Technical Advances and Outcomes of Fetal Atrial Septal Intervention for Restrictive or Intact Atrial Septum.

Background: Infants with hypoplastic left heart syndrome with severely restrictive or intact atrial septum (R/IAS) have low survival. In-utero creation of an atrial septal communication has been reported, with high complication rates.

Methods: We performed a retrospective cohort study of fetuses with hypoplastic left heart syndrome, double outlet right ventricular with mitral stenosis/atresia, or mitral valve dysplasia and R/IAS from 2012 to 2024 who underwent evaluation for fetal atrial septal intervention (FASI).