Pulseless electrical activity versus asystole as initial pulseless rhythm in children: challenging convention regarding non-shockable rhythms.

BACKGROUND: Pulseless electrical activity (PEA) and asystole are the predominant initial rhythms in pediatric in-hospital cardiac arrest (IHCA) and are often grouped as "non-shockable." Whether they represent distinct entities in children remains unclear. METHODS: We analyzed pediatric (<18 years) IHCA cases from the American Heart Association Get With The Guidelines-Resuscitation (GWTG®-R) registry (2000-2023). Patients with an initial rhythm of PEA or asystole were included. Outcomes were return of spontaneous circulation (ROSC), restoration of circulation (ROC, defined as ROSC or ROC with ECMO), and survival to hospital discharge. Mixed-effects regression adjusted for demographics, comorbidities, event features, and hospital factors. Additional analyses excluded NICU events and stratified patients by age. RESULTS: Of 9423 patients, 5416 (57.5%) had PEA and 4007 (42.5%) had asystole. Compared with PEA, asystole was associated with lower odds of ROSC (aOR 0.70, 95% CI 0.64-0.77), ROC (aOR 0.71, 95% CI 0.64-0.78), and survival to discharge (aOR 0.89, 95% CI 0.81-0.99). In the NICU-excluded cohort, asystole remained associated with lower odds of ROSC and ROC, but survival to discharge no longer differed between rhythms (36.1% vs 34.1%; aOR 0.99, 95% CI 0.90-1.11). Age-stratified analyses showed the overall survival difference was driven by neonates; in older age groups, survival to discharge did not differ between PEA and asystole. CONCLUSION: PEA and asystole differ in patient characteristics and short-term resuscitation outcomes in pediatric IHCA. However, the overall survival difference appears driven by neonates and NICU-associated events, with no significant survival difference in older children.