Outcomes in children with Noonan syndrome and hypertrophic cardiomyopathy: a study from the Pediatric Cardiomyopathy Registry.

BACKGROUND: Studies of cardiomyopathy in children with Noonan syndrome (NS) have been primarily small case series or cross-sectional studies with small or no comparison groups. METHODS: We used the Pediatric Cardiomyopathy Registry database to compare the survival experience of children with NS and hypertrophic cardiomyopathy (HCM) with children with idiopathic or familial HCM and to identify clinical and echocardiographic predictors of clinical outcomes. RESULTS: Longitudinal data in 74 children with NS and HCM and 792 children with idiopathic or familial isolated HCM were compared. Children with NS were diagnosed with HCM before 6 months old more often (51%) than children with HCM (28%) and were more likely to present with congestive heart failure (CHF) (24% vs 9%). The NS cohort had lower crude survival than the group with other HCM (P = .03), but survival did not differ after adjustment for CHF and age at diagnosis. Within the NS cohort (1-year survival 78%), a diagnosis of HCM before age 6 months with CHF resulted in 31% 1-year survival. Lower height-for-age z score (hazard ratio 0.26, P = .005) in place of CHF and lower left ventricular fractional shortening z score (hazard ratio 0.79, P = .04) also independently predicted mortality. CONCLUSIONS: Patients with NS with HCM have a worse risk profile at presentation compared with other children with HCM, resulting in significant early mortality (22% at 1 year). Decreased height-for-age and lower, although still supranormal, left ventricular fractional shortening z score are independent predictors of mortality in patients with NS with HCM. Such patients should have an aggressive therapeutic approach including potential listing for cardiac transplantation.

Characteristics and outcomes of cardiomyopathy in children with Duchenne or Becker muscular dystrophy: a comparative study from the Pediatric Cardiomyopathy Registry.

OBJECTIVE: The aim of this study was to determine in pediatric Duchenne (DMD) and Becker muscular dystrophy (BMD) or other dilated cardiomyopathies (ODCM) whether outcomes differ by diagnosis. BACKGROUND: Children with dilated cardiomyopathy are treated as a single undifferentiated group. METHODS: This cohort study of 128 children with DMD, 15 with BMD, and 312 with ODCM uses outcome measures of left ventricular (LV) size and function, death, heart transplant, and death or transplant. RESULTS: At cardiomyopathy diagnosis, the DMD and BMD groups had similar mean ages (14.4 and 14.6 years), prevalence of congestive heart failure (CHF) (30% and 33%), and LV fractional shortening (FS) Z-scores (median, -5.2 for DMD and -6.7 for BMD). The BMD group had more severe mitral regurgitation (P = .05) and a higher mean LV end-diastolic dimension Z-score than the DMD group (2.9 +/- 1.5 vs 1.2 +/- 1.9, P = .002). Duchenne muscular dystrophy group survival was lower than in BMD or ODCM groups (P = .06) at 5 years (57%, 100%, and 71%, respectively). In BMD, 25% received cardiac transplants within 0.4 years of cardiomyopathy diagnosis. The combined DMD and BMD group had less LV dilation and a closer-to-normal LV FS at cardiomyopathy diagnosis than the ODCM group. After 2 years, LV dilation increased, and LV FS did not change in the combined DMD and BMD group; for ODCM patients, LV dilation did not progress, and LV FS improved. CONCLUSIONS: Children with DMD and cardiomyopathy have a higher mortality. Becker muscular dystrophy has a high heart transplantation rate in the 5 years after diagnosis of cardiomyopathy. Serial echocardiography demonstrates a different disease course for DMD and BMD patients compared with ODCM patients.