Cyanotic heart disease refers to a group of heart problems that occur at birth. The condition can cause abnormally low oxygen levels in the blood and lead to a bluish skin color.

Congenital heart disease refers to conditions that cause heart problems at birth, including heart defects (abnormalities).

The Centers for Disease Control and Prevention (CDC) estimates that congenital heart defects affect around 1% of births annually in the United States. Around 1 in 4 of these cases will be critical and require surgery or another procedure within the first year of life.

Of infants with congenital heart disease, around 25% have cyanotic heart disease. If a person gives birth to a baby with congenital heart disease, the risk of congenital heart disease and cyanotic heart disease increases during a second pregnancy.

This article discusses the symptoms, causes, and treatments for cyanotic heart disease.

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Congenital heart disease can be cyanotic or noncyanotic. In cyanotic heart disease, the heart pumps blood out to the body without enough oxygen from the lungs.

The low oxygen blood levels cause the skin to turn a bluish color. Noncyanotic heart disease is where a birth abnormality is present without low oxygen levels in the blood.

Cyanotic heart disease causes the skin to turn blue due to the spread of low-oxygen blood. Blue skin may be particularly noticeable on the:

  • lips
  • fingers
  • toes
  • nail beds

Other symptoms can include:

  • short, clubbed fingers
  • puffy eyes
  • difficulty feeding and a reduced appetite
  • fatigue and weakness
  • shortness of breath

Cyanotic heart disease results from red, oxygenated blood mixing with blue, deoxygenated blood.

The heart pumps blood from its right side to the lungs, where it collects oxygen and returns to the left side of the heart. The heart then pumps oxygen-rich blood from the left side of the heart to the rest of the body.

Blood normally returns to the heart on the right side after delivering oxygen around the body.

However, cyanotic heart disease causes disruptions to this process whereby the left side of the heart pumps out low oxygen blood to the body.

Several conditions can cause these disruptions, including heart valve abnormalities. The heart valves control the flow and direction of blood into the heart.

Some examples of heart abnormalities include:

  • tricuspid, pulmonary, or aortic valve narrowing
  • truncus arteriosus
  • pulmonary valve atresia
  • tetralogy of Fallot
  • Ebstein’s anomaly
  • total anomalous pulmonary venous return

These conditions develop in the womb, which means they are sometimes the result of genetic inheritances.

Other factors that affect pregnancy, such as an infection or diabetes in the pregnant person, can also cause these conditions.

Smoking and taking certain medications during pregnancy also increase the risk of heart abnormalities.

There are three subtypes of cyanotic heart disease:

  • Right heart obstructive lesions: These lesions cause a reduction in blood flowing from the right to the left side of the heart, reducing blood flow between the heart and lungs. Examples of this lesion include pulmonary atresia and tricuspid atresia.
  • Left heart obstructive lesions: These lesions affect blood flowing from the left to right side of the heart and reduce blood flow from the heart to the rest of the body. Examples of these lesions include hypoplastic left heart syndrome and critical aortic stenosis.
  • Mixing lesions: This is where the condition affects blood flow between the heart and lungs and the heart and the rest of the body. Examples of these lesions include the transposition of the great arteries and truncus arterioles.

Doctors may diagnose cyanotic heart disease before birth using a fetal echocardiogram. After delivery, areas of blue skin around the body may indicate the disease. Doctors may order additional tests to confirm the diagnosis. Examples include:

Almost a quarter of infants born with cyanotic heart disease will need life-sustaining surgery or other medical treatment.

Treatment may involve:

  • oxygen therapy
  • medications to reduce fluid buildup
  • medications to widen blood vessels and support the heart
  • medications to treat abnormal heart rhythms
  • surgery

The outlook for people diagnosed with cyanotic heart disease depends on several factors, including early detection and treatment. This is a serious condition that may require invasive and immediate treatment, such as surgery.

Around 75% of babies with cyanotic heart disease survive their first year, and 68% survive until age 18.

Possible complications of the disease include:

Cyanotic heart disease refers to conditions that cause low oxygen blood to circulate around the body.

Several heart abnormalities and conditions can cause oxygen-rich blood to mix with oxygen-free blood, resulting in abnormally low oxygen levels. The condition causes the skin to turn blue and requires early treatment to help prevent serious complications.

Doctors may prescribe various medications and other treatments to manage cyanotic heart disease. Some infants require surgery to address heart abnormalities and prevent long-term damage or death.

Cyanotic heart disease is a serious condition, but with timely treatment, many infants survive.