Background Cardiomyopathies are heterogeneous diseases with clinical presentations varying from asymptomatic to life-threatening events, including severe heart failure and sudden cardiac death. The role of underlying genetic and disease-modulating factors in children and adolescents is relatively unknown. In this prospective study, in-depth phenotypic and genetic characterization of pediatric patients with primary cardiomyopathy and their first-degree family members (FMs) was performed. Outcome was assessed to identify clinical risk factors. Methods and Results Sixty index patients with primary cardiomyopathy (median age: 7.8 years) and 124 FMs were enrolled in the RIKADA (Risk Stratification in Children and Adolescents with Primary Cardiomyopathy) study. Family screening included cardiac workup and genetic testing. Using cardiologic screening, we identified 17 FMs with cardiomyopathies and 30 FMs with suspected cardiomyopathies. Adverse events appeared in 32% of index patients and were more common in those with lower body surface area (P=0.019), increased NT-proBNP (N-terminal pro-brain natriuretic peptide; P<0.001), and left ventricular dysfunction (P<0.001) and dilatation (P=0.005). The worst prognosis was observed in dilated and restrictive cardiomyopathies. Genetic variants of interest were detected in patients (79%) and FMs (67%). In all 15 families with at least 1 FM with cardiomyopathy, we found a variant of interest in the index patient. Increased number of variants of interest per patient was associated with adverse events (P=0.021). Late gadolinium enhancement was related to positive genotypes in patients (P=0.041). Conclusions Lower body surface area, increased NT-proBNP, left ventricular dysfunction or dilatation, late gadolinium enhancement, and increased number of variants of interest were associated with adverse outcome and should be considered for risk assessment in pediatric primary cardiomyopathies. Clinical Trial Registration URL: https://www.clinicaltrials.gov/. Unique identifier: NCT03572569.
Keywords: cardiomyopathy; heart failure; pediatrics; risk assessment.