Atrioventricular Septal Defect: Causes, Symptoms, and Treatment

Medically reviewed by Achuta Uppu, MD, Internal Medicine. Last reviewed: October 23, 2026.

What kind of doctor treats Atrioventricular Septal Defect?

A pediatric cardiologist, a doctor who treats children's heart problems, usually leads the care for a baby with atrioventricular septal defect. Heart surgeons repair the defect, and the child's regular doctor helps coordinate follow-up care. A direct primary care or concierge doctor can be a first stop for an evaluation and can refer you to a specialist when needed.

What is atrioventricular septal defect?

Atrioventricular septal defect (AVSD) is a congenital heart defect, which means it is present at birth. In AVSD, there are holes between the chambers of the right and left sides of the heart. The valves that control blood flow between these chambers may not form correctly.

Because of the holes, blood flows where it normally should not go. Extra blood can flow to the lungs, so the heart and lungs work harder than usual. This may lead to heart failure, when the heart cannot pump enough blood and oxygen for the body.

AVSD is also called atrioventricular canal defect or endocardial cushion defect. There are two general types. In a complete AVSD, there is a large hole in the center of the heart and one common valve instead of two separate valves. In a partial AVSD, there is usually a hole in one of the heart walls, and one valve may not close completely.

Symptoms

Babies with a complete AVSD usually have symptoms within the first few weeks after birth. When symptoms occur, they may include:

  • Breathing problems.
  • Weak pulse.
  • Ashen or bluish skin color.
  • Poor feeding and slow weight gain.
  • Tiring easily.
  • Swelling of the legs or belly.

Babies with a partial AVSD may have small holes, so signs may not show up early. Some people with a partial AVSD are not diagnosed for years. Signs that the defect is getting worse include arrhythmia (an abnormal heart rhythm), heart failure, and pulmonary hypertension (high blood pressure in the lung arteries).

Causes and who gets it

The causes of AVSD in most babies are unknown. Some babies have heart defects because of changes in their genes or chromosomes. Genes plus other risk factors may raise the risk. These can include things in the mother's environment, what she eats or drinks, or medicines she uses during pregnancy.

AVSD is common in babies with Down syndrome, a genetic condition that causes developmental delays. MedlinePlus notes that endocardial cushion defect is strongly linked to Down syndrome. About 1 in 1,587 babies in the United States is born with an AVSD each year.

How doctors diagnose it

AVSD may be found during pregnancy or soon after birth. An ultrasound, a tool that makes pictures of the baby, may detect it. If AVSD is suspected, the provider can order a fetal echocardiogram, an ultrasound of the unborn baby's heart that shows more detail.

After birth, a doctor may hear a heart murmur, a whooshing sound from irregular blood flow through the heart. Tests to confirm it include an echocardiogram (an ultrasound of the heart), an electrocardiogram (which measures the heart's electrical activity), and a chest X-ray.

Treatment

All AVSD types usually require surgery. During surgery, the holes in the heart chambers are closed using patches. If the mitral valve, the valve on the left side of the heart, does not close completely, it is repaired or replaced.

The age for surgery depends on the child's health and the structure of the defect. Surgery should happen before permanent damage to the lungs occurs. Medicine may be used to treat heart failure, but only as a short-term measure until the infant can grow large enough for surgery.

Even after surgical repair, a child or adult with AVSD needs regular visits with a cardiologist to track progress and check for problems. With proper treatment, most babies with AVSD grow up to lead healthy, productive lives.

When to see a doctor

Call 911 or go to the emergency room if your child has trouble breathing or has bluish skin or lips. Contact your child's doctor if the child tires easily. Talk to the doctor if your baby is not growing or gaining weight.

How a direct primary care or concierge doctor fits in

A direct primary care doctor charges a flat monthly fee instead of billing insurance, while a concierge doctor usually charges more and often works alongside insurance. Either can follow the child's growth and overall health between cardiology visits and coordinate referrals to a pediatric cardiologist when concerns come up.

Common questions

Is AVSD the same as endocardial cushion defect?

Yes. AVSD is also called atrioventricular canal defect or endocardial cushion defect. The names describe the same problem: holes between the heart's chambers and valves that did not form correctly.

What is the difference between a complete and partial AVSD?

A complete AVSD has a large hole in the center of the heart. It has one common valve instead of two separate valves. A partial AVSD has some, but not all, of these defects. It usually has a hole in one wall and a valve that does not close fully.

Does surgery cure AVSD?

No. Surgical repairs for AVSD are not a cure. The most common complication after repair is a leaky mitral valve, which may need more surgery later. That is why regular checkups with a cardiologist continue.

Do most babies with AVSD do well?

With proper treatment, most babies with AVSD grow up to lead healthy, productive lives. How well a child does depends on the severity of the defect, the child's overall health, and whether lung disease has already developed.

Sources

  1. Centers for Disease Control and Prevention - Atrioventricular Septal Defect (AVSD)
  2. MedlinePlus - Endocardial cushion defect

Medical Disclaimer

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