Processing Speed Partially Mediates Executive Function Impairments in Adolescents with Congenital Heart Disease: Results from a Prospective Cohort Study.

OBJECTIVE: To assess processing speed, fine motor function, attention, and executive function (EF) impairments in adolescents with complex congenital heart disease (CHD) who underwent open-heart surgery during infancy. STUDY DESIGN: We administered a comprehensive neuropsychological test battery evaluating 5 EF domains: working memory, inhibition, cognitive flexibility, fluency, and planning and primary neurodevelopmental processes (PNPs): processing speed, fine motor function, and attention. The sample included 100 adolescents with complex CHD from a previous University Children's Hospital Zurich study, with 104 healthy controls for comparison. We generated scores for each EF domain and computed an EF summary score. Group comparisons and associations were analyzed with multiple regressions accounting for parental education. Mediation analysis explored how PNPs mediate the effect between a CHD diagnosis and EF. RESULTS: In adolescents with complex CHD, all EF domains and the EF summary score were impaired (ß = 0.20 to 0.37, all P < .05). Furthermore, they exhibited slower processing speed (ß = 0.27, P < .01) than healthy controls, with no differences in attention (ß = -0.07, P = .34) and fine motor function (ß = 0.08, P = .34). Processing speed showed a strong association with the EF summary score (ß = 0.60, P < .001) and partially mediated the relationship between CHD diagnosis and the EF summary score (ß = 0.37, 95% CI [0.24, 0.50], P < .001). CONCLUSION: Adolescents with complex CHD show difficulties in EFs and processing speed. Notably, processing speed is strongly associated with EFs and partly accounts for EFs disparities between patients and healthy controls. Early detection and interventions for processing speed difficulties may improve EF outcomes in these patients.

Heart rate variability and cognitive functions in adolescents with complex congenital heart disease.

BACKGROUND: Heart Rate Variability (HRV) originates from the interplay between parasympathetic/sympathetic inputs to the heart, thus serving as an indicator of Autonomic Nervous System regulation. Prior research indicates that decreased HRV, marked by reduced autonomic balance, is related to poorer cognitive performance. While the population with congenital heart disease (CHD) show changes in HRV linked with the heart defect, the association between HRV and cognitive functions in CHD remains unexplored. METHODS: 46 adolescents with CHD who went through infant open-heart surgery and 64 healthy controls (50.9% males, 12.8 ± 1.4 years) underwent neurodevelopmental testing and photoplethysmograph acquisition. Group differences and associations with cognitive functions were analysed with linear regression. P values were FDR-corrected. RESULTS: Adolescents with CHD showed lower HRV (quantified by high-frequency power) compared to controls (p < 0.001). Lower HRV was correlated with worse executive function (ß = 0.24, p = 0.044) and lower IQ (ß = 0.26, p = 0.010) in the whole sample and with lower IQ (ß = 0.35, p = 0.014) in the CHD group. These associations were robust to confounders, including age, sex, and socioeconomic status. CONCLUSION: Our findings demonstrate an association between HRV and cognitive functions in adolescents with complex CHD. Early detection of alterations in HRV/autonomic regulation may help to identify children with CHD at risk for cognitive impairments. IMPACT: Adolescents with congenital heart disease (CHD) showed lower heart rate variability (HRV), indicating an imbalanced autonomic nervous system. Lower HRV was associated with lower IQ and executive function (EF) in the whole sample. The association between HRV and IQ was significantly stronger in CHD than in healthy controls. This study provides the first evidence of a link between altered HRV and cognitive impairments in the CHD population. Neurodevelopmental impairments seen in adolescents with CHD could be linked to their altered cardiac autonomic nervous activity, marked by low HRV.