Abstracts

Rationale: The epileptic baboon provides a natural model of idiopathic generalized epilepsy (IGE) and sudden unexpected death in epilepsy (SUDEP). This retrospective, case-controlled study aims to evaluate potential cardiac biomarkers for SUDEP, specifically QT-interval prolongation and heart rate variability (HRV) in baboons belonging to the same pedigree recorded during scalp electroencephalography (EEG).  Methods: We retrospectively identified 21 epileptic (9 females, mean age 11.4 +/- 5.4 years) and 19 asymptomatic control (12 females, mean age 10.5 +/- 6.3 years) baboons, who had undergone scalp EEG studies with an artifact-free, ten-beat electrocardiogram (ECG) sample. All baboons were sedated with subanesthetic doses of ketamine prior to electrode placement. PR-, QT- and RR-intervals were measured, and QTcF (Fridericia-corrected QT duration) and RMSSD (root mean square of successive differences between RR-intervals, representative for HRV) values were compared between the groups.  Results: The epilepsy group had significantly prolonged QT and QTcF intervals (p=0.005) compared to controls. RMSSD values marginally lower in the epilepsy group, but were decreased in both groups compared to non-sedated baboons, due to ketamine’s sympathomimetic effects.  Conclusions: Nevertheless, this study demonstrates cardiac conduction anomalies and reduction in HRV associated with epilepsy in the baboon, potentially reflecting underlying channelopathies and altered autonomic regulation, which are risk factors for SUDEP in humans. Since this study was performed in a single pedigree, it is possible that genes underlying the QT-prolongation, may also underlie the epilepsy genotype.  Funding: No funding