Electrocardiographic predictors of left ventricular hypertrophy in pediatric hypertension

Objective: To determine the efficacy of electrocardiography (ECG) in detecting left ventricular hypertrophy (LVH) in pediatric hypertension (HT). Study design: Concomitant echocardiograms and electrocardiograms in 108 children with HT were reviewed. Left ventricular mass (LVM), assessed by echocardiography, was used as a basis for a diagnosis of LVH (echo LVH) using accepted pediatric criteria. Using Wilcoxon’s rank-sum test, 14 ECG variables were compared between subjects with and without echo LVH. Spearman correlations were used to examine the linear association between echo LVH and these ECG variables. The sensitivity and specificity of ECG in diagnosing LVH were computed. Results: Of the 108 subjects studied, 35 (32%) met the pediatric criteria for LVH; of these, 8 (7.4%) also met the adult criteria (>51 g/m 2.7) for LVH. Mean values for only 5 ECG criteria differed significantly among the groups: RI, SaVR, RaVL, RI SIII, and SVI RV6 (P<.05). Significant correlations were found for several ECG criteria and at least 1 measure of LVM, but the magnitudes were modest. Standard ECG criteria predicted LVH with high specificity (>90%) but low sensitivity (<35%). RI>10 mm was identified as demonstrating a modestly improved positive likelihood ratio of 3. Conclusions: ECG is not an adequate predictor of LVH for clinical use in HT

Abstract 10895: The Association of Growth Patterns and Clinical Outcomes in Children With Dilated Cardiomyopathy: A Report From the Pediatric Cardiomyopathy Registry Study Group

Introduction: Although malnourishment is associated with mortality in adult dilated cardiomyopathy (DCM), a paradox exists where obesity is protective. We aim to look at the role of these risk factors in pediatric DCM. Hypothesis: We hypothesize malnourishment (MN) and obesity are risk factors for death or heart transplantation. Methods: The NHLBI- funded Pediatric Cardiomyopathy Registry (PCMR) database was used for this analysis of patients (age 95% for ages ≥2years or weight for length >95% for <2 years), and normal. Results: Of 904 DCM patients, 23.7% (214) were MN, 13.3% (120) were obese, and 63.1% (570) were normal (Table). Obese patients were significantly older (p<0.001) and more likely to have a family history of DCM (both p<0.05). MN were more likely to have congestive heart failure, increased cardiac dimensions, and higher ventricular mass (p<0.01). In a Kaplan Meier analysis, there was a difference in time to death or transplant by groups (Figure, p=0.0498). Adjusting for age and myocarditis, MN was associated with increased risk of death (HR: 1.857, 95%CI: 1.159-2.977, p=<0.001), but obesity was not (HR: 1.362, 95%CI: 0.722, 2.566). Competing outcome analysis showed an increased risk of death for MN (p=0.026) but no difference between groups in transplant rate (p=0.159). Conclusion: Malnourishment is significantly associated with poor clinical outcomes. Unlike adult DCM where obesity is protective, obesity is not associated with improved survival in pediatric DCM

Height Versus Body Surface Area to Normalize Cardiovascular Measurements in Children Using the Pediatric Heart Network Echocardiographic Z-Score Database

Normalizing cardiovascular measurements for body size allows for comparison among children of different ages and for distinguishing pathologic changes from normal physiologic growth. Because of growing interest to use height for normalization, the aim of this study was to develop height-based normalization models and compare them to body surface area (BSA)-based normalization for aortic and left ventricular (LV) measurements. The study population consisted of healthy, non-obese children between 2 and 18 years of age enrolled in the Pediatric Heart Network Echo Z-Score Project. The echocardiographic study parameters included proximal aortic diameters at 3 locations, LV end-diastolic volume, and LV mass. Using the statistical methodology described in the original project, Z-scores based on height and BSA were determined for the study parameters and tested for any clinically significant relationships with age, sex, race, ethnicity, and body mass index (BMI). Normalization models based on height versus BSA were compared among underweight, normal weight, and overweight (but not obese) children in the study population. Z-scores based on height and BSA were calculated for the 5 study parameters and revealed no clinically significant relationships with age, sex, race, and ethnicity. Normalization based on height resulted in lower Z-scores in the underweight group compared to the overweight group, whereas normalization based on BSA resulted in higher Z-scores in the underweight group compared to the overweight group. In other words, increasing BMI had an opposite effect on height-based Z-scores compared to BSA-based Z-scores. Allometric normalization based on height and BSA for aortic and LV sizes is feasible. However, height-based normalization results in higher cardiovascular Z-scores in heavier children, and BSA-based normalization results in higher cardiovascular Z-scores in lighter children. Further studies are needed to assess the performance of these approaches in obese children with or without cardiac disease