Overheard medical student talking with pediatrician in the hall. what is atrial septal defect?

Congenital: There are various types of atrial septal defects. The most common is a secundum type. Other types like a ostium primum type, a sinus venosus type, unroofed coronary sinus type, also occur. Other type is a patent foramen ovale. They result in various levels of left to right shunting and right ventricular and pulmonary volume overload. Your pediatric cardiac surgeon can explain your child ASD type.

Defect in a wall: ASD is a hole or window that allows blood to cross between the right atrium (containing oxygen poor blood on its way to the lungs) and the left atrium (containing oxygen rich blood after passing through the lungs, headed for distant organs). Shush! this is privileged information for your eyes only!