Enhanced Cardiac Surveillance in Child Psychiatry: Role of Frontal QRS Angle During Atypical Antipsychotic Treatment

INTRODUCTION: Atypical antipsychotics are widely prescribed in child and adolescent psychiatry and are known to affect cardiac repolarization, most commonly reflected by QTc prolongation. However, QTc alone may not fully capture repolarization heterogeneity. The frontal QRS-T angle f(QRS-T) is an electrocardiographic marker reflecting ventricular depolarization-repolarization mismatch. This study aimed to evaluate and compare f(QRS-T) alongside other repolarization parameters in children and adolescents receiving atypical antipsychotics versus healthy controls. METHODS: This retrospective observational study included 45 children and adolescents (6-17 years) receiving atypical antipsychotics for at least six months and 45 age- and sex-matched healthy controls. Standard 12-lead ECG recordings were obtained to measure f(QRS-T), QTc, Tp-e interval, and Tp-e-based ratios. Correlation analyses assessed associations between f(QRS-T), QTc, and duration of antipsychotic use. Hierarchical multiple linear regression was performed to identify independent predictors of f(QRS-T) in the patient group. Receiver operating characteristic (ROC) analysis evaluated the discriminative ability of f(QRS-T) for QTc prolongation (QTc ≥ 440 ms). RESULTS: Children receiving atypical antipsychotics exhibited significantly higher f(QRS-T), QTc interval, Tp-e interval, Tp-e(c), Tp-e(c)/QT, and iCEBc ratios compared with healthy controls (p < 0.05). Frontal QRS-T angle was positively correlated with QTc (r = 0.406, p < 0.001) but not with the duration of antipsychotic treatment. In hierarchical regression analysis, age, sex, QTc and duration of antipsychotic use were not independent predictors of f(QRS-T). ROC analysis demonstrated that f(QRS-T) moderately discriminated patients with QTc prolongation (AUC = 0.735); a cut-off value of 26.5° yielded a sensitivity of 72% and a specificity of 60%. CONCLUSION: f(QRS-T) is significantly increased in children and adolescents receiving atypical antipsychotics and is associated with QTc prolongation, although it is not independently predicted by treatment duration or conventional QT-based indices. These findings suggest that f(QRS-T) may serve as a complementary electrocardiographic marker of repolarization heterogeneity alongside QTc in the cardiac safety monitoring of pediatric patients treated with atypical antipsychotics.