A complete atrioventricular septal defect (AVSD) is a heart defect that is present at birth (congenital). Normally, the four heart chambers are separated by walls (septum) to keep oxygen rich and oxygen poor blood separate. The blood flow is controlled by valves. In complete AVSD, a hole is located where the four chambers of the heart (atrium and ventricles) meet. Additionally, instead of two AV valves to control blood flow, there is often only one large valve which does not work properly. In AVSD, the oxygen rich and poor blood mix—causing the heart to send too much blood to the lungs. The overworked heart enlarges and the blood pressure in the lungs becomes too high. This situation may eventually lead to heart failure.
Common symptoms may include difficulty breathing, abnormal heartbeats (arrhythmia), and poor blood circulation, which can cause bluish lips and skin and swelling in the legs (edema). Children with AVSD may also have poor appetite and tire easily. Sometimes symptoms may not appear for weeks or months after birth. The causes of AVSDs are believed to be a combination of genetics and environment. Babies with Down syndrome are at an increased risk to develop an AVSD. Other risk factors include drinking alcohol during the pregnancy or poorly controlled maternal diabetes.
Doctors may hear a swishing sound in the heartbeat (a murmur) when listening with a stethoscope. Tests used to confirm an AVSD may include a chest X-ray, electrocardiogram (EKG) (tests the electrical impulses), echocardiogram (using sound waves to create a picture), or cardiac MRI.
Smaller defects may close on their own, but the most common treatment is surgical repair. If your baby or child has been diagnosed with an AVSD, talk to their pediatric cardiologist about the most current treatment options. Support organizations and genetic counselors are also a good source of information and can help connect you with others affected by AVSD.