Significance of the Echocardiographic Assessment of Longitudinal Left Ventricular Systolic Function in Children and Adolescents with Hypertrophic Cardiomyopathy

Background/Objectives: Hypertrophic cardiomyopathy (HCM) in childhood is associated with a risk of adverse cardiovascular events despite preserved left ventricular (LV) ejection fraction (EF). The aim of this study was to evaluate echocardiographic parameters of longitudinal LV systolic function and determine their relationship with cardiac magnetic resonance (CMR) findings and major adverse cardiovascular events (MACE) in children and adolescents with HCM. Methods: This single-centre prospective observational study enrolled 31 children and adolescents with HCM and preserved LV EF. Echocardiographic assessment included mitral annular plane systolic excursion (MAPSE), tissue Doppler mitral annulus systolic velocity (s′), mitral annular displacement index (MADI), and LV global longitudinal strain (GLS). Investigated CMR parameters encompassed LV mass, maximal wall thickness, and late gadolinium enhancement (LGE). Associations between echocardiographic and CMR findings were analyzed, and the discriminative value of longitudinal function parameters for MACE was assessed. Results: Impaired longitudinal systolic function was frequently detected in our cohort. Lower MAPSE and s′ z-scores were present in 61.3% of patients, reduced MADI in 96.8%, and reduced LV GLS in all subjects. Patients with MACE showed significantly lower MADI (p < 0.001) and worse LV GLS (p = 0.003). An exploratory LV GLS cut-off value of −12.1% showed discrimination for MACE in this cohort, with 75% sensitivity and 95.7% specificity. Echocardiographic parameters significantly correlated with CMR markers of hypertrophy and fibrosis, particularly LV GLS, which demonstrated the strongest associations with LV mass and the presence and extent of LGE. Conclusions: Echocardiographic parameters of longitudinal LV systolic function could contribute to closer clinical surveillance in children and adolescents with HCM. LV GLS may identify subtle myocardial dysfunction and provide exploratory prognostic information; however, its role in risk stratification requires prospective validation in larger pediatric HCM cohorts.