Résumé : OBJECTIVES: Cardiac arrest is a catastrophic event that may arise during the management of convulsive status epilepticus. We aimed to report the clinical characteristics, outcomes, and early predictors of convulsive status epilepticus-related cardiac arrest. DESIGN: Retrospective multicenter study. SETTING: Seventeen university or university affiliated participating ICUs in France and Belgium. PATIENTS: Consecutive patients admitted to the participating ICUs for management of successfully resuscitated out-of-hospital cardiac arrest complicating the initial management of convulsive status epilepticus between 2000 and 2015. Patients were compared with controls without cardiac arrest identified in a single-center registry of convulsive status epilepticus patients, regarding characteristics, management, and outcome.None. MEASUREMENTS AND MAIN RESULTS: We included 49 cases with convulsive status epilepticus-cardiac arrest and 235 controls. In the cases, median time from medical team arrival to cardiac arrest was 25 minutes (interquartile range, 5-85 min). First recorded rhythm was asystole in 25 patients (51%) and pulseless electrical activity in 13 patients (27%). A significantly larger proportion of patients had a favorable 1-year outcome (Glasgow Outcome Scale score of 5) among controls (90/235; 38%) than among cases (10/49; 21%; p = 0.02). By multivariate analysis, independent predictors of cardiac arrest were pulse oximetry less than 97% on scene (odds ratio, 2.66; 95% CI, 1.03-7.26; p = 0.04), drug poisoning as the cause of convulsive status epilepticus (odds ratio, 4.13; 95% CI, 1.27-13.53; p = 0.02), and complications during early management (odds ratio, 11.98; 95% CI, 4.67-34.69; p < 0.0001). Having at least one comorbidity among cardiac, respiratory, and neurologic (other than epilepsy) conditions predicted absence of cardiac arrest (odds ratio, 0.28; 95% CI, 0.10-0.80; p = 0.02). CONCLUSIONS: In patients managed for convulsive status epilepticus, relative hypoxemia, on-scene management complications, and drug poisoning as the cause of convulsive status epilepticus were strong early predictors of cardiac arrest, suggesting areas for improvement.