Survival, clinical, and genetic findings in paediatric cardiomyopathy: a five-year prospective study from Brazil.

Background: Although global knowledge on paediatric cardiomyopathies has advanced, prospective cohort studies from Brazil, particularly those integrating clinical and genetic data, remain limited.

Objective: To describe the clinical and genetic characteristics of paediatric cardiomyopathy patients and identify mortality predictors in a metropolitan region of Brazil.

Methods: Prospective observational study of paediatric patients with cardiomyopathies. Clinical data, genetic findings, and survival were analysed using Kaplan-Meier curves.

Results: A total of 45 cases, male predominance (55.6%), and mean age at diagnosis of 6.5 years. Dilated and hypertrophic cardiomyopathy were the most common (33.3%). The main reason for diagnosis was the investigation of cardiovascular symptoms (60.9%). Genetic investigation occurred in 66.6%, a positivity rate of 60%. Multi-organ/system involvement was significantly associated with a positive genetic result (77.7%, p = 0.017). Mortality was 11.1%; survival was significantly lower in the following conditions: ejection fraction < 30% (p < 0.0001), functional class III/IV (p < 0.0001), heart failure (p = 0.0091), use of three or more cardiovascular medications (p < 0.001), N-Terminal Pro-B-Type natriuretic peptide >1000pg/mL (p = 0.004), and heart transplant indication (p < 0.001).

Conclusion: These findings provide novel data in Brazil, highlight a high rate of positive genetic test, particularly among patients with systemic involvement and identify key clinical predictors of mortality to guide risk stratification and care.