Abstracts

Rationale: Ictal bradycardia is hypothesized to be due to activation of the bilateral insular cortices, resulting in excessive parasympathetic activation of reflex pathways that regulate vagal tone during a seizure. This is a rare phenomenon occurring in less than 5% of patients with epilepsy. Complications include traumatic injuries from falls and syncope, as well as sudden unexpected death. As there are still no definitive guidelines or algorithms regarding management of this entity, we present two cases of patients with ictal bradycardia syndrome with the aim of highlighting management and outcomes in surgical and non-surgical patients.

Methods: Case review

Results: Case 1: A 56-year-old man with intractable focal epilepsy of left mesial temporal onset since age 29. Upon Epilepsy Monitoring Unit admission, his interictal EEG showed intermittent focal left temporal slowing with occasional epileptiform discharges in the anterior temporal region (F7-T1). Eight seizures were captured with stereotyped semiology of arousal from sleep, chewing automatisms, head turn to the left, decreased responsiveness and staring, and duration < 1 minute. Ictal EEG showed rhythmic left temporal theta slowing with embedded sharps. Review of ictal EKG tracings showed marked bradycardia and sinus pauses lasting 7 - 18 seconds during seizures (Figure 1). Cardiology was consulted and patient had a Holter monitor placed for one month. Cardiac monitoring captured a brief 3.9-second sinus pause during one of his brief focal seizures. Patient subsequently underwent left temporal lobectomy. Post-operatively, he was seizure-free without further episodes of bradycardia or sinus pauses noted at 4-month follow-up.

Case 2: A 58-year-old man with heavy alcohol use and atrial fibrillation who was evaluated in epilepsy monitoring unit for characterization of events that were described as feeling dizzy and confused followed by loss of consciousness and generalized tonic-clonic activity. Four typical seizures were captured; EEG showed left temporal lobe origin. Ictal EKG revealed ictal asystole in all 4 events lasting 14-47 seconds in duration (Figure 2). Cardiology was consulted and a pacemaker was placed during admission. Patient was optimized on Topiramate and Eslicarbazepine on future follow-ups due to reported nocturnal shaking episodes; however, serial repeat ambulatory EEGs were negative for seizures or arrhythmias. Patient continues to remain seizure-free since 2018.

Conclusions: Surgical resection of seizure focus can lead to resolution of seizures and associated cardiac arrhythmia-related complications in patients with ictal arrhythmias. Conversely, if an epileptogenic focus persists, medication optimization without surgery and consideration of pacemaker placement may also be a route towards seizure-freedom and protection from associated arrhythmic complications.

Funding: Please list any funding that was received in support of this abstract.: None.