Ictal bradycardia and tachycardia observed in the tetanus toxin model of temporal lobe epilepsy in the freely moving rat

Ashby-Lumsden, Alexander Michael John (2013). Ictal bradycardia and tachycardia observed in the tetanus toxin model of temporal lobe epilepsy in the freely moving rat. University of Birmingham. M.Res.

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Abstract

Those with epilepsy have a higher risk of sudden death than the general population; however, the mechanism of these sudden deaths is unknown. Fatal arrhythmia generation during seizure, along with changes in autonomic tone, are hypothesised to be important factors. Six Wistar rats were stereotaxically injected with tetanus toxin into the ventral hippocampus, and implanted with radiotelemeters to record electrocardiogram and electroencephalogram. The heart rate was analysed in pre-ictal, ictal and post-ictal epochs with the aim of demonstrating the changes in autonomic tone during seizure. Ictal bradycardia was observed in 89% of the seizures analysed, with post-ictal tachycardia in 93%. Further, potentially lethal arrhythmias were observed during seizure. Missed beats (59%), ventricular premature depolarisation (22%) and ventricular fibrillation (17%) are risk factors for sudden death in the general population and their presence during seizure could potentially be fatal. Whilst this study has demonstrated changes in autonomic tone and cardioarrhythmia generation; the extent of the changes and their mechanism need to be explored further. Nevertheless, this research validates the tetanus toxin model of temporal lobe epilepsy as a tool for investigating sudden death in epilepsy.

Type of Work:

Thesis (Masters by Research > M.Res.)

Award Type:

Masters by Research > M.Res.

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