Congenitally Corrected Transposition of the Great Arteries (ccTGA)
Information for teenagers and adults with congenitally corrected transposition
Congenitally corrected transposition of the great arteries (ccTGA) is a rare congenital heart condition in which both the connections between the heart’s chambers and the connections between the heart and the major arteries are reversed.
This unusual arrangement means that blood still travels in the correct direction — to the lungs to collect oxygen and then around the body — which is why the condition is described as “corrected.”
However, the two ventricles have effectively swapped jobs. The right ventricle pumps blood around the body, while the left ventricle pumps blood to the lungs.
The right ventricle was not originally designed to pump against the higher pressure of the body’s circulation for an entire lifetime. This is one of the main reasons why people with ccTGA require lifelong follow-up with a cardiologist experienced in adult congenital heart disease.
How is the heart arranged in ccTGA?
In a normal heart:
The right atrium connects to the right ventricle, which pumps blood to the lungs.
The left atrium connects to the left ventricle, which pumps blood through the aorta to the body.
In ccTGA, these connections are reversed twice.
Blood returning from the body enters the right atrium but then passes into the left ventricle, which pumps it to the lungs.
Oxygen-rich blood returning from the lungs enters the left atrium but passes into the right ventricle, which pumps it through the aorta and around the body.
Because there are two reversed connections, the circulation is physiologically “corrected” and oxygen-rich blood still reaches the body.
For this reason, some people with ccTGA can remain well for many years and occasionally the condition is not discovered until adulthood.
What is a systemic right ventricle?
In ccTGA, the right ventricle is responsible for pumping blood through the aorta to the entire body. It is therefore called the systemic right ventricle.
The right ventricle normally pumps blood into the relatively low-pressure circulation of the lungs. In ccTGA, it must instead generate the higher pressure required to supply the body.
Many systemic right ventricles function very well for decades. In some people, however, the right ventricle gradually enlarges or becomes weaker over time.
Monitoring the function of the systemic right ventricle is therefore an important part of lifelong follow-up.
What happens to the tricuspid valve?
The valve associated with the systemic right ventricle is the tricuspid valve.
In ccTGA, this valve sits on the left side of the heart and is exposed to the higher pressure of the body’s circulation.
The tricuspid valve is also frequently shaped differently in people with ccTGA and may sometimes have features similar to an Ebstein anomaly.
Over time, the valve can begin to leak. This is called tricuspid regurgitation.
Significant tricuspid regurgitation places additional volume load on the systemic right ventricle and can contribute to progressive enlargement and reduced function.
For this reason, your cardiologist will pay particular attention to both the systemic right ventricle and the tricuspid valve.
In some people with severe tricuspid regurgitation, valve surgery may be recommended before systemic right ventricular function deteriorates significantly.
Are other heart abnormalities common?
Yes.
Many people with ccTGA have additional congenital heart abnormalities. These may include:
Ventricular septal defect (VSD)
Pulmonary stenosis or obstruction beneath the pulmonary valve
Abnormalities of the tricuspid valve
Less commonly, other abnormalities of the heart valves or great arteries
Some people therefore require surgery during childhood, while others have an isolated ccTGA circulation and may never require childhood surgery.
Your long-term follow-up depends partly on your individual anatomy and any previous operations.
Heart block and pacemakers
The electrical wiring of the heart is arranged differently in ccTGA.
This creates an increased risk of developing heart block, where electrical signals from the upper chambers of the heart do not conduct normally to the ventricles.
Heart block can be present from birth or develop gradually later in life.
For this reason, your heart rhythm is usually checked during routine follow-up.
If significant heart block develops, a pacemaker may be required.
Because pacing can affect how the ventricles contract, the type and position of a pacemaker are particularly important in people with ccTGA. In some situations, more specialised pacing techniques may be considered to help preserve heart function.
Other abnormal heart rhythms
People with ccTGA can also develop other abnormal heart rhythms, particularly as they get older or if they have undergone previous heart surgery.
These can include rhythms arising from the upper chambers of the heart, such as atrial flutter or atrial fibrillation, as well as less common ventricular arrhythmias.
Tell your cardiologist if you develop new palpitations, dizziness, fainting or an unexplained deterioration in exercise capacity.
Does everyone with ccTGA develop heart failure?
No.
There is considerable variation between individuals. Some people maintain excellent systemic right ventricular function and remain active and well into later adult life.
Others gradually develop systemic right ventricular dysfunction or significant tricuspid regurgitation.
This progression is often slow and may initially occur without obvious symptoms.
Regular surveillance allows changes in ventricular function, valve function and exercise capacity to be identified before they become advanced.
How is systemic right ventricular dysfunction treated?
Treatment is individualised.
Medications commonly used to treat other forms of heart failure may sometimes be used when systemic right ventricular function is reduced, particularly when symptoms are present. However, the evidence for these medications in people with a systemic right ventricle is less extensive than it is for people with a conventional left ventricle.
Treatment may also involve:
Managing high blood pressure and other cardiovascular risk factors
Treating abnormal heart rhythms
Treating significant tricuspid regurgitation
Optimising pacemaker or cardiac resynchronisation therapy when appropriate
Using diuretics if fluid retention develops
People with advanced systemic right ventricular failure may require assessment through a specialist advanced heart failure and congenital heart disease service.
What operations are used for ccTGA?
The treatment of ccTGA varies considerably because the anatomy differs between individuals.
Some people never require surgery.
Others may have surgery to repair associated abnormalities such as a VSD or pulmonary stenosis.
In selected children and younger patients, a more complex operation known as a double-switch procedure may be performed. This redirects blood flow so that the left ventricle becomes the ventricle pumping blood to the body.
Whether this operation is appropriate depends on age, anatomy, ventricular pressures and previous treatment. It is generally not an operation that can simply be performed later in adulthood in someone whose left ventricle has spent many years pumping to the low-pressure lung circulation.
Adults with ccTGA therefore require individual assessment rather than a single standard surgical approach.
How to stay well
Keep up with your congenital heart checks
People with ccTGA should generally have lifelong follow-up with an adult congenital heart disease specialist, even when they feel completely well.
Your cardiologist will monitor:
Systemic right ventricular size and function
Tricuspid valve regurgitation
Heart rhythm and electrical conduction
Exercise capacity
Any associated congenital heart abnormalities
Previous surgical repairs or devices
The frequency of review depends on your individual condition.
Stay active
Regular physical activity is beneficial for most people with ccTGA.
The amount and intensity of exercise that is appropriate depends on systemic right ventricular function, tricuspid regurgitation, heart rhythm and any associated abnormalities.
People with good ventricular function and no important rhythm problems may be able to exercise with few restrictions.
If you are considering competitive sport, very high-intensity exercise or heavy resistance training, discuss this with your congenital cardiologist.
Look after your teeth
Good dental hygiene and regular dental care are important.
Most people with ccTGA do not automatically require antibiotics before dental procedures.
Antibiotic prophylaxis is recommended for certain higher-risk people, including those with some prosthetic valves or material, previous infective endocarditis, or particular residual defects.
Your cardiologist or dentist can tell you whether this applies to you.
Don’t smoke or vape
Avoid smoking and vaping. Maintaining a healthy weight, blood pressure and cholesterol is also important, as acquired cardiovascular disease places additional workload on the systemic right ventricle.
Pregnancy
Many women with ccTGA can have successful pregnancies, but the risk varies considerably between individuals.
Pregnancy increases the amount of blood the heart needs to pump and therefore places additional workload on the systemic right ventricle.
Pregnancy risk is higher when there is:
Reduced systemic right ventricular function
Significant tricuspid regurgitation
A history of heart failure
Important abnormal heart rhythms
Significant associated congenital heart disease
Women with ccTGA should ideally have specialist pre-pregnancy assessment with a cardiologist experienced in congenital heart disease and pregnancy.
This allows systemic right ventricular function, tricuspid valve function, medications and rhythm history to be reviewed before pregnancy.
Symptoms to tell your doctor about
Contact your doctor or congenital cardiology team if you develop:
New or increasing shortness of breath
A noticeable reduction in exercise capacity
Frequent or prolonged palpitations
Unusually slow heart rates
Dizziness or near-fainting
New swelling of your ankles or abdomen
Unexplained weight gain from fluid retention
Increasing fatigue
A significant change in your usual symptoms
Because changes in systemic right ventricular function can occur gradually, a persistent reduction in exercise capacity is worth discussing even if you otherwise feel well.
Emergency — get help immediately if
Seek urgent medical attention or call 000 if you develop:
Fainting or loss of consciousness
Severe or rapidly worsening shortness of breath
A sustained rapid or very slow heartbeat associated with dizziness or feeling unwell
Severe chest pain
Sudden severe palpitations associated with fainting or near-fainting
A sudden significant deterioration in your condition
Your regular check-ups
Follow-up for ccTGA may include:
Clinical review
Your cardiologist will ask about exercise capacity, breathlessness, palpitations, dizziness and fluid retention and examine your heart and circulation.
ECG
An electrocardiogram is particularly important in ccTGA because of the risk of progressive heart block and other rhythm abnormalities.
Echocardiogram
An ultrasound assesses systemic right ventricular function, tricuspid regurgitation and other associated heart abnormalities.
Cardiac MRI
Cardiac MRI is particularly useful in ccTGA because it provides detailed and reproducible measurements of systemic right ventricular size and function and can assess blood flow and associated anatomy.
Heart rhythm monitoring
A Holter or longer-term rhythm monitor may be used to look for heart block or abnormal heart rhythms, particularly if you experience palpitations, dizziness or fainting.
Exercise testing
Cardiopulmonary exercise testing can objectively measure exercise capacity and may identify changes that are not yet obvious during everyday activities.
Questions for your doctor
How well is my systemic right ventricle functioning?
Do I have significant tricuspid valve leakage?
Do I have any associated heart defects?
Am I at risk of developing heart block or needing a pacemaker?
Do I need any heart failure medications?
Are there any restrictions on my exercise or sport?
How often should I have an echocardiogram or cardiac MRI?
Is pregnancy safe for me, and should I have specialist assessment beforehand?
What symptoms should prompt me to contact my congenital heart team?
This information is intended as a general guide for teenagers and adults with congenitally corrected transposition of the great arteries. ccTGA varies considerably between individuals, and your congenital cardiologist can provide advice specific to your anatomy, systemic right ventricular function, previous treatment and current health.
