Factors Predisposing to Survival After Resuscitation for Sudden Cardiac Arrest.

Abstract Background In the POST SCD study, the authors autopsied all World Health Organization (WHO)–defined sudden cardiac deaths (SCDs) and found that only 56% had an arrhythmic cause; resuscitated sudden cardiac arrests (SCAs) were excluded because they did not die suddenly. They hypothesized that causes underlying resuscitated SCAs would be similarly heterogeneous. Objectives The aim of this study was to determine the causes and outcomes of resuscitated SCAs. Methods The authors identified all out-of-hospital cardiac arrests (OHCAs) from February 1, 2011, to January 1, 2015, of patients aged 18 to 90 years in San Francisco County. Resuscitated SCAs were OHCAs surviving to hospitalization and meeting WHO criteria for suddenness. Underlying cause was determined by comprehensive record review. Results The authors identified 734 OHCAs over 48 months; 239 met SCA criteria, 133 (55.6%) were resuscitated to hospitalization, and 47 (19.7%) survived to discharge. Arrhythmic causes accounted for significantly more resuscitated SCAs overall (92 of 133, 69.1%), particularly among survivors (43 of 47, 91.5%), than WHO-defined SCDs in POST SCD (293 of 525, 55.8%; p  Conclusions In this 4-year countywide study of OHCAs, only one-third were sudden, of which one-half were resuscitated to hospitalization and 1 in 5 survived to discharge. Arrhythmic cause predicted survival and nearly one-half of nonsurvivors had nonarrhythmic causes, suggesting that SCA survivors are not equivalent to SCDs. Early identification of nonarrhythmic SCAs, such as neurologic emergencies, may be a target to improve OHCA survival.