Atrial septal defect, unspecified

This code represents a congenital heart defect where there is an abnormal opening in the septum (wall) separating the two upper chambers (atria) of the heart. This opening allows oxygenated blood to flow from the left atrium to the right atrium, leading to increased blood flow to the lungs. The "unspecified" nature indicates that the specific type or location of the defect is not documented.

Use this code when documentation confirms the presence of an atrial septal defect but does not specify the type (e.g., ostium secundum, ostium primum, sinus venosus). This code is appropriate when the physician's diagnosis is simply "atrial septal defect" without further detail. Supporting documentation would include echocardiogram reports or physician notes confirming the diagnosis.

• Avoid using this code if the specific type of atrial septal defect is documented; instead, select a more specific code from the Q21.1 subcategory.
• Do not confuse this with patent foramen ovale (PFO), which is a normal fetal opening that fails to close, coded separately.
• If the defect is repaired, code the defect first, followed by the appropriate procedure code for the repair.