ClinicalSudden DeathCardiac arrhythmias and sudden unexpected death in epilepsy: Results of long-term monitoring
Introduction
About 46 million people worldwide have epilepsy.1 Despite the reduced burden of disease in the last 25 years, epilepsy remains associated with higher morbidity, mortality, and disability rate.1 Nearly 1 million patients experience seizures despite antiepileptic therapy.2 More than 50% of patients have had ictal arrhythmias during at least 1 seizure.2, 3, 4, 5 Moreover, neurogenic cardiac arrhythmias are considered to be the leading cause of sudden unexplained death in epilepsy (SUDEP).6,7 Data on the ictal cardiac arrhythmia burden, including the cases of SUDEP,8,9 are mostly obtained by video electroencephalogram (EEG) monitoring.2 Prospective continuous evaluation of ictal cardiac arrhythmias using the implantable loop recorder (ILR) is limited by small sample studies.3,10 The present study aimed to assess the type and prevalence of heart rhythm changes and the underlying causes of SUDEP in a larger sample of patients with drug-resistant epilepsy by using an ILR.
Section snippets
Methods
This prospective observational study included patients with confirmed drug-resistant focal epilepsy who had at least 1 seizure per month and underwent subcutaneous ILR implantation from November 2015 to March 2017.
The inclusion criteria were drug-resistant epilepsy, confirmed by video-EEG monitoring; seizure frequency ≥1 per month; and age 18–60 years. The exclusion criteria were structural heart disease, coronary artery disease (CAD), cardiomyopathies, use of any antiarrhythmic drugs,
Patients characteristics
Table 1 presents the baseline characteristics of the patients. The mean age of the study participants was 35.4 ± 10.3 years; 102 (52.8%) were male. One hundred thirty patients (67.4%) had symptomatic epilepsy; the remaining 63 patients (32.6%) had cryptogenic epilepsy. Ninety-four patients (48.7%) had unilobar epilepsy (temporal 50, frontal 41, occipital 2, and parietal 1); 74 patients (38.3%) had bilobar epilepsy (temporal and frontal); and 25 patients (13%) had multilobar epilepsy. The number
Discussion
To our knowledge, this is the first study that presents the results of the long-term (36-month) heart rhythm monitoring using an ILR in a large sample of patients with drug-resistant epilepsy (n = 193). More than half of the patients enrolled in our study had FBTCS, the most severe clinical manifestation of epilepsy. We hypothesized that this cohort of patients is more likely to develop clinically relevant ictal cardiac arrhythmias, and continuous cardiac monitoring would allow evaluating
Conclusion
Although ictal heart rhythm and rate changes occur in the majority of patients with drug-resistant epilepsy, clinically relevant cardiac events are rare. Clinically significant asystole (>6 seconds) was predominantly detected in patients with extratemporal epilepsy. There were no potentially malignant arrhythmias in patients who died suddenly during the preceding follow-up period. Further multidisciplinary studies are required to further evaluate the mechanisms of sudden death in epilepsy.
Acknowledgments
We thank the patients and their families who participated in this study, as well as the referring health care providers.
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Funding sources: This work was supported by the Ministry of Health of the Russian Federation (8-3/2016). Disclosures: Prof Boytsov is director-general of the National Medical Research Center of Cardiology.
The authors have no conflicts of interest to disclose.