Agreement Between Echocardiography and Cardiac MRI in Assessing Function, Strain, and Fibrosis in Pediatric...

Hypertrophic cardiomyopathy (HCM) is the most common genetic heart disease in children and is associated with arrhythmia, heart failure, and sudden cardiac death. Early detection of myocardial dysfunction and fibrosis is essential for risk stratification. Transthoracic echocardiography (TTE) is the primary diagnostic tool but has limitations, while cardiac magnetic resonance imaging (MRI) provides superior structural and fibrosis assessment. Speckle-tracking echocardiography (STE) offers sensitive markers of subclinical dysfunction, yet comparative pediatric data are limited. To investigate the concordance between TTE, STE, and MRI in pediatric HCM and to evaluate relationships between fibrosis, diastolic function, and strain parameters. Patients were categorized as sarcomeric (genetic/idiopathic) or phenocopy/non-sarcomeric (metabolic, syndromic, or endocrine) HCM according to guideline-based classification. Twenty-five HCM patients were included in this cross-sectional prospective study. All underwent clinical evaluation, TTE, and ECG; MRI was performed when eligible. Sarcomeric and phenocopy subgroups were analyzed separately. Septal thickness, LV mass, EF, and volumes were measured by TTE and MRI, while global and segmental strain values were obtained by 2D-STE. Diastolic function and fibrosis (LGE) were also assessed. Strong agreement was observed between TTE and MRI for septal thickness and LV mass, while EF differed. Complete concordance was found between 2D-STE and MRI for EF and volumes. Global strain values correlated highly, but segmental variability was noted, with strong agreement in the apical lateral segment. GLS was pathological in 77% of sarcomeric and 83% of non-sarcomeric patients. No significant difference in diastolic function was observed according to fibrosis. 2D-STE may serve as a reliable alternative to MRI for serial EF and volume monitoring in pediatric HCM. Despite segmental variability, strong global strain correlation supports complementary use. The observation that diastolic dysfunction may precede fibrosis highlights its role as an early clinical marker.