ABSTRACT
The right atrium Idiopathic enlargement of the right atrium This is a rare entity, described predominantly in the adult population. A few cases have been reported in the pediatric literature 5-8 and during prenatal life. 5,9,10 On anatomic examination, the right atrium appears extremely dilated, and the tricuspid valve normally positioned. Histologically, the right atrial wall shows widespread muscular degeneration and diffuse fibrosis.
