Methylphenidate-treated children with ADHD show wider fQRS-T angles compared to healthy controls in a cross-sectional study.

BackgroundAttention-deficit/hyperactivity disorder (ADHD) has been associated with low-grade systemic inflammation and autonomic dysregulation, but it remains unclear whether these alterations are accompanied by subclinical ventricular electrical heterogeneity in medicated pediatric patients. This study investigated inflammatory markers and the frontal QRS-T angle (fQRS-T) in children and adolescents with ADHD receiving methylphenidate and examined the association between inflammatory burden and fQRS-T.MethodsThis single-center retrospective cross-sectional study included 75 children and adolescents with DSM-5 ADHD who had received continuous methylphenidate treatment for at least 6 months and 75 age- and gender-matched healthy controls. Participants with chronic inflammatory, autoimmune, cardiovascular, systemic, or psychiatric comorbidities were excluded. Complete blood count-derived inflammatory indices, including the systemic immune-inflammation index (SII), systemic inflammation response index (SIRI), and pan-immune-inflammation value (PIV), were calculated. Standard 12-lead electrocardiograms were used to assess heart rate, QT, QTc, QRS duration, and fQRS-T.ResultsThe ADHD and control groups were similar in age and gender distribution. Conventional ECG parameters, including heart rate, QT, QTc, and QRS duration, did not differ significantly between groups. In contrast, the fQRS-T angle was significantly wider in the ADHD group than in controls (31.05° ± 32.03° vs. 18.62° ± 20.02°; p = 0.038). Among inflammatory measures, neutrophil count, SII, and PIV were significantly higher in the ADHD group. Within the ADHD group, fQRS-T was positively correlated with SII (r = 0.363, p = 0.030) and treatment duration (r = 0.340, p = 0.036). Treatment duration was also positively correlated with SII (r = 0.322, p = 0.040). In linear regression analysis, both SII (B = 0.012, 95% CI: 0.002 to 0.022; p = 0.019) and treatment duration (B = 0.945, 95% CI: 0.203 to 1.687; p = 0.014) were associated with fQRS-T.ConclusionChildren and adolescents with ADHD receiving methylphenidate showed a higher inflammatory burden and a wider fQRS-T angle than healthy controls. The association of fQRS-T with SII suggests a possible link between low-grade systemic inflammation and subclinical ventricular electrical heterogeneity in this population. However, because of the retrospective cross-sectional design and the inclusion of only methylphenidate-treated patients, these findings should be interpreted cautiously and considered hypothesis-generating.