In tricuspid atresia, blood can't flow from the right atrium to the right ventricle because the valve between them is missing. This condition often includes a smaller than normal right ventricle, as well as an atrial septal defect and, in some cases, a ventricular septal defect.
Tricuspid atresia is a heart defect present at birth (congenital) in which a valve (tricuspid valve) between two of the heart's chambers isn't formed. Instead, there's solid tissue between the chambers, which restricts blood flow and causes the right lower heart chamber (ventricle) to be underdeveloped.
A baby, child or adult with tricuspid atresia can't get enough oxygen through its body. People with this condition tire easily, are often short of breath and have blue-tinged skin.
Tricuspid atresia is treated with multiple surgeries. Most babies with tricuspid atresia who have surgery live well into adulthood, though follow-up surgeries are often needed.
Tricuspid atresia symptoms become evident soon after birth, and can include:
- Blue tinge to the skin and lips (cyanosis)
- Difficulty breathing
- Tiring easily, especially during feedings
- Slow growth and poor weight gain
Some babies or older people with tricuspid atresia also develop symptoms of heart failure, including:
- Fatigue and weakness
- Shortness of breath
- Swelling (edema) in the legs, ankles and feet
- Swelling of the abdomen (ascites)
- Sudden weight gain from fluid retention
When to see a doctor
Tell your doctor if you notice any of the above symptoms in yourself or your child.
Tricuspid atresia occurs during fetal heart development. Some genetic factors, such as Down syndrome, might increase your baby's risk of congenital heart defects such as tricuspid atresia, but the cause of congenital heart disease is usually unknown.
How the heart works
Chambers and valves of the heart
A normal heart has two upper (receiving) and two lower (pumping) chambers. The upper chambers, the right and left atria, receive incoming blood. The lower chambers, the more muscular right and left ventricles, pump blood out of your heart. The heart valves, which keep blood flowing in the correct direction, are gates at the chamber openings (for the tricuspid and mitral valves) and exits (for the pulmonary and aortic valves).
Your heart is divided into four chambers — the right atrium and right ventricle and left atrium and left ventricle. The right side of the heart moves blood to the lungs, where it picks up oxygen before it circulates to your heart's left side. The left side pumps blood into a large vessel called the aorta, which circulates the oxygen-rich blood to the rest of your body.
Valves control the flow of blood into and out of your heart. These valves open to allow blood to move to the next chamber or one of the arteries, and they close to keep blood from flowing backward.
When things go wrong
In tricuspid atresia, the right side of the heart can't pump enough blood to the lungs because the tricuspid valve is missing. A sheet of tissue blocks the flow of blood from the right atrium to the right ventricle. As a result, the right ventricle is usually small and underdeveloped (hypoplastic).
Blood instead flows from the right atrium to the left atrium through a hole in the wall between them (septum). This hole is either a heart defect (atrial septal defect) or an enlarged natural opening that's supposed to close soon after birth (patent foramen ovale or patent ductus arteriosus). A baby with tricuspid atresia might need medication to keep the natural opening from closing after birth or surgery to create an opening.
Many babies born with tricuspid atresia have a hole between the ventricles (ventricular septal defect). In these cases, some blood can flow through the hole between the left ventricle and the right ventricle, and then blood is pumped to the lungs through the pulmonary artery.
However, the valve between the right ventricle and the pulmonary artery (pulmonary valve) might be narrowed, which can reduce blood flow to the lungs. If the pulmonary valve isn't narrowed and if the ventricular septal defect is large, too much blood can flow to the lungs, which can lead to heart failure.
Some babies may have other heart defects as well.
In most cases, the cause of a congenital heart defect, such as tricuspid atresia, is unknown. However, several factors might increase the risk of a baby being born with a congenital heart defect, including:
- A mother who had German measles (rubella) or another viral illness during early pregnancy
- A parent who has a congenital heart defect
- Older parental age at conception
- Mother's obesity
- Drinking alcohol during pregnancy
- Smoking before or during pregnancy
- A mother who has poorly controlled diabetes
- Use of some types of medications during pregnancy, such as the acne drug isotretinoin (Claravis, Amnesteem, others), some anti-seizure medications and some bipolar disorder medications
- The presence of Down syndrome, a genetic condition that results from an extra 21st chromosome
A life-threatening complication of tricuspid atresia is a lack of oxygen to your baby's tissues (hypoxemia).
Complications later in life
Although treatment greatly improves the outcome for babies with tricuspid atresia, complications can develop later in life, including:
- Formation of blood clots that can lead to a clot blocking an artery in the lungs (pulmonary embolism) or cause a stroke
- Easy tiring when participating in activity or exercise
- Heart rhythm abnormalities (arrhythmias)
- Kidney or liver disease
Congenital heart defects such as tricuspid atresia usually aren't preventable. If you have a family history of heart defects or a child with a congenital heart defect, a genetic counselor and a cardiologist experienced in congenital heart defects can help you look at risks associated with future pregnancies.
Some steps you can take that might reduce your baby's risk of heart and other birth defects in pregnancy include:
- Get adequate folic acid. Take 400 micrograms of folic acid daily. This amount, which is often in prenatal vitamins, has been shown to reduce brain and spinal cord defects, and folic acid may help prevent heart defects, too.
- Talk with your doctor about medication use. Whether you're taking prescription or over-the-counter drugs, an herbal product or a dietary supplement, check with your doctor before using them during pregnancy.
- Avoid smoking or drinking alcohol during pregnancy. Either can increase the risk of congenital heart defects.
- Avoid chemical exposure, whenever possible. While you're pregnant, it's best to stay away from chemicals, including cleaning products and paint, as much as you can.