---
title: Eisenmenger syndrome
description: What Eisenmenger syndrome is, why blood starts to flow from right to left through a large unrepaired heart defect, how it is diagnosed, which treatment approaches clinical guidelines describe and when to call an ambulance.
type: disease
aliases:
  - Eisenmenger
  - Eisenmenger physiology
sources:
  - tier: guideline
    org: minzdrav-rf
    title: Дефект межжелудочковой перегородки
    year: 2024
    url: https://cr.minzdrav.gov.ru/view-cr/806_1
  - tier: guideline
    org: minzdrav-rf
    title: Легочная гипертензия, в том числе хроническая тромбоэмболическая легочная гипертензия
    year: 2024
    doi: 10.15829/1560-4071-2024-6161
    url: https://doi.org/10.15829/1560-4071-2024-6161
  - tier: guideline
    org: esc
    title: 2022 ESC/ERS Guidelines for the diagnosis and treatment of pulmonary hypertension
    year: 2022
    doi: 10.1183/13993003.00879-2022
    url: https://doi.org/10.1183/13993003.00879-2022
  - tier: guideline
    org: esc
    title: 2020 ESC Guidelines for the management of adult congenital heart disease
    year: 2020
    doi: 10.1093/eurheartj/ehaa554
    url: https://doi.org/10.1093/eurheartj/ehaa554
  - tier: reference
    org: msd-manuals
    title: Eisenmenger Syndrome
    year: 2024
    url: https://www.msdmanuals.com/professional/pediatrics/congenital-cardiovascular-anomalies/eisenmenger-syndrome
sources_checked: 2026-10-13
review: null
---

Eisenmenger syndrome is an advanced, severe form of [pulmonary hypertension](../pulmonary-hypertension/) in congenital heart disease.<Cite n={3} /> The pressure in the lung vessels rises to the level of the systemic circulation, and blood flows through a defect between the ventricles, the atria or the great arteries from right to left or in both directions.<Cite n={1} />

The syndrome develops when a large defect with a left-to-right shunt is not repaired in time.<Cite n={[3, 5]} /> Most often it is a [ventricular septal defect](../ventricular-septal-defect/); less often an atrioventricular septal defect, a [patent ductus arteriosus](../patent-ductus-arteriosus/), an [atrial septal defect](../atrial-septal-defect/) or another defect.<Cite n={5} />

<Diagram name="eisenmenger-syndrome">
  <p slot="normal">
    Normally the septum between the ventricles is intact, no blood is shunted between them, and the
    walls of the small lung arteries are thin.<Cite n={[1, 2]} />
  </p>
  <p slot="disease">
    In Eisenmenger syndrome there is a large defect in the septum. At first blood flowed through it
    from left to right and overloaded the lung vessels; over time the walls of the pulmonary arteries
    and arterioles thicken, the resistance of the lung vessels and the pulmonary artery pressure rise, and the
    shunt becomes bidirectional or right-to-left.<Cite n={[1, 2]} /> Oxygen-poor blood enters
    the systemic circulation, so mixed blood reaches the organs and cyanosis
    appears.<Cite n={[3, 5]} />
  </p>
</Diagram>

## Why it happens

<Patient>

With a large defect between the left and right sides of the heart, or between the aorta and the <Structure id="pulmonary-trunk">pulmonary artery</Structure>, blood at first flows from left to right and the lung vessels receive extra blood.<Cite n={[1, 5]} /> If this overload lasts a long time, the resistance of the lung vessels and the pressure in the pulmonary artery rise, and the left-to-right shunt gets smaller.<Cite n={1} /> When the pressure in the lungs becomes very high, blood starts to flow through the defect in both directions and then from right to left.<Cite n={[1, 5]} /> Once the syndrome has developed, the high resistance of the lung vessels and pulmonary hypertension can no longer be reversed.<Cite n={5} />

Repairing the defect at the right age can prevent the syndrome.<Cite n={5} /> People with congenital heart disease and Down syndrome are at higher risk of Eisenmenger syndrome.<Cite n={3} />

</Patient>

<Student>

In the ESC/ERS classification, Eisenmenger syndrome is the first of four groups of pulmonary arterial hypertension (PAH) associated with congenital heart disease (CHD).<Cite n={[1, 3]} /> It includes large defects that begin as systemic-to-pulmonary shunts and progress to severely elevated pulmonary vascular resistance (PVR) and to reversed or bidirectional shunting.<Cite n={3} />

The key mechanism is endothelial dysfunction; the initiating factors are increased pulmonary blood flow, raised pressure and shear stress.<Cite n={1} /> Early medial and intimal hypertrophy is potentially reversible; as the disease progresses, usually in adulthood, irreversible plexiform lesions and arteritis develop.<Cite n={1} /> The right-to-left shunt unloads the <Structure id="right-ventricle">right ventricle</Structure>, sustaining cardiac output at the expense of hypoxaemia and cyanosis.<Cite n={3} />

With pre-tricuspid shunts (ASD, partial anomalous pulmonary venous return) symptoms usually appear at age 20 to 40; with unrepaired post-tricuspid shunts (VSD, PDA, more complex CHD) irreversible, symptomatic pulmonary vascular disease may develop within the first few years of life.<Cite n={5} />

</Student>

<HeartModel highlight={['interventricular-septum', 'pulmonary-trunk', 'right-ventricle']} />

## Symptoms

<Patient>

Eisenmenger syndrome affects the whole body: a constant shortage of oxygen in the blood harms many organs.<Cite n={[1, 3]} /> The main signs are a bluish colour of the skin and lips (cyanosis), breathlessness, tiredness and fainting.<Cite n={[1, 3]} /> Chest pain, palpitations and coughing up blood also occur, and in late stages signs of right ventricular failure.<Cite n={[1, 5]} /> Strokes, brain abscess and sudden death are possible.<Cite n={3} />

The tips of the fingers and toes may become thickened and rounded (clubbing).<Cite n={[4, 5]} /> If the cause is a patent ductus arteriosus, mainly the legs turn blue, sometimes the left arm too, while the rest of the upper body may keep its normal colour.<Cite n={[2, 4]} />

</Patient>

<Student>

Central cyanosis results from an increased amount of reduced haemoglobin; clubbing is typical and scoliosis is frequent.<Cite n={4} /> Secondary erythrocytosis is the physiological response to chronic hypoxaemia.<Cite n={4} />

On auscultation the second heart sound is loud and single, and a pulmonary ejection click is common.<Cite n={5} /> With a large defect the shunt murmur may be absent, because with severe PH there is no or only a minimal pressure gradient across the defect.<Cite n={2} />

Late complications in adults with cyanotic CHD, including Eisenmenger syndrome, according to ESC: haemoptysis (the most common major bleeding event), laminated thrombi in dilated pulmonary arteries, cerebral infarctions, endocarditis, brain abscess, arrhythmias, renal dysfunction, gallstones and gout.<Cite n={4} />

</Student>

## How it is diagnosed

<Patient>

The syndrome is suspected when a person has an unrepaired heart defect; a chest X-ray and an ECG support the suspicion, and an ultrasound scan of the heart (echocardiography) with Doppler confirms the diagnosis.<Cite n={5} /> Blood oxygen saturation is measured with a pulse oximeter at rest for at least 5 minutes, and exercise capacity is checked regularly, preferably with a 6-minute walk test.<Cite n={4} /> With a patent ductus arteriosus, saturation is measured on both the arms and the legs.<Cite n={4} />

Blood tests also check iron stores: almost half of patients are iron deficient.<Cite n={2} /> Right heart catheterisation is needed to confirm pulmonary hypertension, but according to ESC, in Eisenmenger syndrome it is used more sparingly: when important decisions depend on it.<Cite n={[3, 4]} />

</Patient>

<Student>

The work-up of PAH associated with CHD includes medical history, physical examination, pulmonary function tests, arterial blood gases, imaging (especially echocardiography), and exercise and laboratory testing; right heart catheterisation with compartmental oximetry is required to confirm PAH, and PVR may be overestimated because of erythrocytosis.<Cite n={3} />

The chest X-ray usually shows prominent central pulmonary arteries, peripheral pulmonary vessel pruning and right heart enlargement; the ECG shows right ventricular hypertrophy, right axis deviation and occasionally right atrial enlargement.<Cite n={5} />

In a multicentre study, mortality in adults with Eisenmenger syndrome was predicted by a pre-tricuspid shunt, advancing age, low resting oxygen saturation, absence of sinus rhythm and pericardial effusion.<Cite n={[3, 4]} />

</Student>

## How it is treated

<Patient>

Clinical guidelines call closing the defect in Eisenmenger syndrome contraindicated or do not recommend it.<Cite n={[1, 2, 3, 4]} /> Patients are followed up by specialists in adult congenital heart disease and pulmonary hypertension; patient education, lifestyle changes, and social and psychological support are important.<Cite n={[3, 4]} />

Drug treatment uses medicines for pulmonary arterial hypertension: endothelin receptor antagonists, phosphodiesterase-5 inhibitors, prostacyclin analogues and others.<Cite n={[2, 3, 5]} /> They improve exercise capacity; their effect on survival is less well documented.<Cite n={[3, 4, 5]} /> The extra red blood cells are an adaptation to the lack of oxygen, so routine bloodletting is not recommended, and iron deficiency is corrected.<Cite n={[2, 3, 4]} /> Oxygen should be considered if it consistently raises blood oxygen saturation and eases symptoms; it has not been shown to prolong life.<Cite n={[2, 3]} /> Not everyone needs anticoagulants (medicines against blood clots): the risk of clots is weighed against the risk of bleeding in the lungs.<Cite n={[4, 5]} /> If medicines do not help, a lung transplant with repair of the defect or a heart–lung transplant is considered, but donor organs are scarce.<Cite n={[1, 3, 4]} />

The guidelines advise avoiding dehydration, smoking, recreational drugs and excessive alcohol, strenuous exercise, sudden exposure to heat (sauna, hot tub or hot shower) or extreme cold, and rapid ascent to altitudes above 2500 m, and getting vaccinated against influenza and pneumococcal infection.<Cite n={[3, 4, 5]} /> Only essential operations are done, and in a specialised centre; with cyanosis, endocarditis prophylaxis is needed.<Cite n={[3, 5]} /> The guidelines consider pregnancy in Eisenmenger syndrome contraindicated or advise against it because of high maternal mortality and complications for the baby, so reliable contraception is needed.<Cite n={[1, 3]} /> The method of contraception is chosen together with the doctor.<Cite n={4} /> The doctor decides which treatment each person needs.

According to the Russian Ministry of Health guideline, survival in Eisenmenger syndrome is better than in idiopathic PAH of the same functional class but worse than in people without the disease; many patients live into their third or fourth decade, and some into their seventh.<Cite n={1} /> According to ESC/ERS, however, the prognosis is not as favourable as previously thought.<Cite n={3} />

</Patient>

<Student>

ESC/ERS: defect closure is contraindicated in all patients with Eisenmenger syndrome.<Cite n={3} /> ESC 2020 does not recommend closure of a VSD, ASD or PDA, or repair of an atrioventricular septal defect, in patients with Eisenmenger physiology; the Russian Ministry of Health guidelines do not recommend radical surgical or endovascular repair in Eisenmenger syndrome.<Cite n={[1, 2, 4]} />

The Russian Ministry of Health guideline recommends PAH-specific therapy in Eisenmenger syndrome and prefers initial monotherapy, as there are no data on the effect of initial combination therapy on survival and PAH progression.<Cite n={2} /> If symptoms persist, ESC/ERS recommend a sequential, symptom-orientated strategy, starting with an oral endothelin receptor antagonist (or a PDE5 inhibitor) and escalating therapy.<Cite n={3} />

Secondary erythrocytosis is beneficial for oxygen transport and delivery; routine phlebotomy should be avoided whenever possible, and symptoms of hyperviscosity are approached first with appropriate hydration.<Cite n={[2, 3]} />

Heart–lung transplantation or lung transplantation with repair of the defect is an option in highly selected patients who do not respond to medical treatment; mortality is particularly high in the first year after surgery.<Cite n={3} />

</Student>

## When to call an ambulance

The condition can get worse with an arrhythmia, dehydration, bleeding, thromboembolism or a lung infection.<Cite n={3} /> If you cough up blood, call your local emergency number (112 in the EU, 911 in the US and Canada, 999 in the UK): haemoptysis is the most common major bleeding event in the syndrome, and it may be only the visible part of bleeding inside the lungs.<Cite n={4} />

Also call for sudden difficulty speaking or other neurological symptoms: strokes are common in Eisenmenger syndrome.<Cite n={[3, 4, 5]} /> Fever together with a new or different headache may be a sign of a brain abscess; this combination is also a reason to call an ambulance.<Cite n={[3, 4]} /> As with any heart condition, call your local emergency number (112 in the EU, 911 in the US and Canada, 999 in the UK) for fainting, chest pain or severe breathlessness: this is the site's general safety rule, repeated at the bottom of every page.

<Quiz />