Cyanotic heart disease is a heart defect, present at birth (congenital), that results in low blood oxygen levels. There may be more than one defect.

Right-to-left cardiac shunt; Right-to-left circulatory shunt

Normally, blood returns from the body and flows through the heart and lungs.

• Blood that is low in oxygen (blue blood) returns from the body to the right side of the heart.
• The right side of the heart then pumps the blood to the lungs, where it picks up more oxygen and becomes red.
• The oxygen-rich blood returns from the lungs to the left side of the heart. From there, it is pumped to the rest of the body.

Heart defects that children are born with can change the way blood flows through the heart and lungs. This abnormal blood flow is called shunting. 

• The blood that is pumped out to the body is lower in oxygen.
• Less oxygen delivered to the body can make the skin look blue (cyanosis)

Many of these heart defects involve the heart valves. Heart valves are found between the heart and the large blood vessels that bring blood to and from the heart. These valves open up enough for blood to flow through. Then they close, keeping blood from flowing backward.

Heart valve defects that can cause cyanosis include:

• Tricuspid valve (the valve between the two chambers on the right side of the heart) may be absent or unable to open wide enough.
• Pulmonary valve (the valve between the heart and the lungs) may be absent or unable to open wide enough.
• Aortic valve (the valve between the heart and the blood vessel to the rest of the body) is unable to open wide enough.

Other heart defects that may cause cyanosis include:

• Coarctation or complete interruption of the aorta
• Ebstein's anomaly
• Hypoplastic left heart syndrome
• Tetralogy of Fallot
• Total anomalous pulmonary venous return
• Transposition of the great arteries  
• Truncus arteriosus

Cyanotic heart diseases may be caused by:

• Chemical exposure
• Genetic and chromosomal syndromes, such as Down syndrome, trisomy 13, Turner syndrome, Marfan syndrome, and Noonan syndrome
• Infections (such as rubella) during pregnancy
• Poorly controlled blood sugar levels in women who have diabetes during pregnancy
• Medications prescribed by your doctor or bought on your own and used during pregnancy
• Street drugs used during pregnancy

Some heart defects cause major problems right after birth. Others cause few, if any, problems until adulthood.

One symptom is cyanosis, which usually seen as a bluish color of the lips, fingers, and toes. It may occur while the child is resting, or only when the child is active.

Some children have breathing problems (dyspnea). They may get into a squatting position after physical activity to relieve breathlessness.

Others have spells, in which their bodies are suddenly starved of oxygen. During these spells, symptoms may include:

• Anxiety
• Breathing too quickly (hyperventilation)
• Sudden increase in bluish color to the skin

Infants may get tired or sweat while feeding and may not gain as much weight as they should.

Fainting (syncope) and chest pain may occur.

Other symptoms depend on the type of cyanotic heart disease, and may include:

• Feeding problems or reduced appetite, leading to poor growth
• Grayish skin
• Puffy eyes or face
• Tiredness all the time

Physical examination confirms cyanosis. The child may have clubbed fingers.

The doctor will listen to the heart and lungs with a stethoscope. Abnormal heart sounds, a heart murmur, and lung crackles may be heard.

Tests will vary depending on the cause, but may include:

• Chest x-ray
• Checking oxygen levels in the blood using an arterial blood gas test or by checking it through the skin with a pulse oximeter
• Complete blood count (CBC)
• ECG (echocardiogram)
• Looking at the heart structure and blood vessels using echocardiogram or MRI of the heart
• Passing a thin flexible tube (catheter) into the right or left side of the heart, usually from the groin (cardiac catheterization)
• Transcutaneous oxygen monitor (pulse oximeter)
• Echo-Doppler
• Testing the heart's electrical system

Some infants may need to stay in the hospital after birth so they can receive oxygen or be put on a breathing machine. They may receive medicines to:

• Get rid of extra fluids
• Help the heart pump harder
• Keep certain blood vessels open
• Treat abnormal heartbeats or rhythms

The treatment of choice for most congenital heart diseases is surgery to repair the defect. There are many types of surgery, depending on the kind of birth defect. Surgery may be needed soon after birth, or it may be delayed for months or even years.

Your child may need to take water pills (diuretics) and other heart medicines before or after surgery. Be sure to follow the correct dosage. Regular follow-up with your doctor is important.

Many children who have had heart surgery must take antibiotics before, and sometimes after having any dental work or other medical procedures. Make sure you have clear instructions from your child's heart doctor. It is very important to have your child's teeth cleaned regularly.

Ask your child's doctor before getting any immunizations. However, most children can follow the recommended guidelines for childhood vaccinations.

The outlook depends on the specific disorder.

Complications of cyanotic heart disease include:

• Abnormal heart rhythms and sudden death
• Chronic high blood pressure in the blood vessels of the lung
• Heart failure
• Infection in the heart
• Stroke

Call your health care provider if your baby has:

• Bluish skin (cyanosis) or grayish skin
• Breathing difficulty
• Chest pain or other pain
• Dizziness, fainting, or heart palpitations
• Feeding problems or reduced appetite
• Fever, nausea, or vomiting
• Puffy eyes or face
• Tiredness all the time

Women who are pregnant should get good prenatal care.

• Avoid using alcohol and drugs during pregnancy.
• Tell your doctor that you are pregnant before taking any prescribed medications.
• Get a blood test early in the pregnancy to see if you are immune to rubella. If you are not immune, you must avoid any exposure to rubella and should get immunized right after delivery.
• Pregnant women with diabetes should try to get good control over their blood sugar levels.

Some inherited factors may play a role in congenital heart disease. Many family members may be affected. If you are planning to get pregnant, talk to your health care provider about screening for genetic diseases.

Webb GD, Smallhorn JF, Therrien J, Redington AN. Congenital heart disease. In: Zipes DP, Libby P, Bonow RO, eds. Braunwald's Heart Disease: A Textbook of Cardiovascular Medicine, 11th ed. Philadelphia, Pa: Saunders Elsevier; 2011:chap 65.

Bernstein D. Cyanotic congenital heart disease: Evaluation of the critically ill neonate with cyanosis and respiratory distress. In: Kliegman RM, Behrman RE, Jenson HB, Stanton BF, eds. Nelson Textbook of Pediatrics. 19th ed. Philadelphia, Pa: Saunders Elsevier;2011:chap 423.

Perloff JK, Child JS, AboulHosn JA. Congenital Heart Disease in Adults. 3rd ed. Philadelphia, Pa: Saunders Elsevier; 2009.