Clinicopathological correlates of out-of-hospital cardiac arrests.

Background: Sudden cardiac arrest with or without sudden cardiac death (SCD) represents a heterogeneous spectrum of underlying etiology but is often a catastrophic event. Despite improvements in pre-hospital response and post-resuscitation care, outcomes remain grim. Thus, we aim to evaluate the predictors of survival in out-of-hospital cardiac arrests (OHCAs) and describe autopsy findings of those with the uncertain cause of death (COD).

Methods: This is a subgroup analysis of the Singapore cohort from the Pan Asian Resuscitation Outcome Study which studied 933 OHCAs admitted to two Singapore tertiary hospitals from April 2010 to May 2012.

Results: Of the patients analysed, 30.2% ( n  = 282) had an initial return of spontaneous circulation (ROSC) at the emergency department, 18.0% ( n  = 168) had sustained ROSC with subsequent admission and 3.4% ( n  = 32) had survival to discharge. On multivariate analysis, an initial shockable rhythm, a witnessed event, prehospital defibrillation, and shorter time to hospital predicted ROSC as well as survival to discharge. A total of 163 (17.5%) autopsies were performed of which a cardiac etiology of SCD was noted in 92.1% ( n  = 151). Ischemic heart disease accounted for 54.3% ( n  = 89) of the autopsy cohort, with acute myocardial infarction (26.9%, n  = 44) and myocarditis (3.7%, n  = 6) rounding out the top three causes of demise.

Conclusion: OHCA remains a clinical presentation that portends a poor prognosis. Of those with uncertain COD, cardiac etiology appears to predominate from autopsy study. Identification of prognostic factors will play an important role in improving individual-level and systemic-level variables to further optimize outcomes.