Subclinical tonic-clonic epileptic seizure detected by an implantable loop recorder

A 73-year old man received an implantable loop recorder (ILR) for the evaluation of transient loss of consciousness (TLOC) spells. His medical history was without any epileptic convulsions or automatism. ILR recording during a spontaneous episode revealed the presence of a regular, narrow QRS complex tachycardia associated with low-amplitude, high-frequency, continuous or discontinuous artifacts, consistent with myopotentials. During the event, the regular, lowamplitude continuous signals gradually became discontinuous, with a prolongation of the inter-signal cycle length, until their disappearance after manual activation of the ILR. The patient was diagnosed as experiencing subclinical tonic-clonic epileptic seizures. Antiepileptic drug treatment was initiated, and the patient has remained free of TLOC symptoms during 13 months follow-up.