What Is Tetralogy of Fallot?
Tetralogy of Fallot is a common congenital heart disorder that is a combination of four different heart defects:
- There is a hole between the lower chambers of the heart (the "ventricles").
- The aorta (the main artery that carries blood from the heart) lies over the hole between the two lower chambers.
- There is an obstruction or narrowing of the pulmonary artery that goes from the heart to the lungs.
- The muscle of the lower right ventricle is thickened.
These problems result in lower blood oxygen levels. Some people with tetralogy of Fallot also have other heart problems such as a heart murmur.
What Are Symptoms of Tetralogy of Fallot?
Symptoms of tetralogy of Fallot in adults include:
- Exercise intolerance
- Heart palpitations
- A gradual decline in bodily functions
- Shortness of breath on exertion
- Lightheadedness/fainting
- Evidence of right-sided heart failure
- Irregular heartbeats
Symptoms of tetralogy of Fallot in infants include:
- Difficulty with feeding
- Failure to thrive
- Episodes of pale bluish skin, lips, and nails when crying or feeding, or when upset or agitated ("tet spells”), possibly with the baby going limp or unconscious
- Shortness of breath on exertion, usually worsening with age
What Causes Tetralogy of Fallot?
The cause of tetralogy of Fallot is a genetic defect that manifests in a fetus when the heart is developing.
How Is Tetralogy of Fallot Diagnosed?
Tetralogy of Fallot may be detected before a baby is born with an ultrasound.
Shortly after birth, tetralogy of Fallot may be diagnosed if:
- A baby has pale bluish skin, lips, and nails
- Pulse oximetry tests show the baby has low levels of oxygen in the blood
When the baby or child is older, tetralogy of Fallot may be diagnosed if:
- The child’s skin appears blue
- The baby has "tet spells,” in which the baby turns blue, and might go limp or unconscious
- The baby has a heart murmur
Imaging studies to diagnose tetralogy of Fallot include:
- Chest X-ray
- Echocardiograph
- Magnetic resonance imaging (MRI)
- Electrocardiogram (ECG)
- Cardiac catheterization
In adult patients, laboratory studies may be indicated:
- Complete blood cell count
- Coagulation profile
- Arterial blood gas
- Blood cultures
What Is the Treatment for Tetralogy of Fallot?
Most children with tetralogy of Fallot will need surgery to fix the heart problems, and the surgery is usually performed before a baby is 1 year old. Tetralogy of Fallot can cause problems if the heart is not fixed, however, corrective surgery performed in childhood for tetralogy of Fallot does not cure the condition.
A surgical procedure called pulmonary valve replacement is usually performed, typically while under cardiopulmonary bypass.
In some cases, the tetralogy of Fallot is not diagnosed in some people until they are adults. Adults with tetralogy of Fallot also need surgery.
What Are Complications of Tetralogy of Fallot?
If the tetralogy of Fallot is not treated surgically early on in life, a child may not develop properly due to low oxygen levels.
Complications of tetralogy of Fallot also include:
- Increased risk of bacterial infection of the inner lining of the heart or heart valve (infective endocarditis)
- Untreated cases may result in disability by adulthood or even death
Complications of corrective surgery for tetralogy of Fallot include:
