were no worse. Skin temperature alterations and sweating abnormalities resolved.

Adult↗
PubMed1996

Alcohol abuse exaggerates autonomic dysfunction in chronic liver disease.

BACKGROUND: Advanced chronic liver disease is characterized by peripheral arterial vasodilation and increased plasma catecholamine concentrations. These haemodynamic alterations may reflect impaired vascular responsiveness due to autonomic nerve dysfunction. METHODS: Three established non-invasive tests based on the heart reactions to deep breathing (expiratory/inspiratory (E/I) ratio) and to tilt (acceleration and brake indices) were used to evaluate age-related autonomic nerve function in 27 patients with chronic alcoholic and non-alcoholic liver disease. Liver function was estimated by demethylating capacity. The results were compared with a control group consisting of 56 healthy individuals. RESULTS: Overall, 12 patients (52%) had autonomic neuropathy (10 of 13 (77%) patients with alcoholic and 2 of 14 (14%) with non-alcoholic liver disease). Variance analysis showed that the age-corrected E/I ratio, but not the acceleration and brake indices, was significantly decreased compared with controls both in patients with alcoholic and non-alcoholic liver disease, indicating vagal nerve dysfunction (P < 0.0001 and 0.0133, respectively). The decrease in E/I ratio was also significantly more pronounced (-1.77 (0.62) (median (interquartile range)) versus 0.76 (0.70); P = 0.049) in patients with alcoholic compared with non-alcoholic liver disease. Furthermore, in contrast to non-alcoholics, patients with alcoholic liver disease were unable to increase their diastolic blood pressure after return to upright from a tilted position, indicating additional sympathetic neuropathy. CONCLUSIONS: Autonomic, mainly vagal, nerve dysfunction is common in patients with liver diseases and is further exaggerated by alcohol abuse. Autonomic neuropathy may contribute to altered vascular responsiveness in patients with chronic liver diseases.

Autonomic Nervous System Diseases↗
PubMed2002

Physiologic assessment of autonomic dysfunction in pallidopontonigral degeneration with N279K mutation in the tau gene on chromosome 17.

Autonomic function was investigated in five affected and five at-risk members of a single kinship of pallidopontonigral degeneration (PPND), which is a progressive syndrome of parkinsonism and frontotemporal dementia resulting from a mutation in the N279K tau gene on chromosome 17. Affected subjects reported symptoms including hyperhidrosis, sialorrhea, urinary frequency or incontinence, thermal intolerance, male sexual dysfunction, lacrimation, and dryness of the eyes or mouth. None had orthostatic hypotension. Autonomic testing revealed mild-to-moderate abnormalities in all five affected subjects and minor abnormalities in the three oldest, asymptomatic, at-risk subjects. Findings in affected subjects consisted of preganglionic sudomotor dysfunction in all five, impaired cardiovagal function in three, and reduced or absent pupillary near responses in four. Tests of adrenergic function were normal in all subjects. The degree of autonomic dysfunction correlated significantly with disease duration and with indices of disease severity. In conclusion, there is evidence in PPND of a disturbance in the central autonomic network.

Adult↗
PubMed1998

Autonomic dysfunction in elderly bedfast patients.

OBJECTIVE: to quantify autonomic function in bedfast elderly patients. PATIENTS AND METHODS: we analysed orthostatic blood pressure, heart rate response to tilt, heart rate response to deep breathing, quantitative sudomotor axon reflex test (QSART) and beat-to-beat blood pressure during phases II and IV of the Valsalva manoeuvre (VM) in 15 patients with (OH+) and without orthostatic hypotension (OH-) and 12 age-matched controls. RESULTS: all bedfast patients had a poor response in the late phase II of beat-to-beat blood pressure, while OH+ patients had an additional abnormality in phase IV. QSARTs in the distal leg and foot were decreased in both OH+ and OH- groups. There was no difference between the two groups in duration of being bedfast or in activities of daily living. CONCLUSIONS: (i) being bedfast results in postganglionic sympathetic dysfunction in the lower extremities; (ii) some patients who have beta-adrenergic dysfunction have OH and (iii) preventing patients from becoming being bedfast may be important for the maintenance of normal autonomic functions.

Aged↗
PubMed2001

Spontaneous oscillations in cerebral blood flow velocity give evidence of different autonomic dysfunctions in various types of headache.

OBJECTIVES: Our objectives were to determine if: (1) patients with migraine have B wave abnormalities in comparison to normal controls and patients with chronic tension headache and (2) patients with chronic tension headache have an imbalance in autonomic activity that is reflected in differences in Mayer wave activity in comparison to normal controls. BACKGROUND: B waves and Mayer waves are spontaneous oscillations in cerebral blood flow velocity with a frequency of 0.5 to 3 or 4 to 7 cycles per minute, respectively, and can be measured by transcranial Doppler sonography. There is experimental evidence that B waves are generated by certain brain stem nuclei which modulate the lumen of the small intracerebral vessels via monoaminergic nerve endings. In contrast, Mayer waves in cerebral blood flow velocity have no central generator but mirror the Mayer waves in arterial blood pressure which represent peripheral autonomic activity. Migraine may be attributed to a neurotransmitter imbalance in brain stem nuclei. Dysfunctions of the peripheral autonomic nervous system are known in patients with chronic tension headache. METHODS: Using bilateral transcranial Doppler monitoring of the middle cerebral artery B waves and Mayer waves were studied in 30 patients with migraine without aura, 28 subjects with tension-type headache, and 30 normal controls. Coefficient of variation as a quantitative parameter for amplitude of waves and the mean frequency were calculated from the envelope curves of the Doppler spectra. RESULTS: The coefficient of variation of B waves was higher in migrainous patients compared with patients with tension-type headache and normal controls (P<.05), indicating an increase in activity of brain stem nuclei in migraine only. Patients with chronic tension headaches had lower values for Mayer wave activity in comparison with normal controls (P<.05), a sign of an impairment of sympathetic activity. CONCLUSIONS: Our data support the dysfunction of the brain stem monoaminergic/serotonergic system in migraine. In contrast, patients with chronic tension headache have an autonomic dysfunction of peripheral origin presenting as a decrease of sympathetic activity.

Adult↗