Congenital aneurysm of the muscular interventricular septum in a fraternal case diagnosed by fetal echocardiography.

Two siblings with aneurysms of the muscular ventricular septum are presented. Case 1 (the older brother) underwent fetal echocardiography at 26 weeks of gestation. Initially, it was thought that he had a muscular ventricular septal defect; however, postnatal echocardiography revealed an aneurysm of the muscular portion of the ventricular septum. Retrospective review of the 26-weeks gestation fetal echocardiogram confirmed this diagnosis. Case 2 (a younger brother of the first case) was also diagnosed as having an aneurysm of the ventricular septum by fetal echocardiography at 28 weeks of gestation. Postnatal echocardiography confirmed this diagnosis.