Abstracts

RATIONALE: Sudden unexpected death in epilepsy (SUDEP) accounts for >10% of deaths in patients (pts) with epilepsy, particularly in those with refractory epilepsy. Cardiac mechanisms may be involved. The signal-averaged EKG (SAEKG)identifies cardiac late potentials which reflect regions of myocyte injury or death, and is a helpful tool in stratifying risk of ventricular tachyarrhythmias after myocardial infarction. This study utilizes the SAEKG in patients with refractory epilepsy to determine whether myocardial injury occurs in these patients. METHODS: Unselected pts with refractory epilepsy evaluated via CCTV-EEG monitoring for refractory epilepsy who were ?14 and ?50 years of age, and had no history of cardiac disease, a 12-lead EKG revealing no left bundle branch block (masks late potentials)and no evidence of ischemic heart disease, and normal serum electrolytes (which may affect the SAEKG) were included. SAEKGs were considered abnormal if 2/3 criteria were abnormal: 1) filtered QRS >110msec, 2)low amplitude signal duration >40 msec, and root mean square voltage <20 mV. The frequency of abnormal studies was compared to the frequency of SAEKG abnormalities in healthy control populations. RESULTS: 33 pts (21 male, 12 female, mean 33 yrs; epilepsy type: 30 partial, 2 symptomatic generalized, 1 juvenile myoclonic)were evaluated. Five (15.5%)pts had abnormal SAEKGs. All had partial epilepsy: 3 pts had a right-sided seizure focus (2 temporal, 1 occipital), 2 pts had non-lateralized seizures. All other pts had normal SAEKGs. CONCLUSIONS: Pts with refractory epilepsy more frequently have abnormal SAEKGs than expected from healthy population data (0-5% have abnormal SAEKGs). These pts may be at higher risk for developing myocardial fibrosis than the general population. The clinical significance is uncertain at this time, but these findings suggest that uncontrolled seizures may lead to myocardial injury, which could increase the risk for ventricular arrhythmias. Such a mechanism may be responsible for SUDEP in some pts. Further investigation is needed to determine both etiology and clinical consequences of this type of cardiac injury.