Introduction:
Pediatric cardiomyopathies (incidence: 1/100,000) are rare and heterogeneous disorders, often with severe cardiac phenotypes. Etiologies include idiopathic/sarcomeric, syndromic, neuromuscular, inflammatory and metabolic forms, but cause-specific outcomes remain poorly defined. This study analyzed the clinical course of a pediatric cohort with dilated cardiomyopathy (DCM), stratified by etiology.
Methods:
Patients clinically diagnosed with DCM before the age of 18 years at Heidelberg University Hospital, Germany (1992-2025) were included (n=78). Clinical data were compiled by the Medical Data Integration Center and supplemented by manual chart review. Endpoints included arrhythmias, genetic testing, echocardiography, survival, cardiac arrest, heart transplantation, VAD, ICD, and PPM implantation.
Results:
Of 78 patients, n=29 (37.2%) were followed into adulthood. Causes of DCM included idiopathic/sarcomeric (46.2%, n=36), metabolic (19.2%, n=15), myocarditis-induced (17.9%, n=14), neuromuscular (7.7%, n=6), or syndromic (9%, n=7). Diagnosis was made in infancy (<1 year) (32.1%, n=25), childhood (1-18 years) (64.1%, n=50) or before 18 years without details (3.8%, n=3). Etiology did not correlate with infant disease onset. During mean follow-up of 6.5±6.7 years, 24.4% (n=19) died, of whom 68.4% died within the first 4 years of life. The remaining deaths occurred between ages 10-20. Survival was highest in myocarditis-induced DCM (92.9%), and lower in syndromic (85.7%), neuromuscular (83.3%), idiopathic/sarcomeric (77.8%) and metabolic (46.7%) forms. Infantile onset correlated with higher mortality independent of etiology (p=0.014) and within idiopathic/sarcomeric DCM (p=0.042). Deaths were mainly due to combined cardio- and non-cardiovascular causes. Cardiac arrest occurred in 19.2% (n=15) without significant differences by etiology (p=0.167), or onset age (p=0.6), although rates were highest in neuromuscular (50%) and myocarditis-induced (28.6%) DCM. Heart transplantation (p=0.051), VAD (p=0.073), and ICD (p=0.054) were observed only in idiopathic/sarcomeric, neuromuscular, or myocarditis-induced DCM with none in metabolic or syndromic forms. Heart transplantation was performed in 19.2% (n=15); rates differed by etiology (p=0.051), not by onset age (p=0.304). Rates were highest in myocarditis-induced (35.7%) and idiopathic/sarcomeric (25%) DCM. VAD implantation occurred in 14.1% (n=11), not differing significantly by etiology (p=0.073) or onset age (p=0.892), with highest rates in neuromuscular (33.3%) and myocarditis-induced (28.6%) DCM. ICD implantation was rare (2.6%, n=2) and limited to neuromuscular (16.7%) and myocarditis-induced (7.1%) DCM. No PPM implantations occurred in our cohort during follow-up.
Conclusions:
Outcomes in pediatric DCM differ substantially by etiology and age of disease onset. Early infantile presentation and metabolic disease predict poor prognosis, whereas myocarditis-induced DCM shows the most favourable outcome.
