Early repolarization in children with unexplained syncope

Introduction: It has traditionally been believed that early repolarization (ER) is benign. Significant association between ER and sudden cardiac arrest due to idiopathic ventricular fibrillation was recently found in a large cohort of adult survivors of sudden cardiac arrest. In some prior studies, unexplained syncope has been linked to risk of sudden death, but the mechanisms remain speculative.We assessed herein the prevalence of ER in children referred to our center for unexplained syncope. Methods: We evaluated retrospectively electrocardiograms from such children (n = 29; mean age, 12.1 years; range, 7-18 years) for presence of ER, which was defined as an elevation of the QRS-ST junction (J-point) in at least 2 leads of at least 1 mm (0.1 mV) above the baseline level. The anterior precordial leads (V1-V3) were excluded from the analysis to avoid inclusion of patients with right ventricular dysplasia or Brugada syndrome. Agematched children (n = 33; mean age, 12.3 years; range, 7-16 years) with noncardiac chest pain were included as controls. Results: Early repolarization was detected in 45% (13/29) of children with unexplained syncope vs 24% (8/33) in the chest pain group. Among children with syncope, ER was far more frequent in males than in females (8/12 vs 5/ 17, respectively). Echocardiography showed normal functional and structural findings in all children. Conclusion: In this relatively small-scale retrospective study of children with unexplained syncope with otherwise normal cardiac findings, we found particularly among those of male gender a greater prevalence of ER than in controls (noncardiac chest pain).With view to earlier findings of Haisaguerre et al (NEJM 2008), this intriguing association warrants further prospective studies addressing its precise clinical implication and underlying mechanisms

Respiratory Tract Infection and Risk of Hospitalization in Children with Congenital Heart Defects During Season and Off-Season : A Swedish National Study

Respiratory tract infections (RTI) are common among young children, and congenital heart defect (CHD) is a risk factor for severe illness and hospitalization. This study aims to assess the relative risk of hospitalization due to RTI in winter and summer seasons for different types of CHD. All children born in Sweden and under the age of two, in 2006–2011, were included. Heart defects were grouped according to type. Hospitalization rates for respiratory syncytial virus (RSV) infection and RTI in general were retrieved from the national inpatient registry. The relative risk of hospitalization was calculated by comparing each subgroup to other types of CHD and otherwise healthy children. The relative risk of hospitalization was increased for all CHD subgroups, and there was a greater increase in risk in summer for the most severe CHD. This included RSV infection, as well as RTI in general. The risk of hospitalization due to RTI is greater for CHD children. Prophylactic treatment with palivizumab, given to prevent severe RSV illness, is only recommended during winter. We argue that information to healthcare staff and parents should include how the risk of severe infectious respiratory tract illnesses, RSV and others, is present all year round for children with CHD

MYBPC3 hypertrophic cardiomyopathy can be detected by using advanced ECG in children and young adults

Introduction The conventional ECG is commonly used to screen for hypertrophic cardiomyopathy (HCM), but up to 25% of adults and possibly larger percentages of children with HCM have no distinctive abnormalities on the conventional ECG, whereas 5 to 15% of healthy young athletes do. Recently, a 5-min resting advanced 12-lead ECG test ("A-ECG score") showed superiority to pooled criteria from the strictly conventional ECG in correctly identifying adult HCM. The purpose of this study was to evaluate whether in children and young adults, A-ECG scoring could detect echocardiographic HCM associated with the MYBPC3 genetic mutation with greater sensitivity than conventional ECG criteria and distinguish healthy young controls and athletes from persons with MYBPC3 HCM with greater specificity. Methods Five-minute 12-lead ECGs were obtained from 15 young patients (mean age 13.2 years, range 0-30 years) with MYBPC3 mutation and phenotypic HCM. The conventional and A-ECG results of these patients were compared to those of 198 healthy children and young adults (mean age 13.2, range 1 month-30 years) with unremarkable echocardiograms, and to those of 36 young endurance-trained athletes, 20 of whom had athletic (physiologic) left ventricular hypertrophy. Results Compared with commonly used, age-specific pooled criteria from the conventional ECG, a retrospectively generated A-ECG score incorporating results from just 2 derived vectorcardiographic parameters (spatial QRS-T angle and the change in the vectorcardiographic QRS azimuth angle from the second to the third eighth of the QRS interval) increased the sensitivity of ECG for identifying MYBPC3 HCM from 46% to 87% (p <0.05). Use of the same score also demonstrated superior specificity in a set of 198 healthy controls (94% vs. 87% for conventional ECG criteria; p <0.01) including in a subset of 36 healthy, young endurance-trained athletes (100% vs. 69% for conventional ECG criteria, p <0.001). Conclusions In children and young adults, a 2-parameter 12-lead A-ECG score is retrospectively significantly more sensitive and specific than pooled, age-specific conventional ECG criteria for detecting MYBPC3-HCM and in distinguishing such patients from healthy controls, including endurance-trained athletes

Serum biomarkers of early stages of hypertrophic cardiomyopathy in a young population

Background: Hypertrophic cardiomyopathy (HCM) is the most common monogenic cardiac disorder and the leading cause of sudden cardiac death in the young. Although in a majority of HCM cases there are gene mutations coding for sarcomere proteins, the onset for the clinical consequences of these mutations are difficult to predict, as these mutations do not show any clear relationship to the degree of myocardial hypertrophy. Hence identification of early markers for this disease is important. The aim of this study was to investigate novel serum biomarkers reflecting myocardial remodeling, microfibrosis and coronary endotheliopathy in young presymtomatic HCM patients and in individuals at risk for developing HCM. Methods: Eighty-nine participants (18 HCM patients, 14 HCM-risk individuals, and 57 healthy controls) with median age of 15 (range 0-30) years underwent assessment with echocardiography and serum analysis for myostatin, cathepsin S, endostatin, type I collagen degradation marker (ICTP), matrix metalloproteinase (MMP) 9, vascular (VCAM) and intercellular adhesion molecules (ICAM). In some individuals, myocardial perfusion was measured both at rest and after adenosine via magnetic resonance. Results: Both cathepsin S and endostatin were increased in the HCM group (p0.3) and diastolic function, expressed as E/e' (p0.3). In the HCM-risk group, myostatin was decreased (p0.1). Conclusion: To the best of our knowledge, this is the first study to suggest early onset changes in biomarkers of myoblast regulation, endothelial function and matrix remodeling in young presymptomatic HCM patients and in HCM-risk individuals

Can functional cardiac age be predicted from the ECG in a normal healthy population?

We hypothesized that in a normal healthy population changes in several ECG parameters together might reliably characterize the functional age of the heart. Data from 377 healthy subjects (209 men, 168 women, aged 4 to 75 years) were included in the study. In all subjects, ECG recordings (resting 5-minute 12-lead high fidelity ECG) were evaluated via custom software programs to calculate up to 120 different conventional and advanced ECG parameters. Using factor analysis, those 5 parameters that exhibited the highest linear correlations with age and that were mutually the least correlated were evaluated by multiple linear regression analysis to predict the functional electrical age of the heart. Ignoring small differences between males and females, functional electrical age was best predicted (R2 of 0.76, P < 0.001) by multiple linear regression analysis incorporating the RR-interval normalized high frequency variability of RRV; the RR-interval normalized value of a QT variability parameter called QTcor; the mean high frequency QRS (150-250 Hz) amplitude; the mean ST segment level at the J point; and the body mass index. In apparently healthy subjects, functional cardiac age can be estimated by multiple linear regression analysis of mostly advanced ECG parameters