Abstracts

Vartiations in heart rate have been described during seizures by numerous authors. All this information is based on recorded seizures in patients with onset in either the dominant or nondominant hemisphere. No case has ever been reported, to our knowledge, where individual seizure onset in either hemisphere produced a different effect on heart rate in a single patient. We report a patient with bilateral seizure onset where seizure onset in the dominant (left) hemisphere was associated with asystole, while a tachycardia was seen during seizure onset from the nondominant (right) hemisphere. DK is a 35 year old right handed female with a history of a febrile convulsion at age 1 year. The patient began to experience seizures when she was in college. She initially reported having complex partial seizures associated with a [quot]bad taste in her mouth.[quot]. VideoEEG monitoring with bilateral sphenoidal electrodes performed in 1996 demonstrated seizure onset in the right temporal region. An MRI scan, however, demonstrated an enhancing lesion in the left frontal operculum. The patient underwent a partial resection of this lesion. The pathology was consistent with a ganglioglioma. The patient continued to have seizures, but then developed a second seizure type which she described as [quot]blackout spells.[quot] Repeat video EEG monitoring in 2001 demonstrated two seizure types: 1) Seizures with onset in the left temporal region which were associated with bradycardia and asystole and 2) Seizures with onset in the right temporal region which were associated with slight increase in heart rate. The patient subsequently underwent placement of a on-demand cardiac pacemaker to prevent episodes of asystole. She reported an elimination of her [quot]blackout spells[quot] but continued to have her seizures associated with the [quot]bad taste in her mouth.[quot] The patient had failed multiple antiepileptic drugs and subsequently underwent placement of a vagus nerve stimulator (VNS). This did not appreciably change her seizure frequency. Since the cardiac pacemaker had been implanted in the left infraclavicular region, the VNS was implanted in the right infraclavicular region with the VNS lead attached to the left vagus nerve. We believe this case is important to report for a variety of reasons. First, to our knowledge, no single case has ever been reported where independent seizure onset in both hemispheres has been associated with differential effects on heart rate. A volume of information exists about heart rate changes, but is all based on single sides of seizure onset in large cohorts of patients. This case may help provide more insite into the mechanism of Sudden Unexpected Death in patients with Epilepsy. Secondly, this also illustrates the safety of implantation of the VNS battery pack in the right infraclavicular region while stimulating the right vagus nerve. (Supported by Peter Kellaway Foundation For Research.)