This was thought to be a disease affecting both the heart muscle and the endocardium and it was given various names such as: idiopathic hypertrophy of the heart, endocardial sclerosis, cardiac enlargement of unknown cause, etc.

EFE Endocardial Dysplasia Fetal Endomyocardial Fibrosis Subendocardial Sclerosis Elastic tissue hyperplasia Endocardial sclerosis None Endocardial fibroelastosis (EFE) is a rare heart disorder that affects infants and children.