Abstracts

Rationale: It is well recognised that motor seizures in adults are often associated with tachycardia and in fact is utilized in seizure prediction algorithms. There are little data on ictal tachycardia in very young children or correlation to seizure type. This study aims to address these questions in children aged 1 month - 3 years.   Methods: Children with ictal EEG recordings were retrospectively identified from the EEG database at a tertiary referral centre between January 2012 to October 2016. Video-EEG and ECG recordings were reviewed and seizure onset determined. Clinical data was collected on seizure type and aetiology.  ECG recordings were manually extracted from 5 minutes (min) pre to 3 min post-ictal. Heart Rate variability (HRV) was assessed using Kubios HRV software. Baseline was defined as the initial 90 seconds (sec) of the 5 min pre seizure ECG and 30 sec immediately before seizure onset as pre-ictal. Heart rate change from baseline to pre-ictal, ictal and post-ictal was analysed. Data were analysed using SPSS version 23.   Results: Thirty six children met the criteria; age range 5-36 months (median 22.5 months); Male to female ratio was 21:15. Aetiology was mostly structural (27/36) with some being genetic (7/36) presumed metabolic (1/36) or unknown (1/36). Almost all were pharmaco-resistant; drug burden was high (range 1-5, median 2); 3/36 were on ketogenic diet. Ninety three seizures were analysed. Seizure types were: generalised 14/93; focal 79/93 (motor 60/79, non-motor 19/79). Mean ictal HR for all seizures was significantly higher (mean 13 beats per minute (bpm) compared to baseline, p valuePre-ictal HR (±5% from baseline HR) change compared to baseline was seen in 44/93 seizures: increase in HR in 33/93 (median 12.2; range 5.2 - 67.5 bpm) and decrease in HR in 11/93 (median 11.2; range 7.4 to 41.1 bpm). The mean HR increased significantly from 109 bpm at baseline to 126 bpm during the pre-ictal period (p20 bpm in 10/33 seizures. Pre-ictal HR increased in both focal (27/79) and generalized seizures (6/14). Ictal HR change (±5% from baseline HR) was seen in 60/93 seizures: increase in HR in 52/93 (median 21.8; range 5.3 - 66.1 bpm) and decrease in HR in 8/93 (median 11.3; range 8.7 -28.3  bpm).  The mean HR increased significantly from 111 bpm at baseline to 136 bpm during seizure (p20 bpm in 30/52 seizures. Post-ictally the HR remained significantly higher than the baseline HR (p Ictal HR decrease was less common (8/93; < 10 bpm in 3/8; 10-20 bpm in 4/8, >