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Document Type |
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Article In Journal |
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Document Title |
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Time-domain Analysis of Heart Rate Variability in Diabetic Patients With and Without Autonomic Neuropathy. Time-domain Analysis of Heart Rate Variability in Diabetic Patients With and Without Autonomic Neuropathy. |
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Document Language |
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English |
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Abstract |
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The normal heart rate is determined by dynamic interaction between the spontaneous cardiac impulse generated by the sinoatrial (SA) node and conflicting influences of the sympathetic and parasympathetic nervous systems on the conducting tissue of the heart. The rate of spontaneous depolarization of the SA node is itself affected by its metabolic milieu and in the longer term, by hormonal influences. Normal resting heart rate is maintained by the tonic influence of the parasympathetic vagus nerve, and acceleration of the heart rate is affected both by the inhibition of vagal influence and the stimulation of the sympathetic nervous system. The activity of the autonomic is also governed by moment-to-moment changes in blood pressure and respiration, which alter heart rate continuously. The resultant heart rate is the summation of all these influences and thus inherently unpredictable on a beat-to-beat basis.
Recent advances in technology have enabled accurate recordings and the automated analysis of 24-hour ECG to detect beat-to-beat variability, providing not only more detailed, but much more accurate and precise information than the earlier tests. Heart rate variability (HRV) decreases with age, and shows a circadian variation, being maximum during sleep. It is also rate dependant, the heart rate showing more variability at lower heart rates. The loss of this beat-to-beat variability is a sign of disease.
It has long been known that cardiovascular autonomic diabetic neuropathy (CADN) is associated with a loss of heart rate variability. These patients have a poor cardiovascular prognosis, with a 5-year mortality greater than 50%. Some of this may be attributed to micro- or macrovascular disease, however, a recent study has shown the relatively poor prognosis of patients with CADN in the absence of clinically detectable micro- or macrovascular conditions. Clinically detectable autonomic failure is usually evident many years or decades after the onset of diabetes. It is likely that these patients develop subtle deficits in HRV much earlier, and these may include diminution in time-domain analysis. Detection of such changes may be used as markers of pathology, particularly to study the benefits of therapeutic interventions. Thus, the aim of this work was to study HRV in diabetic patients with clinical and sub-clinical autonomic neuropathy (AN), and to determine whether HRV in patients with sub-clinical AN is abnormal in comparison to normal controls. |
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ISSN |
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1004-1319 |
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Journal Name |
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Annuals of Saudi Medicine |
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Volume |
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22 |
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Issue Number |
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6-5 |
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Publishing Year |
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2002 AH
2002 AD |
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Article Type |
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Article |
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Added Date |
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Monday, March 15, 2010 |
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Researchers
| خضر عبدالجليل | Abdel Galil, Khidir | Researcher | Doctorate | |
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