Application of MRI T1mapping to Myocardial Tissue Characterization in Hereditary Cardiomyopathies in Children (RF_TH_204)

In adult cardiomyopathies, diffuse myocardial fibrosis is associated with poor clinical outcomes. However, its relevance in pediatric patients remains relatively unknown. The aim was to assess the extracellular volume of myocardium reflecting diffuse myocardial fibrosis by cardiovascular magnetic resonance T1mapping and to analyze the correlation between clinical and functional data in children with different genetic phenotypes.

Methods:

Children with hereditary cardiomyopathies, including primary dilated cardiomyopathy (DCM), hypertrophic cardiomyopathy (HCM), and myocardial densification insufficiency, admitted to our hospital from January 2020 to December 2023 were selected, and their general data, symptoms and signs, laboratory findings, electrocardiograms, chest radiographs, echocardiograms, therapeutic medications, and genetic tests were collected, and underwent Cardiac magnetic resonance imaging (CMR) was performed, and the scan results were analyzed to evaluate the relationship between the presence or absence of LGE and the New York Heart Association (NYHA) cardiac function class, the cardiac function parameters on CMR examination, and the correlation between the clinical and functional data in children with different genetic phenotypes.

Results:

A total of 59 children (median age 10.0 years; dilated cardiomyopathy: n = 29, hypertrophic cardiomyopathy: n = 21; myocardial densification insufficiency: n = 9) were enrolled in this study. 35 children (59.3%) had delayed enhancement (LGE). those with LGE (+) had a poorer NYHA cardiac function classification than those with LGE (-) (P< 0.05), and the most frequently involved myocardial segment was the anterior interventricular wall of the base. interstitial wall. The difference in LGE pattern between genes was statistically significant (P < 0.001). Whereas children with FLNC variants showed predominantly subepicardial and septal LGE; and patients with LMNA2, LMNA3, and MYBPC3 variants showed nonspecific LGE.

Conclusion:

LGE(+) identified by LGE-CMR reflects myocardial fibrosis, LGE(+) is associated with impaired structural function after left ventricular remodeling, the greater the number of segments involved in LGE(+), the worse the cardiac function, and the pattern of hereditary cardiomyopathies LGE in children has a specific distribution according to the affected genes.