Every parent wants their child to live a happy, healthy life. But for parents of children with Down syndrome, the healthy part can be more complicated. If you have a child with this condition, your doctor may have talked to you about the risk for cardiac (heart) disease or congenital heart defects — health problems present from birth.

Hearing that your child may have congenital heart disease can be scary, but you’re not alone. In this article, we’ll talk about what congenital heart disease is and how it’s connected to Down syndrome. You’ll also learn about the types of congenital heart disease that are common in people with Down syndrome. Finally, we’ll talk about the diagnosis, treatment, and long-term effects of congenital heart disease.

What Is Congenital Heart Disease?

To understand congenital heart disease, it’s important to talk first about the structure and function of a healthy heart. Your heart’s main job is to pump blood throughout the body.

A healthy heart is made up of four chambers. The chambers on the top of the heart are called atria (left and right). The chambers on the bottom of the heart are called ventricles (left and right). The chambers on each side of the heart are connected, so the left atrium is connected to the left ventricle, and the right atrium is connected to the right ventricle.

Blood flows through your heart and blood vessels in a loop. The right side of the heart sends blood to the lungs, where it picks up oxygen. The left side of the heart delivers that oxygen-rich blood to the rest of the body.

There are also valves in between the different chambers of the heart. These valves open and close like a door to allow blood to move in the right direction through the heart and blood vessels.

Congenital heart disease refers to several heart conditions that involve problems with the heart’s structure. It’s something you're born with, happening when a baby’s heart doesn’t develop properly during pregnancy. There are many types of congenital heart disease, and some are more common in people with Down syndrome.

What Types of Congenital Heart Disease Are Common in People With Down Syndrome?

About 50 percent of babies with Down syndrome have some form of congenital heart disease. People with Down syndrome have a 40 to 50 times higher chance of having congenital heart defects than people without Down syndrome, but scientists don’t know why it’s so common. There are four types of congenital heart disease that develop more frequently in people with Down syndrome, described below.

Atrioventricular Septal Defect

Atrioventricular septal defects (AVSDs) are the most common form of congenital heart disease in those with Down syndrome. AVSD happens when there are holes between the left and right sides of the heart. These holes may connect all four chambers of the heart or just some of them. There may also be issues with the heart valves. Because of these problems, blood from different sides of the heart can mix. This mixing of blood makes the lungs and heart work harder than they should.

Ventricular Septal Defect

Ventricular septal defects are the second most common type of congenital heart disease in Down syndrome. If a person has a ventricular septal defect, this means there is a hole between the left and right ventricles of the heart (not the atria). Ventricular septal defects also allow blood from both sides of the heart to mix, which makes the heart and lungs work harder.

Patent Ductus Arteriosus

Before a baby is born, they have a small artery called the ductus arteriosus connecting the aorta and the pulmonary artery (two of the major blood vessels of the heart). The ductus arteriosus takes blood leaving the right ventricle and brings it to the left atrium without going through the lungs. Bypassing the lungs is important because a fetus (unborn baby) gets oxygen from their mother during pregnancy, not from their own lungs.

All babies are born with a ductus arteriosus, but it normally closes a few days after birth. If it doesn’t close, this is called patent ductus arteriosus (PDA). Babies with PDA have more blood going to the lungs, which makes the heart and lungs work harder than they should.

Tetralogy of Fallot

Tetralogy of Fallot is a condition when there are four different problems with the heart and blood vessels. About 6 percent of people with Down syndrome who have congenital heart defects have this condition. Tetralogy of Fallot is a very serious congenital heart defect that lowers the amount of oxygen reaching the rest of the body.

How Is Congenital Heart Disease Diagnosed?

Congenital heart disease is a serious medical condition and the leading cause of death for people with Down syndrome in the first two years of life. Early diagnosis of a congenital heart defect is important so the baby can get the medical care they need. Doctors recommend performing an ultrasound to look at the fetal heart during the second trimester of pregnancy. An ultrasound is a noninvasive test that uses sound waves to see inside the body. Ultrasounds during pregnancy are very good at discovering congenital heart defects.

If the ultrasound suggests a cardiac abnormality, doctors will perform a second test called an echocardiogram. Echocardiography works the same way normal ultrasounds do, but the test is more focused on looking at the heart. An echocardiogram can diagnose more than 90 percent of congenital heart disease cases in fetuses with Down syndrome.

However, not all cases of congenital heart disease are diagnosed before birth. The American Academy of Pediatrics recommends that all newborns with Down syndrome see a pediatric cardiology specialist (heart specialist for children) within the first month of life. Even if an echocardiogram was performed during pregnancy, babies with Down syndrome should have an echocardiogram after they’re born to look for heart defects.

How Do Doctors Treat Congenital Heart Disease?

The treatment for congenital heart disease depends on the size and severity of the cardiac defect. Some minor cases of congenital heart disease may not need to be treated and can just be monitored by health care providers. Medications can also be used to treat symptoms of congenital heart disease. Medications won’t fix the heart defect, but they can be used to reduce the risk of complications.

More serious cases of congenital heart disease are usually treated with heart surgery. In the past, many doctors were concerned about doing heart surgery on people with Down syndrome. However, surgical techniques have improved in recent decades. In addition, people with Down syndrome usually aren’t at higher risk during heart surgery than people without Down syndrome.

The timing and type of surgical repair depend on the size and severity of the heart defect. Some types of congenital heart disease can be repaired using a long, thin tube called a catheter. The catheter goes through blood vessels to the heart so the doctor can repair the congenital defect.

Larger heart defects should be repaired in the first six months of life. These types of congenital heart disease are usually fixed with open heart surgery. People with Down syndrome have good survival rates after surgery but still have high risks of complications. Heart surgery on people with Down syndrome should be done by experienced teams who will monitor the patient closely.

In certain cases, doctors may try to fix the congenital heart defect before the baby is born. This is done to allow the fetus to develop more normally in the womb. However, this is very rare, and most heart disease repairs are done after the baby is born.

What Are the Long-Term Impacts of Congenital Heart Disease?

If the congenital heart defects are left untreated, people with Down syndrome are at risk for other cardiovascular diseases. The type of complications depends on the type of congenital heart disease. One common complication is pulmonary hypertension (high blood pressure) in the arteries of the lungs. Early surgery lowers the risk of pulmonary hypertension in people with Down syndrome.

Developmental delays (when a child doesn’t reach a developmental milestone as expected) are also common in children with congenital heart disease. However, surgery can help lower the long-term risk of problems with brain development. School-aged children who had surgery to correct heart defects have similar brain development to other children with Down syndrome.

People with Down syndrome and congenital heart disease need lifelong care by specialists. Talk to your child’s doctor if you have questions or concerns about congenital heart disease. They can also tell you more about what to expect as your child grows older.

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