What is Atrioventricular Canal Defect? Symptoms, Causes, & Treatment

An atrioventricular canal defect is a heart condition present from birth where the walls separating the heart's chambers don't form properly. This creates openings between the upper and lower chambers of the heart, allowing blood to mix when it shouldn't.

This condition affects the normal flow of blood through your baby's heart, which can make the heart work harder than usual. While it sounds overwhelming, many children with this condition live full, active lives with proper medical care and treatment.

What is Atrioventricular Canal Defect?

Atrioventricular canal defect happens when the tissue that normally separates your heart's four chambers doesn't develop completely during pregnancy. Instead of having solid walls between the chambers, there are gaps that allow blood to flow where it shouldn't.

Your heart has four chambers - two upper ones called atria and two lower ones called ventricles. Normally, oxygen-poor blood stays on the right side while oxygen-rich blood stays on the left side. With this defect, blood mixes between these sides, which means your body might not get enough oxygen-rich blood.

This condition is also called atrioventricular septal defect or endocardial cushion defect. It's one of the more complex congenital heart defects, meaning it's present from birth and affects multiple parts of the heart's structure.

What are the Types of Atrioventricular Canal Defect?

There are two main types of this heart defect, and understanding which type affects your child helps doctors plan the best treatment approach.

Partial atrioventricular canal defect involves an opening in the wall between the two upper chambers of the heart. The heart valves that control blood flow might also be abnormally shaped, but they're still separate from each other. This type typically causes fewer symptoms and may not be noticed until later in childhood.

Complete atrioventricular canal defect is more complex, with openings in both the upper and lower chamber walls. The heart valves are also connected, forming one large valve instead of two separate ones. This type usually causes symptoms earlier in infancy because more blood mixing occurs.

Some children have what doctors call an intermediate or transitional form, which falls somewhere between partial and complete. Your pediatric cardiologist will determine which type your child has using special heart tests and imaging.

What are the Symptoms of Atrioventricular Canal Defect?

The symptoms your child experiences depend on how severe the defect is and how much blood is mixing in their heart. Some children show signs very early, while others may not have obvious symptoms for months or even years.

Here are the most common signs parents notice in babies and young children:

• Difficulty feeding or eating, with babies getting tired quickly during nursing or bottle feeding
• Poor weight gain despite normal appetite, as the heart has to work extra hard
• Rapid or difficult breathing, especially during activities or feeding
• Bluish color around the lips, fingernails, or skin, particularly when crying or active
• Excessive sweating during feeding or light activity
• Frequent respiratory infections or pneumonia
• Fatigue or seeming less active than other children their age

As children get older, you might notice they can't keep up with playmates during physical activities. They may need to rest more often or avoid activities that make them feel short of breath.

Some children with milder forms of this condition may not show obvious symptoms until they're toddlers or even school-age. This is why regular pediatric checkups are so important - your doctor can detect heart murmurs or other subtle signs during routine examinations.

What Causes Atrioventricular Canal Defect?

This heart defect develops during the first eight weeks of pregnancy when your baby's heart is forming. The exact cause isn't always clear, but it happens when the tissue that should separate the heart chambers doesn't grow properly during this critical time.

Most cases occur randomly without any specific trigger or parental action causing them. It's important to understand that nothing you did or didn't do during pregnancy caused this condition - it's simply how your baby's heart developed.

However, there are some factors that can increase the likelihood of this defect occurring:

• Genetic conditions, particularly Down syndrome, which is associated with about 40-50% of atrioventricular canal defects
• Family history of congenital heart defects
• Certain medications taken during early pregnancy
• Maternal diabetes that wasn't well-controlled during pregnancy
• Maternal infections during early pregnancy, such as rubella
• Excessive alcohol consumption during pregnancy

Even with these risk factors present, most babies are born with normal hearts. The vast majority of atrioventricular canal defects happen in families with no previous history of heart problems.

When to See a Doctor for Atrioventricular Canal Defect?

If you notice any symptoms that concern you about your child's breathing, feeding, or energy levels, it's always better to have them checked sooner rather than later. Trust your instincts as a parent - you know your child best.

Contact your pediatrician promptly if your child shows any of these signs:

• Persistent difficulty breathing or rapid breathing, especially at rest
• Bluish coloring around the lips, face, or fingernails
• Poor feeding with excessive tiredness during meals
• Failure to gain weight despite normal appetite
• Unusual fatigue or inability to keep up with normal activities
• Frequent respiratory infections

Call emergency services immediately if your child has severe difficulty breathing, becomes very pale or blue, or seems unusually lethargic and unresponsive. These could be signs that their heart isn't pumping effectively enough to meet their body's needs.

Remember that early detection and treatment lead to much better outcomes. Many children with this condition do very well when their care is managed by experienced pediatric heart specialists.

What are the Risk Factors for Atrioventricular Canal Defect?

While most cases happen randomly, certain factors can increase the chances of a baby being born with this heart defect. Understanding these risk factors can help you know what to expect and when closer monitoring might be needed.

The strongest risk factor is Down syndrome, as nearly half of children with this genetic condition also have atrioventricular canal defects. If your child has Down syndrome, your medical team will likely monitor their heart very closely from birth.

Other factors that may increase risk include:

• Family history of congenital heart defects in parents or siblings
• Maternal age over 35 at the time of conception
• Poorly controlled diabetes in the mother during pregnancy
• Certain genetic syndromes beyond Down syndrome
• Exposure to specific medications during early pregnancy
• Maternal infections like rubella during the first trimester

It's crucial to remember that having risk factors doesn't mean your child will definitely have this condition. Many babies born to mothers with multiple risk factors have perfectly normal hearts, while others with no risk factors can still develop heart defects.

What are the Possible Complications of Atrioventricular Canal Defect?

Without proper treatment, this heart defect can lead to serious complications over time. However, with appropriate medical care and surgery when needed, most of these complications can be prevented or managed effectively.

The most common complications that can develop include:

• Heart failure, where the heart becomes too weak to pump blood effectively throughout the body
• Pulmonary hypertension, which means high blood pressure in the lungs from too much blood flow
• Frequent respiratory infections due to extra fluid in the lungs
• Poor growth and development from the heart not delivering enough oxygen to growing tissues
• Irregular heart rhythms that can affect how well the heart pumps
• Blood clots that could travel to other parts of the body

More serious but less common complications can include stroke, especially in children with the complete form of the defect. Some children may also develop a condition called Eisenmenger syndrome, where the blood vessels in the lungs become permanently damaged from high pressure.

The good news is that early surgical repair significantly reduces the risk of these complications. Most children who have surgery at the appropriate time go on to live normal, healthy lives with very low risk of serious heart problems.

How is Atrioventricular Canal Defect Diagnosed?

Diagnosis often begins when your pediatrician hears an abnormal heart sound called a murmur during a routine checkup. Not all heart murmurs indicate problems, but your doctor will want to investigate further to make sure your child's heart is working properly.

The first step is usually an echocardiogram, which is like an ultrasound of the heart. This test uses sound waves to create detailed pictures of your child's heart structure and shows how blood flows through the chambers. It's completely painless and doesn't require any needles or medications.

Your doctor might also order these additional tests:

• Chest X-ray to see the size and shape of the heart and lungs
• Electrocardiogram (ECG) to check the heart's electrical activity and rhythm
• Cardiac catheterization in some cases, where a thin tube is inserted into blood vessels to get detailed pressure measurements
• CT scan or MRI for more detailed images of the heart's structure

Sometimes this condition is detected before birth during routine pregnancy ultrasounds. If doctors suspect a heart defect during pregnancy, you might have a specialized fetal echocardiogram to get a clearer picture of your baby's heart development.

Getting an accurate diagnosis helps your medical team plan the best treatment approach and timing for your child's specific situation.

What is the Treatment for Atrioventricular Canal Defect?

Treatment depends on the type and severity of your child's specific defect. The main goal is to restore normal blood flow through the heart and prevent complications from developing over time.

For partial defects with mild symptoms, doctors might initially monitor your child closely while managing symptoms with medications. These medicines can help the heart pump more efficiently and reduce fluid buildup in the lungs.

Surgery is the definitive treatment for most children with this condition. The timing depends on your child's symptoms and how well their heart is functioning:

• Complete defects usually require surgery within the first 6-12 months of life
• Partial defects might be repaired between ages 2-5, or earlier if symptoms develop
• Emergency surgery may be needed if severe heart failure develops

During surgery, the cardiac surgeon closes the abnormal openings with patches and repairs or replaces the abnormal heart valves. Most children need only one surgery, though some may require additional procedures as they grow.

The surgical success rate is very high, especially when performed at specialized pediatric heart centers. Most children recover well and can participate in normal childhood activities within a few months after surgery.

How to Provide Home Care During Treatment?

Caring for a child with this heart condition at home involves monitoring their symptoms, following medication schedules, and creating an environment that supports their health and development.

Before surgery, focus on helping your child conserve energy and grow as well as possible. This might mean offering smaller, more frequent meals if feeding is difficult, or allowing extra rest time during the day.

Here are important aspects of home care:

• Give medications exactly as prescribed, even if your child seems to be feeling better
• Monitor weight gain and report any sudden weight loss or poor appetite to your doctor
• Watch for changes in breathing patterns or increased difficulty with activities
• Protect against infections by keeping up with vaccinations and practicing good hygiene
• Maintain regular follow-up appointments with your pediatric cardiologist

After surgery, your child will need time to heal, but most children bounce back remarkably quickly. Follow your surgeon's instructions about activity restrictions, wound care, and when to resume normal activities.

Remember that every child recovers at their own pace. Some children feel better within weeks, while others may take a few months to regain their full energy and strength.

How Should You Prepare for Your Doctor Appointment?

Being well-prepared for medical appointments helps ensure you get the most helpful information and feel confident about your child's care plan. Write down your questions beforehand so you don't forget important concerns during the visit.

Bring a complete list of any medications or supplements your child takes, including doses and timing. Also gather any previous test results, medical records, or referral information from other doctors.

Consider preparing these questions for your medical team:

• What type of atrioventricular canal defect does my child have?
• When will surgery be needed, and what does the procedure involve?
• What symptoms should prompt me to call you immediately?
• Are there any activity restrictions my child should follow?
• How often will we need follow-up appointments?
• What is the long-term outlook for my child?

Don't hesitate to ask for clarification if medical terms or treatment plans seem confusing. Your healthcare team wants to make sure you fully understand your child's condition and feel comfortable with the care plan.

Bring a notebook or ask if you can record important parts of the conversation. Medical information can be overwhelming, and having notes to refer to later can be very helpful.

What's the Key Takeaway About Atrioventricular Canal Defect?

While learning that your child has a heart defect can feel frightening, it's important to know that atrioventricular canal defects are well-understood conditions with excellent treatment outcomes. Most children who receive appropriate care go on to live completely normal lives.

The key to success is working with experienced pediatric heart specialists who can guide you through the treatment process. Modern surgical techniques have made repair of these defects very safe and effective, with success rates exceeding 95% at major pediatric heart centers.

Your child's medical team will create a personalized care plan based on their specific type of defect and overall health. With proper treatment, most children with this condition can participate in all normal childhood activities, including sports and other physical activities.

Remember that you're not alone in this journey. Many families have walked this path before you, and there are excellent support resources available to help you navigate the medical and emotional aspects of your child's care.