Prenatal Detection of Interatrial Septal Aneurysm With Postnatal Follow-Up: A Rare Pediatric Case of Arrhythmia in a Two-Year-Old Male.

Interatrial septal aneurysm (IASA) is not uncommon in fetal and neonatal screening echocardiography. However, its persistence into childhood is rare. The presence of an IASA was associated with increased risk of arrhythmias and embolic events. Fetal tachycardia was suspected at 34 weeks of gestational age. Fetal echocardiography showed a large IASA with a normal fetal heart rate and no other congenital abnormalities. The case presented again at the age of two years with recurrent syncopal attacks, with confirmed atrioventricular (AV) nodal re-entry tachycardia correlated with the symptoms. Echocardiography showed a large type R1 IASA. The patient was referred to cardiac electrophysiology for further management. Persistence of interatrial aneurysms into childhood is rare. It can be associated with arrhythmogenic complications. A new class of classification of IASA dedicated to fetal diagnosis is suggested.