The effect of long-term use of methylphenidate on cardiac autonomic functions and ventricular arrhythmogenesis: a prospective case-control study.

OBJECTIVE: We aimed to assess cardiac autonomic balance with heart rate variability by using 24-hour Holter electrocardiography and also to assess susceptibility to ventricular arrhythmias by using microvolt T wave alternance in children with attention deficit hyperactivity disorder. METHOD: This study was conducted with age- and gender-matched groups of 40 patients taking long-acting methylphenidate for more than a year and 55 healthy controls. Heart rate variability analysis for cardiac autonomic functions and microvolt T wave alternance measurements for susceptibility to ventricular arrhythmias were evaluated by 24-hour Holter electrocardiography. RESULTS: The mean age 10.9 ± 2.7 years, mean duration of therapy 22.76 months, and mean methylphenidate doses were 37.64 mg/day. The study group had considerably higher rMSSD, higher HF, and a lower LF/HF ratio (respectively, p : 0.02, p : 0.001 and p : 0.01). While parasympathetic activity parameters were elevated, sympathetic activity parameters were low during the sleep period. Increase in the microvolt T wave alternance values of the study group was not found to be statistically significant (p > 0.05). CONCLUSION: In children taking long-acting methylphenidate, the autonomic balance was shown to be in favour of the parasympathetic system. Determination of the vulnerability to life-threatening ventricular arrhythmias has been evaluated for the first time in children with attention deficit hyperactivity disorder. Accordingly, microvolt T-wave alternance values give the notion that drug use is safe.

Is there any relationship between platelet indices and myocarditis in children?

BACKGROUND: Platelet indices are used to evaluate platelet activation and function which change in inflammatory diseases. We hypothesise that platelet indices such as plateletcrit, mean platelet volume, and platelet distribution width may be more useful as prognostic indicators for myopericarditis in children. METHODS: A total of 60 children were included in this study. Group 1 consists of children with myopericarditis, Group 2 is those with respiratory infections, and Group 3 consists of control group children of similar age and gender with the patient groups. Complete blood count parameters, C-reactive protein, and troponin values of the whole study group were recorded. Myopericarditis was diagnosed based on acute chest pain, dyspnea, palpitations, heart failure signs, arrhythmia symptoms and ST/T wave change, low voltage, supraventricular tachycardia/ventricular tachycardia on ECG, or elevated troponin T/troponin I levels or functional abnormalities on echocardiography. A comparison of the platelet indices made during diagnosis and 2 weeks after treatment was done for the myopericarditis patients. RESULTS: There was no statistically significant difference in platelet indicies values. However, the increase in platelets and plateletcrit values after the treatment of myopericarditis was statistically significant. This study pointed out that there was a negative correlation between platelet-plateletcrit values and the troponin I-C-reactive protein. CONCLUSION: We found that platelet count and plateletcrit values increased after treatment. This is important as it is the first study in children to investigate the possible role of platelet indications for myopericarditis in children.