Effects of Seizure Repetition on Postictal and Interictal Neurocardiac Regulation in the Rat
Open Access
- 19 June 2003
- Vol. 44 (7), 912-916
- https://doi.org/10.1046/j.1528-1157.2003.48302.x
Abstract
Summary: Purpose: Human epilepsy is associated with abnormalities in cardiac regulation, as measured by reductions of heart rate variability (HRV) and approximate entropy (ApEn), but it is not known how these abnormalities are related to seizure experience. Methods: Baseline electrocardiogram (ECG) was recorded from seizure‐naive rats. They were subjected daily to maximal electroshock (MES), which induced tonic seizures with hindlimb extension, for a total of 10 days. ECG was obtained for 30 min before and after the first and last seizure. R‐R variability, spectral variability, and ApEn were calculated to determine changes in pre‐ and postictal cardiac regulation. Before the last seizure, interictal parameters were compared with baseline values to determine changes in interictal HRV as a consequence of seizure repetition. Postictal values obtained after the last seizure were compared with the initial postictal data to look for changes in postictal cardiac regulation. Results: During the postictal state, a mild, but significant, loss of ApEn was present after either the first or last seizure. Seizure repetition induced loss of R‐R variability and high‐frequency spectral band, which was present both interictally and postictally. Conclusions: The results suggest that convulsive seizures are associated with an immediate reduction of the complexity of cardiac rhythm regulation, as reflected by reductions of ApEn. Seizure repetition may induce long‐term neural abnormalities in neurocardiac regulatory systems, especially parasympathetic, which limit appropriate autonomic responses. These acquired abnormalities may, in turn, predispose individuals to cardiac arrhythmia and sudden unexpected death in epilepsy.Keywords
This publication has 21 references indexed in Scilit:
- Heart rate dynamics in refractory and well controlled temporal lobe epilepsyJournal of Neurology, Neurosurgery & Psychiatry, 2002
- Intravenous Cocaine Decreases Cardiac Vagal Tone, Vagal Index (Derived in Lorenz Space), and Heart Period Complexity (Approximate Entropy) in Cocaine AbusersNeuropsychopharmacology, 2000
- Power spectral density of unevenly sampled data by least-square analysis: performance and application to heart rate signalsIEEE Transactions on Biomedical Engineering, 1998
- Heart rate variability: Standards of measurement, physiological interpretation, and clinical useEuropean Heart Journal, 1996
- The application of methods of non-linear dynamics for the improved and predictive recognition of patients threatened by sudden cardiac deathCardiovascular Research, 1996
- Ictal ECG changes in temporal lobe epilepsyArquivos de Neuro-Psiquiatria, 1995
- Power Spectrum Analysis of Heart Rate Fluctuation: A Quantitative Probe of Beat-to-Beat Cardiovascular ControlScience, 1981
- Least-squares frequency analysis of unequally spaced dataAstrophysics and Space Science, 1976
- A Correlation of Autonomic and EEG Components in Temporal Lobe EpilepsyArchives of Neurology, 1960