ObjectivesTo evaluate patterns and determinants of longitudinal growth among children requiring complex biventricular repair for congenital heart disease, and to assess for associations of growth with early feeding modality, comorbidities, postoperative complications, and socioeconomic characteristics. Study DesignA single-institution retrospective cohort study was performed in children born 2/1999-3/2009 with complex congenital heart disease who underwent biventricular repair before age 4, defined by Risk Adjustment in Congenital Heart Surgery-1 (RACHS-1) category 3-5. Clinical characteristics, height, weight, and body mass index (BMI) from ages 2-12 were collected by chart review. Neighborhood-level socioeconomic data were identified using a geographic information system approach. The adjusted association of covariates with growth outcomes was estimated using multivariable linear regression models using generalized estimating equations. ResultsCompared with population growth curves, the cohort (n = 150) trended toward early decrease in age-adjusted weight and height. Early tube feeding was significantly associated with decreased BMI prior to adolescence (-0.539; 95% CI -1.02, -0.054; p = 0.029). Additionally, other clinical and perioperative characteristics had significant associations with growth, including low birthweight, preoperative tube feeds, need for multiple bypass runs, and diagnosis of feeding disorder. ConclusionsEarly childhood growth in children with complex biventricular repair may be impaired. Early tube feeding was associated with decreased BMI over the course of early childhood, which may indicate a need for continued close nutrition follow-up and support even beyond the duration of tube feeds.