Atrioventricular Septal Defects (AVSD)

Specialized care for children with the congenital heart defect atrioventricular septal defect 

Atrioventricular septal defects impact the way blood flows within the heart, causing increased blood flow to the lungs. The expert team in the Heart Institute at Johns Hopkins All Children’s in St. Petersburg, Florida, specializes in managing and repairing these defects in babies and children. 

What is an atrioventricular septal defect (AVSD)? 

An atrioventricular septal defect (AVSD) is a congenital (meaning present at birth) heart defect in which there are holes between the chambers on the right and left sides of the heart. Additionally, the valves that control blood flow between the upper and lower chambers are not formed correctly. 

Atrioventricular septal defects include a group of congenital heart defects. Other names for these abnormalities include “endocardial cushion defects” and “AV canal defects”. 

Atrioventricular septal defects are common in babies with Trisomy 21 (also known as Down syndrome): 45% of children with Trisomy 21 have congenital heart disease, and 45% of those children have an AVSD. Conversely, 45% of children who are found to have an AVSD also have Trisomy 21.  

There are two main types of atrioventricular septal defects: complete and partial.  

Complete atrioventricular septal defect 

In a complete atrioventricular septal defect there is an atrial septal defect (ASD), or opening in the wall between the upper chambers of the heart. There is also a ventricular septal defect (VSD), or opening in the wall between the lower chambers of the heart. 

The right and left sided chambers share a common inflow valve. Blood flows through the ASD and VSD from the left side to the right side of the heart with extra blood flowing to the lungs. 

This causes an increase in the work of breathing and increased blood pressure in the lungs. Additionally, there may be backward flow due to insufficiency of the common inflow valve which may cause further congestion of the lungs. 

Partial atrioventricular septal defect 

In the partial form, there is a primum ASD (atrial septal defect between the upper chambers) as well as a cleft in the left side of the inflow valve. Blood flows from the left to the right atrium causing increased blood flow to the lungs and enlargement of the right chambers.  

Symptoms of atrioventricular septal defects 

Symptoms vary depending on the type of AVSD. Babies with the complete form of AVSD usually have difficulty breathing and gaining weight in the first month of life. 

Symptoms may include: 

  • Difficulty breathing  
  • Fast breathing  
  • Respiratory infection  
  • Tire more easily  
  • Trouble feeding  
  • Poor growth 

Babies with a partial AVSD may not demonstrate symptoms.  
How are atrioventricular septal defects diagnosed? 

Atrioventricular septal defects may be discovered during routine fetal ultrasounds leading to a prenatal diagnosis. At Johns Hopkins All Children’s Hospital, our Fetal Heart Program team provides expert diagnosis using fetal echocardiogram as well as management before birth of congenital heart defects like AVSD. 

Partial defects are often discovered later in childhood. Your child’s pediatrician may hear a heart murmur during a routine checkup. 

Tests used to diagnose AVSD include an echocardiogram (an ultrasound of the heart) and an electrocardiogram.  

Treatment for atrioventricular septal defects 

Babies with a complete AVSD have extra blood flow and increased blood pressure in their lungs. This causes increased work of breathing and extra fluid in the lungs. Additionally, there may be backward flow or insufficiency of the common inflow valve, which adds to congestion of the lungs. A baby with a complete AVSD often requires medication to help with breathing and weight gain. Surgical repair is generally done in the first 6 months of life. 

Children with a partial AVSD generally require surgical repair at 4 to 5 years of age. Some children have difficulty with weight gain and require medication and earlier surgical repair. 

Follow-up care 

After heart surgery, a child with congenital heart disease is followed by a pediatric cardiologist. 

Older teens and young adults can then transition to receive their care from our experts as adults in the Adult Congenital Heart Disease Program. Adults with congenital heart defects benefit from seeing a provider who understands how congenital heart defects can impact health long term. 

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