Heart rate variability (HRV) in children and adolescents with epilepsy

Abstract-Text (inklusive Referenzen und Bildunterschriften)

Introduction

Heart rate variability (HRV) is a measure of the neurovegetative activity and autonomic function of the heart and characterizes the temporal change from heartbeat to heartbeat. A low HRV strongly predicts an increased risk of sudden death in patients with heart disease and all-cause mortality in older adults. People with epilepsy show altered interictal HRV, suggesting a shift in autonomic balance toward sympathetic dominance. HRV may be useful as a biomarker for risk of sudden unexpected death in epilepsy (SUDEP). In epilepsy cohorts, decreased interictal HRV is associated with drug resistance and epilepsy chronicity, and with an increased risk of SUDEP. However, changes in HRV in children and adolescents with epilepsy have been little studied. The few studies show decreased HRV compared to controls, however they included few (from 11 to 35) and older (median 7 to 11 years) patients, mostly with a certain type of seizure. Studies with larger patient series and younger patients are therefore still needed.

We perform a retrospective monocentric study to describe HRV in children and adolescents with epilepsy and to try to identify a subgroup of patients who are more likely to have lower HRV and may therefore be at increased risk of SUDEP.

Patients and Methods

We retrospectively review the ECG of approximately 300 children and adolescents with ages 0 to 14 years with a diagnosis of epilepsy, who underwent video-EEG-monitoring from 2010 to 2022 at the Freiburg Epilepsy Center. At least one epileptic seizure must have occurred during the monitoring. Exclusion criteria include a diagnosed cardiac disease.

Data related to interictal HRV, including time-domain parameters (root mean square of successive differences (RMSSD), standard deviation of RR interval (SDNN), percentage of consecutive RR intervals differing by more than 50 milliseconds (pNN50)) and frequency domain parameters (very low frequency [VLF] power, low frequency [LF] power, high frequency [HF] power, and LF/HF ratio) will be assessed at 5-minute interictal video-EEG intervals while awake and during sleep (Myers KA et al. Epilepsia 2018). Interical video-EEG intervals are defined as follows: (1) at least 8 hours after the last tonic-clonic seizure; (2) at least 1 hour after the last clinical seizure (excluding tonic-clonic seizures) or the last subclinical seizure; and (3) at least 1 hour before the next clinical seizure.

Clinical data will be collected retrospectively from the patient files, including type of epilepsy, age at epilepsy onset and age at video-EEG-monitoring.

Discussion

Our research could identify a subgroup of patients who are more likely to have lower HRV and may therefore be at increased risk of SUDEP. This may lead to a better-based diagnosis /therapeutic strategy in the future.