---
title: Transposition of the great arteries
description: What transposition of the great arteries is, why a baby with this defect turns blue right after birth, how it is found, how it is operated on, how adults are followed up after surgery and when urgent help is needed.
type: disease
aliases:
  - TGA
  - d-TGA
  - Transposition of the great vessels
sources:
  - tier: guideline
    org: minzdrav-rf
    title: Транспозиция магистральных артерий
    year: 2024
    url: https://cr.minzdrav.gov.ru/view-cr/807_1
  - 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: Transposition of the Great Arteries (TGA)
    year: 2023
    url: https://www.msdmanuals.com/professional/pediatrics/congenital-cardiovascular-anomalies/transposition-of-the-great-arteries-tga
sources_checked: 2026-10-12
review: null
---

Transposition of the great arteries (TGA) is a congenital heart defect in which the two main arteries leave the heart the "wrong way round": the aorta arises from the right ventricle and the pulmonary artery from the left.<Cite n={[1, 2, 3]} /> The atria are connected to their usual ventricles.<Cite n={[1, 2]} />

Because of this, the two circulations do not work one after the other, as they normally do, but in parallel: oxygen-poor blood goes back to the body, and oxygen-rich blood goes back to the lungs.<Cite n={[1, 3]} /> A baby can survive only while blood from the two circulations mixes through openings in the heart or vessels: most often through an opening between the atria or a [patent ductus arteriosus](../patent-ductus-arteriosus/), less often through a [ventricular septal defect](../ventricular-septal-defect/).<Cite n={[1, 3]} />

<Diagram name="transposition-of-the-great-arteries">
  <p slot="normal">
    Normally the two circulations run one after the other, not in parallel: the right ventricle
    sends oxygen-poor blood through the pulmonary artery to the lungs, and the left ventricle sends
    oxygen-rich blood through the aorta to the body.<Cite n={1} />
  </p>
  <p slot="disease">
    In transposition the aorta arises from the right ventricle and the pulmonary artery from the
    left.<Cite n={[1, 2, 3]} /> Each circulation loops back on itself: oxygen-poor blood goes back
    to the body, and oxygen-rich blood goes back to the lungs.<Cite n={[1, 3]} /> A small amount of
    blood mixes through an opening between the atria and through the open ductus
    arteriosus.<Cite n={[1, 3]} />
  </p>
</Diagram>

## Why it happens

<Patient>

The defect forms while the heart develops before birth; its cause is unknown.<Cite n={2} /> While the baby is in the womb, the defect does not disturb the circulation, but right after birth it becomes life-threatening: the blood going to the body carries too little oxygen.<Cite n={1} />

Usually little blood mixes, especially if the opening between the atria is small, so the lack of oxygen is severe.<Cite n={1} /> If there is a large ventricular septal defect, the baby is less blue, but heart failure and pulmonary hypertension develop early.<Cite n={1} />

According to the ESC, boys are affected about twice as often as girls.<Cite n={2} /> According to the Russian Ministry of Health guideline, the defect is more common in babies whose mothers have diabetes.<Cite n={1} />

</Patient>

<Student>

TGA is a conotruncal anomaly characterised by atrioventricular concordance and ventriculo-arterial discordance.<Cite n={[1, 2]} /> It is the most common cyanotic congenital heart disease (CHD) after [tetralogy of Fallot](../tetralogy-of-fallot/); according to the Russian Ministry of Health guideline, it accounts for 2.5–5% of all CHD.<Cite n={1} /> This article is about dextro-transposition (d-TGA); congenitally corrected transposition (l-TGA), in which the ventricles are also inverted, is a separate defect.<Cite n={3} />

In the ESC classification, TGA is called simple in the absence of associated anomalies and complex when they are present: ventricular septal defect (VSD, 45%), left ventricular outflow tract obstruction (25%) and coarctation of the aorta (5%); long-term outcome of complex TGA is worse regardless of the type of surgical repair.<Cite n={2} /> The degree of hypoxaemia depends on the size of the communications between the circulations and the amount of mixing.<Cite n={1} />

</Student>

## Symptoms

<Patient>

A baby with TGA is unwell from birth.<Cite n={1} /> The main sign is blueness (cyanosis), which hardly improves when the baby breathes oxygen.<Cite n={1} /> Severe cyanosis appears within hours of birth, and soon the lack of oxygen in the tissues leads to acidosis, a shift in the acidity of the blood.<Cite n={3} /> When the ductus arteriosus closes, the baby becomes even more unwell.<Cite n={1} />

If the baby has a moderate or large [atrial septal defect](../atrial-septal-defect/), a large ventricular septal defect or a patent ductus arteriosus, the blueness is usually milder, but signs of heart failure may appear in the first weeks of life: fast breathing, breathlessness, a fast pulse, sweating and poor weight gain.<Cite n={3} />

Adults who have had surgery may develop heart failure and heart rhythm problems, which are felt as skipped beats and palpitations.<Cite n={1} />

</Patient>

<Student>

Apart from generalised cyanosis, the physical examination is rather unremarkable: murmurs may be absent unless associated anomalies are present, and the second heart sound is single and loud.<Cite n={3} /> The Russian Ministry of Health guideline lists tachycardia, dyspnoea and hepatomegaly among the findings.<Cite n={1} />

</Student>

## How it is diagnosed

<Patient>

The defect may be found before birth. The baby is then delivered in a hospital with a neonatal intensive care unit close to a heart surgery centre.<Cite n={1} />

After birth, doctors measure the oxygen level in the blood (pulse oximetry) and the blood pressure on an arm and a leg to rule out [coarctation of the aorta](../coarctation-of-the-aorta/).<Cite n={1} /> The main test is a heart ultrasound (echocardiography): it is used to make the diagnosis and choose the treatment.<Cite n={[1, 3]} />

</Patient>

<Student>

The ECG is often normal in a newborn; right ventricular hypertrophy and right axis deviation appear later.<Cite n={[1, 3]} /> On the chest X-ray the cardiac shadow may have the classic egg-on-a-string appearance with a narrow upper mediastinum.<Cite n={3} /> The diagnosis is established by two-dimensional echocardiography with colour flow and Doppler studies; cardiac catheterisation is not usually needed for diagnosis but may be done for balloon atrial septostomy or to clarify complex coronary artery anatomy.<Cite n={3} />

In adults after an atrial switch, echocardiography is the first-line test, and cardiac MRI assesses systemic right ventricular function more reliably.<Cite n={2} /> After an arterial switch, CT is the preferred non-invasive technique for imaging the coronary arteries when stenosis is suspected.<Cite n={2} />

</Student>

## How it is treated

<Patient>

Without surgery, almost all children with TGA die in their first year of life.<Cite n={1} /> Before the operation, as soon as a drip line is in place, the newborn is given a medicine from the prostaglandin group into a vein to keep the ductus arteriosus open.<Cite n={[1, 3]} /> Sometimes a balloon atrial septostomy (Rashkind procedure) is done: a catheter with a balloon is used to widen the opening between the atria so that more blood mixes.<Cite n={[1, 3]} />

The main treatment is the arterial switch operation (Jatene operation): the aorta and pulmonary artery are cut and swapped over, and the coronary arteries are moved to the new aorta.<Cite n={3} /> According to the Russian Ministry of Health guideline, if there is no hole in the wall between the ventricles, the operation is done in the first 2–4 weeks of life, while the left ventricle can still pump blood to the body.<Cite n={1} /> According to the ESC, survival up to 30 years after this operation is excellent, more than 90% of those discharged from hospital, and most of them have no symptoms.<Cite n={2} />

Until the early 1980s, an atrial switch (the Mustard or Senning operation) was done instead: blood was redirected inside the atria.<Cite n={3} /> In adults who had this operation the right ventricle often weakens over time, and heart rhythm problems and narrowing of the channels inside the atria occur; according to the ESC, 60–75% survive over follow-up of up to 40 years.<Cite n={[2, 3]} />

Everyone who has had surgery for TGA needs lifelong follow-up by a cardiologist in a specialised congenital heart disease centre, at least once a year.<Cite n={[1, 2]} /> The doctor decides which treatment each person needs.

</Patient>

<Student>

Prostaglandins are given to all newborns with TGA as soon as venous access is established.<Cite n={1} /> If the foramen ovale is small they can make things worse, so they are used with caution and close monitoring.<Cite n={3} /> The Russian Ministry of Health guideline recommends balloon atrial septostomy in the first days of life for newborns with an intact ventricular septum, to prevent the atrial communication from becoming restrictive.<Cite n={1} />

Patients with TGA, VSD and pulmonary stenosis often have a Rastelli-type repair: the VSD patch directs blood from the left ventricle to the aorta, and the right ventricle is connected to the pulmonary artery with a valved conduit.<Cite n={2} /> Replacement of the conduit is the most common reason for reoperation, and most patients eventually need repeat interventions.<Cite n={2} />

Late complications of the arterial switch are neo-aortic root dilatation with aortic regurgitation, supravalvular pulmonary stenosis and pulmonary branch stenosis; less often, left ventricular dysfunction and ventricular arrhythmias, which may be related to problems with the coronary arteries.<Cite n={[1, 2]} /> After an atrial switch, typical problems are systemic right ventricular dysfunction, tricuspid regurgitation, bradycardia with loss of sinus rhythm, atrial flutter and baffle stenosis.<Cite n={[1, 2]} /> The ESC lists heart failure and sudden death, probably caused by arrhythmia, among the causes of death after an atrial switch.<Cite n={2} /> Conventional heart failure medication has not been shown to benefit patients with a systemic right ventricle; in overt heart failure, diuretics relieve symptoms.<Cite n={[1, 2]} /> A permanent pacemaker is recommended for complete heart block, and an implantable cardioverter-defibrillator for life-threatening arrhythmias.<Cite n={1} />

</Student>

## When to call an ambulance

TGA is life-threatening right after birth.<Cite n={1} /> If a newborn turns blue, especially in the first hours and days of life, call your local emergency number (112 in the EU, 911 in the US and Canada, 999 in the UK).<Cite n={[1, 3]} /> Do not wait to see whether the blueness goes away: with this defect it does not, and when the ductus arteriosus closes the baby gets worse.<Cite n={1} />

Adults who have had surgery should not put off seeing a cardiologist if they notice skipped beats or palpitations: these may be signs of a heart rhythm problem.<Cite n={1} />

<Quiz />