Body mass index predicts ventricular repolarisation in obese children: differential effects across obesity levels

BACKGROUND: Childhood obesity is associated with cardiac electrical remodelling, yet the relationship between body mass index (BMI) and ventricular repolarisation (VR) heterogeneity remains incompletely characterised in paediatric obesity. METHODS: This prospective observational comparative study enrolled 184 children (112 obese, 72 normal-weight; age 8-17 years). Electrocardiographic analysis included traditional (QT, QTc, JT) and novel VR parameters (Tp-e interval, Tp-e/QT, Tp-e/QTc ratios). Multiple linear regression and receiver operating characteristic (ROC) analyses identified independent predictors and clinically applicable thresholds. RESULTS: as the optimal threshold for abnormal repolarisation (AUC = 0.682, sensitivity 76.1%, specificity 50.0%, p < 0.001). CONCLUSION: Childhood obesity is associated with VR abnormalities independently of metabolic dysfunction and structural cardiac changes. This study suggests that repolarisation abnormalities occur in the early stages of obesity and through different pathophysiological mechanisms. The defined BMI threshold provides a clinically applicable tool for early risk stratification, highlighting the critical importance of intervention before obesity becomes established.