Abstracts

Ictal asystole (IA) has been recorded in a small number of patients mostly with temporal lobe epilepsy. It has been implicated as a potential preventable cause of sudden unexplained death in epilepsy (SUDEP), although direct evidence linking IA to SUDEP is missing. Asystole in the setting of a neurocardiogenic syncope is a benign condition, often triggered by a centrally mediated reflex (e.g. fear) and IA could therefore represent a benign central autonomic response provoked by epileptic activity.
The goal of this study was to investigate the ECG characteristics of patients with IA compared to a control group of patients with Tilt-table induced vasovagal asystole (VVA)., Electronic database search of all patients undergoing longterm Video-EEG monitoring between April 1994 and April 2006 with episodes of IA during simultaneous ECG acquisition was performed. A control group of patients with asystolic response during Tilt Table was identified. Demographics and clinical features were assessed. Baseline (BL) and peri-ictal heart rate (HR) characteristics were analyzed including: tachycardic response (HR [gt] BL + 1/3 BL), bradycardic response ([lt] 50bpm), duration of asystole and bradycardia before and after the asystole, slope (bpm/sc) of HR acceleration and deceleration before and after asystole. Statistical analysis was performed using the Mann-Whitney test., IA was seen in 6 patients with temporal lobe epilepsy (0.1% of all patients recorded). Each of the groups consisted of two male and four female patients. VVA patients (mean age 26 yrs) were younger than patients with epilepsy (mean age 40.8 yrs). The mean BL HR was similar for both groups (68.9bpm and 71.1bpm). Four patients in the IA and three in the VVA group had a peri-ictal tachycardia. There was no statistical difference in duration of asystole between IA [16.9 sc (range 5-36)] and VVA patients [32.2 sc (range 3-113)] nor in the duration of the bradycardia. There was also no difference in the HR deceleration before asystole: 2.4 bpm/sc (range 1-4.0) vs. 2.37 bpm/sc (range 1.6-5) or of the postictal acceleration: 3.33 bpm/sc (range 1.1-5.3) vs. 2.23 bpm/sc (range 0.3-3.6) including the maximal HR slopes. The therapeutic approach to the asystole event, however, was significantly different among the groups: Five out of six patients in the IA group have had a pacemaker implanted, while none of the VVA patients received pacing., We did not find any significant difference in the HR behavior between patients with IA and VVA. It remains unclear if patients with a cardioinhibitory ictal response are at increased risk for SUDEP. This phenomenon might well represent a benign central autonomic response similar to the one seen in vasovagal syncope. This suspicion is further supported by a recent study which did not find an increased incidence of ictal bradycardia/asystole among patients who later died of SUDEP.,