Objectives: To estimate the incidence and timing of spontaneous closure of atrial septal defects within the oval fossa, to study the modalities for diagnosis, and predict the need for therapeutic intervention.
Methods: We reviewed retrospectively the medical records of patients with isolated atrial septal defects within the oval fossa, so-called "secundum defects", diagnosed between January 1990 and February 2003. Based on the initial echocardiographic evaluation, we divided defects into small ones measuring from 3 to 5 mm, medium ones from 5 to 8 mm, and large ones greater than 8 mm.