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Heart rate dynamics in refractory and well controlled temporal lobe epilepsy
H Ansakorpi1, J T Korpelainen, H V Huikuri
1Departments of Neurology and Medicine, Division of Cardiology, University of Oulu, Oulu, Finland. htansakorpi@hotmail.com
Journal of Neurology, Neurosurgery, and Psychiatry
|January 11, 2002
Summary
Temporal lobe epilepsy (TLE) patients show reduced heart rate (HR) variability and altered fractal complexity. These changes in autonomic cardiovascular regulation may increase the risk of dangerous arrhythmias in TLE.
Area of Science:
- Cardiology
- Neurology
- Biomedical Engineering
Background:
- Autonomic nervous system dysfunction, particularly cardiovascular dysregulation, is common in temporal lobe epilepsy (TLE).
- Previous studies quantified heart rate (HR) variability using traditional time and frequency domain measures from short-term ECGs.
- Advanced non-linear and fractal dynamics (
Purpose of the Study:
- To evaluate interictal autonomic cardiovascular regulatory function in TLE patients using novel complexity and fractal measures of HR variability.
- To compare HR variability in refractory TLE, well-controlled TLE, and healthy control groups.
- To investigate if advanced HR variability measures reveal patterns missed by conventional methods.
Main Methods:
- 24-hour ambulatory ECG recordings were analyzed in 19 refractory TLE patients, 25 well-controlled TLE patients, and 34 healthy controls.
- Traditional time and frequency domain HR variability measures were assessed.
- Fractal correlation properties, approximate entropy (ApEn), and power law slope of RR interval dynamics were calculated.
Main Results:
- Patients with TLE exhibited reduced traditional HR variability measures compared to controls (p<0.05).
- The power law slope (p<0.005) and ApEn (p<0.05) were significantly lower in TLE patients.
- ApEn was further reduced in refractory TLE versus well-controlled TLE (p<0.01), and long-term fractal correlation (alpha2) was lower in well-controlled TLE (p<0.05).
Conclusions:
- TLE is associated with not only reduced overall HR variability but also altered long-term fractal organization and complexity of HR dynamics.
- These HR abnormalities may contribute to adverse cardiovascular events, including life-threatening arrhythmias, in TLE patients.
- Non-linear and fractal analyses provide deeper insights into autonomic dysfunction in TLE.