Cardiological Findings in Children and Adolescents Before and After Guanfacine Treatment for Attention Deficit and Hyperactivity Disorder

Objective: This study evaluates the short-term cardiovascular effects of guanfacine treatment in children and adolescents with attention deficit/hyperactivity disorder (ADHD). The treatment’s impact on novel electrocardiographic parameters was also investigated. Methods: In a retrospective study conducted between January 2023 and June 2024, 37 patients aged 6–18 years with ADHD underwent baseline and follow-up cardiac evaluations including electrocardiography (ECG) and blood pressure measurements. Novel ECG markers (QRS-T angle, QT dispersion, QTc dispersion, Tp-e interval, Tp-e dispersion, Tp-e/QT ratio, and Tp-e/QTc ratio) were analyzed alongside standard parameters such as heart rate, QT, and corrected QT (QTc) intervals. Guanfacine was initiated at 1 mg and titrated weekly until an optimal clinical response was achieved. Results: Guanfacine treatment led to a significant reduction in heart rate (−12.3 bpm; p < 0.001) and P wave axis (−12.3°; p = 0.038) and an increase in QT interval (+16.8 ms; p = 0.014). However, no significant changes were observed in blood pressure, QTc duration, or the novel ECG parameters. Importantly, the absence of any changes in these advanced markers supports the cardiovascular safety of guanfacine. Two patients experienced side effects (bradycardia and hypotension), leading to treatment discontinuation. ANCOVA analysis indicated that the duration between ECG evaluations significantly influenced the QT interval changes, emphasizing the importance of timing when monitoring cardiovascular effects. Conclusions: Guanfacine demonstrated minor, statistically significant effects on the selected cardiac parameters without clinically meaningful changes to or adverse impacts on the novel ECG markers investigated. As extended-release guanfacine has only been available in Türkiye for the management of ADHD for approximately two years, studies evaluating its clinical efficacy and side effects are critical for clinicians working in this field.