Abstract
Fibroelastosis is a rare cardiac disorder usually occurring in infants, characterized by thickening and fibrosis of the endocardium. It can be secondary to congenital heart disease such as aortic stenosis or hypoplastic left heart syndrome and is a primary cause of restrictive cardiomyopathy in children. The ventricular stiffening from the fibrotic thickening of the endocardium impairs diastolic filling and decreases diastolic volume, leading to atrial enlargement. Systolic function is generally preserved, but the prognosis is poor.