Can heart rate variability in children with epilepsy be used to predict seizures?

PURPOSE The aim of this study was to examine interictal, pre-ictal and ictal autonomic system disturbance by comparing heart rate variability in children with uncontrolled epilepsy with that seen in healthy controls and children with controlled epilepsy. METHODS Our study group included 20 children with refractory epilepsy, our control groups were composed of 20 children with well-controlled epilepsy and 20 healthy children. All subjects were evaluated by Holter ECG monitoring and 12-lead ECG to assess heart rate variability and QTc dispersion. The study group was also evaluated by Holter ECG during seizures. RESULTS The study group exhibited significantly more pathological QTc dispersion than did the control groups. Heart rate variability was significantly suppressed: reduced parasympathetic activity with lower low frequency (LF) and high frequency (HF) band values were observed in the study group. Findings were similar in the well-controlled epilepsy group and the healthy group but differed from the uncontrolled epilepsy group. The examination of heart rate variability parameters during and before seizures revealed higher nLF and LF/HF ratio and lower nHF values demonstrating increased sympathetic activity. CONCLUSION We suggest that children with refractory epilepsy have abnormalities of autonomic nervous system functioning which could be linked to the increased risk of sudden unexpected death seen in the patient group. It is possible that a chronically reduced vagal tone predisposes patients to a more dramatic stress response during their seizures. It is possible that heart rate variability parameter arising prior to seizures could be used to predict future seizures.