What is congenital heart disease?

Congenital (which means born with) heart disease is a term used to describe several different conditions that affect the heart. These heart abnormalities are problems that occur as a baby's heart is developing during pregnancy. Congenital heart disease (CHD) affects 1 in 100 babies born in the United States, making heart defects the most common type of birth defect.

Types of congenital heart disease

We can classify the different types of congenital heart disease into categories to better understand the problems your baby may experience. These categories include:

Problems that cause too much blood to pass through the lungs

The following defects allow blood that already has oxygen to go back to the lungs instead of traveling to the body. This causes extra blood flow and stress in the lungs.

• Patent ductus arteriosus (PDA): This defect creates an extra pathway between the pulmonary artery and the aorta, letting blood mix. Before birth, this passage is supposed to be open, but it usually closes shortly after birth. If it stays open, some blood flows back to the lungs. PDA is common in premature babies.
• Atrial septal defect (ASD): In this condition, there is an opening between the two upper chambers of the heart — the right and left atria — causing abnormal blood flow through the heart.
• Ventricular septal defect (VSD): In this condition, there is a hole in the ventricular septum (the wall that divides the lower chambers, or ventricles, of the heart). This allows blood to flow from the left ventricle into the right ventricle, since the left ventricle has higher pressure. This extra blood then goes to the lungs, which can cause congestion and make a child work harder to breathe.
• Atrioventricular canal (AVC or AV canal): AVC is a complex heart problem that involves abnormalities of the structures inside the heart, including an atrial septal defect, ventricular septal defect, and mitral and/or tricuspid valves that have formed abnormally.

Problems that cause too little blood to pass through the lungs

These conditions let blood that hasn’t gone to the lungs for oxygen travel to the body. As a result, the body doesn’t get enough oxygen. Babies with these types of heart problems may look blue, a condition called cyanosis. 

• Tricuspid atresia: In this condition, there is no tricuspid valve, which means no blood flows from the right atrium to the right ventricle.
• Pulmonary atresia: In this condition, the pulmonary valve (which sends blood to the lungs) develops abnormally. When the pulmonary valve is closed, blood can’t get from the right ventricle to the lungs.
• Tetralogy of Fallot (TOF): This condition includes four defects — an abnormal opening, or ventricular septal defect; narrowing (called stenosis) at or just below the pulmonary valve that partly blocks blood from flowing from the right side of the heart to the lungs; a right ventricle that is more muscular than normal and usually enlarged; and an aorta positioned directly over the ventricular septal defect.
• Double outlet right ventricle (DORV): In this condition, both the aorta and the pulmonary artery are connected to the right ventricle. Typically, this condition also includes a ventricular septal defect.
• Truncus arteriosus: In this condition, the aorta and pulmonary artery start out as a single blood vessel that is supposed to split into two separate arteries. Truncus arteriosus happens when this vessel doesn’t fully separate, leaving a connection between the aorta and pulmonary artery. Typically, this condition also includes a ventricular septal defect.

In transposition of the great arteries (TGA), the positions of the two main arteries leaving the heart — the pulmonary artery and the aorta — are switched. This causes blood with oxygen to keep circulating only between the heart and lungs, and blood without oxygen to keep circulating through the body. Because the two systems don’t mix, the body doesn’t get the oxygen it needs, even though there is adequate blood flow to the lungs. 

Problems that cause too little blood to travel to the body

These defects happen when parts of the heart are too small or when blood vessels are blocked, keeping enough blood from reaching the body.

• Coarctation of the aorta (CoA): In this condition, the aorta — the artery that carries blood from the left ventricle to the body — is narrowed. This makes it harder for blood to reach the lower part of the body and raises blood pressure above the narrowing.
• Aortic stenosis (AS): In this condition, the aortic valve between the left ventricle and the aorta doesn’t form properly and is too narrow, which makes it harder for the heart to pump blood to the body.
• Hypoplastic left heart syndrome (HLHS): This condition includes several heart and blood vessel problems that cause the left side of the heart to be underdeveloped, or smaller than normal.

In some cases, a child will have a combination of several different heart defects.

Causes of congenital heart disease

Parents may wonder if something they did during pregnancy caused their child’s heart problem. In most cases, CHD has no clear cause. Some heart defects can run in families, so there may be a genetic link. Other heart problems can happen if the mother had certain illnesses or took certain medicines, like anti-seizure drugs, during pregnancy.

Testing and diagnosis of congenital heart disease

Many serious congenital heart diseases are found before birth, during a routine ultrasound exam. Other conditions are diagnosed shortly after birth. Less serious heart conditions may not be diagnosed until a child is older and begins to show certain symptoms of congenital heart disease.

If your doctor believes your unborn baby has a heart defect, you will likely be referred to a pediatric cardiologist for more testing. At Children’s Hospital of Philadelphia (CHOP), you will be seen at the Cardiac Center’s Fetal Heart Program. The Fetal Heart Program at CHOP can monitor both you and your child throughout your pregnancy and create a plan for labor and care after the birth. 

Several different tests are used to diagnose CHD. The type of tests performed depend on the form of CHD your child may have. Examples include:

• Electrocardiogram (EKG or ECG), which is a record of the electrical activity of the heart
• Echocardiogram (also called echo or ultrasound), which is when sound waves create an image of the heart
• Cardiac MRI, which is a 3D image that shows the heart's abnormalities
• Cardiac catheterization

Treatments for congenital heart disease

Congenital heart problems can be simple or very complex. Some heart problems can be watched by your child's cardiologist and managed with medicine, while others require heart surgery or cardiac catheterization — sometimes as soon as the first few hours after birth.

Some conditions, such as PDA or ASD, may resolve on their own as your child grows. More complex forms of congenital heart disease, or a combination of different types, will require several operations or catheter interventions and ongoing care throughout a child’s life.

Outlook and follow-up care for congenital heart disease

Babies with congenital heart disease are followed by specialists called pediatric cardiologists. These experts diagnose heart conditions and help manage your child’s health before and after surgical repair. Specialists who correct heart problems in the operating room are known as pediatric cardiovascular or cardiothoracic surgeons.

It is very important that children born with CHD transition to the appropriate type of cardiac care when they reach adulthood. The type of care required is based on the type of CHD. Adults with a simple type of CHD can generally be cared for by a community adult cardiologist. Those with more complex conditions will need to be cared for at a center that specializes in adult congenital heart disease, such as the Philadelphia Adult Congenital Heart Center, a joint program of CHOP and Penn Medicine.