Long-term outcomes of dilated cardiomyopathy diagnosed during childhood: results from a national population-based study of childhood cardiomyopathy.

BACKGROUND Existing studies of childhood dilated cardiomyopathy deal mainly with early survival. This population-based study examines long-term outcomes for children with dilated cardiomyopathy. METHODS AND RESULTS The diagnosis of dilated cardiomyopathy was based on clinical, echocardiographic, and pathological findings. The primary study end point included time to the combined outcome of death or cardiac transplantation. There were 175 patients 0 to <10 years of age at the time of diagnosis. Survival free from death or transplantation was 74% (95% confidence interval, 67-80) 1 year after diagnosis, 62% (95% confidence interval, 55-69) at 10 years, and 56% (95% confidence interval, 46-65) at 20 years. In multivariable analysis, age at diagnosis <4 weeks or >5 years, familial cardiomyopathy, and lower baseline left ventricular fractional shortening Z score were associated with increased risk of death or transplantation, as was lower left ventricular fractional shortening Z score during follow-up. At 15 years after diagnosis, echocardiographic normalization had occurred in 69% of surviving study subjects. Normalization was related to higher baseline left ventricular fractional shortening Z score, higher left ventricular fractional shortening Z score during follow-up, and greater improvement in left ventricular fractional shortening Z score. Children with lymphocytic myocarditis had better survival and a higher rate of echocardiographic normalization. At the latest follow-up, 100 of 104 of survivors (96%) were free of cardiac symptoms, and 83 (80%) were no longer receiving pharmacotherapy. CONCLUSIONS Death or transplantation occurred in 26% of patients with childhood dilated cardiomyopathy within 1 year of diagnosis and ~1% per year thereafter. Risk factors for death or transplantation include age at diagnosis, familial cardiomyopathy, and severity of left ventricular dysfunction. The majority of surviving subjects are well and free of cardiac medication.