A Case of Loss of Consciousness due to Epilepsy Diagnosed Using an Implantable Loop Recorder

Abstract

We report a case of clonic-tonic seizures diagnosed using an implantable loop recorder, a device for detecting cardiac arrhythmias. A 65-year-old man was referred to our hospital for loss of consciousness with myotonic jerks during sleep. He had experienced several similar episodes. No family history of sudden death was evident, and no structural heart disease was present. Coronary angiography with intracoronary acetylcholine (ACh) showed neither organic stenosis nor vasospastic angina. Ventricular tachyarrhythmias were not induced by programmed electrical stimuli. Sleep electroencephalography, brain magnetic resonance imaging and magnetic resonance angiography revealed no specific findings. We implanted a loop recorder to monitor rhythm abnormalities. One month later, an attack occurred at night. His wife recognized the episode and activated the implantable loop recorder. No arrhythmia was recorded, but myopotentials characteristic of tonic-clonic seizures were detected. (J Arrhythmia 2011; 27: 76-79)

Syncope and Ictal Asystole Caused by Temporal Lobe Epilepsy

“…Myopotential noise during convulsion have been clearly demonstrated using ILR in patients with generalized tonic-clonic seizure in previous reports. 3, 4 In the present case, ictal asystole, without myopotential noise, was demonstrated with ILR as a complex partial seizure of typical TLE. Furthermore, bradyarrhythmias requiring permanent pacing were documented in 20% of epileptic patients monitored with an ILR, 5 suggesting a relationship with the syndrome of sudden unexpected death, which affects approximately 7-17% of the epileptic population, 6 or an estimated 0.12% of epilepsy patients per year.…”

Subclinical Tonic-Clonic Epileptic Seizure Detected by an Implantable Loop Recorder

“…4,5) The present case describes a patient presenting with TLOC in the absence of apparent convulsions, in whom ILR monitoring detected myopotentials consistent with a subclinical epileptic seizure.…”

“…However, the detection, by the ILR, of myotonic electrical signals associated with tonic-clonic epileptic seizures, has been described previously and has been used to confirm an epilepsy diagnosis. 4,5) Convulsions may be observed during epileptic seizures as well as during syncope of cardiac or noncardiac origin. TLOC associated with convulsion, abnormal movement, or automatism is an important finding in the diagnosis of epilepsy, because the diagnosis of epilepsy is made by clinical symptoms with or without abnormal EEG findings.…”