Matt Every year, 1 million babies around the world – and 40,000 babies in the United States – are born with some type of heart defect, making congenital heart disease (CHD) the most common type of birth defect in children.

Congenital heart defects develop in the early stages of pregnancy as the baby's heart forms. Some abnormalities in the heart structure, electrical system and heart function are seen early in life and can be suspected when a child has a heart murmur, poor growth, abnormal coloring or signs of heart failure. Other congenital heart problems may not be picked up until later in childhood or even during adolescence.   

The following types of congenital heart disease may not be diagnosed until a child is older:

Bicuspid aortic valve

The aortic valve is the main valve that lets the blood out of the heart to the body. Normally it has three leaflets, but commonly the valve can have only two leaflets (bicuspid). Bicuspid aortic valves can function normally, or they may develop some blockage or leakage over time. The majority of patients are free of any symptoms.

Diagnosis can be made if a doctor hears a heart murmur or a click. Bicuspid aortic valves can occur alone, or in combination with other congenital heart abnormalities; often there is some enlargement of the aorta, the large blood vessel that carries the blood to the body. A bicuspid aortic valve is present for life and requires periodic evaluation by a cardiologist to see if there are changes over time. Occasionally the function of a bicuspid aortic valve will be abnormal enough to require a procedure, which can be either a cardiac catheterization intervention or surgical repair or replacement. Signs and symptoms include:

  • Heart murmur
  • Easy fatigability or changing level of stamina
  • Fainting, chest pain, palpitations

Mitral valve prolapse (MVP)

The mitral valve channels red blood from the lungs to the main left pumping chamber of the heart, so it can be pumped to the body. If this valve leaks, then blood can go backwards towards the lungs. This results in more work for the heart and less efficient flow of blood to the body.

In mitral valve prolapse, the valve leaflets are thickened and floppy so when the valve closes there are gaps between the leaflets. These gaps allow blood to move backwards towards the lungs when the heart pumps. In general this is very well tolerated and the valve leakage is mild. This valve problem can occur on its own in otherwise healthy children and teens, but is sometimes associated with genetic syndromes.

In most cases, MVP is mild and does not require any surgical intervention. However, it does need to be checked periodically by a cardiologist to monitor for any increase in valve leakage. In more severe cases, a surgical valve repair or replacement may be needed, but that is very uncommon in childhood. In most cases, children and adolescents have no symptoms related to MVP, but some possible symptoms include:

  • Change in exercise capacity
  • Shortness of breath
  • Palpitations

Atrial septal defect (ASD)

All babies are born with a hole in the wall between the two upper heart chambers (atria) that usually closes completely in the first year of life. In some children the hole remains open and can vary in size and location. This is called an atrial septal defect (ASD).

If the ASD is large enough to allow blood from the left side of the heart to cross into the right side of the heart, enlarging those chambers and sending too much blood to the lungs, then it is considered to be an important abnormality of the heart. A large ASD can make the work of the heart less efficient, and over time, lead to enlargement of the heart. Treatment varies depending upon the size and location of the ASD. Some require surgical closure with a patch, while others can be closed non-surgically.  

ASD diagnosis can be made in all age groups, including adulthood, as most patients are free of symptoms. Symptoms include:

  • Heart murmur
  • Palpitations
  • Change in exercise capacity
  • Abnormal ECG or chest X-ray


When the heart muscle is abnormally formed, that is called a cardiomyopathy. Most cardiomyopathies are diagnosed during the teen years or in young adulthood, although the most serious forms can appear at much younger ages. The heart muscle can be weak and cause an enlarged heart, called a dilated cardiomyopathy, or the heart muscle can be excessively thickened, called hypertrophic cardiomyopathy (HCM).

HCM, which can be genetic and passed down through generations, can cause blockage of blood flow out of the heart and/or serious heart rhythm problems. When a patient collapses during physical activity, this is a likely cause. Patients with HCM may need medication and/or defibrillators to protect them from life-threatening events.

Dilated cardiomyopathy can also be genetic or caused by a viral infection. Treatment generally includes medication, and for more severe cases, defibrillators or heart transplantation.

Patients with all types of cardiomyopathy are usually followed by cardiac specialists familiar with heart failure. Symptoms for cardiomyopathies include:

  • Fainting, especially with physical activity
  • Heart murmur
  • Chest pain and palpitations
  • Change in exercise level and stamina
  • Abnormal ECG

The Children's Hospital of Philadelphia is a proven leader in cardiac care and heart surgery. Specialists at the Cardiac Center are experts at diagnosing and treating every congenital heart condition.


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