https://kidshealth.org/en/parents/atrial_septal_defect_animation.html
What's an Atrial Septal Defect (ASD)? (Video) | Nemours KidsHealth
An atrial septal defect (ASD) is a heart defect in which there is an abnormal opening in the dividing wall between the upper filling chambers of the heart.
atrial septal defectnemours kidshealthasdvideo