Recovery of echocardiographic function in children with idiopathic dilated cardiomyopathy: results from the pediatric cardiomyopathy registry

Abstract

Objectives: This study sought to determine the incidence and predictors of 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 <18 years of age from the Pediatric Cardiomyopathy Registry who had both depressed left ventricular (LV) function (fractional shortening or ejection fraction z-score <-2) and LV dilation (end-diastolic dimension [LVEDD] z-score >2) at diagnosis and who had at least 1 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 the inclusion criteria, 741 (85%) had both echocardiograms. At 2 years, 22% had recovered normal LV function and size; 51% had died or undergone heart transplantation (median, 3.2 months), and 27% had persistently abnormal echocardiograms. Younger age (hazard ratio [HR]: 0.92; 95% confidence interval [CI]: 0.88 to 0.97) and lower LVEDD z-score (HR: 0.78; 95% CI: 0.70 to 0.87) independently predicted normalization. Nine children (9%) with normal LV function and size within 2 years of diagnosis later underwent heart transplantation 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 of recovery, such as genetic 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. (Pediatric Cardiomyopathy Registry; NCT00005391).

Keywords: cardiomyopathy; echocardiography; heart failure; pediatrics.

Figure 1. Sample selection to identify echocardiographic normalization in children with idiopathic dilated cardiomyopathy

Sample selection to identify echocardiographic normalization in children with idiopathic dilated cardiomyopathy.

Figure 2. Estimated cumulative incidence rates for recovering normal echocardiographic function in the presence of the competing risk for death or transplant

At any given time point, the probabilities associated with the 3 states totals to 1.0. At 2 years, 22% of children had normal echocardiographic values, 51% had died or undergone transplant, and 27% remained abnormal with respect to LV size and function.

Figure 3. Estimated cumulative incidence rates for echocardiographic normalization by age at diagnosis

The cumulative incidence for recovery of normal echocardiographic function and size is lowest in children diagnosed after 10 years old (10% by 2 years; Figure 3C) and similar for the two younger age groups: 24% for those diagnosed before age 1 year (Figure 3A) and 26% for those diagnosis before between 1 and 10 years (Figure 3B). Black lines, echocardiographic normalization; red lines, death-or-transplant; green lines, persistently abnormal echocardiogram.

Figure 4. Cumulative incidence rates for echocardiographic normalization by end-diastolic dimensions (EDD) z-score tertile from the time of diagnosis

Children with lower EDD z-scores at diagnosis were more likely to have recovered normal cardiac function by 2 years: 30% for EDD z-scores less than 4.29 (Figure 4A), 21% for the middle tertile (Figure 4B), and 13% for EDD z-scores 6.29 or higher (Figure 4C). Black lines, echocardiographic normalization; red lines, death-or-transplant; green lines, persistently abnormal echocardiogram.