RÉSUMÉ
Objectives To evaluate the clinical value of heart rate variability (HRV) analysis in school-age healthy chil-dren with functional ST-T changes in electrocardiogram (ECG). Methods In 143 school-age children (50 cases of functional ST-T changes, 43 cases of myocarditis children with ST-T change, 50 cases of healthy controls without ST-T changes), HRV time domain value was measured in three groups with 24 dynamic electrocardiogram. Results Compared with healthy controls, PNN50, rMSSD and SDSD were decreased while the heart rate, SDNN and SDANN were increased in children with functional ST-T changes (P all<0.05). Meanwhile, compared with children with functional ST-T changes and healthy controls, the heart rate was increased while PNN50, rMSSD, SDSD, SDNN and SDANN were decreased in the myocarditis children with ST-T change (P<0.05). Conclusions The autonomic nervous system of school-age children is not stable. The functional ST-T changes are related with the imbalance between sympathetic and vagus nerve activities. HRV analysis has important diagnostic signifi-cance in the functional ST-T changes.