Authors :
Presenting Author: Atakan Selte, MD – Harbor-UCLA Medical Center
Subapriya R, MD – Rancho Los Amigos National Rehabilitation Center
Susan Shaw, MD – Rancho Los Amigos National Rehabilitation Center
Hui Gong, MD – Rancho Los Amigos National Rehabilitation Center
Satish Balasubramanian, MD – Rancho Los Amigos National Rehabilitation Center
Grace Chen, MD – Rancho Los Amigos National Rehabilitation Center
Michelle Armacost, MD – Rancho Los Amigos National Rehabilitation Center
Rationale:
Cardiac arrhythmias, including third-degree atrioventricular (AV) block and asystole, can present with chest sensations and convulsive movements, leading to misdiagnosis as epileptic aura and seizures respectively.1 Such misdiagnosis may lead to inappropriate long-term use of anti-seizure medications (ASMs) and to delays in correct diagnosis and treatment. We report two cases of high-grade AV block initially diagnosed as epilepsy, in which video-EEG with ECG monitoring was crucial for accurate diagnosis and management.
Methods:
Two adult male patients with a prior diagnosis of epilepsy and persistent seizure-like episodes despite treatment were admitted to Rancho Los Amigos National Rehabilitation Center for further evaluation with continuous video-EEG and ECG monitoring. Chart review was performed to obtain all clinical information.
Results:
Case 1: A 57-year-old male diagnosed with epilepsy in 2023 reported stereotyped events beginning with abnormal sensation in his chest followed by unresponsiveness, stiffness, bilateral upper extremity shaking, and post-event confusion. Despite taking three ASMs, event frequency was increasing. No events were captured in two prior epilepsy monitoring unit (EMU) stays. During a third EMU evaluation, multiple events were captured of chest tightness followed by unresponsiveness and myoclonic jerks. EEG during these events showed diffuse attenuation and slowing without epileptiform activity; concurrent ECG revealed complete heart block with a prolonged period of no ventricular escape, preceding the EEG changes. A permanent pacemaker was placed. Patient has been successfully weaned off two ASMs with complete resolution of episodes.
Case 2: A 57-year-old male with epilepsy diagnosis in 2021, treated with three ASMs, was hospitalized with hyperammonemic encephalopathy due to valproate. Seizures were described as loss of consciousness with full-body shaking. During inpatient monitoring, two stereotyped episodes were recorded with upward/rightward eye deviation and loss of consciousness. EEG showed generalized slowing and attenuation without epileptiform activity. Simultaneous ECG captured approximately 20 seconds of third-degree AV block, onset prior to EEG changes. A permanent pacemaker was placed. Two ASMs have been tapered off with no recurrence of events.
Conclusions:
Third-degree AV block can mimic epileptic seizures, especially when accompanied by chest pressure, convulsive movements, and post-event confusion. These cases highlight the critical importance of video-EEG with simultaneous ECG evaluation, including repeat monitoring, particularly in patients with atypical features or refractory events. Recognition of cardiac syncope masquerading as epilepsy is essential for reducing ASM morbidity and securing timely, potentially life-saving cardiac intervention.
1. Zarraga IG, Ware DL. Syncope, seizure, or both? An unusual case of complete heart block. J Electrocardiol. 2007;40(6):493-495. doi:10.1016/j.jelectrocard.2007.03.244
Funding:
This study was conducted in Rancho Los Amigos National Rehabilitation Center, a facility affiliated with the Los Angeles County-Department of Health Services. No specific funding was provided.