Pulseless electrical activity vs. asystole in adult in-hospital cardiac arrest: Predictors and outcomes

Aim: This observational cohort study aimed to identify factors associated with pulseless electrical activity (PEA) and asystole in in-hospital cardiac arrest (IHCA) patients and to determine whether differences in outcome based on the initial rhythm were explained by patient-and cardiac arrest characteristics. Methods: Adults with IHCA from 2017 to 2018 were included from the Danish IHCA Registry (DANARREST). Additional data came from population based registries. Unadjusted (RRs) and adjusted risk ratios (aRRs) were estimated for predictors of initial rhythm, return of spontaneous circulation (ROSC), and survival. Results: We included 1495 PEA and 1285 asystole patients. The patients did not differ substantially in patient characteristics. Female sex, age>90 years, pulmonary disease, and obesity were associated with initial asystole. Ischemic heart disease and witnessed and monitored cardiac arrest were associated with initial PEA. In unadjusted and adjusted analyses, PEA was associated with increased ROSC (aRR = 1.21, 95% confidence interval [CI] 1.10; 1.33). PEA was also associated with increased 30-day and 1-year survival in the unadjusted analysis, while there was no clear association between the initial rhythm and 30-day (aRR = 0.88, 95% CI 0.71; 1.11) and 1-year (aRR = 0.85, 95% CI 0.69; 1.04) survival when patient-and cardiac arrest characteristics were adjusted for. Conclusion: In patients with IHCA presenting with PEA or asystole, there were no major differences in patient demographics and comorbidities. The patients differed substantially in cardiac arrest characteristics. Initial PEA was associated with higher risk of ROSC, but there was no difference in 30-day and 1-year survival.