BACKGROUND:

Atrial septal aneurysm is a saccular deformation of the thin tissue of the interatrial septum usually located in the foramen ovale, whose deformation can occur toward the right atrium, left atrium or both. It is a rare finding during fetal echocardiographic examination, with a prevalence of 0.6 to 1.7%.

CLINICAL CASES:

Case 1: 20-year-old female patient. On cardiac echocardiographic examination at 36 weeks a situs solitus was found with cardiac axis at 40 degrees, cardiothoracic area 0.25-0.35 normal, fetal heart rate 134 beats per minute, regular rhythm, no pericardial effusion. Postnatal transthoracic echocardiography showed: situs solitus, concordant connections, without evidence of intra or extracardiac shunts. Case 2: 20-year-old patient. Advanced cardiac ultrasound examination at 37 weeks found: situs solitus, cardiac axis at 47 degrees, normal cardiothoracic area, fetal heart rate of 140 beats per minute, regular rhythm, no pericardial effusion. Postnatal transthoracic echocardiography reported: situs solitus, concordant connections, without evidence of intra or extracardiac shunts.

CONCLUSIONS:

Although interatrial septal aneurysms are usually an isolated finding in fetal echocardiography, they are considered a benign and transient process. Sometimes they are associated with other cardiac anomalies, so when the diagnosis is suspected, basic and advanced echocardiography should be performed to rule out associated anomalies.