Factors associated with preventable out-of-hospital nontraumatic cardiac arrest.

To identify ways to decrease the risk of out-of-hospital cardiac arrest (CA) caused by an acute coronary syndrome, we examined factors associated with the development of CA > or = 1 hour after symptom onset. Multivariate analysis revealed that a low level of physical activity, a history of diabetes mellitus, and a history of unstable angina are associated with out-of-hospital CA occurring > or = hour after symptom onset.