Evaluation of Cardiovascular Effects of Methylphenidate in Children with Attention-deficit Hyperactivity Disorder

Objective: In patients with attention-deficit hyperactivity disorder (ADHD), methylphenidate (MPH) treatment may lead to serious cardiac problems. Therefore, this study was undertaken to assess cardiac effects and electrocardiographic (ECG) changes regarding risks of ventricular arrhythmia occurring after initiation of MPH treatment in ADHD patients.Method: Thirty patients (mean age: 8.9 +/- 1.93 years) diagnosed with ADHD and 41 healthy subjects (mean age: 9.78 +/- 3.07 years) were included in this study blood pressures, heart rates, and ECGs of the patients were evaluated before and third month of treatment. ECG parameters including QRS, QT, corrected QT interval (QTc), QTdispersion (QTdis), Tp-Te, Tp-Te dispersion, and Tp-Te/QTc ratio were also assessed.Results: Untreated patients with ADHD and healthy subjects had similar systolic blood pressures and heart rates, although ADHD patients had higher diastolic blood pressures. An increase in heart rates, systolic and diastolic blood pressures was observed in the patient group in third month of treatment. Prior to MPH treatment, patients with ADHD and control subjects were compared in terms of ECG parameters: QRS, QT, QTc, QTdis, Tp-Te, Tp-Te dispersion, Tp-Te/QTc ratio but without any intergroup difference. Following MPH treatment, QRS, QT, QTc, QTdis did not change in the patient group but significant increases were observed in Tp-Te, Tp-Te dispersions, Tp-Te/ QTc ratios.Conclusion: Use of the MPH in ADHD patients is associated with alterations in ECG parameters, heart rates, diastolic and systolic blood pressures. Assessment of ECG parameters such as Tp-Te, Tp-Te dispersions, Tp-Te/QTc ratios may prove more beneficial for evaluating the risk of ventricular arrythmia in pediatric patients with ADHD.