Patent Ductus Arteriosus (PDA)

Heart With Patent Ductus Arteriosus (PDA)

An animation of how a heart with patent ductus arteriosus (PDA) functions.

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The ductus arteriosus is a normal connection in utero between the pulmonary artery and the aorta. Since the lungs are still developing, the baby receives oxygenated blood from the mother during pregnancy. The ductus arteriosus allows the greater part of the oxygenated blood to bypass the non-aerated lungs by flowing directly from the pulmonary artery to the aorta. After the baby is born and begins breathing, hormonal changes occur causing the ductus arteriosus to close. A patent ductus arteriosus, or PDA, is when this connection does not close as it normally should. If the ductus remains open, the direction of flow reverses and some of the oxygen-rich blood from the aorta flows to the pulmonary artery and into the lungs. This may cause an excessive amount of blood flow to the lungs.

There are two reasons that necessitate the closure of a PDA. The first is the size of the ductus, which in turn determines the volume of extra blood being directed to the lungs. A large volume overload may result in enlargement of the heart and over time heart failure. The second reason is to avoid the risk of developing an infection in the heart known as endocarditis. Approximately, one-eighth of patients with a PDA will develop endocarditis. This increases mortality by 50% whereas the risk of surgery is almost zero.

Depending on the size of the ductus, a PDA may be treated in one of two ways. If the ductus is large, the child may require surgery that involves closing off the ductus with a clamp or suture. However, in many cases, the PDA can be closed using a spring coil or a synthetic plug. Both devices are introduced through a heart catheter, which is passed through a vein in the leg that leads up to the heart.


How Does Patent Ductus Arteriosus (PDA) Differ From Normal Cardiac Anatomy?

If your child has patent ductus arteriosus (PDA) or another congenital heart defect, there's usually something wrong with the structure of his or her heart.

 
Learn More About How Patent Ductus Arteriosus (PDA) Differs From Normal Cardiac Anatomy

Heart with Normal Cardiac Anatomy

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When your child has a congenital heart defect, there's usually something wrong with the structure of his or her heart's structure.

The heart is composed of four chambers. The two upper chambers, known as atria, collect blood as it flows back to the heart. The two lower chambers, known as ventricles, pump blood with each heartbeat to the two main arteries (the pulmonary artery and the aorta). The septum is the wall that divides the heart into right and left sides. The atrial septum separates the right and left atria; likewise, the ventricular septum separates the two ventricles.

There are four valves that control the flow of blood through the heart. These flap-like structures allow blood to flow in only one direction. The tricuspid and mitral valves, also known as the atrioventricular valves, separate the upper and lower chambers of the heart. The aortic and pulmonary valves, also known as the arterial valves, separate the ventricles from the main arteries. Oxygen-depleted blood returns from the body and drains into the right atrium via the superior and inferior vena cavas. The blood in the right atrium then passes through the tricuspid valve and enters the right ventricle.

Next, the blood passes through the pulmonary valve, enters the pulmonary artery, and travels to the lungs where it is replenished with oxygen. The oxygen-rich blood returns to the heart via the pulmonary veins, draining into the left atrium. The blood in the left atrium passes through the bicuspid, or mitral, valve and enters the left ventricle.

Finally, the oxygen-rich blood flows through the aortic valve into the aorta and out to the rest of the body.

Congenital Heart Defects

What Is a Congenital Heart Defect?

A congenital heart defect is a problem in the heart's structure that is there when a baby is born. Heart defects can range from mild to severe.

What Causes a Congenital Heart Defect?

Congenital heart defects happen because of incomplete or abnormal development of the fetus' heart during the very early weeks of pregnancy. Some are known to be associated with genetic disorders, such as Down syndrome.

But the cause of most congenital heart defects isn't known. While they can't be prevented, many treatments are available for the defects and related health problems.

Common Heart Defects

Common types of congenital heart defects, which can affect any part of the heart or its surrounding structures, include:

What Are the Signs & Symptoms of a Heart Defect?

Because congenital defects often affect the heart's ability to pump blood and to deliver oxygen to the tissues of the body, they often produce telltale signs such as:

  • a bluish tinge or color (cyanosis) to the lips, tongue, and/or nailbeds
  • an increased rate of breathing or difficulty breathing
  • poor appetite or difficulty feeding
  • failure to thrive (weight loss or failure to gain weight)
  • abnormal heart murmur
  • sweating, especially during feedings
  • a weaker pulse

If you notice any of these signs in your baby or child, call your doctor right away. If your doctor notices these signs, you may be referred to a pediatric cardiologist (a doctor who specializes in treating heart problems).

How Is a Heart Defect Diagnosed?

Some congenital heart defects cause serious symptoms right at birth. For those, a baby will go to the newborn intensive care unit (NICU) in the hospital for immediate evaluation by a cardiologist. Other defects might not be diagnosed until the teen years — or even adulthood.

Newborn Screening

Newborns in the U.S. are screened at least 24 hours after birth to look for serious congenital heart problems that can lower oxygen levels. This screen is a simple, painless test using a machine called a pulse oximeter. The oximeter uses a sensor put on a baby's skin that estimates how much oxygen is in the baby's blood. This test can help spot heart problems early on so that they can be treated right away. The screening will find most serious heart defects, but some babies who test normal could still have a problem, especially COA or other defects on the left side of the heart.

Testing

After a complete physical exam, including evaluation of the baby's heart rate and blood pressure, the cardiologist will order an electrocardiogram (EKG).

The cardiologist will probably order an echocardiogram — a test that uses sound waves to create a picture of the heart and its circulation. Echocardiograms are the primary tool for diagnosing congenital heart defects.

A fetal echocardiogram is a specialized type of ultrasound that allows diagnosis of heart problems in utero. This can be done as early as 16–18 weeks into the pregnancy. These tests are ordered when a possible heart abnormality is seen on a level II ultrasound. They're also done if another close family member has a congenital heart defect or if the mother has a condition, such as diabetes, that might make a heart problem in the fetus more likely.

Sometimes, doctors order a chest X-ray or a cardiac catheterization.

When Should I Call the Doctor?

If you think your child may have a heart problem or you notice any signs (such as difficulty breathing or feeding, or blue lips or tongue) that concern you, call your doctor. If your baby suddenly turns very blue or loses consciousness, call 911.

More treatments than ever are available for congenital heart defects, and most defects are treated successfully. Children with heart problems are best cared for by a team of specialists, which usually will include:

  • pediatric cardiologists
  • pediatric heart surgeons
  • pediatric cardiac anesthesiologists
  • doctors specialized in the intensive care of children with heart problems and specialized nurses, nurse practitioners, physician assistants, and many others

Many kids with heart problems benefit from having their hearts fixed surgically or through a cardiac catheterization procedure. The sooner they get medical attention, the better the chances for the fullest recovery possible.

With all the medical resources available, a congenital heart defect won't necessarily prevent a child from leading a normal life. By working with the health care team, you'll get the best care possible for your child.

Reviewed by: Steven Dowshen, MD
Date reviewed: October 30, 2017