Eisenmenger (I-sun-meng-uhr) syndrome is a long-term complication of an unrepaired heart defect that someone was born with (congenital).

The congenital heart defects associated with Eisenmenger syndrome cause blood to circulate abnormally in your heart and lungs. When blood doesn't flow normally, the blood vessels in your lungs become stiff and narrow, increasing the pressure in your lungs' arteries (pulmonary arterial hypertension). This permanently damages the blood vessels in your lungs.

With early diagnosis and repair of congenital heart defects, this life-threatening condition can usually be avoided. If Eisenmenger syndrome does develop, it requires careful medical monitoring. Medications can improve symptoms and prognosis.


Eisenmenger syndrome signs and symptoms include:

  • Bluish or grayish skin color (cyanosis)
  • Large, rounded fingernails or toenails (clubbing)
  • Easily tiring and shortness of breath with activity
  • Shortness of breath while at rest
  • Chest pain or tightness
  • Skipped or racing heartbeats (palpitations)
  • Dizziness or fainting
  • Coughing up blood
  • Numbness or tingling in fingers or toes
  • Headaches

When to see a doctor

If you have any signs or symptoms of Eisenmenger syndrome, make an appointment to see your doctor. Even if you haven't previously been diagnosed with a heart defect, symptoms such as cyanosis and shortness of breath are signals that you have a health problem that needs medical attention.


Eisenmenger syndrome usually develops due to a hole between the chambers of your heart. To understand how Eisenmenger syndrome affects your heart and lungs, it's helpful to know how your heart works.

How the heart works

Your heart is divided into four chambers, two on the right and two on the left. The right side moves blood into vessels that lead to your lungs. In your lungs, oxygen enriches your blood, which then circulates to your heart's left side. The left side of your heart pumps blood into a large vessel called the aorta, which circulates blood to the rest of your body.

Valves control the flow of blood into and out of the chambers of your heart. These valves open to allow blood to move to the next chamber or to one of the arteries, and then close to keep blood from flowing backward.

How Eisenmenger syndrome develops

Eisenmenger syndrome is typically due to an unrepaired hole (shunt) between the main blood vessels or chambers of your heart. This shunt is a heart defect you're born with (congenital). Heart defects that can cause Eisenmenger syndrome include:

  • Atrioventricular canal defect. In this heart defect, there's a large hole in the center of the heart where the walls between the upper chambers (atria) and lower chambers (ventricles) meet. Some of the valves in your heart also may not function properly.
  • Atrial septal defect. An atrial septal defect is a shunt in the wall of tissue that divides the right and left sides of the upper chambers of your heart (atria).
  • Patent ductus arteriosus. This heart defect is an opening between the pulmonary artery that carries oxygen-poor blood to the lungs and the artery that carries oxygen-rich blood to the rest of your body (aorta).
  • Ventricular septal defect. This shunt in the wall of tissue that divides the right and left sides of your heart's main pumping chambers (ventricles) is the most common cause of Eisenmenger syndrome.

In any of these defects, blood is flowing in a way it normally doesn't, which increases the pressure in your pulmonary artery. Over time, this increased pressure damages the smaller blood vessels in your lungs. The damaged blood vessel walls make it difficult to pump blood to the lungs.

Eisenmenger syndrome causes increased blood pressure in the side of the heart that has low oxygen-containing blood (blue blood). This allows the low oxygen-containing blood to cross the hole (shunt) in the heart or blood vessels, which lets oxygen-rich and oxygen-poor blood mix. This lowers the oxygen level in your blood and causes a bluish tint to your skin (cyanosis). This also leads to an increase in your red blood cell count to try to make up for the lack of oxygen.

Risk factors

A family history of heart defects also increases the risk of a baby developing a congenital heart defect, including the possibility of developing Eisenmenger syndrome. Talk to your doctor about screening other family members for heart defects if you've been diagnosed with a heart defect or Eisenmenger syndrome.


Without proper treatment and monitoring, your complications of Eisenmenger syndrome may include:

  • Low oxygen levels in your blood (cyanosis). The reversed blood flow through your heart lowers the amount of oxygen your body's tissues and organs receive. This causes you to have a lower tolerance for physical activity and your skin to have a bluish or a grayish color. Cyanosis will worsen over time.
  • High red blood cell count. Because you aren't getting enough oxygen-rich blood circulating throughout your body, your kidneys release a hormone that increases your number of red blood cells — the cells that carry oxygen throughout your body. The increase in red blood cells allows more oxygen to be delivered to the body's tissues, which is an important way the body compensates for decreased oxygen levels.
  • Irregular heart rhythm. Enlargement and thickening of the walls in the heart, along with low oxygen levels, may cause an irregular heart rhythm (arrhythmia). Some types of arrhythmias can cause blood to pool in your heart's chambers, where it can clot. If the clot travels out of your heart and blocks an artery, you can have a heart attack or stroke.
  • Sudden cardiac arrest. If you develop an abnormal rhythm from the bottom chamber of the heart (the ventricle), the heart rate can be too fast to allow the heart to effectively pump blood to the body, and can eventually cause the heart to stop functioning. Sudden cardiac arrest is the sudden, unexpected loss of heart function, breathing and consciousness. Without immediate medical attention, you can die of sudden cardiac arrest in minutes.

    You can also go into cardiac arrest during surgical procedures, usually related to changes in blood pressure caused by anesthesia.

  • Heart failure. The increased pressure in your heart can cause your heart muscle to weaken, making it harder for your heart to pump blood. Eventually, this can lead to heart failure.
  • Coughing up blood. Increased pressure in the lungs and problems with your blood caused by Eisenmenger syndrome can cause life-threatening bleeding into your lungs and airways. This can cause you to cough up blood and further lower your blood oxygen level. Bleeding can also occur in other parts of the body.
  • Stroke. If a blood clot travels from the right to left side of the heart without being filtered out by your lungs, the clot may then block a blood vessel in the brain, leading to a stroke.
  • Kidney problems. Low oxygen levels in your blood may lead to problems with your kidneys. Eisenmenger syndrome can also increase your risk of developing gout.
  • Increased risk of infection. People with Eisenmenger syndrome have a higher risk of infection in the heart (endocarditis).
  • Pregnancy risks. Due to the demands pregnancy puts on a mother's heart and lungs, women who have Eisenmenger syndrome shouldn't become pregnant. Pregnancy for a woman who has Eisenmenger syndrome poses a high risk of death for both the mother and baby.

Eisenmenger syndrome is a life-threatening condition. The prognosis for people diagnosed with Eisenmenger syndrome depends on the type of congenital heart defect and other medical conditions. Some people diagnosed with Eisenmenger syndrome have survived into their 50s, 60s or even longer.

Eisenmenger syndrome care at Mayo Clinic

Dec. 05, 2020
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