Relationship between seizure episode and sudden cardiac arrest in patients with epilepsy: a community-based study.

BACKGROUND Among patients with epilepsy, sudden cardiac arrest (SCA) is a major cause of death. It is commonly thought that SCA in epilepsy occurs after a seizure, though the strength of evidence supporting this is limited. We sought to evaluate the relationship between seizures and SCA in patients with epilepsy. METHODS AND RESULTS From the ongoing Oregon Sudden Unexpected Death Study, cases of SCA identified using prospective, multisource ascertainment (Portland metropolitan area, Oregon; population≈1 million; February 1, 2002, to March 1, 2012) were evaluated for history of epilepsy. In the subset with witnessed SCA, clinical presentations were analyzed for evidence of seizure activity immediately before the event as well as lifetime clinical history, including nature of seizures before SCA. Only 34% of patients with history of epilepsy and a witnessed arrest had evidence of seizure activity before the arrest. Rates of survival to hospital discharge after attempted resuscitation were 2.7% in patients with history of epilepsy versus 11.9% for patients without epilepsy (P=0.014). Patients with epilepsy had a significantly lower rate of presentation with ventricular tachycardia/ventricular fibrillation as opposed to pulseless electrical activity/asystole (epilepsy, 26%; no epilepsy, 44%; P=0.002), despite nearly identical response times. CONCLUSIONS In the majority (66%) of epilepsy patients, there was no relationship between seizure and SCA, implying that SCA in epilepsy patients often may not involve seizure as a trigger. The significantly worse rate of survival from SCA in epilepsy patients warrants urgent investigation.