Atrioventricular Valvar Atresia

What is atrioventricular valvar atresia?

Atrioventricular valvar atresia is a rare heart condition that is present at birth (congenital). The heart has two atrioventricular valves: the tricuspid valve, which sits between the right upper chamber (right atrium) and the right lower chamber (right ventricle), and the mitral valve, which sits between the left upper chamber (left atrium) and the left lower chamber (left ventricle). Atresia means that a valve or opening did not form properly and is either completely closed or missing. In atrioventricular valvar atresia, one of these two valves has no working opening, so blood cannot pass directly from the upper chamber to the lower chamber on that side of the heart.

Doctors usually describe the condition by the valve that is affected. Tricuspid atresia is the more common form; the right ventricle is often small and underdeveloped because little or no blood flows into it before birth. Mitral atresia is less common and is often part of a broader group of problems on the left side of the heart in which the left ventricle is very small. Because only one lower chamber does most of the pumping work, both forms are considered types of single-ventricle heart disease.

For a baby to survive, blood must find another route. Before and shortly after birth, natural openings such as the foramen ovale (a small hole between the two upper chambers) and the ductus arteriosus (a blood vessel connecting the two main arteries) allow blood to mix and reach the lungs and body. Many babies with this condition also have a hole between the lower chambers, called a ventricular septal defect. These extra openings are the reason many newborns look reasonably well in the first hours of life, and they also explain why symptoms can appear suddenly when the openings begin to close.

Atrioventricular valvar atresia affects newborns and is usually recognized before birth or within the first days or weeks of life. It is a serious condition, but staged surgery has allowed many children to grow into adulthood. Care is typically shared between pediatric cardiologists and congenital heart surgeons; in Acibadem hospitals this falls under the Cardiovascular Surgery department working together with pediatric cardiology.

Atrioventricular valvar atresia symptoms

Symptoms depend on how much blood is able to reach the lungs and how much oxygen-poor blood mixes into the circulation. Common atrioventricular valvar atresia symptoms in newborns include:

• A blue or gray tint to the lips, tongue, skin, or nail beds (cyanosis), often noticed in the first days of life
• Fast or labored breathing, flaring of the nostrils, or grunting
• Tiring quickly or sweating during feeds
• Poor feeding and slow weight gain
• Unusual sleepiness or low energy
• A heart murmur (an extra sound heard with a stethoscope)
• Cool, pale, or mottled hands and feet
• Swelling of the abdomen, legs, or around the eyes if the heart starts to fail

The pattern of symptoms often differs by type. In many babies with tricuspid atresia, blood flow to the lungs is limited, so cyanosis is the leading sign and may worsen when the ductus arteriosus narrows in the first days of life. In babies whose lungs receive too much blood, for example when a large ventricular septal defect is present, rapid breathing, sweating, and feeding difficulty from heart failure (the heart cannot keep up with the body’s needs) may be more prominent than blueness. Mitral atresia with a small left ventricle can cause the baby to become gray, cold, and very unwell quickly if the ductus arteriosus closes, because the body then loses its main source of blood flow.

Older children and adults who have had staged surgery usually do not have the newborn symptoms above, but they may notice reduced stamina during exercise, mild cyanosis, palpitations from heart rhythm problems, or swelling. These late symptoms are discussed further in the outlook section.

Causes and risk factors

Atrioventricular valvar atresia causes are not fully understood. The heart forms during the first eight weeks of pregnancy, and the valves develop from small cushions of tissue that must separate and open at the right time. In this condition, that process does not complete, and the valve remains sealed or does not form at all. In most families no single cause can be identified.

Factors that researchers believe may contribute include:

• Genetic changes — some babies have chromosomal differences or single-gene variants that affect heart development, although many have no identifiable genetic cause
• Family history — having a parent or sibling with a congenital heart defect modestly increases the chance, though most affected babies have no family history
• Maternal health conditions during pregnancy, such as poorly controlled diabetes or certain viral infections, which are linked with congenital heart defects in general
• Exposures during early pregnancy, including some medications, alcohol, and smoking, which are associated with a higher overall risk of heart defects
• Association with other heart differences — the condition frequently occurs alongside a ventricular septal defect, transposition of the great arteries (the two main arteries arise from the wrong ventricles), or narrowing of the aorta

It is important to stress that in the majority of cases nothing a parent did or did not do caused the defect. Parents often ask this question, and doctors generally reassure them that these conditions arise from complex developmental events that are largely outside anyone’s control.

Atrioventricular valvar atresia diagnosis

Atrioventricular valvar atresia diagnosis often begins before birth. During a routine pregnancy ultrasound around the middle of pregnancy, the sonographer looks at the four chambers of the heart. If one lower chamber appears very small or a valve does not seem to open, the mother may be referred for a fetal echocardiogram, a detailed ultrasound of the baby’s heart performed by a specialist. A prenatal diagnosis lets the birth be planned at a center where the baby can be treated immediately.

After birth, doctors use several tools to confirm the condition and map the exact anatomy:

• Pulse oximetry — a painless sensor on the hand or foot that measures oxygen levels; low readings in a newborn screening test can prompt further evaluation
• Echocardiogram — an ultrasound of the heart, which is the main test used to confirm the diagnosis. It shows the closed valve, the size of each chamber, any holes between chambers, and the direction of blood flow
• Electrocardiogram (ECG) — records the heart’s electrical activity and may show signs of an enlarged or underdeveloped chamber
• Chest X-ray — shows heart size and how much blood is reaching the lungs
• Cardiac MRI or CT scan — detailed imaging that may be used before surgery to see blood vessels that are hard to view on ultrasound
• Cardiac catheterization — a thin tube is guided through a blood vessel into the heart to measure pressures and take pictures; this is not always needed at diagnosis but is commonly performed before later stages of surgery
• Genetic testing — may be offered to look for chromosomal changes that can affect care planning and future family counseling

There is no single number or score that defines the condition. Doctors confirm the diagnosis when imaging clearly shows an absent or completely sealed atrioventricular valve together with the associated changes in chamber size and blood flow. They also classify the defect according to the position of the great arteries and the size of any ventricular septal defect, because these details guide treatment.

Atrioventricular valvar atresia treatment options

There is no way to open or replace a valve that never formed in a newborn, so atrioventricular valvar atresia treatment focuses on rerouting blood so that one working ventricle can supply the body while blood reaches the lungs by another path. Treatment is almost always staged over the first few years of life. The exact plan depends on the anatomy and is individualized for each child.

Immediate care after birth. Newborns are usually cared for in a neonatal or cardiac intensive care unit. A medication called prostaglandin E1 is often given through a vein to keep the ductus arteriosus open so blood can continue to reach the lungs or the body. Oxygen, fluids, and support for breathing may be needed. If the hole between the upper chambers is too small, a balloon atrial septostomy may be performed, in which a catheter with a small balloon enlarges the opening so blood can cross more freely.

First-stage surgery (newborn period). The type of operation depends on whether the lungs are receiving too little or too much blood. If too little, surgeons may place a shunt, a small tube that carries blood from a body artery to the lung arteries. If too much, a band may be placed around the pulmonary artery to limit flow. Babies with mitral atresia and a very small left ventricle may need a more extensive first-stage operation that rebuilds the aorta so the right ventricle can pump blood to the body.

Second-stage surgery (usually within the first year). In the Glenn procedure, the large vein returning blood from the upper body is connected directly to the lung arteries. This allows oxygen-poor blood from the head and arms to reach the lungs without passing through the heart and reduces the workload on the single ventricle.

Third-stage surgery (typically in early childhood). The Fontan procedure connects the vein returning blood from the lower body to the lung arteries as well. After this stage, nearly all oxygen-poor blood flows directly to the lungs, and the single ventricle pumps only oxygen-rich blood to the body. This usually improves oxygen levels and reduces cyanosis, although the circulation remains different from a normal heart.

Medications. Depending on the stage, children may take medicines that help the heart pump, remove excess fluid (diuretics), thin the blood to prevent clots, or control abnormal heart rhythms. Your child’s doctor may adjust these over time.

Heart transplantation. In some children the single ventricle weakens or the staged operations are not suitable. In these cases, a heart transplant may be considered. It is not a first-line treatment and involves its own long-term challenges, including lifelong medications to prevent rejection.

Rehabilitation and supportive care. Feeding support, physical therapy, developmental follow-up, and nutrition counseling are common parts of care, because infants with complex heart disease may grow more slowly and reach milestones at different times.

Living with atrioventricular valvar atresia and outlook

Outcomes have improved considerably as surgical techniques and intensive care have advanced, and many children who complete staged surgery live into adulthood, attend school, and work. However, the condition is not cured by surgery. The Fontan circulation places long-term strain on the body, and lifelong follow-up with a cardiologist experienced in congenital heart disease is recommended.

Possible long-term issues that doctors monitor include:

• Abnormal heart rhythms (arrhythmias), which may need medication, a pacemaker, or a catheter procedure
• Gradual weakening of the single ventricle
• Liver changes related to higher pressure in the veins
• Protein loss from the gut or fluid buildup in the chest in some individuals
• Blood clots, which is why some people take blood-thinning medication
• Reduced exercise capacity compared with peers

Most children can take part in regular activities, though very intense competitive sports may need to be discussed with the cardiology team. Good dental care matters because heart valve and surgical material can be affected by bacteria entering the bloodstream; your doctor may recommend antibiotics before some dental procedures. Routine vaccinations are usually encouraged. Adolescents should be transitioned to adult congenital heart disease care so that follow-up continues without gaps.

Pregnancy in women who have had a Fontan operation carries added risks for both mother and baby and should be planned in advance with a specialist team. Families often benefit from psychological support and connection with other families, because a long treatment journey can be stressful for parents and siblings as well as for the child.

Frequently asked questions

What is the difference between atrioventricular valvar atresia and valve stenosis?

In stenosis, a valve exists but is narrowed, so some blood still passes through. In atresia, the valve is completely closed or absent and no blood passes directly across it. Atresia is generally the more severe of the two and almost always requires surgery in infancy, whereas mild stenosis may only need monitoring.

What are the first atrioventricular valvar atresia symptoms in a newborn?

The earliest sign is often a bluish color of the lips and skin, sometimes appearing within hours to days of birth. Fast breathing, difficulty feeding, and unusual sleepiness are also common. Some babies seem well at first and become ill only when the natural openings in the heart begin to close, which is why newborn oxygen screening and careful observation are important.

Are atrioventricular valvar atresia causes genetic or environmental?

Both may play a role, but in most individual cases no specific cause is found. Certain genetic syndromes and family history increase the likelihood, and some pregnancy exposures are associated with congenital heart defects in general. Doctors typically emphasize that parents are not to blame, and genetic counseling can help families understand any risk for future pregnancies.

Can atrioventricular valvar atresia be diagnosed before birth?

Yes, in many cases. A routine mid-pregnancy ultrasound may show a small ventricle or an unusual valve, and a fetal echocardiogram can then confirm the diagnosis. Prenatal diagnosis does not change the heart defect itself, but it allows the birth to be planned at a hospital that can start treatment right away.

Is atrioventricular valvar atresia treatment a cure?

No. Surgery reroutes blood flow so the child can live with a single pumping chamber, but it does not create a normal heart. Most people need lifelong follow-up and may need further procedures or medication over time. Even so, staged treatment has allowed many people to lead active lives.

How many surgeries does a child usually need?

Most children go through a series of two or three staged operations during the first few years of life, and some need additional catheter procedures in between. The exact number depends on the anatomy and how the child responds at each stage. Your child’s care team can outline the expected plan, while noting that it may change as the child grows.

What does long-term follow-up involve?

Regular visits with a congenital heart specialist typically include physical examination, echocardiograms, ECGs, and sometimes blood tests, liver imaging, exercise testing, or MRI. The frequency varies by age and stage but continues throughout life, including a planned handover to adult congenital heart services during the teenage years.

When to see a doctor

Any newborn with a blue tint to the lips or skin, fast or labored breathing, or difficulty feeding should be assessed by a doctor promptly. For children and adults already living with atrioventricular valvar atresia, keep scheduled follow-up appointments even when feeling well, and seek medical care sooner if new symptoms appear.

Seek emergency care immediately if you notice any of the following red-flag signs:

• Sudden or worsening blueness or grayness of the lips, face, or body
• Struggling to breathe, grunting, or pauses in breathing
• Limpness, extreme sleepiness, or difficulty waking
• Refusal to feed for several feeds in a row, or repeated vomiting
• Cold, pale, or mottled arms and legs
• Fainting or collapse
• A very fast, very slow, or irregular heartbeat, especially with dizziness
• Rapid swelling of the abdomen, legs, or face
• Fever with signs of poor circulation in a child who has had heart surgery
• Signs of a stroke such as sudden weakness on one side, facial droop, or trouble speaking

These signs can indicate that the heart is not delivering enough oxygen to the body and need urgent evaluation. Early treatment can make an important difference in this condition.