Complete Atrioventricular Canal

Complete atrioventricular canal is a serious heart problem that a baby is born with. In this condition there is a big hole in the center of the heart where the upper chambers (atria) and lower chambers (ventricles) meet, and there is one “common” atrioventricular valve instead of two separate valves (mitral and tricuspid). Because of this, blood can move freely between the right and left sides of the heart, so extra blood goes to the lungs. This makes the heart work much harder and can quickly lead to heart failure and high blood pressure in the lungs if it is not treated.

Complete atrioventricular canal (CAVC) is a birth defect of the heart where there is a big hole in the center of the heart and only one shared valve instead of two separate valves between the upper and lower chambers. This causes blood from the left and right sides of the heart to mix, so too much blood goes to the lungs and the heart has to work very hard.

Doctors also call this “complete atrioventricular septal defect.” It is often seen in babies with Down syndrome, but it can happen in any baby. If it is not treated, high pressure in the lung blood vessels (pulmonary hypertension) and heart failure can develop early in life. Because of this risk, most children need surgery in the first months of life to close the holes and separate the valve into two valves.

In complete atrioventricular canal, the defect combines three problems in one: a hole between the top chambers, a hole between the bottom chambers, and a badly formed valve in the middle. Doctors call this combination a “complete atrioventricular septal defect.” The extra blood flow to the lungs can cause fast breathing, poor growth, and other signs of heart failure in the first weeks or months of life. Surgery in early infancy is usually needed to close the holes and repair the valve.

Other names

Doctors use several names for the same basic problem. One common name is atrioventricular septal defect (AVSD). When they say “complete AVSD,” they mean the full form with both atrial and ventricular holes plus the common valve.

Another name is atrioventricular canal defect (AV canal defect). This name focuses on the central “canal” area of the heart, where the defect sits. Because the central cushion tissue that should separate the chambers does not form correctly, older literature also calls it an endocardial cushion defect. You may also see the terms common atrioventricular canal or simply AV canal used in medical articles. All of these names describe the same family of defects in the middle of the heart.

Types of Complete atrioventricular canal

Even within complete atrioventricular canal, there are different structural patterns. One useful way to group them is the Rastelli classification, which looks at how the leaflets (flaps) of the common valve attach to the heart walls.

In Type A complete AV canal, the upper bridging leaflet of the common valve is attached firmly to the wall of the left ventricle by short chords (string-like supports). This is the most common pattern in babies with Down syndrome.

In Type B, the upper bridging leaflet is attached more toward the right side of the septum. This type is less common. The way the leaflet attaches can affect how blood flows and how surgeons plan the repair, but parents usually do not need to know every detail of these internal attachments.

In Type C, the upper bridging leaflet is “free-floating,” meaning it is not fixed to the septum in the usual way. This can make the valve leak more and can make surgery more complex. Doctors study these patterns carefully with echocardiography (heart ultrasound) before surgery to decide the safest repair method.

Another important way to describe complete AV canal is to say whether it is balanced or unbalanced. In a balanced defect, the common valve sits fairly evenly over both ventricles. In an unbalanced defect, the valve sits more over one ventricle, so one side of the heart is much smaller. This unbalanced pattern can make surgery more difficult and may affect whether a child can have a normal two-ventricle circulation or needs a single-ventricle pathway.

Causes of Complete atrioventricular canal

1. Genetic cause: Down syndrome (trisomy 21)
   The strongest known cause of complete atrioventricular canal is Down syndrome. A child with Down syndrome is hundreds of times more likely to have this defect than a child with normal chromosomes. Changes in chromosome 21 affect how the central heart tissues form in early pregnancy, leading to the typical holes and common valve.

2. Other chromosomal abnormalities (trisomy 18, trisomy 13, others)
   Complete AV canal can also occur in babies with trisomy 18, trisomy 13, and other rare chromosome problems such as deletions in the short arm of chromosome 8. These genetic changes disturb normal heart development and often come with other birth defects.

3. Family history of congenital heart disease
   Having a close relative (parent or sibling) with a congenital heart defect slightly increases the risk that a baby will be born with a defect, including AVSD. This suggests there are inherited gene variants that make heart formation more fragile, even when no single gene mutation is identified.

4. Maternal diabetes before or during pregnancy
   Women who have diabetes before pregnancy, especially if blood sugar is not well controlled, have a higher risk of having a baby with congenital heart disease, including atrioventricular septal defects. High blood sugar levels can interfere with organ formation in the first weeks of pregnancy.

5. Maternal obesity
   Studies show that mothers who are very overweight before pregnancy have a greater chance of having a baby with heart defects. Excess body fat is linked to inflammation, insulin resistance, and other metabolic changes that may disturb normal heart development in the embryo.

6. Maternal smoking in early pregnancy
   Smoking during pregnancy exposes the baby to nicotine, carbon monoxide, and many other chemicals. Research suggests that smoking in early pregnancy is associated with a higher risk of congenital heart disease in general, including septal defects and AV canal.

7. Maternal alcohol use in early pregnancy
   Heavy alcohol use around the time of conception and early pregnancy can cause fetal alcohol spectrum disorders and increase the risk of heart defects. Alcohol can damage the cells that form the central heart structures, contributing to AV canal and other septal defects.

8. Exposure to certain epilepsy medicines (for example, valproic acid)
   Some anti-seizure medicines, especially valproic acid, have been linked to a higher rate of congenital heart defects when taken in early pregnancy. These drugs can affect gene expression and cell signaling needed for proper heart formation.

9. Maternal congenital heart disease
   When the mother herself has a congenital heart defect, the risk that her baby will have a heart defect is higher than in the general population. This is true even if she has had surgery and feels well, and AVSD is one of the defects more often seen in these families.

10. Maternal phenylketonuria (poorly controlled)
    Women with phenylketonuria (PKU) who do not keep their blood phenylalanine levels low before and during pregnancy have a high risk of having babies with heart defects and other problems. High phenylalanine is toxic to the developing embryo and can damage heart tissues.

11. Maternal infections such as rubella (German measles)
    When a pregnant woman catches rubella in early pregnancy, the virus can cross the placenta and damage the baby’s organs, including the heart. This can lead to a range of heart defects, including AV canal, as part of congenital rubella syndrome.

12. Maternal autoimmune disease (for example, lupus)
    Autoimmune diseases like systemic lupus erythematosus can affect the placenta and blood flow to the embryo. Some studies suggest a higher rate of congenital heart disease in babies of mothers with autoimmune conditions, although the exact risk for AV canal is less clear.

13. Older maternal age
    Advanced maternal age, especially age 35 years or older, is associated with a higher chance of chromosome problems such as trisomy 21. Because Down syndrome is strongly linked with complete AV canal, older maternal age indirectly increases the risk of this defect.

14. Use of assisted reproductive technologies (IVF and similar methods)
    Some research has suggested a slightly higher rate of congenital heart disease in babies conceived by in-vitro fertilization or other assisted techniques. This may relate to parental factors or to the methods themselves, though the exact role in AV canal is still being studied.

15. Nutritional deficiencies (for example, low folate)
    Low folate intake before and in early pregnancy is known to cause neural tube defects and may also increase the risk of some heart defects. Folate is important for DNA synthesis and cell division, processes that are critical when the heart septum and valves are forming.

16. Maternal exposure to certain industrial chemicals or pesticides
    Exposure to some organic solvents, pesticides, or other toxic chemicals at work or in the environment has been linked in some studies to a higher risk of congenital heart disease. These agents may interfere with cell signaling and blood vessel growth during early heart development.

17. Maternal high hemoglobin or blood thickness in early pregnancy
    Research has found that mothers with unusually high hemoglobin levels at the start of pregnancy may have a higher chance of having a baby with congenital heart disease, including AVSD. High hemoglobin can reflect reduced plasma volume or other conditions that may impair placental blood flow.

18. Poor general maternal health and chronic illnesses
    Chronic conditions such as uncontrolled high blood pressure, severe kidney disease, or long-term lung disease can affect the oxygen and nutrient supply to the embryo. This may increase the chance of heart defects, including holes in the septum and valve problems.

19. Random developmental error (sporadic cause)
    In many babies with complete AV canal, no clear cause can be found. Even without known risk factors, small random errors can occur while the heart is forming. Tiny changes in genes or cell behavior at this time can be enough to cause a major defect, even when pregnancy seems normal.

20. Combination of genetic tendency and environmental factors
    Most experts agree that AV canal often results from a mix of genetic susceptibility and outside factors. A baby may inherit gene variants that make heart development more vulnerable, and then environmental factors like maternal illness or medicines push the process toward a defect. This “multi-factor” model explains why risk is higher in some families yet still not fully predictable.

Symptoms of Complete atrioventricular canal

1. Fast breathing (tachypnea)
   Babies with complete AV canal often breathe very fast because too much blood is flowing to the lungs. The lungs become congested with fluid, and the baby must work harder to move air in and out. Parents may notice that the chest moves quickly or that the baby’s nostrils flare with each breath.

2. Shortness of breath during feeding
   Feeding is hard work for a young baby. When the heart and lungs are under strain, the baby may stop sucking often, breathe rapidly, or seem out of breath while feeding. This is a key early sign that something is wrong with the heart or lungs.

3. Poor feeding and slow weight gain
   Because feeding is tiring and the body is using extra energy to pump blood, many babies with complete AV canal do not eat well and gain weight slowly. Doctors call this “failure to thrive.” Parents may see that clothes stay loose and growth charts flatten or drop.

4. Excessive sweating, especially with feeds
   Babies with heart failure from AV canal often sweat a lot, particularly on the forehead during feeding or crying. The body releases sweat as it works harder to pump blood and maintain temperature, and the skin can feel cold and damp.

5. Rapid heart rate (tachycardia)
   The heart beats faster to try to push enough blood to the body and to handle the extra blood returning from the lungs. Caregivers may notice a very fast pulse or feel the heart pounding in the chest. Doctors confirm this by listening or with an ECG.

6. Bluish color of lips or skin (cyanosis)
   In some babies, especially when lung blood pressure rises, the blood that goes to the body has less oxygen than normal. This can make the lips, tongue, or fingertips look bluish or gray, especially during crying or feeding.

7. Weak pulse or low blood pressure
   When the heart cannot pump strongly enough, the pulse may feel weak, and blood pressure can be low. This reflects poor forward flow of blood to vital organs and is a sign that the heart is struggling.

8. Swelling of legs, feet, or belly (edema)
   As heart failure worsens, fluid can build up in the body. In infants this is often seen as swelling in the legs, ankles, or scrotum, and as a swollen, tender belly due to an enlarged liver.

9. Frequent chest infections or pneumonia
   Extra blood in the lungs makes them more vulnerable to infection. Babies with complete AV canal may get frequent colds that worsen quickly or may develop pneumonia more easily than other infants.

10. Poor growth in length and head size
    Over time, not only weight but also length and head growth can slow down. The body is using energy to fight heart failure instead of growing, and poor feeding adds to this problem.

11. Tiredness and low activity level
    Babies and young children with AV canal often seem unusually sleepy, quiet, or inactive. They may stop feeding early, play less, or tire quickly. Older children may not keep up with peers during exercise or play.

12. Irritability and restlessness
    Constant breathlessness and hunger from poor feeding can make babies irritable. They may cry often, have trouble settling, or sleep poorly because their bodies are under stress from heart failure.

13. Heart murmur heard by a doctor
    A heart murmur is an extra sound heard when blood flows turbulently through holes or abnormal valves. In complete AV canal, doctors often hear a loud murmur along with other abnormal heart sounds when listening with a stethoscope.

14. Signs of pulmonary hypertension (high pressure in lung arteries)
    If the defect is not repaired, high blood pressure can develop in the lung arteries. Children may have more pronounced cyanosis, worsening breathlessness, and eventually signs of right-sided heart strain, such as more swelling and enlarged liver.

15. Palpitations or irregular heartbeats in older patients
    After surgery or in patients diagnosed later, abnormal heart rhythms (arrhythmias) can occur. Patients may feel fluttering, skipped beats, or pounding in the chest. This can be due to surgical scars or long-standing heart enlargement.

Diagnostic tests for Complete atrioventricular canal

Doctors use a combination of bedside checks, manual tests, lab work, electricity-based heart tests, and imaging to diagnose complete AV canal and plan treatment.

Physical exam tests

1. Overall inspection of the baby (color, breathing, body shape)
   The doctor first looks at the baby’s general condition: breathing rate, skin color, level of alertness, and body build. Fast breathing, poor weight gain, bluish lips, and signs of distress raise suspicion for a serious heart defect like complete AV canal, especially in the first months of life.

2. Listening to the heart with a stethoscope (cardiac auscultation)
   By placing a stethoscope on the chest, the doctor listens for murmurs and extra heart sounds. In complete AV canal, there is often a loud systolic murmur from increased blood flow across the pulmonary valve and the holes, and sometimes a murmur from leaky valves. This physical finding guides the need for echocardiography.

3. Lung examination for crackles or wheeze
   Using the stethoscope over the back and chest, the doctor listens for wet crackles that suggest fluid in the lungs from heart failure, or other abnormal sounds. These findings, combined with signs of heart stress, support the diagnosis of a left-to-right shunt like AV canal.

4. Abdominal exam for liver enlargement (hepatomegaly)
   The doctor gently feels the abdomen to check the size and tenderness of the liver. In heart failure, blood backs up into the liver, making it bigger and sometimes painful. A large, tender liver in a baby with breathlessness and murmur strongly suggests heart failure from a defect such as complete AV canal.

Manual bedside tests

5. Palpation of pulses and precordium (feeling the chest and pulses)
   The doctor feels the pulses in the arms and legs and places a hand on the chest over the heart. Strong, bounding pulses and a forceful heartbeat can point to a large left-to-right shunt. Weak pulses may suggest poor heart output. These simple manual checks help judge how severe the problem is.

6. Blood pressure measurement in arms and legs
   Measuring blood pressure in different limbs helps detect low systemic pressure from heart failure or other defects like coarctation. In complete AV canal, blood pressure may be low or normal, but tracking it over time is vital to see how the heart and circulation are coping.

7. Capillary refill time test (nail bed refill)
   The doctor presses on the nail bed or skin to blanch it and then releases it, watching how quickly color returns. Slow refill suggests poor blood flow to the skin and possible low cardiac output, which can be seen in babies with severe heart failure from AV canal.

8. Growth and nutrition assessment (weight, length, head circumference)
   Regular measurement of weight, length, and head size allows the team to see if the child is growing properly. Poor weight gain or falling off the growth curve is an important manual test result pointing toward chronic heart failure and the need for more aggressive treatment or surgery.

Lab and pathological tests

9. Complete blood count (CBC)
   A CBC measures red blood cells, white blood cells, and platelets. In babies with long-standing heart defects, red cell counts may rise to carry more oxygen, or anemia may be present. Infection, which is common in these infants, can also be detected. This test does not diagnose AV canal by itself, but it gives important background information.

10. Arterial or venous blood gas and oxygen levels
    Blood gas tests show how much oxygen and carbon dioxide are in the blood and whether the blood is too acidic. In AV canal, they help determine how well the lungs and heart are working together and whether there is significant low oxygen (hypoxemia) or retained carbon dioxide from lung congestion.

11. Serum electrolytes and kidney function tests
    These blood tests measure sodium, potassium, creatinine, and other chemicals. Babies with heart failure often take medicines like diuretics that can change electrolyte levels and strain the kidneys. Monitoring these values keeps treatment safe while the child awaits surgery.

12. Brain natriuretic peptide (BNP or NT-proBNP)
    BNP is a hormone released by heart muscle cells when they are stretched by volume overload or pressure. High BNP levels in infants and children support the diagnosis of heart failure from conditions like complete AV canal and help track response to treatment.

13. Genetic testing (karyotype, microarray, or FISH)
    Because AV canal is strongly associated with chromosomal problems, genetic testing is often recommended. A karyotype or microarray can confirm Down syndrome or other abnormalities such as trisomy 18 or 8p deletions. Knowing the genetic diagnosis helps with long-term care planning and family counseling.

Electrodiagnostic tests

14. Resting 12-lead electrocardiogram (ECG)
    An ECG records the heart’s electrical activity. In complete AV canal it may show left axis deviation, signs of enlargement of both ventricles, and sometimes conduction problems. While it cannot show the actual holes, it supports the diagnosis and helps identify rhythm issues that may need treatment.

15. Holter monitor (24-hour ECG recording)
    A Holter monitor is a small device worn for a day or longer that records every heartbeat. It is useful for detecting intermittent arrhythmias in children with AV canal, either before surgery or later in life, especially if they report palpitations, fainting, or episodes of fast heart rate.

16. Hospital telemetry or event monitoring
    In the hospital, continuous ECG telemetry allows doctors to watch the heart rhythm in real time. Event monitors can also be used at home to record the rhythm when the patient feels symptoms. This is important because patients with AV canal, especially after repair, are at long-term risk of arrhythmias.

Imaging tests

17. Chest X-ray
    A simple chest X-ray can show an enlarged heart and increased blood flow markings in the lungs, both of which are common in complete AV canal. It is not specific, but it is quick, widely available, and helps support the diagnosis and follow changes over time.

18. Transthoracic echocardiography (2D and Doppler echo)
    Echocardiography is the main test used to diagnose AV canal. A small probe on the chest sends ultrasound waves into the heart, creating moving pictures. Echo clearly shows the central hole, the common valve, and how blood flows between the chambers, and it helps classify the defect type and plan surgery.

19. Three-dimensional or transesophageal echocardiography
    In some cases, more detailed echocardiography is needed. Three-dimensional echo or transesophageal echo (in which the probe is placed in the esophagus under anesthesia) can give very clear images of the valve leaflets and attachments. This helps surgeons understand complex anatomy before operating.

20. Cardiac catheterization with angiography and pressure measurements
    Cardiac catheterization is an invasive test in which thin tubes are inserted into blood vessels and guided to the heart. Doctors measure pressures in the heart and lungs and inject contrast dye to see blood flow on X-ray. In complete AV canal, catheterization is used when doctors need precise information about lung artery pressure and resistance before deciding on surgery.

Non-pharmacological treatments (therapies and other measures)

Below are common non-drug approaches used to support a baby or child with complete atrioventricular canal. These do not replace surgery or medicines, but they help the child stay as strong and comfortable as possible. Always follow your child’s cardiologist’s advice.

1. Specialized heart-center care and regular follow-up
Babies with CAVC need frequent check-ups with a pediatric cardiologist to monitor heart function, lung pressure, oxygen level, weight gain, and symptoms. Regular visits allow early adjustment of treatment and timely planning of surgery. Echocardiograms, blood pressure checks, and oxygen saturation measurements are used to follow the child closely.

2. Parent and caregiver education
Parents learn to watch for warning signs such as faster breathing than usual, sweating while feeding, blue lips or fingers, poor feeding, or fewer wet nappies. Simple training in giving medicines, measuring weight at home, and knowing when to call the doctor can prevent serious emergencies. Written care plans and teaching sessions are a key part of treatment.

3. High-calorie nutrition to support growth
Many infants with CAVC burn extra calories because their hearts and lungs work harder, and they may tire easily during feeds. Dietitians often advise high-calorie breast milk or formula, sometimes by concentrating the feed or adding special fortifiers, so the baby can gain weight without having to drink very large volumes. Good growth helps the baby tolerate surgery and recover better.

4. Feeding support and pacing
Feeding may be broken into smaller, more frequent feeds, with rest breaks during feeding to reduce tiredness and breathlessness. Some babies need special nipples, feeding positions, or temporary tube feeding (nasogastric feeds) to make feeding safer and less stressful. This can reduce the risk of poor growth and failure to thrive.

5. Careful fluid management under medical guidance
Even though many babies need extra calories, they cannot always tolerate large fluid volumes. The healthcare team may set a limit on daily fluid intake and adjust the concentration of feeds so the baby gets enough calories without too much fluid. This helps reduce lung congestion and swelling while still supporting growth.

6. Preventing respiratory infections
Respiratory infections like RSV or influenza can be very dangerous in babies with CAVC because their lungs are already under stress. Families are taught to practice good hand hygiene, avoid cigarette smoke, and keep the baby away from people who are sick. In some countries, high-risk infants may receive preventive RSV antibody injections (a drug, but the overall infection-prevention plan is a non-drug strategy).

7. Creating a smoke-free environment
Exposure to tobacco smoke can worsen breathing problems and increase the risk of lung infections. Keeping the home and car completely smoke-free helps protect the baby’s lungs and makes it easier for the heart to pump blood through the lungs. Relatives and visitors should not smoke around the child.

8. Positioning to ease breathing
Babies with heart failure often breathe more comfortably in a slightly upright position. Parents may be advised to hold the baby semi-upright while feeding and avoid lying the baby flat for long periods when awake, always following safe-sleep advice for sleep times. Proper positioning can reduce work of breathing and improve feeding tolerance.

9. Temperature and illness management
Fever or dehydration can overload the heart, so caregivers are told to watch carefully for fever, vomiting, or diarrhea and seek medical advice early. Keeping the child well-hydrated (within fluid limits) and promptly treating infections can prevent sudden worsening of heart failure symptoms.

10. Regular growth and development monitoring
Health-care teams track the child’s weight, length, and head circumference and watch for delays in sitting, crawling, or talking. Early intervention programs, including physical, occupational, and speech therapy if needed, can support brain development and motor skills, which may be affected by long-term illness or repeated hospital stays.

11. Developmental and psychological support for the family
Long hospital stays and repeated procedures can be stressful for parents and older siblings. Social workers, psychologists, and support groups can help families cope emotionally, understand the condition, and feel less alone. This emotional support indirectly helps the child because parents who are less stressed can care more confidently for their baby.

12. Dental and oral hygiene to reduce infection risk
Good dental care is important, especially after surgery when certain children may need temporary protection against infective endocarditis. Brushing teeth regularly as the child grows, treating dental problems early, and visiting a dentist experienced with heart patients lowers the chance of bacteria entering the bloodstream from the mouth.

13. Pre-operative optimization
Before surgery, doctors try to make sure the child’s lungs, nutrition status, and any other medical issues (such as anemia) are as stable as possible. This can include adjusting medicines, treating infections, improving nutrition, and planning blood products if needed. Good pre-operative preparation reduces the risk of complications during and after surgery.

14. Post-operative physiotherapy and rehabilitation
After surgery, breathing exercises, gentle movement, and age-appropriate physical therapy help clear the lungs, prevent stiffness, and support return to normal activities. Therapists also help parents learn how to lift, hold, and play with the child safely while the chest is healing.

15. Safe activity planning
Children with repaired CAVC are often encouraged to be active within limits set by their cardiologist. Normal play is usually fine, but extreme exertion may be restricted depending on heart function and valve status. Simple explanations and school notes can help teachers and caregivers support the child’s safe participation in activities.

16. Vaccinations as scheduled (planning aspect)
Keeping routine childhood vaccinations up to date helps reduce the chance of infections that could stress the heart and lungs. This is a non-drug planning strategy, even though vaccines themselves are medicines. The cardiologist may recommend extra vaccines, such as influenza and pneumococcal vaccines, depending on local guidelines.

17. School and social support after repair
As the child grows, guidance for teachers and school nurses about the heart history, activity limits, and need for medicines during school time can make daily life smoother. Encouraging normal friendships and inclusion in school life supports emotional health and quality of life.

18. Transition planning for teenagers and adults with repaired CAVC
Older children and teenagers with repaired CAVC need help moving from pediatric to adult congenital heart disease services. This includes teaching them about their heart, the need for lifelong follow-up, and issues like exercise, work, and pregnancy in the future.

19. Genetic counseling for families
Because CAVC can be linked with genetic conditions such as Down syndrome or other chromosome changes, some families may be offered genetic counseling. Counselors explain recurrence risks and discuss testing options in future pregnancies so parents can make informed choices.

20. Family support groups and peer networks
Meeting other families who have children with congenital heart disease can reduce isolation and provide practical tips. Many heart foundations and hospitals organize parent groups, online forums, or information sessions. These networks can be a powerful emotional “therapy” for parents and older children.

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Drug treatments (used by doctors for symptoms and complications)

Important safety note:
Medicines for complete atrioventricular canal are specialist drugs. Doses depend on weight, age, kidney function, and the baby’s exact heart problem. Only a pediatric cardiologist or pediatrician should choose and dose these medicines. Never start, stop, or change any heart medicine without a doctor’s advice.

Below are key drug classes commonly used before or after surgery to control symptoms and complications. Most are approved by the FDA for heart failure, edema, or related heart problems, and are used in infants and children following official labeling plus specialist guidelines.

1. Loop diuretics (for example, furosemide / Lasix®)
Loop diuretics help the kidneys remove extra salt and water from the body. This reduces fluid in the lungs and swelling in the body, so the heart does not have to pump against so much volume. Furosemide is FDA-approved to treat edema (fluid build-up) in adults and children with heart failure and other conditions. Side effects can include dehydration, low blood pressure, and changes in blood minerals like potassium, so blood tests and careful monitoring are essential.

2. Thiazide diuretics (for example, chlorothiazide)
Sometimes a thiazide diuretic is added when a loop diuretic alone is not enough. Thiazides act in a different part of the kidney and can boost the effect of loop diuretics, helping to control stubborn fluid overload. Doctors use them carefully because they can also disturb electrolyte balance and cause low sodium or potassium levels.

3. Potassium-sparing diuretics (for example, spironolactone)
Spironolactone blocks the hormone aldosterone and helps the body excrete salt and water while holding on to potassium. In children with heart failure, it may be combined with other diuretics to help control fluid without causing very low potassium. Side effects can include high potassium levels and changes in kidney function, so regular blood tests are needed.

4. ACE inhibitors (for example, captopril, enalapril)
ACE inhibitors relax blood vessels and reduce afterload (the resistance the heart pumps against). In babies with large left-to-right shunts, these drugs can lower the amount of blood flowing to the lungs and reduce heart failure symptoms. FDA labeling for captopril shows its use in heart failure in combination with diuretics and other drugs in adults; in children, dosing is carefully adjusted by specialists, and low blood pressure or kidney problems are possible side effects.

5. Digoxin
Digoxin helps the heart muscle squeeze more strongly and can slow the heart rate slightly. In infants with congestive heart failure due to large shunts, it may improve symptoms and feeding tolerance. However, because too much digoxin can be toxic, doctors adjust the dose very precisely and may check blood levels if there are concerns such as vomiting, poor appetite, or rhythm changes.

6. Beta-blockers (for example, propranolol, carvedilol in selected cases)
Beta-blockers slow the heart rate and reduce how hard the heart has to work. In some children with arrhythmias or heart failure, they can improve symptoms and long-term heart function. They must be started at low doses and increased slowly because they can lower heart rate and blood pressure too much in some patients.

7. Pulmonary vasodilators (for example, sildenafil, bosentan in selected patients)
In children with significant pulmonary hypertension despite repair or while waiting for repair, pulmonary vasodilators may be used by specialists. These drugs relax the blood vessels in the lungs and can reduce lung pressure. They require careful monitoring in specialized centers because dosing, side effects, and long-term benefits must be balanced carefully.

8. Inotropes used in intensive care (for example, milrinone, dopamine)
During severe heart failure episodes or around the time of surgery, intravenous inotropes such as milrinone or dopamine may be used in the intensive care unit. They can increase the strength of heart contraction and improve blood flow to the body while the child is critically ill. These medicines are given only under close monitoring because they can affect blood pressure and heart rhythm.

9. Anticoagulants (for example, warfarin) in special situations
If a child has a mechanical valve, certain rhythm problems, or blood clots, anticoagulant drugs like warfarin may be prescribed to reduce the risk of further clots. Blood tests (INR) are checked regularly to make sure the dose is safe and effective. Parents must be taught how to give the medicine and what signs of bleeding to watch for.

10. Antiplatelet drugs (for example, low-dose aspirin)
Low-dose aspirin may sometimes be used after certain heart surgeries or when there is a risk of clots forming on patches or reconstructed valves. It reduces the stickiness of platelets. Side effects include stomach irritation and bleeding risk, so the cardiologist decides if the benefits outweigh the risks.

11. Antibiotics for infective endocarditis prophylaxis
Routine daily antibiotics are not needed for most children with repaired CAVC. However, for the first few months after surgery or if there is a residual defect, guidelines may suggest a single preventive antibiotic dose (such as amoxicillin) before certain high-risk dental or surgical procedures to reduce the risk of infective endocarditis.

12. Pain relief medicines after surgery (for example, paracetamol / acetaminophen)
After heart surgery, careful pain control helps children breathe deeply, move, and recover better. Paracetamol (acetaminophen) is commonly used because it reduces pain and fever with fewer effects on platelets and kidneys compared with some other painkillers. Doctors choose the dose and schedule based on age and weight.

(There are many other medicines used in specific situations, but these are among the main groups most children with CAVC may encounter. Exact drug, dose, and duration always depend on the individual child.)

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Dietary molecular supplements (general support, not a cure)

There are no supplements that can fix the heart defect itself. They only support overall health, growth, and immunity. Supplements should be used only if a doctor or dietitian finds a deficiency or special need.

1. Energy-dense formulas and breast-milk fortifiers
Special high-energy formulas or breast-milk fortifiers are often the most important “supplement” for infants with CAVC. They increase calories per milliliter so babies can grow without drinking large volumes. This helps prepare them for surgery and improves recovery, because well-nourished infants handle stress better than undernourished ones.

2. Iron supplements when iron deficiency is present
If blood tests show low iron, iron drops or syrups may be prescribed. Adequate iron is needed to make healthy red blood cells that carry oxygen. Improving anemia can reduce symptoms like tiredness and breathlessness, but too much iron can be harmful, so doses must follow lab results and medical advice.

3. Vitamin D supplements
Vitamin D helps with bone health and immune function. Children with chronic illnesses are sometimes at higher risk of low vitamin D because of less sunlight exposure or special diets. Supplementation after testing can support normal growth and reduce risk of weak bones, especially if diuretics or restricted diets are used.

4. General pediatric multivitamins (when diet is limited)
If feeding is difficult and the child cannot take a wide variety of foods, a pediatric multivitamin may be suggested. This can help fill gaps in vitamins such as A, C, and B-complex, which support immunity, wound healing, and energy metabolism. It does not treat the heart defect, but it helps maintain overall resilience.

5. Calcium and phosphorus support in special cases
Some infants on long-term diuretics or restricted diets may be at risk of bone mineral problems. In these cases, dietitians and doctors may adjust formula composition or prescribe extra calcium and phosphorus to support bone strength and growth, especially in very young or post-operative infants.

6. Omega-3 fatty acids (with caution and only if advised)
Omega-3 fats (for example from fish oil) support general heart and brain health in older children and adults. Evidence in infants with congenital heart disease is limited, so supplements should only be used if a specialist recommends them, considering bleeding risk and interactions with anticoagulants.

7. Zinc supplements when deficiency is confirmed
Zinc deficiency can impair wound healing and immune function. If blood tests show low zinc or the child has poor growth with frequent infections, doctors may suggest short-term zinc supplements. Doses must be tailored carefully to avoid stomach upset and interactions with other minerals.

8. Protein supplements for older children with poor intake
In older children with very poor appetite, protein powders or high-protein drinks may be used under dietitian guidance. Adequate protein supports muscle mass, immune function, and recovery after surgery. However, kidney function needs to be checked before giving high-protein products.

9. Medium-chain triglyceride (MCT) oils in selected cases
Some infants with fat-absorption problems or very high energy needs may receive formulas enriched with MCT oils. These fats are easier to absorb and provide concentrated calories, supporting growth without large fluid loads. This is used only when clearly indicated by the nutrition team.

10. Electrolyte supplements (like potassium) only when prescribed
Because diuretics can change blood salt levels, doctors sometimes prescribe potassium or other electrolyte supplements. These should never be given without blood tests and medical supervision, because both low and high levels can cause dangerous heart rhythm problems.

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Immunity booster, regenerative and stem-cell-related drugs

For complete atrioventricular canal, there are no FDA-approved stem cell drugs or regenerative medicines that can repair the heart instead of surgery. Research on stem-cell and regenerative therapies for congenital heart disease is ongoing, but these are still experimental and not routine treatment.

Instead, doctors focus on medical strategies that indirectly support immunity and healing:

1. Routine childhood vaccines and seasonal flu vaccine – These reduce serious infections that could overload the heart and lungs. Scheduling and timing are adjusted by the cardiologist, especially around surgery.

2. RSV monoclonal antibody injections for high-risk infants – In some regions, high-risk babies with complex heart disease may receive preventive antibodies against RSV to reduce hospitalizations from severe bronchiolitis.

3. Good nutrition and growth support – Adequate calories, protein, vitamins, and minerals are some of the most powerful “natural immunity boosters,” helping the body fight infection and recover after surgery.

4. Avoiding unnecessary antibiotics – Using antibiotics only when truly needed helps prevent resistant bacteria and keeps the child’s microbiome healthier, which also supports immunity.

5. Early treatment of infections – Quick medical review and treatment when the child has fever, cough, or breathing trouble can prevent minor infections from becoming severe and straining the heart.

6. Participation in research trials (only under expert care) – In the future, some children may be offered clinical trial therapies, such as new medicines or cell-based treatments, but these are strictly controlled and not standard care.

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Surgeries and procedures

Surgery is the main definitive treatment for complete atrioventricular canal.

1. Complete intracardiac repair of CAVC
The standard operation uses one or more patches to close the hole between the upper chambers (atrial septal defect) and the hole between the lower chambers (ventricular septal defect). The surgeon also splits the single common valve into two separate valves (mitral and tricuspid) and reconstructs them to work as normally as possible. This reduces abnormal blood flow to the lungs and improves heart efficiency.

2. Timing of surgical repair in infancy
Many centers aim to repair complete AV canal in early to mid-infancy (often before 6 months of age), before high and irreversible pressure builds up in the lung blood vessels. If symptoms are severe or lung pressures are rising quickly, some babies are operated on even earlier. The cardiology team decides the best timing for each child.

3. Pulmonary artery banding (palliative procedure in selected cases)
In babies who are too small or unstable for full repair, a temporary operation called pulmonary artery banding may be done. A band is placed around the main lung artery to limit blood flow to the lungs, reduce heart failure symptoms, and protect the lungs until the child is big enough for complete repair. Later, the band is removed during the definitive surgery.

4. Re-operation for residual valve leakage or defects
After the main repair, some children develop leakage of the reconstructed left atrioventricular valve or have remaining holes. If these problems are severe and cause symptoms, another operation or catheter-based procedure may be needed to repair or replace the valve or close the residual defect.

5. Treatment of associated lesions (for example, patent ductus arteriosus, other septal defects)
Some children with CAVC have extra heart problems, such as a patent ductus arteriosus (PDA) or additional small holes. These may be closed at the time of the main surgery or sometimes with catheter-based methods. Treating all significant lesions helps the circulation work more normally and reduces long-term complications.

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Prevention (what can and cannot be prevented)

Most cases of CAVC cannot be fully prevented, but some steps may reduce risks or prevent serious complications:

1. Healthy pregnancy care – Good prenatal care, control of maternal illnesses (like diabetes), and avoiding alcohol, smoking, and certain drugs during pregnancy may reduce the risk of some congenital heart defects.

2. Genetic counseling for families with history of CAVC or Down syndrome – This helps parents understand recurrence risks and options for prenatal testing in future pregnancies.

3. Early ultrasound and fetal echocardiography when indicated – Detecting CAVC before birth or soon after allows timely planning for delivery in a specialist center and early care.

4. Prompt referral to a pediatric cardiologist – Early diagnosis and specialist management reduce the time a baby spends with uncontrolled symptoms and high lung blood flow.

5. Good nutrition and growth monitoring – Preventing malnutrition and growth failure improves surgical outcomes and lowers complications.

6. Infection prevention (vaccines, hygiene) – Reduces pneumonia and other illnesses that can push the heart and lungs into crisis.

7. Avoiding exposure to tobacco smoke – Protects lung function and reduces respiratory infections that worsen heart failure.

8. Regular dental care and good oral hygiene – Lowers the risk of infective endocarditis, particularly after repair when patches and reconstructed valves are present.

9. Lifelong cardiology follow-up after repair – Helps detect valve problems, rhythm issues, or pulmonary hypertension early, so they can be treated before causing major damage.

10. Education and emergency plans for families and schools – Knowing what to do in emergencies and how to spot warning signs can prevent delays in treatment during a crisis.

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When to see a doctor (or emergency department)

You should contact your child’s cardiologist or pediatrician urgently if you notice:

• Faster breathing than usual, especially at rest or with feeding

• Sweating, especially on the head during feeds

• Poor feeding, taking much longer to feed, or refusing feeds

• Very poor weight gain or weight loss

• Increased tiredness, sleeping much more than usual, or being unusually fussy

These may be signs of worsening heart failure.

You should go to the emergency department immediately (or call local emergency services) if your child has:

• Very fast or difficult breathing

• Blue or gray color of lips, tongue, or fingernails

• Very cold hands and feet or decreased responsiveness

These can be signs of a life-threatening problem and need urgent medical help.

Even after successful repair, any new chest pain, fainting, or palpitations should be discussed with the cardiologist, because they can sometimes signal rhythm problems or valve issues.

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What to eat and what to avoid

Diet is always planned with the cardiology and nutrition team, especially in infants.

What to encourage

• High-calorie breast milk or formula as advised – So the baby can grow without drinking huge volumes.

• Frequent small feeds – Less tiring for babies with fast breathing.

• Balanced diet for older children – Fruits, vegetables, whole grains, lean proteins, and healthy fats support healing, immunity, and energy.

• Adequate protein – Supports muscle and tissue repair after surgery (meats, eggs, dairy, legumes) as tolerated.

• Plenty of safe fluids within limits set by the doctor – To avoid dehydration but not overload the heart.

What to limit or avoid

• Very salty foods (for older children) – Too much salt can cause fluid retention and worsen heart failure, so processed foods, chips, and instant noodles are often limited.

• Sugary drinks – Provide empty calories and may affect appetite for nutritious foods.

• Caffeine (for teens) – In sodas or energy drinks, caffeine can affect heart rhythm; cardiologists often advise minimizing or avoiding it.

• Unapproved supplements or herbal products – These can interact with heart medicines or affect blood clotting and should never be used without specialist advice.

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FAQs about complete atrioventricular canal

1. Is complete atrioventricular canal always serious?
Yes. CAVC is a major heart defect because it causes a large left-to-right shunt and extra blood flow to the lungs. Without surgery, most children develop severe heart failure and lung damage early in life. Thankfully, with modern surgery and care, many children grow up to lead active lives.

2. What causes CAVC?
CAVC happens when the heart does not form correctly in early pregnancy. In many cases, the exact cause is unknown. It is more common in babies with certain chromosome conditions such as Down syndrome, but it can also occur without any known genetic problem. Parents usually did nothing wrong to cause it.

3. Can medicines alone cure CAVC?
No. Medicines like diuretics, ACE inhibitors, and digoxin can control symptoms such as fluid overload and breathlessness, but they cannot close the holes or create two normal valves. Surgery is needed to correct the structural problem.

4. When is surgery usually done?
Most centers aim to repair complete AV canal in the first months of life, often before 6 months, and sometimes earlier if symptoms or lung pressures are severe. The timing is individualized based on the baby’s condition and growth.

5. What are the main risks of surgery?
Like all open-heart surgery, CAVC repair carries risks such as bleeding, infection, rhythm disturbances, valve leakage, and, rarely, death. However, outcomes have improved greatly in modern centers, and many children do very well in the long term.

6. Will my child need more operations later?
Some children need later surgery or catheter procedures if the reconstructed valves leak significantly or if there are residual holes or rhythm problems. Others may not need further major surgery for many years. Lifelong follow-up is essential.

7. Can children with repaired CAVC play sports?
Many children with repaired CAVC can play and exercise, but activity limits depend on heart function, valve status, and lung pressure. The cardiologist will advise what is safe for each child and may restrict very intense or competitive sports in some cases.

8. Does my child always need antibiotics before dental work?
Not always. Current guidelines usually recommend endocarditis prophylaxis only for certain high-risk situations: for example, for the first 6 months after repair or if there is a residual defect near a patch. Your cardiologist or dentist will advise for your child’s specific situation.

9. Can my child live a normal life span after repair?
Many people with repaired CAVC now survive into adulthood and live active lives, especially when they have early surgery and regular follow-up. Long-term outcomes depend on valve function, lung pressures, and other health factors.

10. Is pregnancy safe for someone with repaired CAVC?
Many women with repaired CAVC can have successful pregnancies, but pregnancy puts extra strain on the heart. They should be followed by adult congenital cardiologists and high-risk obstetricians, and pregnancy should be planned, not accidental.

11. Will future children in the family definitely have CAVC?
Not necessarily. The risk of having another child with a congenital heart defect is higher than in the general population but still not 100%. Genetic counseling can help estimate the risk and discuss testing options.

12. Are there stem cell or regenerative cures available now?
At the moment, there are no approved stem-cell or regenerative treatments that can replace surgery for CAVC. Research is ongoing, but current standard care is still surgical repair plus medical and nutritional support.

13. Why is good nutrition such a big focus?
Infants with CAVC often have high energy needs and feeding difficulties. Poor growth is linked to more complications and longer hospital stays after surgery. Good nutrition improves strength, healing, and brain development.

14. How long will my child need heart medicines?
Many children need medicines like diuretics and ACE inhibitors before surgery and sometimes for a period after surgery. If heart function and valve function are good, medicines may eventually be stopped. Some children need long-term treatment. This is always decided by the cardiology team.

15. Is this information a substitute for my doctor’s advice?
No. This explanation is general and educational. Every child with CAVC is different. Only your child’s cardiologist and medical team, who know the full details, can decide the right tests, medicines, surgery timing, and follow-up plan. Always follow their advice and ask them to explain anything that is not clear.

Disclaimer: Each person’s journey is unique, treatment plan, life style, food habit, hormonal condition, immune system, chronic disease condition, geological location, weather and previous medical  history is also unique. So always seek the best advice from a qualified medical professional or health care provider before trying any treatments to ensure to find out the best plan for you. This guide is for general information and educational purposes only. Regular check-ups and awareness can help to manage and prevent complications associated with these diseases conditions. If you or someone are suffering from this disease condition bookmark this website or share with someone who might find it useful! Boost your knowledge and stay ahead in your health journey. We always try to ensure that the content is regularly updated to reflect the latest medical research and treatment options. Thank you for giving your valuable time to read the article.

The article is written by Team RxHarun and reviewed by the Rx Editorial Board Members

Last Updated: February 27, 2025.