Out-of-hospital Cardiac Arrest Patient Characteristics: Comparing ventricular arrhythmia and Pulseless Electrical Activity.

Background: The proportion of patients suffering out-of-hospital cardiac arrest presenting with ventricular arrhythmias/ventricular fibrillation (VT/VF) is decreasing, while the proportion presenting with pulseless electrical activity (PEA) is increasing. Cardiac arrest interventions target VT/VF and survival rates from PEA are much lower. The aim of this study was to compare clinical characteristics of those suffering PEA and VT/VF.

Methods: We examined the past medical history of all patients suffering cardiac arrest in the Wellington region between 2008-2012 and compared clinical features of those with PEA to VT/VF.

Results: We identified 749 cardiac arrests in the study period, and were able to obtain detailed medical histories in 735 (98%) cases. The presenting rhythm was VF/VT in 337 (46%) cases, PEA in 127 (17%), and asystole in 271 (37%). Patients with PEA were older (68±14 versus 63±15 years, p=0.003), a higher proportion were female (35% versus 22%, p=0.002) and were less likely to have prior cardiovascular disease than those with VT/VF (48% versus 59%, p=0.03). Respiratory disease was more common in those with PEA (35% versus 23%, p=0.008).

Conclusion: The population suffering PEA differs from the VT/VF cohort in a number of ways, and PEA is associated with significantly worse outcomes.