Topic updated: May 2013

Congenital Heart Defects

What Are Congenital Heart Defects?

Congenital (kon-JEN-i-tal) heart defects are problems with the heart's structure that are present at birth. These defects can involve:

Congenital heart defects change the normal flow of blood through the heart.

There are many types of congenital heart defects. They range from simple defects with no symptoms to complex defects with severe, life-threatening symptoms.

Congenital heart defects are the most common type of birth defect. They affect 8 of every 1,000 newborns. Each year, more than 35,000 babies in the United States are born with congenital heart defects.

Many of these defects are simple conditions. They need no treatment or are easily fixed. Some babies are born with complex congenital heart defects. These defects require special medical care soon after birth.

The diagnosis and treatment of complex heart defects has greatly improved over the past few decades. As a result, almost all children who have complex heart defects survive to adulthood and can live active, productive lives.

Most people who have complex heart defects continue to need special heart care throughout their lives. They may need to pay special attention to how their condition affects issues such as health insurance, employment, birth control and pregnancy, and other health issues.

In the United States, more than 1 million adults are living with congenital heart defects.

How the Heart Works

To understand congenital heart defects, it's helpful to know how a normal heart works. Your child's heart is a muscle about the size of his or her fist. It works like a pump and beats 100,000 times a day.

The heart has two sides, separated by an inner wall called the septum. The right side of the heart pumps blood to the lungs to pick up oxygen. The left side of the heart receives the oxygen-rich blood from the lungs and pumps it to the body.

The heart has four chambers and four valves and is connected to various blood vessels. Veins are the blood vessels that carry blood from the body to the heart. Arteries are the blood vessels that carry blood away from the heart to the body.

Heart Chambers

The heart has four chambers or "rooms."

  • The atria (AY-tree-uh) are the two upper chambers that collect blood as it comes into the heart.
  • The ventricles (VEN-trih-kuls) are the two lower chambers that pump blood out of the heart to the lungs or other parts of the body.

Heart Valves

Four valves control the flow of blood from the atria to the ventricles and from the ventricles into the two large arteries connected to the heart.

  • The tricuspid (tri-CUSS-pid) valve is in the right side of the heart, between the right atrium and the right ventricle.
  • The pulmonary (PULL-mun-ary) valve is in the right side of the heart, between the right ventricle and the entrance to the pulmonary artery, which carries blood to the lungs.
  • The mitral (MI-trul) valve is in the left side of the heart, between the left atrium and the left ventricle.
  • The aortic (ay-OR-tik) valve is in the left side of the heart, between the left ventricle and the entrance to the aorta, the artery that carries blood to the body.

Valves are like doors that open and close. They open to allow blood to flow through to the next chamber or to one of the arteries, and then they shut to keep blood from flowing backward.

When the heart's valves open and close, they make a "lub-DUB" sound that a doctor can hear using a stethoscope.

  • The first sound - the “lub” - is made by the mitral and tricuspid valves closing at the beginning of systole (SIS-toe-lee). Systole is when the ventricles contract, or squeeze, and pump blood out of the heart.
  • The second sound - the “DUB” - is made by the aortic and pulmonary valves closing at beginning of diastole (di-AS-toe-lee). Diastole is when the ventricles relax and fill with blood pumped into them by the atria.

Arteries

The arteries are major blood vessels connected to your heart.

  • The pulmonary artery carries blood pumped from the right side of the heart to the lungs to pick up a fresh supply of oxygen.
  • The aorta is the main artery that carries oxygen-rich blood pumped from the left side of the heart out to the body.
  • The coronary arteries are the other important arteries attached to the heart. They carry oxygen-rich blood from the aorta to the heart muscle, which must have its own blood supply to function.

Veins

The veins are also major blood vessels connected to your heart.

  • The pulmonary veins carry oxygen-rich blood from the lungs to the left side of the heart so it can be pumped out to the body.
  • The vena cava is a large vein that carries oxygen-poor blood from the body back to the heart.

Types of Congenital Heart Defects

With congenital heart defects, some part of the heart doesn’t form properly before birth. This changes the normal flow of blood through the heart.

There are many types of congenital heart defects. Some are simple, such as a hole in the septum. The hole allows blood from the left and right sides of the heart to mix. Another example of a simple defect is a narrowed valve that blocks blood flow to the lungs or other parts of the body.

Other heart defects are more complex. They include combinations of simple defects, problems with the location of blood vessels leading to and from the heart, and more serious problems with how the heart develops.

Examples of Simple Congenital Heart Defects

Holes in the Heart (Septal Defects)

The septum is the wall that separates the chambers on left and right sides of the heart. The wall prevents blood from mixing between the two sides of the heart. Some babies are born with holes in the septum. These holes allow blood to mix between the two sides of the heart.

Atrial septal defect (ASD). An ASD is a hole in the part of the septum that separates the atria—the upper chambers of the heart. The hole allows oxygen-rich blood from the left atrium to flow into the right atrium, instead of flowing into the left ventricle as it should. Many children who have ASDs have few, if any, symptoms.

ASDs can be small, medium, or large. Small ASDs allow only a little blood to leak from one atrium to the other. They don't affect how the heart works and don't need any special treatment. Many small ASDs close on their own as the heart grows during childhood.

Medium and large ASDs allow more blood to leak from one atrium to the other. They’re less likely to close on their own.

About half of all ASDs close on their own over time. Medium and large ASDs that need treatment can be repaired using a catheter procedure or open-heart surgery.

Ventricular septal defect (VSD). A VSD is a hole in the part of the septum that separates the ventricles—the lower chambers of the heart. The hole allows oxygen-rich blood to flow from the left ventricle into the right ventricle, instead of flowing into the aorta and out to the body as it should.

VSDs can be small, medium, or large. Small VSDs don't cause problems and may close on their own. Medium VSDs are less likely to close on their own and may require treatment.

Large VSDs allow a lot of blood to flow from the left ventricle to the right ventricle. As a result, the left side of the heart must work harder than normal. Extra blood flow increases blood pressure in the right side of the heart and the lungs.

The heart’s extra workload can cause heart failure and poor growth. If the hole isn't closed, high blood pressure can scar the arteries in the lungs.

Doctors use open-heart surgery to repair VSDs.

Narrowed Valves

Simple congenital heart defects also can involve the heart's valves. These valves control the flow of blood from the atria to the ventricles and from the ventricles into the two large arteries connected to the heart (the aorta and the pulmonary artery).

Valves can have the following types of defects:

  • Stenosis (steh-NO-sis). This defect occurs if the flaps of a valve thicken, stiffen, or fuse together. As a result, the valve cannot fully open. Thus, the heart has to work harder to pump blood through the valve.
  • Atresia (ah-TRE-ze-AH). This defect occurs if a valve doesn't form correctly and lacks a hole for blood to pass through. Atresia of a valve generally results in more complex congenital heart disease.
  • Regurgitation (re-GUR-jih-TA-shun). This defect occurs if a valve doesn't close tightly. As a result, blood leaks back through the valve.

The most common valve defect is pulmonary valve stenosis, which is a narrowing of the pulmonary valve. This valve allows blood to flow from the right ventricle into the pulmonary artery. The blood then travels to the lungs to pick up oxygen.

Pulmonary valve stenosis can range from mild to severe. Most children who have this defect have no signs or symptoms other than a heart murmur. Treatment isn't needed if the stenosis is mild.

In babies who have severe pulmonary valve stenosis, the right ventricle can get very overworked trying to pump blood to the pulmonary artery. These infants may have signs and symptoms such as rapid or heavy breathing, fatigue (tiredness), and poor feeding. Older children who have severe pulmonary valve stenosis may have symptoms such as fatigue while exercising.

Some babies may have pulmonary valve stenosis and PDA or ASDs. If this happens, oxygen-poor blood can flow from the right side of the heart to the left side. This can cause cyanosis (si-ah-NO-sis). Cyanosis is a bluish tint to the skin, lips, and fingernails. It occurs because the oxygen level in the blood leaving the heart is below normal.

Severe pulmonary valve stenosis is treated with a catheter procedure.

Example of a Complex Congenital Heart Defect

Complex congenital heart defects need to be repaired with surgery. Advances in treatment now allow doctors to successfully repair even very complex congenital heart defects.

The most common complex heart defect is tetralogy of Fallot (teh-TRAL-o-je of fah-LO), which is a combination of four defects:

  • Pulmonary valve stenosis.
  • A large VSD.
  • An overriding aorta. In this defect, the aorta is located between the left and right ventricles, directly over the VSD. As a result, oxygen-poor blood from the right ventricle can flow directly into the aorta instead of into the pulmonary artery.
  • Right ventricular hypertrophy (hi-PER-tro-fe). In this defect, the muscle of the right ventricle is thicker than usual because it has to work harder than normal.

In tetralogy of Fallot, not enough blood is able to reach the lungs to get oxygen, and oxygen-poor blood flows to the body.

Babies and children who have tetralogy of Fallot have episodes of cyanosis, which can be severe. In the past, when this condition wasn't treated in infancy, older children would get very tired during exercise and might faint. Tetralogy of Fallot is repaired in infancy now to prevent these problems.

Tetralogy of Fallot must be repaired with open-heart surgery, either soon after birth or later in infancy. The timing of the surgery will depend on how narrow the pulmonary artery is.

Children who have had this heart defect repaired need lifelong medical care from a specialist to make sure they stay as healthy as possible.

Read the rest of this article, and related material from the National Heart, Lung and Blood Institute.

 

Abstract illustration of the human heart

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