Accuracy of surface electrocardiograms for differentiating children with hypertrophic cardiomyopathy from normal children

Inherited Arrhythmias in the Pediatric Population: An Updated Overview

Pediatric cardiomyopathies (CMs) and electrical diseases constitute a heterogeneous spectrum of disorders distinguished by structural and electrical abnormalities in the heart muscle, attributed to a genetic variant. They rank among the main causes of morbidity and mortality in the pediatric population, with an annual incidence of 1.1-1.5 per 100,000 in children under the age of 18. The most common conditions are dilated cardiomyopathy (DCM) and hypertrophic cardiomyopathy (HCM). Despite great enthusiasm for research in this field, studies in this population are still limited, and the management and treatment often follow adult recommendations, which have significantly more data on treatment benefits. Although adult and pediatric cardiac diseases share similar morphological and clinical manifestations, their outcomes significantly differ. This review summarizes the latest evidence on genetics, clinical characteristics, management, and updated outcomes of primary pediatric CMs and electrical diseases, including DCM, HCM, arrhythmogenic right ventricular cardiomyopathy (ARVC), Brugada syndrome (BrS), catecholaminergic polymorphic ventricular tachycardia (CPVT), long QT syndrome (LQTS), and short QT syndrome (SQTS).

Patterns of Electrocardiographic Abnormalities in Children with Hypertrophic Cardiomyopathy

Hypertrophic cardiomyopathy (HCM), a common cardiomyopathy in children, is an important cause of morbidity and mortality. Early recognition and appropriate management are important. An electrocardiogram (ECG) is often used as a screening tool in children to detect heart disease. The ECG patterns in children with HCM are not well described.ECGs collected from an international cohort of children, and adolescents (≤ 21 years) with HCM were reviewed. 482 ECGs met inclusion criteria. Age ranged from 1 day to 21 years, median 13 years. Of the 482 ECGs, 57 (12%) were normal. The most common abnormalities noted were left ventricular hypertrophy (LVH) in 108/482 (22%) and biventricular hypertrophy (BVH) in 116/482 (24%) Of the patients with LVH/BVH (n = 224), 135 (60%) also had a strain pattern (LVH in 83, BVH in 52). Isolated strain pattern (in the absence of criteria for hypertrophy) was seen in 43/482 (9%). Isolated pathologic Q waves were seen in 71/482 (15%). Pediatric HCM, 88% have an abnormal ECG. The most common ECG abnormalities were LVH or BVH with or without strain. Strain pattern without hypertrophy and a pathologic Q wave were present in a significant proportion (24%) of patients. Thus, a significant number of children with HCM have ECG abnormalities that are not typical for "hypertrophy". The presence of the ECG abnormalities described above in a child should prompt further examination with an echocardiogram to rule out HCM.

Electrocardiographic abnormalities in elite high school athletes: comparison to adolescent hypertrophic cardiomyopathy

BACKGROUND

In athletes, ECG changes from physiological cardiac remodelling are common but can overlap with findings from a pathological disorder. We compared ECG findings in a group of elite high school athletes to a cohort of adolescents with hypertrophic cardiomyopathy (HCM).

METHODS/RESULTS

We prospectively performed 15-lead ECGs and echocardiograms in 147 elite high school athletes. Student-athlete ECGs were compared in blinded fashion to ECGs of 148 adolescents with HCM of similar age and ethnicity. Standard ECG hypertrophy criteria and established expert opinion guidelines (European Society of Cardiology, ESC and Seattle criteria) were analysed. All student-athletes had normal echocardiograms. Overall, 77/147 (52%) of student-athletes met standard ECG criteria for ventricular hypertrophy compared to 126/148 (85%) adolescents with HCM (p<0.0001). There were 112/148 (76%) adolescents with HCM who had pathological Q-waves, T-wave inversion and/or ST-segment depression compared to 1/147 (1%) athletes (p<0.0001). Most patients with HCM (84%, 124/148) had ≥1 abnormal ECG finding(s) according to Seattle criteria, compared to 1% of student-athletes (2/147). Similarly, 130/148 (88%) patients with HCM met group-2 ESC criteria (abnormal), compared to 36/147 (24%) student-athletes (p<0.0001).

CONCLUSIONS

Over 50% of elite high school athletes with echocardiographically confirmed normal hearts satisfied standard voltage criteria for ventricular hypertrophy. Pathological Q-waves, T-wave inversion or ST-segment depression were most helpful in distinguishing adolescents with HCM from normals. Both ESC and Seattle criteria successfully stratified the student-athlete and HCM cohorts, however each had a false-negative rate >10% for the HCM cohort. The Seattle criteria demonstrated a significantly lower false-positive rate (1%) than the ESC criteria (24%).

Correlation of precordial voltages to left ventricular mass on echocardiogram in adolescent patients with hypertrophic cardiomyopathy compared with that in adolescent athletes

Electrocardiograms continue to be part of screening programs for athletes and familial hypertrophic cardiomyopathy (HC). Whether electrocardiographic (ECG) findings of left ventricular (LV) hypertrophy can distinguish between healthy populations and those with HC remains unclear. We sought to (1) analyze the relation between ECG voltage and LV mass in patients with HC and (2) evaluate ECG characteristics of patients with phenotypical HC. Retrospective cohort of patients with HC aged 13 to 18 years. Relation between ECG voltages (RV6, SV1, and RV6 + SV1) and echocardiogram measurements of LV mass was investigated using smoothing splines to display relations and compared with those in a prospectively obtained population of adolescents. Frequency of abnormal LV voltages and nonvoltage ECG changes (Q waves, T-wave changes, and ST changes) were analyzed for association with HC. Fifty-three patients with HC (72% men) were age and gender matched to 104 control patients. Smoothing splines demonstrated that parabolic rather than linear relations existed between LV mass and SV1, RV6, and RV6 + SV1 in patients with HC and not the control cohort. LV hypertrophy by ECG voltage criteria was present in 34% of patients with HC and associated with poor sensitivity (29%). In patients with HC, 56% demonstrated nonvoltage ECG abnormalities and were associated with improved sensitivity (68%) and high specificity (94%). In conclusion, there is a parabolic relation between LV voltages and LV mass in adolescents with HC that may lead to "pseudonormalization." Voltage abnormalities were associated with poor sensitivity, whereas nonvoltage criteria were associated with improved sensitivity with high specificity.

Novel electrocardiographic screening criterion for hypertrophic cardiomyopathy in children

Electrocardiography is often advocated as a screening tool in children for hypertrophic cardiomyopathy (HC). We sought to establish an electrocardiographic screening tool to identify children with HC. We hypothesized that a pediatric-specific electrocardiographic criterion would perform better than the popular criteria used for screening children for left ventricular hypertrophy and HC. The earliest available electrocardiogram for children (n=108) with HC (ages 7 to 21 yrs) was reviewed. We sought to compare the diagnostic accuracy of 4 screening algorithms: (1) Sokolow-Lyon criterion (SV1+RV5/RV6>35 mm), (2) Cornell criterion (RaVL+SV3>28 mm in men, 20 mm in women), (3) total 12-lead voltage criterion (R wave to the nadir of Q/S wave>175 mm), and (4) pediatric-specific criterion (RaVL+SV2>23 mm). The same criteria were applied to a cohort of age-matched and gender-matched controls without cardiac disease. Statistically significant correlations were found between children with HC and positive screen using all 4 criteria. However, comparison of receiver operating characteristic demonstrated an area under the curve of 0.67 for Sokolow-Lyon criterion, 0.70 for Cornell criterion, 0.83 for total 12-lead criterion, and 0.82 for pediatric-specific criterion. Pediatric-specific criterion had superior sensitivity in gene-positive children and superior overall specificity than total 12-lead criterion. In conclusion, our study demonstrates that the pediatric-specific criterion employing leads RaVL+SV2 is more accurate in identifying children with HC in comparison with other popular screening criteria.

Electrocardiogram interpretation by Canadian general paediatricians: Examining practice, accuracy and confidence

BACKGROUND

Paediatric electrocardiograms (ECGs) are ordered and interpreted by general paediatricians; however, no previous studies have evaluated the accuracy of their ECG interpretations.

OBJECTIVE

To determine general paediatricians' practice and opinions regarding ECG use, accuracy of their interpretation of paediatric ECGs, and the relationship between accuracy and self-perceived confidence.

METHODS

In the present cross-sectional study, Canadian general paediatricians were asked to complete a questionnaire and interpret 18 paediatric ECGs. The questionnaire assessed characteristics of ECG use, self-perceived confidence and opinions regarding ECG use in general paediatric practice. For the ECGs provided, respondents were asked whether the ECG was normal or abnormal, what abnormality the ECG demonstrated and how confident they were in this interpretation.

RESULTS

ECG interpretation was performed by 124 general paediatricians. General paediatricians frequently use ECGs in their practice and regard this investigation as useful in patient assessment. The mean (± SD) accuracy of identifying ECGs as normal or abnormal, and identifying the specific abnormality was 80±12% and 56±20%, respectively. The sensitivity and specificity of identifying abnormal ECGs were 80% (95% CI 78% to 82%) and 79% (95% CI 75% to 83%), respectively. Correct ECG interpretation for isolated rhythm disturbances (73%) was significantly better than for abnormalities in axis (25%), chamber hypertrophy (41%) and ECG intervals (49%) (P<0.001). Overall confidence in ECG interpretation correlated with and was the only significant predictor of interpretation accuracy (r=0.396, P<0.001).

CONCLUSION

General paediatricians were adept at detecting abnormal ECGs, but were less able to identify the abnormalities. Further education in ECG interpretation may be important for this population.

Electrocardiogram screening for disorders that cause sudden cardiac death in asymptomatic children: a meta-analysis

BACKGROUND AND OBJECTIVES

Pediatric sudden cardiac death (SCD) occurs in an estimated 0.8 to 6.2 per 100 000 children annually. Screening for cardiac disorders causing SCD in asymptomatic children has public appeal because of its apparent potential to avert tragedy; however, performance of the electrocardiogram (ECG) as a screening tool is unknown. We estimated (1) phenotypic (ECG- or echocardiogram [ECHO]-based) prevalence of selected pediatric disorders associated with SCD, and (2) sensitivity, specificity, and predictive value of ECG, alone or with ECHO.

METHODS

We systematically reviewed literature on hypertrophic cardiomyopathy (HCM), long QT syndrome (LQTS), and Wolff-Parkinson-White syndrome, the 3 most common disorders associated with SCD and detectable by ECG.

RESULTS

We identified and screened 6954 abstracts, yielding 396 articles, and extracted data from 30. Summary phenotypic prevalences per 100 000 asymptomatic children were 45 (95% confidence interval [CI]: 10-79) for HCM, 7 (95% CI: 0-14) for LQTS, and 136 (95% CI: 55-218) for Wolff-Parkinson-White. The areas under the receiver operating characteristic curves for ECG were 0.91 for detecting HCM and 0.92 for LQTS. The negative predictive value of detecting either HCM or LQTS by using ECG was high; however, the positive predictive value varied by different sensitivity and specificity cut-points and the true prevalence of the conditions.

CONCLUSIONS

Results provide an evidence base for evaluating pediatric screening for these disorders. ECG, alone or with ECHO, was a sensitive test for mass screening and negative predictive value was high, but positive predictive value and false-positive rates varied.

Hypertrophic cardiomyopathy: electrocardiographic manifestations and other important considerations for the emergency physician

Hypertrophic cardiomyopathy (HCM) is one of the most common inherited primary cardiac disorders and the most common cause of sudden cardiac death in young athletes. With advances in technology, it is now recognized that HCM affects individuals of all ages. Many patients with HCM will have a benign course with few symptoms. Some patients, however, possess risk factors that greatly increase the likelihood of sudden death if their disease remains undiagnosed. Therefore, it is imperative that emergency physicians be familiar with the symptoms and typical electrocardiogram manifestations of HCM. Three illustrative cases are presented with a review of the disease.

Exercise recommendations and risk factors for sudden cardiac death

This article reviews the risk factors that are associated with exercise that can lead to sudden cardiac death and what can be done to identify those who are at risk. Additionally, exercise recommendations to reduce the chance of sudden cardiac death and comments about restrictions and quality of life issues are addressed.

Chronologic electrocardiographic changes in patients with hypertrophic cardiomyopathy associated with cardiac troponin 1 mutation

BACKGROUND

Deletion of lysine 183 (K183del) in the cardiac troponin I (cTnI) gene is one of the mutations that causes hypertrophic cardiomyopathy (HCM). However, the phenotypic expression of this mutation has not been well established.

METHODS AND RESULTS

We analyzed 10 probands with HCM associated with a K183del in the cTnI gene, as well as their family members. Forty-seven of these 80 subjects were found to be carriers and 33 were noncarriers. In the carrier subjects, electrocardiogram (ECG) abnormalities were initially noted during the early teenage years preceding echocardiographic abnormalities. Abnormal Q waves were found first and most frequently compared with other ECG abnormalities. Abnormal Q waves were frequently observed in leads II, III, aVF, V5, and V6 in teenage patients, whereas they were observed in many leads in patients >20 years old. The youngest of the 11 patients who had sudden cardiac death among studied pedigrees was a 14-year-old boy.

CONCLUSIONS

These results suggest that the first phenotypic manifestation in patients with HCM associated with a K183del mutation in the cTnI gene is abnormal Q waves in leads II, III, aVF, V5, and V6 during the early teenage years. To prevent sudden death in family members of patients with this mutation, it may be necessary to genetically diagnose it before age 10 years and to pay careful attention to any development of abnormal Q waves.