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.

Prevention of Saprolegniasis in rainbow trout (Oncorhynchus mykiss) eggs using oregano (Origanum onites) and laurel (Laurus nobilis) essential oils.

The present study investigated the antifungal effects of essential oils of oregano (Origanum onites) and laurel (Laurus nobilis) on Saprolegniasis, a disease that occurs in rainbow trout eggs during the incubation period. Oregano and laurel were ground after drying, and essential oils were obtained by water distillation method using a Clevenger apparatus. The essential oils were added to potato dextrose agar (PDA) at the rates of 1-1000 ppm, and the minimum inhibitory concentration (MIC) was determined as 250 ppm whereas the minimum lethal concentration (MLC) was determined to be 500 ppm for both plants. In the in vivo trials, fertilized eggs were treated with predetermined doses either by bathing during water hardening and incubation period or only during incubation period, and death rates were monitored during embryological development. The best larvae hatching rate was determined in 500 ppm oregano and 500 ppm laurel groups treated during water hardening plus daily as 82.11% and 79.87%, respectively. According to the results, it was determined that oregano and laurel essential oils exhibited better results in all doses compared with the negative control group, and 500 ppm dose had a better effect than the positive control group treated with formalin.

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.

Prolonged T-wave peak-end interval in Down syndrome patients with congenitally normal hearts.

BACKGROUND: Heterogeneity of ventricular repolarization has been assessed using the QT dispersion in Down syndrome (DS) patients with congenitally normal hearts. Novel repolarization indexes, that is, T-wave peak-end (Tp-e) interval and Tp-e/QT ratio, however, have not previously been evaluated in these patients. The aim of this study was therefore to evaluate the Tp-e interval and Tp-e/QT ratio in DS patients without congenital heart defects. METHODS: Tp-e interval, Tp-e dispersion, and Tp-e/QT ratio were compared between 160 DS patients and 110 age- and sex-matched healthy controls on 12-lead surface electrocardiogram. RESULTS: Heart rate, Tp-e interval, Tp-e dispersion, Tp-e/QT and Tp-e/QTc ratios were significantly higher in the DS group than the control group. CONCLUSION: Myocardial repolarization indexes in DS patients with congenitally normal hearts were found to be prolonged compared with those in normal controls. Further evaluation is warranted to elucidate the relationship between prolonged repolarization indexes and arrhythmic events in these patients.

Cardiac function in children with premature ventricular contractions: the effect of omega-3 polyunsaturated fatty acid supplementation.

BACKGROUND: Premature ventricular contractions are accepted as benign in structurally normal hearts. However, reversible cardiomyopathy can sometimes develop. Omega-3 polyunsaturated fatty acids have anti-arrhythmic properties in animals and humans.AimWe evaluated left ventricular function in children with premature ventricular contractions with normal cardiac anatomy and assessed the impact of omega-3 fatty acid supplementation on left ventricular function in a prospective trial. METHODS: A total of 25 patients with premature ventricular contraction, with more than 2% premature ventricular contractions on 24-hour Holter electrocardiography, and 30 healthy patients were included into study. All patients underwent electrocardiography, left ventricular M-mode echocardiography, and myocardial performance index testing. Patients with premature ventricular contraction were given omega-3 fatty acids at a dose of 1 g/day for 3 months, and control echocardiography and 24-hour Holter electrocardiography were performed. Neither placebo nor omega-3 fatty acids were given to the control group. RESULTS: Compared with the values of the control group, the patients with premature ventricular contraction had significantly lower fractional shortening. The myocardial performance index decreased markedly in the patient groups. The mean heart rate and mean premature ventricular contraction percentage of Group 2 significantly decreased in comparison with their baseline values after the omega-3 supplementation. CONCLUSION: In conclusion, premature ventricular contractions can lead to systolic cardiac dysfunction in children. Omega-3 supplementation may improve cardiac function in children with premature ventricular contractions. This is the first study conducted in children to investigate the possible role of omega-3 fatty acid supplementation on treatment of premature ventricular contractions.

Report of a Myocarditis Outbreak among Pediatric Patients: Human Herpesvirus 7 as a Causative Agent?

BACKGROUND: The etiology of myocarditis in children has not yet been completely elucidated. OBJECTIVE: Medical records of eight pediatric patients diagnosed with acute myocarditis within a 41-day period in a small-town hospital were retrospectively analyzed. METHODS: We examined antibody titers of adenovirus, Epstein-Barr virus, herpes simplex virus, respiratory syncytial virus, varicella-zoster virus and cytomegalovirus in peripheral blood. We used polymerase chain reaction (PCR) amplification to detect genetic sequences from Human herpesvirus (HHV) 7, HHV 6, enterovirus, measles or parvovirus in peripheral blood. RESULTS: The causative agent was HHV 7 in four patients. HHV 7 sequences were detected through PCR in one patient with rapid deterioration. Of four patients with HHV 7, two presented with dilated cardiomyopathy. CONCLUSION: To our knowledge, this is the first report to suggest HHV 7 as a causative agent for acute myocarditis. We believe HHV 7 should be considered as a possible etiologic pathogen for patients with suspected myocarditis.

Echocardiographic evaluation of cardiac functions in newborns of mildly preeclamptic pregnant women within postnatal 24-48 hours.

The aim of this study is to detect preeclampsia-related cardiac dysfunction within 24-48 hours of delivery in newborns born from preeclamptic mothers. Forty newborns from mildly preeclamptic mothers formed the study group and the control group was formed by 40 healthy newborns. Cardiac function for the groups were evaluated using conventional echocardiography and myocardial performance index (MPI) within the first 24-48 hours of their lifetime and the results of both groups were compared. A significant difference between the groups was observed especially in the PW Doppler MPI measurements (the left ventricle MPI 0.37 ± 0.09 and 0.26 ± 0.11, p < .001; the right ventricle MPI 0.29 ± 0.08 and 0.26 ± 0.07, p < .035) for the control group and the study group. Elongation in the left and right ventricle MPI was detected to be more significant in terms of comparing systolic and diastolic functions to determine preeclampsia-related cardiac injury in newborns from preeclamptic mothers within the first 24-48 hours of their lifetime. Impact statement Today, the methods which may detect cardiac injury earlier than conventional echocardiographic methods are used for evaluating cardiac functions. Among them, myocardial performance index (MPI) measurement with PW Doppler is the most common ones. While studies are available in the literature evaluating foetal cardiac functions with MPI in foetuses of preeclamptic women, studies evaluating cardiac functions with MPI index within the first 24-48 hours in postnatal period are not available. This is the first study to detect cardiac injury by measuring cardiac functions of the newborns of preeclamptic babies using conventional echocardiography (EF, SF, mitral and tricuspid E/A) and myocardial performance index within the first 24-48 hours of life and compare these values with those of a control group composed of healthy newborns with similar demographic characteristics. According to the results of the study, elongation in right and left ventricle MPI was detected to be more significant compared to systolic and diastolic functions for determining preeclampsia-related cardiac injury in newborns of preeclamptic mothers within 24-48 hours of delivery. Ventricle functions of the newborns of preeclamptic mothers should also be evaluated with MPI measurement besides conventional echocardiographic measurements.

Assessment of early atherosclerosis and left ventricular dysfunction in children with 21-hydroxylase deficiency.

AIM: We analysed 25 children with 21-hydroxylase deficiency who received glucocorticoid and/or mineralocorticoid treatment for at least 12 months to determine the effects of the disease and its treatment on vascular structures and ventricular function. METHODS: Twenty-five patients with 21-hydroxylase-deficient congenital adrenal hyperplasia (CAH) and 25 control subjects were enrolled into this observational, cross-sectional study. The patients were investigated in terms of fasting blood glucose and insulin; fasting serum lipid profile; serum 17-hydroxyprogesterone; dehydroepiandrosterone sulphate; androstenedione; and adrenocorticotropic hormone. M-mode tracings of the wall motion of major arteries were obtained to measure carotid intima-media thickness (cIMT), as well as elasticity and distensibility of the aorta and carotid artery. Conventional and relatively new tissue Doppler imaging techniques were employed to assess ventricular systolic and diastolic functions. RESULTS: The median age and weight of patients were 9·4 years (1·5-16·75) and 35·5 kg (7·5-76·3), respectively. The median duration of treatment was 52·2 months. Tissue Doppler imaging measurements revealed left ventricular diastolic impairment in the patient group compared to the controls. Carotid intima-media thickness, stiffness index, elastic modulus of the aorta and carotid artery were significantly higher; meanwhile, aortic distensibility and carotid distensibility were lower in the patient group, all of which indicates the presence of subclinical atherosclerosis. BMI was found to be an independent variable for cIMT (ß: 0·5, P = 0·01) and aortic stiffness index (ß: 0·52, P < 0·001). CONCLUSION: Cardiovascular function and the elastic properties of major arteries are disturbed in children and adolescents with 21-hydroxylase-deficient CAH.

Low Iron Stores in Otherwise Healthy Children Affect Electrocardiographic Markers of Important Cardiac Events.

Both an excess of iron and iron deficiency (ID) may lead to significant cardiac problems. Parameters that represent ventricular repolarization heterogeneity, like QT dispersion (QTd), corrected QT dispersion (QTcd), the interval between the peak and the end of the T wave (Tp-e), and Tp-e dispersion, have not been evaluated in otherwise healthy children with low iron levels before. Here we assessed the effects of low iron storage on P wave dispersion (PWd), QTd, Tp-e intervals, and Tp-e dispersion in otherwise healthy children. We prospectively reviewed 283 patients who were referred to pediatric cardiology department for cardiac evaluation due to murmurs and who were found to have no structural heart disease. The patients were divided into three groups according to their ferritin levels: Group 1: ferritin <15 ng/mL (n = 58); Group 2: ferritin 15-25 ng/mL (n = 80); Group 3: ferritin >25 ng/mL (n = 145). P wave duration (PW), QT and Tp-e intervals, and PW, QT, corrected QT (QTc), and Tp-e dispersions were significantly higher in patients whose ferritin level was <15 ng/mL. A negative correlation was found between ferritin level and QT and QTc intervals, and QT, QTc, and Tp-e dispersions. Our results showed that a low serum ferritin level is associated with changes in some ECG parameters such as prolonged PWd, Tp-e interval, QT, QTc, and Tp-e dispersions in otherwise healthy children, and studies of other populations indicated that these parameters may predict arrhythmias in selected patients. These patients may be considered at some risk of developing arrhythmias. Therefore, careful evaluation of these ECG parameters is necessary in otherwise healthy children with low iron stores.

The Impact of 3:1 Ketogenic Diet on Cardiac Repolarization Changes in Children with Refractory Seizures: A Prospective Follow-Up Study.

Background The association between ketogenic diet (KD) and prolonged QT interval, life-threatening ventricular arrhythmias, and sudden death is controversial. Aim We aimed to prospectively evaluate the effect of KD on electrocardiography (ECG) measures in children with refractory epilepsy. Method A total of 70 children with drug-resistant epilepsy who received a KD for at least 12 months were included in the study. The standard 12-lead electrocardiography was performed in all patients before the beginning and in the 12th month of KD. Heart rate, P-wave duration and dispersion, corrected QT interval and QT dispersion, and Tp-e interval were measured. Results All ECG-derived parameters, but P-wave dispersion increased after 12 months of KD compared with the baseline values. However, these changes were not statistically significant. Conclusion A 12-month long 3:1 KD treatment exerts no deleterious effect on cardiac repolarization measures.

Prolonged Tp-e Interval and Tp-e/QT Ratio in Children with Mitral Valve Prolapse.

Although it is considered to be a benign condition, previous studies have shown that a subset of patients with mitral valve prolapse (MVP) may be at risk of ventricular arrhythmia and sudden cardiac death (SCD). Previous studies have suggested that the interval between the peak and the end of the T wave (Tp-e) can be used as a marker for the transmural dispersion of repolarization. Increased Tp-e interval and Tp-e/QT ratio are associated with ventricular arrhythmias and SCD. The aim of this study was to assess alterations in ventricular repolarization by using the Tp-e interval and Tp-e/QT ratio in children with MVP and to investigate their relationships with the degree of valvular regurgitation. This study prospectively investigated 110 children with MVP and 107 age- and sex-matched healthy control subjects. Tp-e interval, Tp-e/QT ratio, and QT and QTc dispersions were measured from a 12-lead electrocardiogram and compared between groups. QT and QTc dispersions, Tp-e interval, and Tp-e/QTc ratio were found to be significantly higher in patients with MVP. A positive correlation was found between Tp-e/QTc ratio and increase in the degree of mitral regurgitation (MR) (p < 0.05; r = 0.2). However, the degree of MR was not associated with QT, QTc, or Tp-e intervals; QT, QTc, or Tp-e dispersions; or Tp-e/QT ratio (all p values >0.05). Individuals with MVP may be more prone to ventricular arrhythmias due to prolonged QTd, QTcd, and Tp-e interval and increased Tp-e/QT and Tp-e/QTc ratios. Therefore, due to their longer life expectancy, children with MVP should be followed up on regarding life-threatening arrhythmias.

A Valuable Tool in Predicting Poor Outcome due to Sepsis in Pediatric Intensive Care Unit: Tp-e/QT Ratio.

OBJECTIVE: To assess the feasibility of 12-lead electrocardiographic (ECG) measures such as P wave dispersion (PWd), QT interval, QT dispersion (QTd), Tp-e interval, Tp-e/QT and Tp-e/QTc ratio in predicting poor outcome in patients diagnosed with sepsis in pediatric intensive care unit (PICU). METHODS: Ninety-three patients diagnosed with sepsis, severe sepsis or septic shock and 103 age- and sex-matched healthy children were enrolled into the study. PWd, QT interval, QTd, Tp-e interval and Tp-e/QT, Tp-e/QTc ratios were obtained from a 12-lead electrocardiogram. RESULTS: PWd, QTd, Tp-e interval and Tp-e/QT, Tp-e/QTc ratios were significantly higher in septic patients compared with the controls. During the study period, 41 patients had died. In multivariate logistic regression analyses, only Tp-e/QT ratio was found to be an independent predictor of mortality. CONCLUSION: The ECG measurements can predict the poor outcome in patients with sepsis. The Tp-e/QT ratio may be a valuable tool in predicting mortality for patients with sepsis in the PICU.

Risk Factors for Thrombosis, Overshunting and Death in Infants after Modified Blalock-Taussig Shunt.

BACKGROUND: The Modified Blalock-Taussig shunt procedure can provide increased flow of blood to the lungs for babies born with certain congenital heart defects. We evaluated 44 subjects under 2 years of age who had a Modified Blalock-Taussig shunt (MBTS) procedure performed from 2009-2013, to investigate risk factors for thrombosis, overshunting and death. METHODS: The study subjects included in our investigation were severely cyanotic newborns with pulmonary stenosis or atresia and duct dependent circulation, and infants having Tetralogy of Fallot with small pulmonary arteries who underwent a MBTS procedure in our facility from 2009-2013. We duly noted patient preoperative characteristics such as hemoglobin, hematocrit, mean platelet volume, prothrombin time and partial thromboplastin time. Our study investigated the risk factors for post-operative overcirculation, thrombosis and death. RESULTS: The age and weight of patients in our study at the time of procedure ranged from 1 day to 20 months old (median 12 days), and 2.4 kg to 12 kg (mean 4.6 kg), respectively. A total of 8 patients died following surgery, and. 4 (9.1%) had shunt thrombosis, of which one died during shunt revision. Partial thromboplastin time was 28.7 seconds in patients with thrombosis, and 35 in all other patients (p = 0.04). Overcirculation was detected in 5 patients; shunt size/body weight was 1.25 in patients who had overcirculation, and 1.06 in all other patients. CONCLUSIONS: It is important to assess risk factors associated with the MBTS operation. The results of our study suggest that a preoperative low aPTT value may be an indicator for thrombosis in infants who have undergone MBTS surgery.

Different haemodynamic patterns in head-up tilt test on 400 paediatric cases with unexplained syncope.

OBJECTIVE: To assess haemodynamic patterns in head-up tilt testing on 400 paediatric cases with unexplained syncope. METHODS: Medical records of 520 children who underwent head-up tilt testing in the preceding year were retrospectively evaluated, and 400 children, 264 (66%) girls and 136 (34%) boys, aged 12.6±2.6 years (median 13; range 5-18), with unexplained syncope were enrolled in the study. Age, sex, baseline heart rate, baseline blood pressure, frequency of symptoms, and/or fainting attacks were recorded. The test protocol consisted of 25 minutes of supine resting followed by 20 minutes of 70° upright positioning. Subjects were divided into nine groups according to their differing haemodynamic patterns. RESULTS: There were no statistically significant differences between the groups with regard to age, gender, baseline blood pressure, and frequency of syncope (p>0.05). The response was compatible with orthostatic intolerance in 28 cases (7.0%), postural orthostatic tachycardia syndrome in 24 cases (6.0%), asymptomatic postural orthostatic tachycardia syndrome in 26 cases (6.5%), orthostatic hypotension in seven cases (1.7%), vasovagal syncope in 38 cases (9.5%), and negative in 274 cases (69.2%). Vasovagal syncope response patterns were of type 3 in nine cases (2.2%), type 2A in 10 cases (2.5%), type 2B in two cases (0.5%), and type 1 (mixed) in 17 cases (4.25%). CONCLUSIONS: In the 400 paediatric cases with unexplained syncope, nine different haemodynamic response patterns to head-up tilt testing were discerned. Children with orthostatic intolerance syndromes are increasingly referred to hospitals because of difficulty in daily activities. Therefore, there is need for further clinical trials in these patient groups.

Unusual Presentation of Pre-T Cell Acute Lymphoblastic Leukemia: Massive Pericardial Effusion Only.

Despite the infectious and connective tissue diseases are most encountered, etiological factors, pericardial effusions, can also rarely emerge because of malign disease in childhood and it often develops during the course of chemotherapy and radiotherapy. Unfortunately, pericardial involvement is one of the frequently encountered symptoms of pediatric malignancies. Herein, we present a rare case who was admitted with pericardial effusion and whose disease was diagnosed as pre-T cell acute lymphoblastic leukemia without peripheral blood involvement.

A rare cause of respiratory distress in the emergency department: anomalous origin of the left coronary artery from the pulmonary artery.

Anomalous origin of the left coronary artery from the pulmonary artery is the most common cause of myocardial ischemia and infarction in children and infants. Most of the affected individuals become symptomatic, owing to dilated cardiomyopathy during the infant period. Because of congestive heart failure, pulmonary congestion and respiratory distress can be seen. Herein, we report a 35-day-old infant with anomalous origin of the left coronary artery from the pulmonary artery who presented with respiratory distress and dilated cardiomyopathy to draw attention to this rare surgically treatable anomaly.

Pulmonary and ventricular functions in children with repaired tetralogy of Fallot.

OBJECTIVE: This study aimed to evaluate biventricular function, brain natriuretic peptide levels, respiratory function test and 6 minute walking test (6MWT) in children with repaired tetralogy of Fallot (TOF), and analyse the correlation between these variables and clinical status. METHODS: Twenty-five children (14 boys, 11 girls; aged 6 to 17 years) with repaired TOF (Group 1) and 25 age-sex matched healthy controls (Group 2) were enrolled in the study. Tissue Doppler echocardiography, respiratory function test, 6MWT distance and brain natriuretic peptide levels were measured. RESULTS: Mean ages of the children at TOF corrective surgery and at study time were 5.1±3.5 years and 11.6±2.7 years respectively. The duration between palliative operation and corrective surgery was 4.3±2.0 years, and the follow-up period after corrective surgery was 6.3±3.0 years. The right ventricular and left ventricular myocardial performance indices (MPIs), and isovolumic relaxation and contraction times were significantly higher in Group 1 than in Group 2 (p<0.01). Spirometry displayed significantly reduced forced vital capacity (FVC), forced expiratory volume in one second (FEV1), forced expiratory flow 25-75% (FEF25-75) and inspirational capacity in Group 1 compared to Group 2 (p<0.01). In Group 1, 6MWT distances were significantly lower than in Group 2 (p=0.001). Right ventricular MPI is correlated with FEV1, FVC and 6MWT distance in the current study. CONCLUSION: The children with repaired TOF had impaired ventricular and pulmonary functions. Hence, right ventricular MPI along with FEV1, FVC and 6MWT distance may be useful in the follow-up of children with repaired TOF.

Are mean platelet volume and platelet distribution width useful parameters in children with acute rheumatic carditis?

Rheumatic fever (RF) is an inflammatory disease caused by autoimmune response to a preceding group A streptococcal infection. Mean platelet volume (MPV) reflects the platelet size and the rate of platelet production in bone marrow, and it may be used as an indicator of platelet activation and severity of inflammation. Fifty-three consecutive patients diagnosed with acute rheumatic carditis and 53 control subjects were enrolled into this study. Leukocyte and platelet counts were significantly higher in patients with acute carditis before treatment compared with controls, whereas MPV and platelet distribution width (PDW) values were not significantly different between groups. Platelet counts, erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP) values were decreased significantly in patients with RF after treatment. There was not a significant difference in terms of platelet count between the controls and the patient group after treatment. ESR was found to be correlated with CRP in patients before and after treatment. In conclusion, the results of our study showed that MPV and PDW levels do not change during acute rheumatic carditis before and after treatment.

Increased P-wave and QT dispersions necessitate long-term follow-up evaluation of Down syndrome patients with congenitally normal hearts.

Reports state that Down syndrome (DS) patients with congenitally normal hearts might experience the development of cardiac abnormalities such as cardiac autonomic dysfunction, valvular lesions, bradycardia, and atrioventricular block. However, the presence of any difference in terms of P-wave dispersion (PWd) and QT dispersion (QTd) was not evaluated previously. This study prospectively investigated 100 DS patients with structurally normal hearts and 100 age- and sex-matched healthy control subjects. Standard 12-lead electrocardiograms were used to assess and compare P-wave and QT durations together with PWd and QTd. The median age of the DS patients and control subjects was 48 months. Heart rates and P-wave and QT dispersions were significantly greater in the DS group than in the control group (113 ± 22.9 vs 98.8 ± 16.6 bpm, p < 0.001; 31.3 ± 9.5 vs 24 ± 8.6 ms, p < 0.001; and 46.6 ± 15.9 vs 26 ± 9.1 ms, p < 0.001, respectively). A positive correlation was found between PWd and age in the DS patients (p < 0.05; r = 0.2). All children with DS should be followed up carefully with electrocardiography in terms of increased P-wave and QT dispersions even in the absence of concomitant congenital heart disease for management of susceptibility to arryhthmias.

The Effects of Methylphenidate on Ventricular Repolarization Parameters in Children with Attention-Deficit Hyperactivity Disorder.

Background: Long-acting methylphenidate (MPH), a psychostimulant agent, is widely used in the treatment of attention-deficit hyperactivity disorder (ADHD). Methylphenidate might cause an increment in the risk of lethal arrhythmias by deteriorating ventricular repolarization. QT intervals, the corrected QT (QTc), QT dispersion, T-peak to T-end (TpTe), and the TpTe/QTc ratio are the most utilized indicators of ventricular repolarization in electrocardiogram (ECG). The present study was conducted to examine the effects of long-term MPH use on the ECG in pediatric patients. Methods: A total of 52 children with ADHD and 51 age- and gender-matched controls were enrolled in the study. The children had been using MPH regularly for at least 6 months. Comparisons were made regarding ECG parameters, including the mean intervals of QT, QTc, QTc dispersion interval duration, TpTe intervals, TpTe/QT, and TpTe/QTc ratio. Results: The median duration of treatment with MPH was 30 months (minimum-maximum: 6-120), and the median MPH dose was 30 mg/day (minimum-maximum: 18-54). The main findings showed significantly prolonged P-wave dispersion, TpTe interval, TpTe dispersion, and TpTe/QT and TpTe/QTc ratios in the ADHD group compared to the healthy controls (P < .001). These parameters were not associated with MPH dose or treatment duration. Additionally, nearly half of the patients had QTc values of 460 ms or higher, but there were no significant differences in treatment duration and dose compared to the remaining group (P = .792 and P = .126). Conclusion: Methylphenidate may have proarrhythmogenic effects in children with ADHD, which may not be adversely affected by long-term use and treatment dose. Considering the extensive use of MPH, cardiac monitoring of these children is important.