In this scientific statement from the American Heart Association, experts in the field of cardiomyopathy (heart muscle disease) in children address 2 issues: the most current understanding of the causes of cardiomyopathy in children and the optimal approaches to diagnosis cardiomyopathy in children. Cardiomyopathies result in some of the worst pediatric cardiology outcomes; nearly 40% of children who present with symptomatic cardiomyopathy undergo a heart transplantation or die within the first 2 years after diagnosis. The percentage of children with cardiomyopathy who underwent a heart transplantation has not declined over the past 10 years, and cardiomyopathy remains the leading cause of transplantation for children >1 year of age. Studies from the National Heart, Lung, and Blood Institute–funded Pediatric Cardiomyopathy Registry have shown that causes are established in very few children with cardiomyopathy, yet genetic causes are likely to be present in most. The incidence of pediatric cardiomyopathy is ≈1 per 100 000 children. This is comparable to the incidence of such childhood cancers as lymphoma, Wilms tumor, and neuroblastoma. However, the published research and scientific conferences focused on pediatric cardiomyopathy are sparcer than for those cancers. The aim of the statement is to focus on the diagnosis and classification of cardiomyopathy. We anticipate that this report will help shape the future research priorities in this set of diseases to achieve earlier diagnosis, improved clinical outcomes, and better quality of life for these children and their families.

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(1990-2008 Nϭ3375) for cases of RCM. Cases were defined as pure when RCM was the only assigned diagnosis. Additional documentation of HCM at any time was used as the criterion for RCM/HCM phenotype. RCM accounted for 4.5% of cases of cardiomyopathy. In 101 (66%), pure RCM was diagnosed; in 51 (34%), there was a mixed phenotype. Age at diagnosis was not different between groups, but 10% of the pure RCM group was diagnosed in infancy versus 24% of the RCM/HCM group. Freedom from death was comparable between groups with 1-, 2-, and 5-year survival of RCM 82%, 80%, and 68% versus RCM/HCM 77%, 74%, and 68%. Transplant-free survival was 48%, 34%, and 22% and 65%, 53%, and 43%, respectively (Pϭ0.011). Independent risk factors at diagnosis for lower transplant-free survival were heart failure (hazard ratio 2.20, Pϭ0.005), lower fractional shortening z score (hazard ratio 1.12 per 1 SD decrease in z score, Pϭ0.014), and higher posterior wall thickness in the RCM/HCM group only (hazard ratio 1.32, PϽ0.001). Overall, outcomes were worse than for all other forms of cardiomyopathy. Conclusions-Transplant-free survival is poor for RCM in childhood. Survival is independent of phenotype; however, the RCM/HCM phenotype has significantly better transplant-free survival. Clinical Trials Registration-URL: http://www.clinicaltrials.gov. Unique Identifier: NCT00005391.

Background Left ventricular noncompaction (LVNC) is a distinct form of cardiomyopathy characterized by hypertrabeculation of the left ventricle. The LVNC phenotype may occur in isolation or with other cardiomyopathy phenotypes. Prognosis is incompletely characterized in children. Methods and Results Using diagnoses from the National Heart, Lung, and Blood Institute-funded Pediatric Cardiomyopathy Registry from 1990-2008, 155 of 3219 children (4.8%) had LVNC. Each LVNC patient was also classified as having an associated echocardiographically diagnosed cardiomyopathy phenotype (dilated cardiomyopathy (DCM), hypertrophic cardiomyopathy (HCM), restrictive cardiomyopathy (RCM), isolated, or indeterminate). The time to death or transplant differed among the phenotypic groups (P = 0.035). Time to listing for cardiac transplantation significantly differed by phenotype (P < 0.001), as did time to transplantation (P = 0.015). The hazard ratio for death/transplant (with isolated LVNC as the reference group) was 4.26 (95% confidence interval [CI], 0.78 to 23.3) for HCM, 6.35 (95% CI, 1.52 to 26.6) for DCM, and 5.66 (95% CI, 1.04 to 30.9) for the indeterminate phenotype. Most events occurred in the first year after diagnosis. Conclusion LVNC is present in at least 5% of children with cardiomyopathy. The specific LVNC-associated cardiomyopathy phenotype predicts the risk of death/transplant and should inform clinical management.

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Objectives To determine the incidence of and predictors for recovery of normal echocardiographic function among children with idiopathic dilated cardiomyopathy (DCM). Background Most children with idiopathic DCM have poor outcomes; however, some improve. Methods We studied children less than 18 years old in the Pediatric Cardiomyopathy Registry who had both depressed left ventricular (LV) function (fractional shortening [FS] or ejection fraction [EF] z-score <−2) and LV dilation (end-diastolic dimension [LVEDD] z-score >2) at diagnosis and who had at least one follow-up echocardiogram 30 days to 2 years from the initial echocardiogram. We estimated the cumulative incidence and predictors of normalization. Results Among 868 children who met inclusion criteria, 741 (85%) had both echocardiograms. At 2 years, 22% had recovered normal LV function and size; 51% had died or undergone heart transplant (median, 3.2 months), and 27% had persistently abnormal echocardiograms. Younger age (hazard ratio, 0.90; 95% CI, 0.86 to 0.95) and lower LVEDD z-score (0.75; 95% CI, 0.68 to 0.84) independently predicted normalization. Nine children (9%) with normal LV function and size within 2 years of diagnosis later underwent heart transplant or died. Conclusions Despite marked LV dilation and depressed function initially, children with idiopathic DCM can recover normal LV size and function, particularly those younger and with less LV dilation at diagnosis. Investigations related to predictors for recovery, such as gene associations, serum markers, and the impact of medical therapy or ventricular unloading with assist devices are important next steps. Longer follow-up after normalization is warranted as cardiac failure can recur. Clinical Trials Registration # NCT00005391

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