BackgroundHeart failure constitutes significant morbidity and mortality among the pediatric population. Few data exist on the prevalence and mortality rate of pediatric heart failure (pHF) in the United States.ObjectivesThis study aimed to determine the in-hospital mortality and the principal diagnoses in pediatric patients with heart failure who died while being hospitalized in the United States.MethodsThis is a retrospective cross-sectional study using data from the 2019 Kid Inpatient Database (KID). The KID contained data on hospitalized children below 21 years of age. Using Stata 17 software (StataCorp LLC, College Station, Texas), the data were searched for heart failure diagnoses using International Classification of Diseases 10th revision Clinical Modification (ICD-10-CM) codes. By using the “rank” command in Stata, the most common principal diagnoses were placed in descending order of frequency, and these were further divided into different ICD-10 code categories.ResultsThere were 16,206 pHF admissions in 2019. Of these admissions, 1,023 (6.31%) patients died. The top five principal ICD 10 code categories among all pHF deaths in descending order were circulatory system (17.95%), congenital/chromosomal abnormalities (17.43%), respiratory system (10.28%), infectious diseases (9.24%, and perinatal diseases (7.90%). Among all pHF deaths, sepsis of unspecified organisms (5.14%), hypoplastic left heart syndrome (HLHS) (3.19%), and acute respiratory failure with hypoxia (3.14%) were the most common primary diagnoses.Conclusion and significancePediatric heart failure in-hospital overall mortality is 6.31%, and sepsis of unspecified organisms, HLHS, and acute respiratory failure are the most common principal diagnoses among these children. Preventive measures and prompt treatment of infections are paramount to reducing pHF mortality.