QT Dispersion In Children Research Articles

Evaluating QT dispersion in children with syncope attacks

Background and Aims: Syncope is due to brain dysfunction and is a common compliant among children. It accounts for almost 3% of all emergency departments (ED) visits. The aim of this study was to evaluate the QT dispersion in children with syncope in Shahid Beheshti Hospital of Kashan in 2014.Methods: This was a descriptive cross-sectional study performed among 50 children with syncope attacks (case group) referred to the Clinic of Shahid Beheshti Hospital in Kashan during 2014 and 50 healthy children (control group) referred to the center for causes such as a cold or developmental examination. ECG was taken and QT, QTd (QT dispersion), QTc (Corrected QT interval) and QTcd (QTmin-QTmax =QT dispersion) intervals were studied. After proper explanation to the parents, data was obtained from the case and control group and was analyzed using Chisquare, Mann-Whitney, Kolmogorov–Smirnov, Levene›s, Kruskal-Wallis statistical tests.Results: Total, there were 100 children in the study, the participants were divided into two groups of case (n=50) and control (n=50). Among the studied children, a total of 46 of them (46%) were boys. The mean age range of children in the case and control groups were 7.73± 2.33 and 8.09± 2.31 years, respectively (P-value 0.440). The mean QTmax, QTcmax, QTd and QTcd in the case group were 348.80 ± 46.93, 464.94±48.71, 47.80±19.72, 68.36±24.59 ms (millisecond) respectively and 305.28 ±35.52, 395.70 ±50.05, 29.68±13.45, and 45.16±24.46 ms respectively in the control group. There was a significant difference in terms of each of the 4 parameters (P <0.001), and the value of indices in the control group was significantly less than that of the patient group.Conclusion: According to the results of the study, the QTd and QTcd values in the children with syncope attacks were higher than those in the control group. Therefore, precise ECG examination in children suspected of syncope attacks can be helpful in confirming the incidence of syncope. Additionally, the recurrence of attacks can also be predicted in children with higher QTd and QTcd values.

Electrocardiographic Analysis of Repolarization Changes in South Indian Children with Kawasaki Disease after the Acute Phase of Illness.

Background Cardiac involvement in children with Kawasaki disease (KD) may present with repolarization abnormalities which are associated with increased risk of ventricular arrhythmias and sudden cardiac events. Methods Twenty children with history of KD without cardiac involvement in the acute phase were recruited along with age and sex-matched controls. Twelve-lead ECG was obtained from both groups using CARDIART 610T ECG system at 25 mm/sec and 50 mm/sec paper speed. ECG was repeated in 19 children in the study group after 9 ± 2 months. Measurements (QT dispersion (QTd), T-wave peak to end (Tp-Te) interval, and Tp-Te/QT ratio) were made using standard digital calipers. Statistical analysis was performed with student t-test and analysis of variance (ANOVA) using SSPS version 17.0. Results The mean value of QTd in the first ECG in cases was significantly high: 43.15 ± 14.13 versus 29.47 ± 8.637 in the controls (p = 0.001). The follow-up ECG in 19 cases showed a mean value of 46.26 ± 16.25 versus 43.89 + −14.53 at baseline (p = 0.440). QTd was increased in the follow-up ECG but was not statistically significant. There was no statistical significance seen in the Tp-Te interval and Tp-Te/Qt ratio as observed in Lead II and Lead V5. Conclusion Significant increase in the QTd in children with KD indicates repolarization changes in the myocardium even in the absence of clinical carditis. The persistence of this change on follow-up could indicate a possible increased risk for ventricular arrhythmia and warrants long term assessment of the cardiovascular status.

Mid-term Risk for Subclinical Atherosclerosis and Chronic Myocarditis in Children with Kawasaki Disease and Transient Coronary Abnormalities.

There is evidence for premature atherosclerosis and systemic arterial stiffening during follow-up of children with Kawasaki disease (KD) and coronary artery abnormalities (CAA). Moreover, patients with KD may also have subclinical myocardial involvement and inhomogeneous ventricular repolarization. The inhomogeneous ventricular repolarization manifests as increased QT dispersion on electrocardiography. There is a paucity of studies in endothelial dysfunction and QT dispersion in children with KD and transient CAA. Twenty children with KD and transient CAA were studied at least 1year after resolution of CAA. Mean follow-up period between KD onset and enrolment in the study was 53.7months. Twenty age and sex-matched controls were enrolled. High-resolution B-mode ultrasonography was used to analyze brachial artery dilatation in response to reactive hyperemia (cases and controls) and sublingual nitroglycerine (cases only). Carotid artery intima-media thickness (cIMT) and stiffness index were calculated. The difference between maximum and minimum QTc intervals on 12 lead electrocardiogram was calculated as QTc dispersion (QTcd). No statistically significant difference was noted in percent flow-mediated dilatation of brachial arteries in response to reactive hyperemia between cases (13.31±10.41%) and controls (12.86±7.09%). Sublingual nitroglycerine-mediated dilatation in children with KD was 14.88±12.03%. Mean cIMT was similar in cases (0.036±0.015cm) and controls (0.035±0.076cm; p=0.791). No statistically significant difference between groups was observed in mean QTcd values (0.057±0.018s vs. 0.059±0.015s in controls, p=0.785). No evidence of significant endothelial dysfunction or increased QT dispersion in patients with KD and transient coronary artery abnormalities was found in our cohort when studied at a mean follow-up of 53.7months. This is reassuring, and indicates that risk of subclinical atherosclerosis and myocarditis in a subset of children with KD and transient coronary artery abnormalities is not significant.

Prolonged P-Wave and QT Dispersion in Children with Inflammatory Bowel Disease in Remission.

Objectives. Ulcerative colitis (UC) and Crohn's disease (CD) are chronic inflammatory bowel diseases (IBD) with unclear underlying aetiologies. Severe cardiac arrhythmias have been emphasised in a few studies on adult IBD patients. This study aimed to investigate the alteration of the P-wave and QT interval dispersion parameters to assess the risk of atrial conduction and ventricular repolarisation abnormalities in pediatric IBD patients. Patients and Methods. Thirty-six IBD patients in remission (UC: 20, CD: 16) aged 3–18 years and 36 age- and sex-matched control patients were enrolled in the study. Twelve-lead electrocardiograms were used to determine durations of P-wave, QT, and corrected QT (QTc) interval dispersion. Transthoracic echocardiograms and 24-hour rhythm Holter recordings were obtained for both groups. Results. The P-wave dispersion, QT dispersion, and QTc interval dispersion (Pdisp, QTdisp, and QTcdisp) were significantly longer in the patient group. The mean values of Pminimum, Pmaximum, and QTcminimum were significantly different between the two groups. The echocardiography and Holter monitoring results were not significantly different between the groups. Furthermore, no differences in these parameters were detected between the CD and UC groups. Conclusion. Results suggest that paediatric IBD patients may carry potential risks for serious atrial and ventricular arrhythmias over time even during remission.

Evaluation of QT Dispersion in Children with Breath Holding Spells.

Breath holding spells (BHS) are common involuntary reflexes in infancy and early childhood. Differential diagnosis should embrace Long QT Syndrome (LQTS) and paroxysmal abnormalities of rhythm. The aim of this study was to compare QT dispersion (QTd) in children with breath holding spells and normal controls. QT dispersion and Corrected QT(QTc) dispersion were measured in 12 lead surface electrocardiograms in 56 patients with BHS and compared with healthy children of the same age referred to the clinic for regular checkup visits. The most common type of BHS was cyanotic (83.9%). Seven patients (12.5%) had pallid and two patients (3.5%) had mixed spells. There was a history of breath holding spells in 33.9% of the children. QT dispersion was 61.6± 22.5 and 47.1±18.8 ms in patient and control groups, respectively. QTc dispersion (QTcd) was 104 ± 29.6 and 71.9 ±18.2 ms, respectively. There was a significant difference between patient and control groups in terms of QTd and QTcd (P<0.001). QTd and QTcd were increased in children with BHS. Therefore, the evaluation of EKG for early diagnosis of rhythm abnormalities seems reasonable in these children.

QT dispersion in children with Kawasaki disease

Background: We analyzed the changes in QT dispersion (QTd) in children with Kawasaki disease (KD), and determined the presence of repolarization abnormality in these children even in the absence of coronary artery abnormalities. Methods: Ninety-one children with KD and 20 healthy controls were enrolled in this retrospective study. Serial echocardiographic and electrocardiographic (ECG) measurements in the beginning of treatment, 2nd month and 6th month after the diagnosis were compared. Fifty-one of 91 children had at least 2 serial ECG data. The number of patients who had 3 consecutive ECG data was 23. Results: Among the 67 KD patients with no coronary artery changes, the consecutive mean QTd values were 41.86 ms, 37.84 ms, and 25.47 ms, respectively (26 ms for controls). In the analysis of changes among KD patients without coronary artery abnormalities, QTd showed a significant decrease with time (p=0.01). Especially, the 1st month and the 6th month QTd values were significantly different (p=0.028). The mean QTd values in KD patients with coronary artery changes were significantly higher than those in KD patients with no coronary artery changes at each time (1st, 2nd, and 6th month exam). Conclusion: QTd is significantly increased in children during the early stage of KD. Repolarization abnormality may exist during the acute stage of KD, regardless of the echocardiographic changes.

P-wave and QT interval dispersion analysis in children with Eisenmenger syndrome

P-wave and QT dispersion are increased and associated with atrial and ventricular arrhythmia and an increase in sudden death in a variety of diseases. This study aimed to investigate P-wave and QT dispersion in children with Eisenmenger syndrome (ES). The study group included 27 children (15 females, 12 males) with both congenital heart disease (CHD) and ES. The control group consisted of 30 children with CHD without pulmonary arterial hypertension. Electrocardiographic records were used to determine P-wave, QT, and corrected QT (QTc) dispersions. 24-hour (h) rhythm Holter was fitted in all patients. Atrial volumes, ventricular dimensions and tricuspid annular plane systolic excursion (TAPSE) were measured by echocardiography. There was no difference between groups with regard to age, sex, weight, and body surface area (p>0.05). Right atrial volume was significantly larger in the ES group than in the control group. P-wave, QT and QTc dispersions were higher in the patients with ES (50.10±11.12 vs. 26.32±8.90, p<0.001; 57.40±24.21 vs. 38.20±8.92 ms, p<0.001; and 78.20±16.02 vs. 56.52±13.92 ms, p<0.001, respectively). Ventricular and supraventricular ectopy were significantly more frequent in the ES group. Four patients (14.8%) in the study group had tachyarrhythmias during 24-h Holter monitoring. In our study, P-wave and QT dispersion were found to be greater in children with ES than in the healthy control subjects.

QTc and QTd in Children with Type 1 Diabetes Mellitus during Diabetic Ketoacidosis

Cardiac arrest has been described in children with diabetic ketoacidosis (DKA). Aim. To evaluate QTc and QTd in type 1 diabetic children with DKA. Methods. Twelve-lead ECG was done to 30 type 1 diabetic children with DKA at presentation and recovery. Corrected QT interval and QT dispersion (QTd) were assessed. Results. QTc and QTd mean values were significantly decreased in patients after than before DKA recovery (P < 0.01). Procedure. Sixteen patients (53, 3%) had prolonged QTc during DKA (range 451–538 ms) that dropped to one patient after recovery, his QTc (453 ms) returned to normal 5 days after hospital discharge. Nineteen patients (63.3%) had prolonged QTd (>50 ms) that dropped to three after recovery. The fact that three patients had normal QTc but prolonged QTd increases the privilege of QTd over QTc as a better marker for cardiac risk in those patients. Anion gap was significantly associated with QTc and QTd prolongation (P < 0.0001). Patients had no electrolyte abnormalities or hypoglycemia to account for QTc or QTd prolongation. Conclusion. Prolonged QTc and QTd frequently occur in DKA positively correlated to ketosis. Cardiac monitoring for patients with DKA is mandatory.

Effects of atomoxetine on cardiovascular functions and on QT dispersion in children with attention deficit hyperactivity disorder

Atomoxetine is a central norepinephrine reuptake inhibitor used to treat attention deficit/hyperactivity disorder. The effects of atomoxetine on cardiovascular functions and QT dispersion in children with attention deficit/hyperactivity disorder have not been previously reported. The aim of this study was to analyse cardiovascular functions and QT dispersion on the surface electrocardiogram of children with attention deficit/hyperactivity disorder during atomoxetine therapy. A total of 40 children - with a mean age of 8.6 plus or minus 2.3 years and a median age of 11 years; ranged from 8 to 14 years - with attention deficit/hyperactivity disorder - with six girls and 34 boys - were included in the study. We recorded the mean systolic and diastolic blood pressure, heart rate, corrected QT interval, QT dispersion, and left ventricular systolic functions at baseline and 5 weeks after atomoxetine therapy. Atomoxetine decreased baseline mean systolic and diastolic blood pressure; baseline mean heart rate decreased; and baseline mean corrected QT interval and QT dispersion mildly increased. Atomoxetine decreased baseline mean ejection fraction and baseline mean shortening fraction. The results of our study suggest that atomoxetine does not cause clinically significant alterations in QT dispersion, systolic and diastolic blood pressure, heart rate, corrected QT interval, and left ventricular systolic functions during short-term treatment in children with attention deficit/hyperactivity disorder.

Kawasaki Disease

Kawasaki disease (KD) is an acute systemic inflammatory illness that occurs predominately in children <5 years of age. The reported incidence varies widely depending on the ethnicity of the population and the method of case ascertainment. Recent reports would suggest the annual incidence is ≈20 to 25 per 100 000 children <5 years of age in North America, with the highest reported incidence of 188 being in Japan, where the disease was first described in 1967.1 The illness is self-limited and of unknown cause, but is complicated by a systemic vasculitis with a predilection for small- to medium-sized arteries, particularly the coronary arteries. The majority of patients will have either transient coronary artery dilation or no coronary artery luminal changes as noted on echocardiography. Long-term prognosis for these patients is considered to be excellent. Coronary artery aneurysms occur in 25% of patients, but the prevalence is reduced to ≈4% for patients treated with intravenous immunoglobulin infusion within 10 days of illness onset. Aneurysms are associated with an intense inflammatory cell infiltrate, destruction of the internal elastic lamina, and smooth muscle cell death. Coronary artery involvement is usually maximal within 6 to 8 weeks after the acute episode. Regression of aneurysms can occur primarily through myointimal proliferation, although the arterial structure and function remains abnormal,2 and there is an important ongoing risk of stenoses and occlusions.3 Long-term cardiology assessment and management is required, and some of these patients may require revascularization procedures or, rarely, cardiac transplantation. KD has become the most prevalent acquired cardiac disease in children in developed countries. Article see p 60 Although coronary artery complications are the predominant cause of morbidity and mortality, other cardiovascular abnormalities can occur. Valvulitis is a less prevalent complication, and there have been case reports of important long-term aortic and …

QT Dispersion in Children with Leukemia

QT Dispersion in Children with Leukemia

QT Dispersion in Healthy Chinese Children and Adolescents

Background:QT dispersion (QTd) reflects the interlead difference in QT interval. It may provide a measure of repolarization inhomogeneity. Studies on QTd mainly involve adults, while QTd in children are less well studied. The aim of this study was to evaluate QTd in healthy children and assess the relationship of gender, age, and anthropometric parameters, viz. weight (W), height (H), body mass index (BMI), and body surface area (BSA) to QTd. Methods:Five hundred and one Chinese children and adolescents (243 boys, 258 girls) with no history of cardiovascular diseases were studied. Their ages ranged from 6.3 to 17.5 years. Surface 12‐lead electrocardiograms were measured in each child at rest. QT and R‐R intervals in each of the 12 leads were manually measured at a magnification of 2X. QT was corrected to QTc according to Bazett's formula. QTd was calculated as the difference between the maximum and minimum QT of the measured leads, while corrected QTd (QTcd) was the difference between the maximum and minimum QTc of the measured leads. Adjusted QTd was QTcd divided by the square root of the number of measurable leads. Results:Mean QTd of all subjects was 34 ms (95% Cl 33.6–35.1 msl. Mean QTd for boys and girls was 35 ms and 34 ms, respectively (P = 0.18). Mean QTcd for the whole group was 47 ms (95% Ci 45.8–48.2 ms), while mean adjusted QTcd was 14 ms (95% Cl 13.8–14.5 ms). There were no significant gender differences in QTcd or adjusted QTcd. Weak negative correlation existed between age and QTd, QTd and adjusted QTcd (r =−0.22, r =−0.26, r =−0.21, respectively, P &lt; 0.001 Similarly, QTcd also had a weak significant negative correlation with W (r =−0.20), H (r =−0.21) and BSA (r =−0.22), P &lt; 0.001. However, multiple stepwise regression analysis revealed that only age was significantly related to QTcd (R2 = 0.066) and QTd (R2 = 0.059), P &lt; 0.001. Conclusions:The results of this study indicate a trend of decreasing QTd and QTcd with increasing age, supported by multiple regression analysis. However indices of QTd in children are not influenced by anthropometry. This information may be useful for the clinical application of QTd in children. A.N.E. 1999;4(3):281–285

QT dispersion in children with ventricular arrhythmia and a structurally normal heart.

In adults, increased QT dispersion has been shown to predict arrhythmic risk as well as risk of sudden death in several clinical settings. It is not known whether or not QT dispersion is increased in children with idiopathic ventricular arrhythmia. We studied three groups of children: (1) 20 patients with idiopathic VT (aged 3-18 years; mean 11.2 years); (2) 30 patients with benign PVCs (aged 1-20 years; mean 10.5 years); and (3) 30 control subjects (aged 4-17 years; mean 12 years). Standard ECGs were reviewed and the dispersion of both QT and JT intervals was compared. No patient had structural heart disease or long QT syndrome. The QT and QTc dispersion (QT delta, QTc delta) among the three groups did not differ: QTc delta of the VT group was 70 ms +/- 30 ms, QTc delta of PVC patients was 60 ms +/- 30 ms, and the QTc delta of the control group was 65 ms +/- 30 ms. The JTc delta among the three groups did not differ as well: JTc delta of the VT group was 70 ms +/- 30 ms, the JTc delta of the PVC group was 60 msec +/- 25 msec, and the JTc delta of the control group was 70 ms +/- 30 ms. We conclude that QT and JT dispersion are not significantly altered in children with idiopathic VT or benign PVCs when compared to control subjects. QT dispersion is not a reliable marker for arrhythmic risk in children with idiopathic ventricular arrhythmias and structurally normal hearts.