This study aimed to determine the causes of sudden cardiac arrest (SCA) in apparently healthy children at a single center in the era of primary prevention (screening questionnaire [SQ]) and secondary prevention (automated external defibrillator [AED] and the automated implantable cardioverter defibrillator [AICD]). Any child 0 to 18 years of age without prior known disease, except for attention deficit disorder, who underwent out-of-the hospital cardiopulmonary resuscitation was included in the study as a SCA subject. A retrospective chart review was used to evaluate the efficacy of the SQ, electrocardiogram (ECG), chest roentgenogram (CXR), and echocardiogram. The findings showed that for 44 of 6,656 children admitted to intensive care with SCA, an AED was used for 39%, an AICD was placed in 18%,and survival to hospital discharge was 50%. The etiology for SCA was identified in 57% of the cases, mostly in those older than 1 year, and the majority of these had a cardiac etiology (50%), whereas 7% had rupture of an arteriovenous malformation. Stimulant medication use was seen in 11% of the SCA subjects. In the best-case scenario of hypothesized primary prevention, a prior SQ, CXR, ECG, or echocardiogram may have detected respectively 18, 9, 23 and 16% of the at-risk cases, and 32% of the cases may have been detected with ECG and SQ together. Based on a historical control cohort, a positive ECG was significantly higher in the children with SCA (p = 0.014). An ECG together with a screening SQ may be more effective in identifying children potentially at risk for SCA than an SQ alone.