Symbolic transfer entropy reveals enhanced cardiac autonomic influence on cortical activity in infants with congenital heart disease

Congenital heart disease (CHD) is associated with neurodevelopmental vulnerability, but directional cardiac–cortical statistical dependencies in early childhood remain incompletely characterized. We analyzed simultaneous electrocardiography and electroencephalography recordings during sleep from 14 infants and toddlers with heterogeneous CHD diagnoses and 16 healthy controls. Heart rate variability features, including the low-frequency/high-frequency (LF/HF) ratio, and EEG band-power features were temporally aligned. Bidirectional symbolic transfer entropy based on amplitude-bin quantization was summarized using a net directionality index. Both groups exhibited predominantly positive net directionality indexes, while the CHD group showed higher net cardiac-to-cortical estimates for LF/HF–alpha and LF/HF–beta under permutation-based false discovery rate control. These exploratory group-level differences do not establish a uniform CHD phenotype, altered physiological coupling or individual clinical risk. Interpretation remains limited by patient heterogeneity, acquisition-setting differences and unresolved effects of the underlying feature statistics. Longitudinal studies and methodological validation are required before considering prognostic or intervention applications.