Abstracts

Sudden unexpected death in epilepsy (SUDEP) is most commonly seen in patients with refractory epilepsy. The etiology is uncertain, although a cardiac arrhythmia may be responsible for death in some patients. Video-EEG/EKG monitoring reveals that many patients have EKG rhythm and repolarization abnormalities in association with their seizures. However, thus far only limited data are available re: cardiac rhythm in these patients over several months.
Objective: Assess the types of and frequency of cardiac rhythm and repolarization abnormalities over a 14-month period in patients with refractory epilepsy. Patients with refractory epilepsy with [ge]1 complex partial, generalized tonic-clonic, tonic, or atonic seizure/month underwent cardiac rhythm monitoring using a subcutaneously implanted recording monitor (Medtronic Reveal), to be implanted for a total of 14 months. Individuals [ge] 50 yrs of age or who had a history of cardiac disease or abnormal EKG were excluded. Patients were evaluated by a neurologist and cardiologist at 1 month after device implantation, then every 3 months thereafter for a maximum duration of 14 months for device interrogation. At each interrogation, data regarding heart rate and rhythm as well as repolarization abnormalities were noted. Patients or caretakers were asked to keep a seizure log and activate the device at the time of seizures. In addition, automated heart rate detection of rates [lt] 30 and [gt]180 BPM was programmed. Thus far 13 patients (mean age 38.7 yrs, range 23-47 yrs; 8 men, 5 women) with refractory epilepsy (2 idiopathic generalized, 3 symptomatic generalized, and 8 partial) have been implanted and recorded over an average of 6.8 months (range 0.5 - 14 months). Patients had a history of epilepsy onset at a mean age of 7 years and epilepsy duration of 31.7 years. An average of 31 seizures/ patient occurred during the study period. 3 patients had active vagal nerve stimulators. 2 patients (who did not have active vagal nerve stimulators) had sinus pauses of up to 4.8 seconds recorded unassociated with seizures. 2 patients had T wave inversions occurring only in association with seizures (1 patient with generalized tonic-clonic seizures, 1 patient with tonic seizures). All other patients had only sinus rhythm or sinus tachycardia associated with their seizures. Preliminary data suggests that patients with refractory epilepsy may be at increased risk for cardiac ischemia during seizures. Additionally, sinus pauses may occur in these individuals without evidence of a seizure. Further investigation in larger numbers of individuals is needed to determine the clinical significance of such abnormalities in this patient population. (Supported by Medtronic, Inc.)