Reginald T Ho1, Tammi Wicks, Dale Wyeth, Maromi Nei. 1. Department of Medicine, Thomas Jefferson University Hospital, Philadelphia, Pennsylvania 19107, USA. reginald.ho@jefferson.edu
Abstract
BACKGROUND: Both syncope and seizures are important causes of recurrent, unexplained episodes of loss of consciousness. Implantable loop recorders have identified serious arrhythmias in patients with repeated syncope; however, implantable loop recorder detection of seizures is less well established. OBJECTIVES: The purpose of this study was to provide in-depth analysis of a characteristic myopotential pattern recorded by implantable loop recorders during generalized tonic-clonic seizures. METHODS: Fourteen patients with refractory, video-EEG-documented epilepsy (complex partial, atonic, tonic, or generalized tonic-clonic seizures) underwent implantable loop recorder placement as part of a study protocol evaluating cardiac rhythm abnormalities in patients at high risk for sudden unexpected death in epilepsy. RESULTS: Twelve generalized tonic-clonic seizure episodes were detected by the implantable loop recorder in six patients. Implantable loop recorder and EEG recordings of generalized tonic-clonic seizures were identical and revealed a tonic phase (sustained, rapid, high-frequency myopotentials) transitioning to a clonic phase (periodic bursts of high-frequency myopotentials with a decelerating burst frequency from 3-6 Hz to 1-2 Hz) prior to seizure termination. With the nonprogrammable bandpass filter of 0.85 to 32 Hz in the implantable loop recorder, all generalized tonic-clonic seizure episodes had escaped automatic detection and required activation by family members. None of the 76 nongeneralized tonic-clonic seizure episodes recorded on the implantable loop recorder in the 14 patients exhibited the stereotypical tonic-clonic pattern that defines generalized seizures. CONCLUSION: Recognizing this specific myopotential pattern on an implantable loop recorder might help diagnose generalized tonic-clonic seizures as a cause of recurrent, unexplained episodes of loss of consciousness. Having a programmable bandpass filter in the implantable loop recorder might increase its diagnostic yield for such patients.
BACKGROUND: Both syncope and seizures are important causes of recurrent, unexplained episodes of loss of consciousness. Implantable loop recorders have identified serious arrhythmias in patients with repeated syncope; however, implantable loop recorder detection of seizures is less well established. OBJECTIVES: The purpose of this study was to provide in-depth analysis of a characteristic myopotential pattern recorded by implantable loop recorders during generalized tonic-clonic seizures. METHODS: Fourteen patients with refractory, video-EEG-documented epilepsy (complex partial, atonic, tonic, or generalized tonic-clonic seizures) underwent implantable loop recorder placement as part of a study protocol evaluating cardiac rhythm abnormalities in patients at high risk for sudden unexpected death in epilepsy. RESULTS: Twelve generalized tonic-clonic seizure episodes were detected by the implantable loop recorder in six patients. Implantable loop recorder and EEG recordings of generalized tonic-clonic seizures were identical and revealed a tonic phase (sustained, rapid, high-frequency myopotentials) transitioning to a clonic phase (periodic bursts of high-frequency myopotentials with a decelerating burst frequency from 3-6 Hz to 1-2 Hz) prior to seizure termination. With the nonprogrammable bandpass filter of 0.85 to 32 Hz in the implantable loop recorder, all generalized tonic-clonic seizure episodes had escaped automatic detection and required activation by family members. None of the 76 nongeneralized tonic-clonic seizure episodes recorded on the implantable loop recorder in the 14 patients exhibited the stereotypical tonic-clonic pattern that defines generalized seizures. CONCLUSION: Recognizing this specific myopotential pattern on an implantable loop recorder might help diagnose generalized tonic-clonic seizures as a cause of recurrent, unexplained episodes of loss of consciousness. Having a programmable bandpass filter in the implantable loop recorder might increase its diagnostic yield for such patients.
Authors: Francesco Brigo; Monica Storti; Luigi Giuseppe Bongiovanni; Antonio Fiaschi Journal: J Clin Monit Comput Date: 2011-04-22 Impact factor: 2.502