Effects Of Acute Ischemic Stroke On Autonomic Function Parameters Assessed By Heart Rate Variability(HRV)

[Objective] 1. Stroke has been shown to alter autonomic function .To explore the differential effects of stroke localization on autonomic function parameters assessed by HRV. 2. To study the circadian fluctuation of HRV in the acute phase of ischemic stroke (5days and 4 weeks) and the relationship between HRV and the factors which may affect the alteration of the autonomic function. [Methods] 1.Cerebrel CT verified hemispheric brain infarction, 68 cases were divided into 4 groups: right hemispheric brain infarction , right insular, left hemispheric brain infarction > left insular. HRV were obtained twice from patients in acute stroke (5 days and 4 weeks) and 50 age-and sex-matched health control subjects. 2. Neurological deficits of the patients were scored according to the Scandinavia Stroke Scale. And the disability was evaluated with Barthel Index. The myocardial enzyme, free blood glucose, blood fat and average artery pressure measurement were finished twice (5 days and 4 weeks). [Results]1. In the acute phase of stroke (5 days), all components of heart rate variability, standard deviation of RR intervals, total power, high-frequency power and low-frequency had significantly decreased (P<0.01). Patients with right-middle cerebral artery(R-MCA) and insular lesions had significantly lower power spectrum analysis values compared with all other localization P<0.05 ). 2. All components of HRV were similar at night (from midnight to 6 AM) and during the day (from 9 AM to 9PM),indicating that the circadian oscillation of HRV had been abolished. At 4 weeks after brain infarction, the circadian rhythm had returned partly and the components obtained 4 weeks later were significantly higher than those in 5 days. 3. In multiple linear analysis , HRV were correlated with age, average artery pressureand Neurological deficit scores. [Conclusions] 1. Acute cerebral infarction significantly decreases heart rate variability as a result of cardiovascular autonomic dysregulation , the decreased autonomic function is reversibly returned 4 weeks after the infarction. 2. Age, average artery pressure and Neurological deficit scores were correlated with the alteration of HRV in patients with acute cerebral infarction.