Evaluation and application of electrocardiographic age model for children.

ECG-age, derived from ECG signals using deep neural networks (DNNs), correlates with health status but has been predominantly studied in adults, neglecting the unique development trajectories of pediatric hearts. This study evaluates and proposes a pediatric-specific ECG-age model for clinical application. Validated on 58,672 ECGs from healthy children, three approaches were assessed: a pre-trained adult model, the same model retrained on pediatric data, and feature-enhanced models which was used to enhance the interpretability of the model. Results demonstrate limited applicability of adult-derived models, while dedicated pediatric models achieved accurate age assessment (MAE: 7.878 ± 6.658 months, R²=0.821), further confirmed on external data. Analysis of 209,644 ECGs across 21 pediatric diseases and 102,441 ECGs with 20 abnormalities revealed that an large ECG-age gap between chronological age indicates stronger associations with diseases or abnormalities. In a specific scenario study, ECG-age significantly correlated with postoperative complications in tetralogy of Fallot (TOF) surgery children. These findings indicate that pediatric-specific ECG-age models can effectively measure children's cardiac development and signal pathological conditions, supporting their potential as a widely applicable clinical digital biomarker in pediatrics.