Eisenmenger (I-sun-meng-ur) syndrome is a long-term complication of an unrepaired heart problem present at birth (congenital heart defect). Eisenmenger syndrome is life-threatening.

In Eisenmenger syndrome, there is irregular blood flow in the heart and lungs. This causes the blood vessels in the lungs to become stiff and narrow. Blood pressure rises in the lungs' arteries (pulmonary arterial hypertension). Eisenmenger syndrome permanently damages the blood vessels in the lungs.

Early diagnosis and repair of congenital heart defects usually prevents Eisenmenger syndrome. If it does develop, treatment involves regular medical visits and medications to improve symptoms.


Symptoms of Eisenmenger syndrome include:

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

When to see a doctor

If you have any symptoms of Eisenmenger syndrome, see your health care provider. Make an appointment even if you have never been diagnosed with a heart problem. Symptoms such as shortness of breath or chest pain require medical attention.


Eisenmenger syndrome is usually caused by an unrepaired hole (shunt) between the main blood vessels or chambers of the heart. A shunt is a heart problem present at birth (congenital heart defect).

To understand how Eisenmenger syndrome affects the heart and lungs, it's helpful to know how the heart typically works.

How the heart works

The heart is divided into chambers — two upper chambers (atria) and two lower chambers (ventricles).

  • The right side of the heart moves blood to the lungs through blood vessels (pulmonary arteries).
  • In the lungs, blood picks up oxygen and then returns to the left side of the heart through the pulmonary veins.
  • The left side of the heart then pumps the blood through the aorta and out to the rest of the body.

Heart valves control the flow of blood into and out of the chambers of the 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

Heart problems present at birth (congenital heart defects) that can cause Eisenmenger syndrome include:

  • Ventricular septal defect. This is the most common cause of Eisenmenger syndrome. There is a hole (shunt) in the wall of tissue that divides the right and left sides of the heart's main pumping chambers (ventricles).
  • Atrioventricular canal defect. This is 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 the heart also may not work properly.
  • Atrial septal defect. This is a hole in the wall of tissue that divides the right and left sides of the upper chambers of the heart (atria).
  • Patent ductus arteriosus. This 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 the body (aorta).

In any of these heart problems, blood flows in a way it usually doesn't. As a result, pressure rises in the pulmonary artery. Over time, the increased pressure damages the smaller blood vessels in the lungs. The damaged blood vessel walls make it difficult to pump blood to the lungs.

In Eisenmenger syndrome, there's increased blood pressure in the side of the heart that has oxygen-poor blood (blue blood). The blue blood goes through the hole (shunt) in the heart or blood vessels. Oxygen-rich and oxygen-poor blood now mix. This causes low blood oxygen levels.

Risk factors

A family history of congenital heart defects increases the risk of similar heart problems in a baby. If you've been diagnosed with Eisenmenger syndrome, talk to your health care provider about screening other family members for congenital heart defects.


Eisenmenger syndrome is a life-threatening condition. The outlook for people diagnosed with Eisenmenger syndrome depends on the specific cause and if there are other medical conditions.

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

  • Low blood oxygen levels. The reversed blood flow through the heart reduces oxygen to the body's tissues and organs. Without prompt treatment, the oxygen levels worsen over time.
  • Irregular heart rhythms (arrhythmias). Eisenmenger syndrome causes the heart walls to get bigger and thicker. It also causes oxygen levels to lower. These changes may cause irregular heart rhythms. Some arrhythmias increase the risk of blood clots that can cause heart attacks or strokes.
  • Sudden cardiac arrest. This is the sudden loss of heart activity due to an irregular heart rhythm. If not treated immediately, sudden cardiac arrest can quickly lead to death. Survival is possible with fast, appropriate medical care.
  • Heart failure. The increased pressure in the heart can cause the heart muscle to weaken. It becomes harder for the heart to pump blood.
  • Bleeding in the lungs. Eisenmenger syndrome can cause life-threatening bleeding in the lungs and airways. This can cause you to cough up blood and further lower your blood oxygen levels. 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, the clot may block a blood vessel in the brain, leading to a stroke.
  • Kidney problems. Low oxygen levels in the blood may lead to problems with the kidneys.
  • Gout. Eisenmenger syndrome can increase the risk of a type of arthritis called gout. Gout causes sudden, severe attacks of pain and swelling in one or more joints, usually the big toe.
  • Heart infection. People with Eisenmenger syndrome have a higher risk of a heart infection called endocarditis.
  • Pregnancy risks. During pregnancy, the heart and lungs have to work harder to support the growing baby. Because of this, pregnancy with Eisenmenger syndrome poses a high risk of death for both you and the baby. If you have Eisenmenger syndrome, talk to your care provider about your specific pregnancy risks.

Eisenmenger syndrome care at Mayo Clinic

Aug. 04, 2022
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