ImportanceData on trends in incidence and mortality for in-hospital cardiac arrest (IHCA) in children with cardiac disease in the intensive care unit (ICU) are lacking. Additionally, there is limited information on factors associated with IHCA and mortality in this population.ObjectiveTo investigate incidence, trends, and factors associated with IHCA and mortality in children with cardiac disease in the ICU.Data SourcesA systematic review was conducted using PubMed, Web of Science, EMBASE, and CINAHL, from inception to September 2021.Study SelectionObservational studies on IHCA in pediatric ICU patients with cardiac disease were selected (age cutoffs in studies varied from age ≤18 y to age ≤21 y).Data Extraction and SynthesisQuality of studies was assessed using the National Institutes of Health Quality Assessment Tools. Data on incidence, mortality, and factors associated with IHCA or mortality were extracted by 2 independent observers. Random-effects meta-analysis was used to compute pooled proportions and pooled ORs. Metaregression, adjusted for type of study and diagnostic category, was used to evaluate trends in incidence and mortality.Main Outcomes and MeasuresPrimary outcomes were incidence of IHCA and in-hospital mortality. Secondary outcomes were proportions of patients who underwent extracorporeal membrane oxygenation (ECMO) cardiopulmonary resuscitation (ECPR) and those who did not achieve return of spontaneous circulation (ROSC).ResultsOf the 2574 studies identified, 25 were included in the systematic review (131 724 patients) and 18 in the meta-analysis. Five percent (95% CI, 4%-6%) of children with cardiac disease in the ICU experienced IHCA. The pooled in-hospital mortality among children who experienced IHCA was 51% (95% CI, 42%-59%). Thirty-nine percent (95% CI, 29%-51%) did not achieve ROSC; in centers with ECMO, 22% (95% CI, 14%-33%) underwent ECPR, whereas 22% (95% CI, 12%-38%) were unable to be resuscitated. Both incidence of IHCA and associated in-hospital mortality decreased significantly in the last 20 years (both P for trend < .001), whereas the proportion of patients not achieving ROSC did not significantly change (P for trend = .90). Neonatal age, prematurity, comorbidities, univentricular physiology, arrhythmias, prearrest mechanical ventilation or ECMO, and higher surgical complexity were associated with increased incidence of IHCA and mortality odds.Conclusions and RelevanceThis systematic review and meta-analysis found that 5% of children with cardiac disease in the ICU experienced IHCA. Decreasing trends in IHCA incidence and mortality suggest that education on preventive interventions, use of ECMO, and post-arrest care may have been effective; however, there remains a crucial need for developing resuscitation strategies specific to children with cardiac disease.