Serious Cardiac Arrhythmias Detected by Subcutaneous Long-term Cardiac Monitors in Patients With Drug-Resistant Epilepsy

Abstract

Background:Epilepsy is associated with an increased risk of cardiovascular disease and premature mortality, including sudden unexpected death in epilepsy (SUDEP). Of concern, serious cardiac arrythmias might go undetected from routine epilepsy and cardiac investigations.Methods:This prospective cohort study aimed to detect cardiac arrhythmias in patients with chronic drug-resistant epilepsy (≥5 years duration) using subcutaneous cardiac monitors for a minimum follow-up duration of 12 months. Participants with known cardiovascular disease or those with abnormal 12-lead electrocardiograms were excluded. The device was programmed to automatically record episodes of tachycardia ≥140 beats per minute (bpm), bradycardia ≤40 bpm for ≥3 seconds, or asystole ≥3 seconds.Findings:Thirty-one patients underwent subcutaneous cardiac monitoring for a median recording duration of 2.2 years (range 0.5 to 4.2). During this time, 28 (90.3%) patients had episodes of sustained (≥30s) sinus tachycardia, 8/31 (25.8%) had sinus bradycardia, and 3 (9.7%) had asystole. Three (9.7%) patients had serious cardiac arrhythmias requiring additional cardiac interventions. Among them, two patients had prolonged sinus arrest and ventricular asystole (>6 seconds), leading to pacemaker insertion in one; and another patient with an epileptic encephalopathy had multiple episodes of recurrent non-sustained polymorphic ventricular tachycardia and bundle branch conduction abnormalities. The time to first detection of a clinically significant cardiac arrhythmia ranged between 1.2 to 26.9 months following cardiac monitor insertion.Conclusions:Implantable cardiac monitors detected a high incidence of clinically significant cardiac arrhythmias in patients with chronic drug resistant epilepsy, which may contribute to the incidence of premature mortality including SUDEP.

Seizures and Cardiac Dysrhythmias: And the Beat (Sometimes) Goes On

“…If the incidence of serious arrhythmias is indeed as high as reported by Sivathamboo et al, 9 should we recommend long-term monitoring with IRL for all patients with drug-resistant epilepsy? It could be that early detection and treatment of serious arrhythmias may prevent premature mortality and potentially SUDEP.…”

“…In the current study by Sivathamboo et al 9 report on the incidence of serious cardiac arrhythmias, defined as warranting additional cardiologist assessment or intervention, in a prospective observational study of 31 adult patients with refractory epilepsy. The primary endpoint was detection of serious arrhythmias, and the secondary endpoint was the time to the first detection of a serious event.…”

The role of the adenosine system in epilepsy and its comorbidities

“…However, a growing body of evidence suggests that damage caused by repeated seizures in uncontrolled epilepsy leads to incremental electrical and mechanical cardiac dysfunction (Tigaran et al, 2003; Verrier et al, 2020). Specifically, long‐term monitoring studies of patients with chronic epilepsy revealed a significant proportion with clinically relevant cardiac arrhythmia and T‐wave alternans, but this was not observed in newly diagnosed cases (Pang et al, 2019; Sivathamboo et al, 2022). Myocardial infarction (MI) is another serious cardiac comorbidity associated with epilepsy.…”

It is premature for a unified hypothesis of sudden unexpected death in epilepsy: A great amount of research is still needed to understand the multisystem cascade

“…33,35,36 In people with drug-resistant epilepsy, implantable cardiac monitors detected a high incidence of clinically significant cardiac arrhythmias. 37 Ictal and postictal arrhythmias, such as asystole and ventricular fibrillation, have been reported, some of which are associated with (near) SUDEP. [38][39][40] Although the authors discuss the temporal dissociation of cardiac and respiratory dysfunction, these events can arise concurrently as well as one without the other.…”

“…The incidence of electrocardiographic (ECG) abnormalities is higher in intractable forms of epilepsy, surrounding seizures, and in SUDEP cases 33,35,36 . In people with drug‐resistant epilepsy, implantable cardiac monitors detected a high incidence of clinically significant cardiac arrhythmias 37 . Ictal and postictal arrhythmias, such as asystole and ventricular fibrillation, have been reported, some of which are associated with (near) SUDEP 38–40 .…”