Abstracts

Rationale: Sudden unexpected death in epilepsy (SUDEP) is an important cause of mortality for patients with epilepsy. Identification of individual patients at risk of SUDEP is challenging and careful analysis of heart rate (HR) is usually omitted in video-EEG monitoring (VEM) . The aims of this study were to analyze the frequency of HR and conduction abnormalities related to seizures and to determine risk factors and associated clinical characteristics in patients with drug resistant epilepsy. Methods: We analyzed EEG, ECG and video data of patients who had been diagnosed with drug resistant epilepsy and had ictal HR and rhythm changes during VEM. We investigated in a standardized manner whether there was a correlation between HR changes and seizure type, left/right origin, different semiological components and auras for each seizure. All included patients did not have history of an active cardiovascular disease or any disorder that might affect the autonomic nervous system. Ictal HR was assessed from one minute prior to the moment of clinical or electrographic seizure onset up to two minutes after the end of seizure. HR was estimated by counting beats over 10-second epochs and multiplying that value by six (one minute). The highest and lowest ictal HRs were determined. The timing of the earliest epoch in which the heart rate exceeded the baseline by 10 beats/minute was detected. Results: We included 25 patients (15 females, 10 males, mean age 32 years, range 19-57 years). All patients had consistent cardiac irregularities during seizures. Brain MRI detected lesions in 21 cases including hippocampal sclerosis (n=17), focal cortical dysplasia (n=2), sequela from previous surgery for menengioma (n=1), hemispheric atrophy and lesions due to Rasmussen's encephalitis (n=1).There were 58 focal, 9 secondarily generalized and 1 primary generalized seizures. We were able to lateralize seizure focus in 62 out of 68 seizures. Fifty-eight percent of the seizures (n=40) lateralized to the left hemisphere whereas the remaining originated from the right side. Majority of the seizures had temporal lobe onset (%60). Mesial temporal onset was responsible for HR changes in 63%. Potentially serious ictal ECG changes occurred in 4/68 seizures (6%) and 3/25 patients (12%). These included ventricular extrasystole, sinoatrial arrest and supraventricular tachycardia. The mean ictal HR was 125 beats per minute (range 84-157). The mean of maximum ictal HR was 138 beats per minute (range 120-186). There was an increase in HR of at least 10 beats/ minute in 42% of seizures before the seizure onset. Unfortunately, one patient who was otherwise in good health died in his sleep before epilepsy surgery but the autopsy evidence was unavailable. Conclusions: There were no defining characteristics of seizures with HR changes. We recommend routine analysis of ictal ECG in VEM units. Accurately identifying patients at higher risk of SUDEP is important. Appropriate medical and cardiologic managements besides earlier consideration of epilepsy surgery may decrease mortality in these patients.