Congenital Heart Defects

How the heart develops

The heart forms in the first 8 weeks of pregnancy. Defects happen when this process does not complete normally: walls between chambers may not close, valves may not form properly, or blood vessels may connect in the wrong places. As a result, blood may flow through holes from the left side to the right side (too much blood to the lungs), oxygen-poor blood may reach the body (causing blue color, called cyanosis), or flow may be blocked.

Common types of congenital heart defects

Causes and risk factors

Most CHDs have no single identifiable cause. Known risk factors include:

• Genetic conditions: Down syndrome (about half have a heart defect), Turner syndrome, 22q11.2 deletion (DiGeorge) syndrome, Noonan syndrome, Williams syndrome and Marfan syndrome
• Family history: a parent or sibling with CHD raises the risk
• Maternal health: poorly controlled diabetes before and during early pregnancy, obesity, phenylketonuria, and rubella infection in pregnancy
• Medicines and substances in pregnancy: isotretinoin, some anti-seizure medicines, alcohol and smoking

Signs and symptoms

In babies

• blue or gray lips, tongue or skin (cyanosis)
• fast breathing or breathlessness
• sweating, tiring or breathing hard during feeds
• poor weight gain (failure to thrive)
• unusual sleepiness or irritability
• cold hands and feet, weak pulses

In older children and adults

• breathlessness or tiredness with exercise
• palpitations or an irregular heartbeat
• fainting during exercise
• swelling of the legs or belly
• a heart murmur found on examination

Many mild defects cause no symptoms and are found by chance.

How CHDs are diagnosed

• Prenatal ultrasound: the mid-pregnancy anatomy scan at about 18 to 22 weeks detects many defects. A fetal echocardiogram gives detail.
• Newborn pulse oximetry screening: a painless sensor on the hand and foot measures oxygen levels after 24 hours of age. It is used across the US to detect critical CHD before discharge.
• Physical exam: murmurs, pulses and color.
• Echocardiogram: the main test; an ultrasound of the heart.
• ECG, chest X-ray, cardiac MRI or CT, and cardiac catheterization for detail.
• Genetic testing when a syndrome is suspected.

Treatment

• Watchful monitoring: many small VSDs, ASDs and PDAs close on their own.
• Medicines: diuretics and other heart medicines for heart failure; prostaglandin to keep the ductus open in some critical newborn defects.
• Catheter procedures: closing holes with devices, opening narrow valves or vessels with balloons and stents.
• Surgery: repairing holes, valves and vessels; some complex defects need several operations over years.
• Heart transplant: in rare cases.
• Nutrition support: high-calorie feeds for babies who tire while feeding.

Complications

• heart failure
• arrhythmias, which may need medicines, ablation or a pacemaker
• pulmonary hypertension
• infective endocarditis
• stroke
• developmental delays, particularly after complex surgery in infancy
• reduced exercise capacity

Adult congenital heart disease

More adults than children in the US now live with congenital heart disease. Many who had repairs as children need further procedures later, such as valve replacement or rhythm treatment. Lifelong follow-up at an adult congenital heart disease center is recommended, even if you feel well. Pregnancy planning should include specialist advice, because some defects increase pregnancy risks, and a parent with CHD has a higher chance of having a child with CHD.

Some people with certain CHDs need antibiotics before dental procedures to prevent endocarditis. Good dental hygiene is important for everyone with CHD.

Prevention

Not all CHDs can be prevented, but risks can be reduced:

• control diabetes before and during pregnancy
• take folic acid before conception and in early pregnancy
• be vaccinated against rubella before pregnancy
• avoid alcohol, smoking and harmful medicines in pregnancy
• review all medicines with your doctor when planning pregnancy

Frequently asked questions

What are the most common congenital heart defects?

The most common are ventricular septal defects (holes between the lower chambers), atrial septal defects, patent ductus arteriosus, pulmonary valve stenosis and bicuspid aortic valve. More complex defects include tetralogy of Fallot, transposition of the great arteries and hypoplastic left heart syndrome.

What are the signs of a heart defect in a baby?

Warning signs include blue or gray skin or lips, fast or labored breathing, sweating or tiring during feeds, poor weight gain, unusual sleepiness and cold hands and feet. A baby with blue color or breathing difficulty needs emergency care.

What causes congenital heart defects?

In most cases the cause is unknown. Genetic conditions such as Down syndrome, a family history of CHD, diabetes in pregnancy, some medicines, alcohol, smoking and rubella infection during pregnancy all raise the risk.

Can congenital heart defects be fixed?

Many can be repaired with surgery or catheter procedures, and some small holes close on their own. Complex defects may need several operations and lifelong care. A repair does not always mean a cure, so follow-up continues into adulthood.

Can you live a normal life with a congenital heart defect?

Many people with CHD live full, active lives, work, exercise and have families. Some have activity limits or need further procedures. Regular specialist follow-up helps catch problems early and keep you as healthy as possible.