Ictal heartrate changes in children and adolescents – comparison of temporal versus frontal lobe seizures

Objectives: Cardiovascular dysregulation is a well known phenomenon in focal seizures and may be a cause of sudden unexplained death in epilepsy (SUDEP). Investigations so far have focused on patients with temporal lobe epilepsy.

We compared ictal heart rate (HR) changes in pediatric patients with either temporal (TLE) or frontal lobe epilepsy (FLE) and determined the influence of focus localization and laterality.

Material and Methods: Patients younger than 18 years with unilateral TLE or FLE who presented with at least one artifactfree partial seizure during presurgical noninvasive EEG-monitoring were included. Single channel EKG recordings were analyzed during the preictal and ictal stages.

Results: 36 patients –20 with TLE and 16 with FLE – could be enrolled. 138 seizures –72 in TLE patients and 66 in FLE patients – were analyzed.

In the preictal stage 27,8% of temporal lobe seizures (TLS) and 21,2% of frontal lobe seizures (FLS) presented with heart rate elevations higher than 10 bpm above baseline HR.

In the ictal stage 98% of TLS and 100% of FLS were associated with HR elevations. Age adjusted absolute tachycardia critera were fulfilled significantly lower in FLS (47% versus 80,6%). In TLS right hemispheric seizures caused either early and high or later and lower HR increase. In FLS no differences were found concerning ictal HR evolution in regard to side of seizure onset.

Although several seizures in both groups presented with preictal bradycadia no ictal bradycardia was found.

Conclusions: Autonomic dysregulation of the cardiovascular system is not limited to partial seizures originating in the temporal lobe. Tachycardia however is less pronounced in FLE. Only in TLE the side of seizure origin determines the evolution and extent of HR increase.