The factors that predict survival in out-of-hospital cardiac arrests and autopsy findings for individuals with unknown cause of death: A systematic review

Background: Histopathological examination in autopsies following cardiac arrest provides important guide into the underlying causes of sudden cardiac death. Common findings include coronary artery atherosclerosis, myocardial infarction, fibrosis, and myocarditis. These changes identify structural or pathological abnormalities missed clinically. Autopsy-based histology is essential for accurate diagnosis, in unexplained deaths, and supports preventive methods and better understanding of cardiovascular pathology. This systematic review aimed to evaluate the predictors of survival following OHCA and to summarize autopsy and postmortem findings where the cause of death was unknown.

Methods: A literature search was conducted in PubMed, PubMed Central, Scopus, and Google Scholar to find eligible studies published between 2010 and 2024. Studies were included if they focused on predictors of survival in adult OHCA cases or provided autopsy findings in unexplained deaths. Data were extracted regarding study design, population characteristics, survival rates, predictors, and outcomes. 

Results: sixteen studies were included. Histopathological findings from included studies indicate coronary atherosclerosis, myocardial infarction, and structural heart changes as an important cause of sudden cardiac death, show autopsy’s role in identifying cardiac pathology and guide prevention strategies. Predictors of survival included initial shockable rhythm, witnessed arrest, early defibrillation, bystander CPR, and rapid EMS response. Early coronary angiography and targeted temperature management correlated with better outcomes. Autopsy findings in unexplained deaths revealed cardiac causes. Molecular autopsy was needed to identify inherited arrhythmia syndromes in structurally normal hearts.

Conclusion: Survival after OHCA is influenced by early intervention and clinical factors. Autopsy, when combined with genetic testing, is essential to diagnose unexplained sudden deaths and guide family risk assessment.