Heart rate variability in children and adolescents with incidentally found early repolarization pattern

Early repolarization pattern (ERP) on electrocardiogram (ECG) was long considered benign, but recent data suggest a potential association with fatal arrhythmia and sudden cardiac death. Its relevance in pediatric populations remains unclear. This study investigated the risk of premature death and arrhythmia in children with incidentally found early repolarization using ECG and heart rate variability parameters.

This cross-sectional study included healthy children aged 6-18 years with incidentally detected ERP (study group) and age- and sex-matched controls without ERP. All participants underwent medical history evaluation, physical examination, 12-lead ECG, transthoracic echocardiography, and 24-h Holter monitoring. ECG parameters (P wave, QTc, JT, Tp-e, and their dispersions), time-domain (SDNN, SDANN, SDNN-i, r-MSSD, pNN50), and frequency-domain (HF, LF, LF/HF) HRV parameters were analyzed.-i, r-MSSD, pNN50 and "Frequency-domain" parameters HF, LF, LF/HF were obtained.

The study group had lower heart rates (p = 0.020) and increased JT dispersion (p = 0.025). Interventricular septal thickness was significantly greater in the ERP group (p = 0.030). LF/HF ratio (p = 0.045), awake HF (p = 0.046), and awake LF/HF (p = 0.036) were significantly higher in ERP patients. Parasympathetic activity predominance was more evident in males. ERP localized in inferolateral leads was associated with higher heart rate and lower SDNN and VLF during sleep (p = 0.049, p = 0.040, p = 0.040, respectively).

Incidental ERP in children was not associated with arrhythmic events but correlated with increased parasympathetic tone. Inferolateral ERP may indicate a relatively higher autonomic imbalance risk.