Introduction and objective: Aneurysm of the atrial septum at the level of the foramen ovale is reported commonly at the routine fetal echocardiographic examination. Cases with entire involvement of the atrial septum have been exceptionally reported. We described the data concerning the prenatal detection of a total redundancy of the atrial septum in 6 cases without congenital heart disease.
Methods: The gestational age was between 28 and 38 weeks, and none of the fetuses had evidence of heart defect. A routine fetal echocardiography was made in all the cases. Rhythm disturbances were studied by M mode. During the first three months of life, a cardiologic control was made in all the cases.
Results: The large displacement of the atrial septum towards the left atrium was clearly visualized in four-chambers view; by using Pulsed Doppler and Color flow mapping, the pulmonary venous return and mitral orifice flow were not impaired. Premature atrial beats were found in two fetuses and no hemodynamic disfunction was observed in all entire study group. Postnatal echocardiographic control was normal in all patients. The atrial septum becomes completely rectified with normal patency of the foramen ovale membrane in the newborn studies. The supraventricular extrasystoles were confirmed in the neonatal period. In both, the arrhythmia disappeared in a few days after delivery without treatment.
Conclusions: Despite the benign follow-up in our cases, the unexpected presence of an extremely redundant atrial septum, leads to a close prenatal attention particularly in the presence of rhythm disturbance. The pathologic substrate of this anomaly might be an intrinsic alteration of the myocardial structure of the septum like seems demonstrated in the aneurysm circumscribed to area of the fossa ovalis [correction of fosa ovale]. The increase in the left atrial pressure after birth will produce a normal 2-D echo patterns in the newborn period.