Seizure in patients with epilepsy may not be a trigger of sudden cardiac arrest (SCA). Eric Stecker, Knight Cardiovascular Institute, Oregon Health and Science University, Portland, USA, and colleagues, from the Cedars-Sinai Heart Institute, Los Angeles, USA, reported in a study recently published in Circulation Arrhythmia and Electrophysiology.
“Cohort studies of patients in epilepsy clinics or undergoing electroencephalographic (EEG) monitoring have led to the widespread belief that SCA usually occurs in relation to an acute seizure […] Though the strength of evidence supporting this is limited,” wrote Stecker et al. Therefore, they sought to evaluate the relationship between seizures and sudden cardiac arrest in epileptic patients.
The researchers used data of SCA patients with history of epilepsy from the ongoing Oregon Sudden Unexpected Death study. They identified 2,417 patients who experienced SCA, during a 10 year follow-up (2002–2010). From those, 106 had a history of epilepsy and 2,311 did not have epilepsy. The epileptic patients were younger (55 years vs. 63 years), more likely to have a history of stroke (20% vs. 12%) and to be taking antiepileptic medications.
Stecker et al found that 66% of patients with epilepsy and a witnessed arrest had no evidence of seizure activity before the arrest. They also found that the rates of these patients’ survival after attempted resuscitation were lower compared to patients without epilepsy (2.7% vs. 11.9%). Moreover, patients with epilepsy had a significantly lower rate of presentation with ventricular tachycardia/ventricular fibrillation as opposed to pulseless electrical activity (26% vs. 44%) despite nearly identical response times. The researchers concluded that because a majority of patients with epilepsy did not have a seizure activity prior to SCA it “questions” the role of seizure as a dominant trigger of SCA in patients with epilepsy.
“These findings question a long-held clinical doctrine and urge us to look for other mechanisms that increase risk of SCA in patients with epilepsy,” said Sumeet Chugh, associate director of the Cedars-Sinai Heart Institute, principal investigator of the Oregon Sudden Unexpected Death study and senior author of this publication.
In relation to the difference in the survival rates for patients with and without epilepsy, the authors wrote: “Future research investigating reasons for survival differences could improve outcomes for patients with epilepsy as well as improve understanding of the overall pathophysiology of SCA.”
