Atrioventricular septal defect is a developmental irregularity in which a hole connects two or more chambers in your child’s heart. This hole may connect the top two, the bottom two, or all four chambers.
AV septal defect goes by other names such as:
- atrioventricular canal (see Healthline article here)
- endocardial cushion defect
- common atrioventricular canal defect
AV septal defects often require open heart surgery shortly after birth. The outlook is often good for children who receive prompt treatment. Some older studies cited in a
If left untreated, AV septal defects can cause permanent damage to the blood vessels that lead to the lungs. Many children with untreated AV septal defects die in childhood.
In this article, we examine AV septal defect in more detail, including its symptoms, treatment options, and outlook.
Your heart is divided into four chambers — two left and two right chambers. The top chambers are called atria (the plural of “atrium”), and the bottom two are called ventricles.
An AV septal defect is a developmental irregularity in which two or more of these chambers are connected by a hole. AV septal defects can be divided into two main categories, which are described below.
Complete AV septal defect
A complete AV septal defect is a hole in the middle of your child’s heart that connects all four chambers of their heart. Usually, there’s a valve between the chambers on the left side of the heart and another on the right side. People with this heart defect have one valve in the middle of the heart.
Partial (incomplete) septal defect
A partial septal defect means that a hole connects two chambers of your child’s heart that are not usually connected.
AV septal defects are also called AV canal defects. The two terms are interchangeable.
Babies with complete AV septal defect usually develop congestive heart failure. This causes fluid buildup in the heart, lungs, and other tissues, especially in the lower body.
Fluid buildup in the lungs can cause symptoms such as:
- trouble breathing
- a bluish or pale tint to their skin, which may be less noticeable in children with darker skin
- rapid heart rate
Children with partial AV septal defects may have milder symptoms. In children with no other heart defects, a partial AV septal defect often
Frequent lung infections are typical in children with complete and partial AV septal defects.
AV septal defects can occur spontaneously, which means they have no known cause.
- CHARGE syndrome
- Ellis-van-Creveld syndrome
- Smith-Lemli-Opitz syndrome
- 3p deletion syndrome
About half of cases of AV septal defects occur in children with Down syndrome or other genetic syndromes, and about 75% of cases of complete AV septal defect occur in people with Down syndrome.
Most research suggests that males and females are affected about equally. In a 2018 study, researchers found evidence that females with Down syndrome may be affected about 30% more often than males with Down syndrome.
The main treatment for an AV septal defect is open heart surgery. Babies with complete AV septal defect usually need to have surgery before 6–12 months of age to avoid permanent damage in the blood vessels leading to their lungs.
Your child may receive supportive treatments before surgery, such as:
- diuretics to reduce fluid buildup
- digoxin to lower their heart rate and increase the strength of their heartbeat
- oxygen to support their breathing
The recommended age of repair for partial AV septal defect in children is usually 3–5 years. Some children may receive treatment at a younger age. But if doctors discover the condition later in a person’s life, they may make repairs in adulthood. Small partial AV septal defects may not need to be repaired.
The loss of lower heart function usually becomes greater the later the repair is made. The risk of death during surgery is less than
The outlook for AV septal defect is often favorable if it’s treated surgically but unfavorable if it’s left untreated. The first successful surgery to treat an AV septal defect occurred in
According to some older research,
AV septal defect involves an unusual hole in your child’s heart. This hole may connect the top two chambers, the bottom two chambers, or all four chambers.
Surgery is often necessary shortly after birth to treat an AV septal defect and avoid complications. Most children who receive treatment live full lives without needing to take medications or undergoing another surgery.