BackgroundPatients with hypertrophic cardiomyopathy may develop symptoms of shortness of breathing due to diastolic dysfunction which is not related to the severity of left ventricular outflow tract obstruction. As these patients usually develop a non-ischemic pattern of myocardial fibrosis, this may represent a mechanism for increased myocardial stiffness leading to impaired diastolic filling. The study aimed to determine the prevalence of myocardial fibrosis assessed by magnetic resonance imaging in children with hypertrophic cardiomyopathy and to evaluate its relationship with echocardiographic parameters including left ventricle diastolic dysfunction and to find echocardiographic indices which correlates with myocardial fibrosis as detected by cardiac magnetic resonance. A cross-sectional study was done for data of 50 children with hypertrophic cardiomyopathy from July 2018 to July 2021, patients were divided into (group 1) having myocardial fibrosis and (group 2) with no myocardial fibrosis, and results of echocardiographic parameters were compared between the two groups.ResultsResults showed strong relationship between presence of myocardial fibrosis and each of the following: Interventricular septum thickness, lower lateral and septal early diastolic tissue velocities (E′),E/E′ ratio, presence of left ventricular out flow tract obstruction and the grade of diastolic dysfunction.ConclusionsThe trans-mitral lateral and septalE/E′ (early mitral inflow to early diastolic mitral annular velocity ratio) allows early detection of left ventricular diastolic dysfunction in children with hypertrophic cardiomyopathy. The prevalence of diastolic dysfunction is higher in obstructive hypertrophic cardiomyopathy. The diastolic dysfunction severity is higher in patients with myocardial fibrosis.