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Abnormal heart rate variability as a manifestation of autonomic dysfunction in hemispheric brain infarction
J T Korpelainen1, K A Sotaniemi, H V Huikuri
1Department of Neurology, University of Oulu, Finland.
Insights
Stroke significantly impairs heart rate variability (HRV) long-term, affecting the cardiovascular autonomic system. This reduced HRV, especially in the acute phase, may indicate a poor prognosis for stroke patients.
Area of Science:
- Cardiology
- Neurology
- Autonomic Nervous System Research
Background:
- Abnormal heart rate variability (HRV) is linked to adverse outcomes in coronary artery disease.
- Similar HRV abnormalities are observed in acute stroke patients using short-term ECGs.
- The clinical significance of long-term HRV in stroke remains unclear.
Purpose of the Study:
- To investigate the clinical significance of long-term heart rate variability (HRV) in patients with hemispheric brain infarction.
- To assess changes in HRV from the acute phase through 6 months post-stroke.
- To compare HRV in stroke patients with healthy controls.
Main Methods:
- Prospective study analyzing 24-hour ECG recordings.
- Measured time and frequency domain HRV components in 31 acute hemispheric infarction patients and 31 controls.
- Follow-up assessments at 1 and 6 months post-infarction.
Main Results:
- Stroke patients exhibited significantly lower HRV components compared to controls at all time points.
- Impaired HRV correlated with neurological deficit severity and disability.
- Patients with increased intracranial pressure showed no relevant spectral components.
Conclusions:
- Hemispheric brain infarction causes lasting damage to the cardiovascular autonomic regulatory system, evidenced by abnormal HRV.
- Distorted HRV during the acute stroke phase may be a prognostically unfavorable sign.
- Long-term HRV assessment offers insights into stroke recovery and autonomic function.
Background And Purpose:
Abnormal heart rate variability is related to prognostically unfavorable ventricular arrhythmias and sudden arrhythmic death in coronary artery disease. Short-term electrocardiographic (ECG) recordings have shown similar abnormalities of heart rate variability in patients with acute stroke. However, there is no information regarding the clinical significance of these abnormalities and of heart rate variability in long-term ECG recordings in stroke.
Methods:
In this prospective study, we analyzed the time domain and frequency domain measures of heart rate variability from 24-hour ECG recordings in 31 consecutive patients with hemispheric brain infarction in the acute phase and at 1 and 6 months after the infarction and in 31 age- and sex-matched healthy control subjects.
Results:
All the measured components of heart rate variability, ie, standard deviation of RR intervals (P < .001), total power (P < .0001), very-low-frequency power (P < .0001), low-frequency power (P < .001), and high-frequency power (P < .05), were significantly lower than those of the control subjects in both the acute phase and 1 and 6 months later. Impaired heart rate variability correlated with the severity of neurological deficits and disability. In five patients with increased intracranial pressure due to large brain infarction, no relevant spectral components were found.
Conclusions:
Hemispheric brain infarction seems to cause significant long-lasting damage to the cardiovascular autonomic regulatory system manifested as abnormalities of heart rate variability. Distorted heart rate variability in the acute phase of stroke may be prognostically unfavorable.