Complete atrioventricular canal defect is a serious heart problem that a baby is born with. In this condition there is one large hole in the middle of the heart, where the top chambers (atria) and bottom chambers (ventricles) meet, and there is also one big common valve instead of two separate valves. Because of this, blood can move freely between the right and left sides of the heart, and the heart has to work much harder than normal. []
Complete atrioventricular canal defect is a serious birth defect of the heart where there is one big hole in the center of the heart and one shared atrioventricular valve instead of a separate mitral and tricuspid valve. This hole lets blood mix between the top chambers (atria) and bottom chambers (ventricles). Because of this, too much blood flows to the lungs and the heart has to work very hard. It is strongly linked with Down syndrome. Medicines can reduce symptoms for a short time, but surgery is needed to repair the defect and protect the lungs and heart.
In a healthy heart, the wall between the atria and the wall between the ventricles are closed, and there are two valves (mitral and tricuspid) that stop blood from leaking backward. In complete atrioventricular canal defect, both walls are partly missing, and the valve is abnormal and often leaky. This allows extra blood to flow to the lungs, which can cause heart failure and high pressure in the lung blood vessels if not treated. []
Other names
Doctors use several names for the same basic problem. You may see any of these terms in reports or on websites: [atrioventricular septal defect], [atrioventricular canal defect], or [endocardial cushion defect]. All of these mean that the area in the centre of the heart, where the walls and valves should meet, has not formed correctly. []
The complete form may also be called [complete common atrioventricular canal] or [complete AVSD]. The word “complete” tells us that both the upper and lower walls are affected and that there is one common valve shared between the right and left sides of the heart. This is different from “partial” forms, where only part of the wall is missing and the valves are formed more normally. []
Types of atrioventricular septal defect (AVSD)
Atrioventricular septal defects form a group of related conditions. Doctors usually describe the types like this: []
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Partial AVSD – There is a hole between the top chambers (a primum atrial septal defect) and often a cleft (split) in the mitral valve, but no big hole between the ventricles. The AV valves are mostly separate.
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Transitional (intermediate) AVSD – There is a hole between the atria and a small or restricted hole between the ventricles, with abnormal AV valves. This sits between partial and complete forms.
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Complete AVSD / complete atrioventricular canal defect – There is a large hole that involves both atrial and ventricular septa and a single common AV valve that serves all four chambers. This is the form we are discussing in this article.
Doctors sometimes also describe complete AVSD as [balanced] or [unbalanced]. In a balanced defect, both ventricles are about the same size and can support normal blood flow after surgery. In an unbalanced defect, one ventricle is much smaller, and surgery may be more complex because it is harder for that side of the heart to pump well. []
Causes of complete atrioventricular canal defect
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Down syndrome (trisomy 21)
Complete AV canal defect is very strongly linked with [Down syndrome]. Many babies with this heart problem also have extra chromosome 21. The extra genetic material changes how the heart forms in early pregnancy, especially the central “cushion” tissue that should build the septum and valves. Because of this, screening for heart defects is recommended for all babies with Down syndrome using echocardiography. [] -
Other chromosomal abnormalities (for example trisomy 18 or 13)
Some babies with complete AV canal defect have other chromosome problems, such as trisomy 18 or trisomy 13. These conditions affect many organs, including the developing heart. The abnormal genetic code can disturb the signals that tell the heart walls and valves how to form, leading to holes and valve defects in the centre of the heart. [] -
Single-gene heart or syndromic disorders
Certain single-gene syndromes that affect heart structure, skeleton, or organs on both sides of the body can include AV canal defects. These gene changes may affect the endocardial cushions, which are early heart tissues that must grow and fuse correctly. When these cushions do not fuse, a combined atrial and ventricular defect with valve problems can appear. [] -
Family history of congenital heart disease
Having a parent or sibling with a congenital heart defect slightly increases the chance that a baby will be born with a heart problem, including AV canal defects. This suggests that some families carry genetic variants that make heart development more fragile, especially in the central part of the heart. However, in most families, the exact gene is not known. [] -
Parental consanguinity (parents being close relatives)
In some studies, children with congenital heart disease, including AVSD, were more likely to be born to parents who are closely related, such as first cousins. This may allow harmful recessive gene variants that affect heart development to come together in the baby, increasing the risk of severe heart defects. [] -
Advanced maternal age
Older maternal age is linked with a higher risk of chromosomal conditions such as Down syndrome and some other congenital heart defects. Even when chromosomes are normal, older eggs may be more prone to small developmental errors. This factor is not a direct cause on its own, but it increases the overall chance of having a baby with AV canal defect. [] -
Pre-existing maternal diabetes (before pregnancy)
Women who already have diabetes before pregnancy have a higher risk of having a baby with congenital heart disease, including atrioventricular septal defects. Poor blood sugar control around the time of conception can interfere with early heart formation. High glucose levels can damage the tiny developing heart cells, especially those forming the septum and valves. [] -
Gestational diabetes (diabetes first noticed in pregnancy)
Mothers who develop diabetes only during pregnancy also have a modestly higher risk of having a child with heart defects. The raised blood sugar can disturb normal cell growth and signaling in the embryo. Good glucose control before and during early pregnancy may lower this risk but does not remove it completely. [] -
Maternal obesity
High body mass index (BMI) before or during early pregnancy is linked with a higher chance of congenital heart disease in the baby. Obesity is often connected with insulin resistance, high blood pressure, and inflammation, which can affect blood flow and chemical signals in the placenta and embryo, including the development of the endocardial cushions that form the central heart structures. [] -
Maternal high blood pressure and preeclampsia
High blood pressure and early-onset preeclampsia are associated with an increased risk of congenital heart defects. Some studies show a stronger link specifically with atrioventricular septal defects. Abnormal placental blood flow and maternal vascular problems may stress the embryo and disturb the fine patterning of the heart during the first trimester. [] -
Maternal smoking during pregnancy
Smoking in pregnancy exposes the fetus to nicotine, carbon monoxide, and many toxic chemicals. Large reviews report that maternal smoking modestly increases the risk of congenital heart defects overall. These toxins may cut oxygen supply and damage the fragile tissues that form the central part of the heart. [] -
Exposure to harmful organic solvents and chemicals
Some mothers work with or are exposed to organic solvents, paints, glues, or industrial chemicals. Research suggests that such exposures during early pregnancy may raise the risk of congenital heart defects. These chemicals can interfere with cell division, DNA repair, and signaling, potentially affecting the cushions and septa. [] -
Use of certain medicines in early pregnancy
Some medicines, such as particular anti-seizure drugs, retinoic acid, or poorly controlled warfarin therapy, are known to increase the risk of congenital malformations, including heart defects. These drugs may disrupt normal gene expression or blood flow during heart formation. Doctors try to avoid such medicines or change them before pregnancy when possible. [] -
Maternal viral infections (for example rubella)
Certain viral infections in early pregnancy, especially rubella, can damage the developing heart. The virus can attack fetal tissues and the placenta, leading to inflammation and poor tissue growth. Babies with congenital rubella syndrome often have heart defects along with eye and ear problems. [] -
Poor folate and micronutrient status
Inadequate intake of folic acid and other key nutrients before and in early pregnancy has been linked with a higher risk of congenital heart disease. Folate is needed for DNA synthesis and cell division. When levels are low, the embryo’s organs, including the heart, may not form correctly. [] -
Multiple pregnancy or assisted reproductive technology
Twins or higher-order pregnancies and some pregnancies conceived with fertility treatments have slightly higher rates of congenital heart defects. The reasons are not fully clear, but may relate to early placental problems, higher rates of prematurity, or underlying parental risk factors. [] -
Heterotaxy and organ position syndromes
Some children with complete AV canal defect have heterotaxy, where organs in the chest and abdomen are not in their usual positions. The same developmental errors that disturb organ sidedness can also disrupt formation of the central heart structures, leading to AV canal defects and abnormal pulmonary veins. [] -
Other congenital heart defects in the family
Even if a close relative has a different heart condition, such as a ventricular septal defect or conotruncal defect, this may signal shared genetic susceptibility. Families with one form of congenital heart disease sometimes show other forms, including AV canal, in other children. This suggests common pathways in early heart development. [] -
Paternal age and factors
Some studies suggest that older paternal age or certain paternal exposures (such as smoking or alcohol) may increase the chance of genetic mutations in sperm. These new mutations can affect heart development in the baby, although the increased risk for any one family is usually small. [] -
Unknown or “sporadic” causes
In many babies with complete AV canal defect, no clear cause is found. Heart development is extremely complex, and small random errors in cell growth, blood flow, or gene expression may be enough to produce a defect. These cases are called sporadic, meaning they occur by chance, though subtle genetic or environmental influences probably play a role. []
Symptoms and signs
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Fast or hard breathing (tachypnea and shortness of breath)
Babies with complete AV canal defect often breathe quickly and seem to work hard to breathe, especially during feeding or crying. Extra blood is pushed into the lungs, so the lungs hold too much fluid and it becomes harder for the baby to move air in and out. [] -
Trouble feeding and getting tired while eating
Feeding is like exercise for a baby. With this defect, the heart already works very hard. When the baby sucks, the heart and lungs must work even more, so the baby may stop after a few minutes, sweat, or fall asleep before finishing. This leads to poor intake of milk or formula. [] -
Poor weight gain and growth (failure to thrive)
Because feeding is difficult and the body uses extra energy to breathe and pump blood, babies with complete AV canal defect may not gain weight as expected. Their clothes may stay the same size, and growth charts may show a flat line instead of steady increase. [] -
Sweating, especially during feeds
Many parents notice that their baby’s head becomes sweaty when feeding. This happens because the heart is under stress and the body releases hormones that cause sweating, similar to how adults may sweat during heavy exercise or heart strain. [] -
Fast heart rate (tachycardia)
The heart beats faster to push more blood to the body and lungs to try to keep up with the body’s needs. Doctors can feel or hear this rapid heartbeat during examination, and it is often one of the first abnormal signs they detect. [] -
Heart murmur
A heart murmur is a whooshing sound caused by turbulent blood flow. In complete AV canal defects, blood flows through the large central hole and through leaky valves, creating a loud, often complex murmur that doctors can hear with a stethoscope. [] -
Bluish skin, lips, or nails (cyanosis)
Some babies may have a blue tinge to their lips, tongue, or fingers, especially when crying or feeding. This can happen when blood in the body is not carrying enough oxygen, either because of mixing of oxygen-rich and oxygen-poor blood or because the lungs are overloaded. [] -
Cool or pale extremities
The hands and feet may feel cool or look pale because the body diverts blood away from the skin towards vital organs like the brain and heart. This is a sign that the circulation is under stress and the heart is struggling to keep up. [] -
Enlarged liver and swollen belly
When the right side of the heart is overloaded, blood can back up into the veins and the liver. Doctors can feel an enlarged liver just under the right ribs. In more severe cases, fluid may build up in the abdomen, leading to a swollen belly. [] -
Swelling of legs or feet (peripheral edema)
Although less common in very small infants, older children with long-standing heart failure from untreated AV canal defect may develop puffiness in the ankles, feet, or lower legs. This happens because fluid leaks out of the blood vessels when venous pressure is high. [] -
Frequent chest infections
Because there is too much blood flow to the lungs, babies may develop frequent respiratory infections, cough, or pneumonia. The lungs stay congested, making it easier for viruses and bacteria to cause illness. [] -
Irritability and low energy
Babies with this defect may be fussy, difficult to settle, or sleepy and less active than expected for their age. Their bodies are under constant strain, and they may not have enough energy to play, smile, or interact as much as other infants. [] -
Signs of pulmonary hypertension (raised lung pressure)
Over time, if the defect is not repaired, the high blood flow to the lungs can damage the lung vessels, causing pulmonary hypertension. Children may then have more severe breathlessness, fainting spells, or worsening cyanosis as blood flow to the lungs becomes limited. [] -
Irregular heartbeats (arrhythmias)
Some patients develop abnormal heart rhythms as they grow older, either from the congenital defect, from scarring after surgery, or from enlargement of the heart chambers. These rhythms can cause palpitations, dizziness, or fainting in older children and adults. [] -
Symptoms appearing at 4–8 weeks of age
Many babies with complete AV canal defect look almost normal at birth. As lung resistance falls during the first weeks of life, more blood flows to the lungs and symptoms such as fast breathing, feeding difficulty, and poor weight gain typically appear around one to two months of age. []
Diagnostic Tests
Physical examination tests (bedside)
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General inspection and growth check
The doctor first looks at the baby’s overall appearance, breathing pattern, and colour, and checks weight, length, and head size on growth charts. Poor growth, fast breathing, and sweating give early clues to heart failure from complete AV canal defect and help decide how urgently further tests are needed. [] -
Vital signs (heart rate, breathing rate, temperature, blood pressure)
Measuring pulse, breathing rate, temperature, and blood pressure is a key step. Fast heart rate and breathing, low blood pressure, or low oxygen levels can all point to significant heart disease. Blood pressure differences between arms and legs may also suggest other associated heart problems. [] -
Cardiac auscultation with a stethoscope
Listening to the heart lets the doctor hear murmurs, extra sounds, or abnormal splitting of heart sounds. The loud, complex murmur and sometimes a “gallop” rhythm in complete AV canal defect help guide the doctor toward this diagnosis before imaging tests are done. [] -
Lung and abdominal examination
The doctor listens to the lungs for crackles that suggest fluid overload and feels the abdomen for an enlarged liver. These simple bedside checks are important signs of heart failure and give a sense of how badly the heart is struggling because of the defect. []
Manual / simple bedside tests
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Pulse oximetry (oxygen saturation test)
A small sensor is placed on the baby’s hand or foot to measure the oxygen level in the blood. In complete AV canal defect, oxygen saturation may be normal or slightly low at rest, but can drop with crying or feeding. This test is painless and is now widely used to screen newborns for serious heart defects. [] -
Capillary refill time
The doctor presses gently on the baby’s fingertip or chest and watches how quickly the colour returns. If the refill time is long, it can mean that the heart is not pumping strongly enough or that the baby’s circulation is under stress, which fits with advanced heart failure. [] -
Four-limb blood pressure measurement
Blood pressure may be measured in both arms and legs. Differences in pressure can reveal other associated heart problems, but even when pressures are similar, this test gives clues about how well the heart is moving blood around the body in the setting of AV canal defect. [] -
Growth chart and nutrition assessment
Plotting weight and length over time helps to show whether the baby is failing to thrive. In complete AV canal defect, calories are often not enough to keep up with energy use. This simple “manual” test using charts and history helps decide when to add extra feeds or tube feeding before surgery. []
Laboratory and pathological tests
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Complete blood count (CBC)
A CBC measures red cells, white cells, and platelets. It can show anemia, which makes the heart work even harder, or signs of infection. While CBC does not diagnose the defect itself, it helps to understand how the body is coping and to plan safe surgery. [] -
Blood chemistry and kidney–liver function tests
These tests look at salts, kidney numbers, and liver enzymes. Heart failure and medicines like diuretics can affect these organs. Checking them helps doctors adjust treatment and decide when it is safe to proceed with anaesthesia and heart surgery. [] -
Brain natriuretic peptide (BNP or NT-proBNP)
BNP is a hormone released when the heart muscle is stretched and stressed. High levels suggest significant heart failure. In babies with complete AV canal defect, elevated BNP can support the clinical impression that the heart is overloaded and that urgent treatment is needed. [] -
Genetic testing (karyotype and microarray)
Because complete AV canal defect is strongly linked with Down syndrome and other chromosomal problems, doctors often send blood for chromosome analysis. A karyotype shows extra or missing chromosomes, and microarray can detect smaller changes. The results help counsel the family and may influence long-term care plans. [] -
Screening for maternal or congenital infections
Blood tests may be done to look for infections such as rubella or other TORCH infections that can damage the developing heart. This is more common when there are other birth defects or signs that suggest an infection during pregnancy. []
Electrodiagnostic and functional cardiac tests
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Standard 12-lead electrocardiogram (ECG)
An ECG records the electrical activity of the heart. In complete AV canal defect it may show enlargement of both ventricles, axis deviation, or rhythm abnormalities. This helps confirm that the heart is under strain and may reveal conduction problems that are important before and after surgery. [] -
Holter monitoring (24-hour ECG recording)
If doctors are worried about irregular heart rhythms, they may use a Holter monitor to record the ECG for a full day. This can detect episodes of fast or slow heart rhythm that are not seen in a short ECG, especially in older children or adults who had surgery in the past. [] -
Exercise testing (in older children and adults)
For patients who are old enough, walking or cycling tests with ECG and blood pressure monitoring can show how the heart responds to effort. Reduced exercise capacity, abnormal blood pressure response, or arrhythmias during the test can reflect the long-term impact of the defect and any valve problems after repair. []
Imaging tests
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Chest X-ray
A chest X-ray shows the size and shape of the heart and the blood vessels in the lungs. In complete AV canal defect, the heart is often enlarged and the lung vessels may look thick and prominent because of increased blood flow. This simple test gives a quick overview of heart failure severity. [] -
Transthoracic echocardiogram (heart ultrasound)
This is the key test for diagnosing complete AV canal defect. A probe on the chest uses sound waves to create moving pictures of the heart. It clearly shows the central hole, the common AV valve, how blood flows between chambers, and whether the valve is leaking. It also helps surgeons plan the repair. [] -
Fetal echocardiography (ultrasound before birth)
If there are risk factors such as Down syndrome or abnormal routine pregnancy scans, a detailed heart ultrasound can be done before birth. Fetal echocardiography can detect complete AV canal defect during mid-pregnancy, allowing early counselling and planning for delivery at a centre with heart surgery services. [] -
Cardiac catheterization and angiography
In this test, thin tubes are passed through blood vessels into the heart. Pressure and oxygen levels are measured, and contrast dye is injected to see blood flow. Cardiac catheterization is used when doctors need exact information about lung pressures, resistance, or associated defects before surgery. It also helps decide if the lung blood vessels are still operable. []
Non-pharmacological (non-drug) treatments
Below are 20 important non-drug therapies and supports. They often work together with medicines and surgery.
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Parental education and counselling
Parents learn what complete atrioventricular canal defect is, why the baby breathes fast or sweats with feeds, and what danger signs to watch for. Clear teaching reduces fear and helps parents give medicines and feeds correctly at home. The health team explains the surgery plan, follow-up visits, vaccines, and how to keep the child safe from infections. Good education helps families make early decisions and seek care quickly when symptoms change. -
Feeding support and pacing
Babies with this defect tire quickly when feeding because the heart and lungs are working harder. Nurses and dietitians show parents how to give smaller, more frequent feeds and to pause often so the baby can rest and breathe. Sometimes special nipples or feeding positions are used. This “feeding pacing” lowers the baby’s energy use and reduces the work of breathing while still giving enough calories. -
High-calorie nutrition and growth monitoring
Many babies with complete atrioventricular canal defect fail to gain weight. Calorie-enriched breast milk or formula can be used so the baby gets more energy in a smaller volume. A dietitian may add special calorie boosters to feeds. Weight, length, and head size are checked often. Good nutrition helps the baby become strong enough for surgery and improves wound healing afterwards. -
Positioning to ease breathing
Simple body positions can make breathing easier. Slight head-up or semi-upright positions help lungs expand and reduce pressure from the belly on the chest. Caregivers are taught to avoid positions that worsen breathing, such as flat on the back in a baby with heavy lung congestion. Proper positioning also lowers the risk of aspiration when feeding. -
Oxygen therapy when prescribed
Some babies need extra oxygen for a short time, especially during infections or before surgery. Oxygen increases the amount of oxygen in the blood and can reduce the work of breathing. However, in some patients with high lung pressure, oxygen has to be used carefully. The cardiology team decides the flow and delivery method. Parents are taught safe home oxygen use when needed. -
Fluid management and careful weighing
Daily weight checks help the team see if the baby is holding too much fluid or losing weight. If weight jumps quickly, it can mean fluid buildup in the lungs or body. Nurses may teach parents how to weigh the baby at home and keep a simple diary. This non-drug monitoring helps doctors adjust diuretics and fluids early, before severe heart failure develops. -
Moderate salt restriction if advised
Too much salt can make the body hold extra water, which worsens lung congestion and heart failure. For some children, doctors advise avoiding very salty foods and not adding extra salt. The goal is a modest reduction, not extreme restriction, so that nutrition stays balanced. Parents are guided on reading food labels when the child is older. -
Protection from respiratory infections
Lung infections like bronchiolitis or pneumonia can be very dangerous in babies with complete atrioventricular canal defect. Families are advised to avoid tobacco smoke, crowded places during virus season, and contact with people who are sick. Good hand hygiene and staying up to date with vaccines are key non-drug tools to keep the lungs healthy and reduce hospital admissions. -
Developmental and physiotherapy support
Because of frequent illness and hospital stays, some babies may have delayed motor skills. Early physiotherapy and occupational therapy help improve muscle strength and movement. Gentle exercises, guided play, and positioning support normal development while respecting the child’s limited energy. This helps the child catch up after surgery and improves quality of life. -
Psychological support for family
Caring for a baby with a serious heart defect is stressful. Counselling, parent support groups, and social work services can help families cope emotionally and practically. This support lowers anxiety, improves adherence to treatment, and helps parents keep a stable home environment, which is very important for the child’s recovery. -
Genetic counselling
Complete atrioventricular canal defect is often associated with trisomy 21 (Down syndrome). A genetics team can explain what this means for the child and discuss the chance of similar heart problems in future pregnancies. They may recommend chromosome testing and talk about early intervention services. This non-drug step helps families plan and understand long-term needs. -
Regular cardiology follow-up and echocardiography
Scheduled visits with a pediatric cardiologist allow careful tracking of heart size, valve leakage, lung pressure, and symptoms. Echocardiograms, chest X-rays, and ECGs guide the timing of surgery and medicine changes. Regular follow-up is a key “therapy” because it prevents silent worsening and catches problems early. -
Pre-operative stabilization
Before surgery, the team focuses on making the baby as stable as possible. This includes optimizing nutrition, adjusting diuretics and afterload-reducing medicines, treating infections, and arranging safe anesthesia plans. Good pre-operative preparation lowers surgical risk and shortens intensive care stay. It is a coordinated non-drug process involving many specialists. -
Post-operative rehabilitation and graded activity
After surgery, children need time to rebuild strength. Nurses and physiotherapists guide safe movement, breathing exercises, and gradual increase in activity. Parents learn how much play is allowed and what signs mean the child is over-tired. Early but gentle mobilization after surgery supports lung function, reduces clots, and improves mood. -
Dental care and endocarditis prevention habits
Good oral hygiene reduces the risk of bacterial endocarditis, an infection of the heart lining and valves. Families are taught to brush the child’s teeth regularly and to see a dentist familiar with heart defects. For some high-risk procedures, antibiotics may be given as drug prophylaxis, but daily non-drug care of the teeth and gums is the foundation. -
Avoiding second-hand smoke and environmental pollutants
Smoke and polluted air irritate the lungs and can worsen breathing and heart failure symptoms. Families are advised that no one should smoke inside the house or car. If possible, the child should avoid areas with heavy pollution or strong chemical fumes. Cleaner air reduces coughing, wheezing, and hospital visits. -
Vaccinations and RSV prevention strategies
Routine childhood vaccines, including influenza, are very important for children with heart defects because infections can be more serious. In some high-risk infants, doctors may recommend special injections to reduce the risk of severe RSV (respiratory syncytial virus) disease. These are partly drug-based, but the planning, scheduling, and family education around them are crucial non-drug elements. -
Care coordination and case management
Many children with complete atrioventricular canal defect see several specialists. A care coordinator or nurse navigator helps arrange appointments, tests, surgery dates, and home care services. This reduces missed visits and mixed messages. Good coordination ensures that nutrition, medications, and surgery plans all work together smoothly. -
Transition planning to adult congenital heart care
As the child grows up, care needs to shift from pediatric cardiology to adult congenital heart disease services. Transition planning includes teaching the young person about their heart condition, surgery history, and the need for lifelong follow-up. This is a long non-drug process that protects heart health in adult life. -
Family lifestyle adjustments (sleep, stress, routines)
Simple routines like regular sleep, calm feeding times, and reduced family stress help the child cope better. A predictable daily schedule with enough rest breaks keeps energy use steady and supports growth. These lifestyle adjustments may seem small, but together they help medicines and surgery work better and improve the whole family’s well-being.
Drug treatments – bridge and support, not a cure
Medicines cannot close the hole in complete atrioventricular canal defect, but they can control symptoms of heart failure and protect the lungs until surgery, and they help recovery after surgery. The exact dose, timing, and choice of drug are always decided by a pediatric cardiologist, based on body weight, age, kidney function, and blood pressure. Never change or start medicines without the heart specialist. Below are 20 important drug types often used around this condition.
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Furosemide (Lasix) – loop diuretic
Furosemide is a strong “water pill” that helps the kidneys remove extra salt and water from the body. It reduces lung congestion and swelling in children with heart failure. FDA labeling notes its use for edema linked with heart failure in adults and children. The dose is calculated per kilogram of body weight and adjusted over time. Side effects can include dehydration, low potassium, low sodium, and changes in kidney function, so blood tests and careful monitoring are essential. -
Chlorothiazide or hydrochlorothiazide – thiazide diuretics
Thiazide diuretics are milder water tablets that can be added when a loop diuretic alone is not enough. They help the kidneys excrete sodium and water from a different part of the kidney tubule. Used together with furosemide, they can give a “sequential” diuretic effect. Doctors monitor electrolytes closely, because these drugs can also lower sodium, potassium, and magnesium and may affect blood sugar and uric acid. -
Spironolactone – potassium-sparing diuretic
Spironolactone blocks the hormone aldosterone, which normally tells the kidneys to keep salt and water. By blocking it, spironolactone helps remove fluid but tends to keep potassium, which can balance the potassium loss from loop and thiazide diuretics. This drug is used as an extra diuretic when needed. Side effects include high potassium, breast swelling, and stomach upset, so regular blood tests are required. -
Enalapril – ACE inhibitor
Enalapril is an angiotensin-converting enzyme (ACE) inhibitor that relaxes blood vessels and reduces pressure the heart must pump against (afterload). FDA labeling describes its benefits in heart failure by suppressing the renin–angiotensin–aldosterone system. In complete atrioventricular canal defect, it can improve forward blood flow and reduce valve regurgitation symptoms. Dose is weight-based and carefully increased. Side effects include low blood pressure, kidney effects, cough, and high potassium. -
Captopril or lisinopril – other ACE inhibitors
Captopril and lisinopril work in a similar way to enalapril by blocking ACE and lowering afterload. They are sometimes used instead of enalapril depending on local practice and patient needs. In infants, doses are small and given several times a day. As with enalapril, doctors watch for low blood pressure, kidney problems, and high potassium, and they adjust the dose slowly to avoid sudden drops in blood pressure. -
Digoxin – cardiac glycoside
Digoxin increases the force of each heartbeat and slows the heart rate slightly. It can help some children with heart failure feel better and may improve feeding and weight gain. The medicine has a very narrow safety window, so the dose is very carefully calculated for body weight and kidney function. Doctors may check blood digoxin levels. Side effects of too much digoxin include vomiting, poor appetite, slow or irregular heartbeat, and vision changes, so families are taught warning signs. -
Carvedilol or other beta-blockers
Beta-blockers like carvedilol slow the heart rate and reduce the effect of stress hormones on the heart. In some children with heart failure and valve leakage, they can improve heart function over time. The dose is started very low and slowly increased under close monitoring of heart rate, blood pressure, and symptoms. Side effects can include tiredness, cold hands and feet, and low blood pressure. -
Milrinone – inotrope and vasodilator (IV only)
Milrinone is an intravenous medicine used in hospital, usually in the intensive care unit. It increases the strength of the heart’s contractions and relaxes blood vessels, improving cardiac output and lowering lung pressures. It is often used around the time of surgery for support. Because it can lower blood pressure and affect heart rhythm, it is only given with continuous monitoring and careful dose control. -
Dopamine and dobutamine – IV inotropes
Dopamine and dobutamine are intravenous drugs used to support blood pressure and heart pumping in very sick infants, often before or just after surgery. They act on the heart and blood vessels to increase cardiac output. These medicines are short-term bridges, not long-term treatments. Side effects include fast heart rate, irregular rhythms, and high blood pressure, so they are used only in intensive care under constant monitoring. -
Epinephrine or norepinephrine – vasopressor support (ICU)
In rare severe cases, epinephrine or norepinephrine may be used to support blood pressure during surgery or critical illness. They tighten blood vessels and increase heart pumping, but they are powerful and can strain the heart if used incorrectly. These drugs are only given by specialists in an intensive care setting and are turned off as soon as the child is stable. -
Sildenafil – pulmonary vasodilator
Sildenafil relaxes the blood vessels in the lungs. In some children with high lung pressures (pulmonary hypertension) related to complete atrioventricular canal defect, it may be used to lower lung vascular resistance, especially after surgery. Doses are weight-based and must be carefully monitored. Side effects can include flushing, headache, low blood pressure, and stomach upset. -
Bosentan or other endothelin-receptor antagonists
Bosentan blocks endothelin, a chemical that tightens blood vessels. It is sometimes used in children with severe pulmonary arterial hypertension, including some with congenital heart disease. Treatment requires strict liver-function monitoring and specialist oversight. It is not used in every child with complete atrioventricular canal defect, but can be part of advanced pulmonary hypertension care. -
Aspirin – antiplatelet agent
Low-dose aspirin makes platelets less sticky and helps prevent clots. It may be used after certain surgeries, especially if a patch or prosthetic material is present, or if there is risk of small clots. Dose is chosen carefully by weight. Side effects include stomach irritation and a rare risk of bleeding, so parents are told to report unusual bruising or dark stools. -
Heparin and low-molecular-weight heparin – anticoagulants
These blood thinners are often used in hospital around surgery, especially when central lines, heart–lung bypass circuits, or high clot risk are present. They reduce clot formation but increase bleeding risk, so doctors monitor clotting tests closely. They are usually short-term and not routine for all patients with complete atrioventricular canal defect. -
Warfarin – long-term anticoagulant (selected cases)
Warfarin may be used in certain children with mechanical valves or special rhythm problems, though mechanical valves are less common in small children. It requires frequent blood tests (INR) to keep the dose in a safe range. Many foods and drugs interact with warfarin, so its use is carefully supervised by a specialist team. -
Antibiotics for endocarditis prophylaxis (e.g., amoxicillin)
For some dental or surgical procedures in high-risk patients, short-term antibiotics may be given before the procedure to reduce the risk of infective endocarditis. The choice of antibiotic and dose follows heart-society guidelines. This is not daily therapy, but a targeted preventive strategy used only when indicated. -
Analgesics and antipyretics (paracetamol/acetaminophen)
Pain and fever increase heart rate and oxygen demand. Simple medicines like paracetamol (acetaminophen) are used to control fever and mild pain after surgery or during infections. Doses are based on weight and kept within safe limits to protect the liver. Caregivers are taught not to mix different pain medicines without medical advice. -
Sedatives (e.g., midazolam) in ICU
Sedatives are sometimes needed during mechanical ventilation or in the immediate post-operative period to keep the child calm and safe. They reduce stress and help healing but are used for the shortest time possible. Doctors carefully watch breathing, blood pressure, and awakening, and taper sedatives to avoid withdrawal symptoms. -
Iron supplements (if iron-deficiency anemia is present)
Some children with chronic heart failure or poor nutrition may develop iron-deficiency anemia, which reduces oxygen carrying capacity. Iron supplements are used only when blood tests confirm deficiency. They help red blood cells carry more oxygen, improving energy and growth. Side effects can include stomach upset and constipation, so doses are adjusted and given with food if needed. -
Proton pump inhibitors or H2 blockers (stomach protection)
Children who are very ill, on multiple medicines, or on blood thinners may be given stomach-protective drugs to lower acid and reduce the risk of ulcers or bleeding. These medicines are supportive, not specific to complete atrioventricular canal defect, but they help protect the gut while the heart is under stress. Doctors review the need regularly and stop them when no longer required.
Dietary molecular supplements
There is no supplement that can repair the heart defect, and many supplements are not well studied in infants. Any supplement must be approved by the child’s cardiologist. Below are 10 commonly discussed nutrients where evidence is mainly supportive or indirect.
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Vitamin D – supports bone growth and immune function; deficiency is common in children with chronic illness. Dose depends on age and blood level. Too much can cause high calcium and kidney problems, so monitoring is needed.
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Iron – if anemia is proven, iron helps red blood cells carry oxygen so the heart does not need to pump as hard. Dose is mg/kg per day, adjusted by blood tests. Over-supplementation can harm organs, so it is never given blindly.
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Folic acid and B-complex vitamins – support red blood cell production and general metabolism. They may be used when dietary intake is low, but they do not change the heart defect itself. High doses should be avoided unless prescribed.
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Omega-3 fatty acids (fish-oil based, for older children) – may have modest benefits for heart rhythm and inflammation in some heart conditions, but evidence in small children with congenital defects is limited. Doses are chosen carefully to avoid bleeding risk, especially if the child is on anticoagulants.
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Zinc – important for growth and immunity. In malnourished children, zinc supplements can support recovery from infections. Excess zinc can upset copper balance, so dose and duration should be supervised.
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Probiotics – may support gut health, which can be disturbed by repeated antibiotics. However, in very sick or immunocompromised children, probiotics may carry risks. They should only be used if the cardiologist and pediatrician agree.
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Coenzyme Q10 – sometimes used in adult heart failure as a supportive antioxidant, but data in infants and children with complete atrioventricular canal defect are limited. Any use is off-label and experimental and must be discussed with specialists.
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Multivitamin drops – basic multivitamin preparations may help ensure adequate intake when appetite is poor. Doses follow age-specific recommendations. They should not contain extra high doses of single vitamins unless a deficiency is proven.
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Calcium (with vitamin D) when feeding is limited – if oral intake is low for a long time, calcium supplements may be needed to protect bones, especially after long ICU stays. Blood levels and kidney function guide dosing.
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Specialized high-calorie formulas – not a “supplement pill”, but a medically designed formula that packs more calories and nutrients into small volumes. This can be vital to help babies gain weight before surgery. Dietitians select the product and adjust the concentration.
Immune-supporting, regenerative and stem-cell related drugs
Right now, there are no approved stem cell or regenerative drugs that can cure or directly repair complete atrioventricular canal defect in routine clinical practice. Research in regenerative cardiology is ongoing but remains experimental and is not standard care for infants with this condition.
Instead, doctors focus on:
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keeping vaccines up to date and using special RSV prevention strategies where indicated
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using antibiotics wisely to treat or prevent serious infections
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giving nutritional support so the immune system works well
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using advanced heart-failure and pulmonary-hypertension drugs when needed
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using transplant medicines only in extremely rare end-stage cases.
Any “immunity booster” or “stem cell” therapy advertised outside properly regulated trials should be viewed with great caution and discussed with the child’s cardiology team.
Surgical treatments
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Complete atrioventricular canal repair (definitive open-heart surgery)
This is the main treatment and the only way to close the large central hole and reconstruct the valves. During open-heart surgery, the surgeon uses patches to close the atrial and ventricular septal defects and reshapes the common valve into two valves. Surgery is usually done in early infancy before permanent lung damage occurs. This operation greatly improves survival and long-term quality of life. -
Pulmonary artery banding (palliative)
In some small or very sick babies who cannot safely have full repair yet, surgeons may place a band around the pulmonary artery to limit blood flow to the lungs. This lowers lung pressure and protects the vessels until the child is bigger and stronger. Later, the band is removed and a complete repair is done. -
Re-operation for residual defects or valve regurgitation
Sometimes, after the first repair, there can still be leakage of the left atrioventricular valve or small residual holes. If these cause significant symptoms or heart enlargement, a second surgery may be needed to repair or replace parts of the valve or patch. The goal is to restore good valve function and prevent long-term heart failure. -
Pacemaker implantation
A small number of children develop heart rhythm problems such as complete heart block either from the defect itself or as a complication of surgery. In those cases, a permanent pacemaker is implanted. The pacemaker sends regular electrical impulses to keep the heart beating at a safe rate, preventing dizziness, fainting, or heart failure. -
Heart transplantation (very rare, last resort)
If severe heart failure continues despite good surgery and medical treatment, or if there is severe lung vascular disease, heart transplantation may be considered. This is rare and involves strict selection, long waiting times, and lifelong medicines to prevent rejection. It is not a standard pathway for most children with complete atrioventricular canal defect, because many do very well after repair.
prevention and risk-reduction strategies
Complete atrioventricular canal defect often cannot be fully prevented, but some steps may lower overall risk or prevent complications:
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Good pre-pregnancy counselling for women with diabetes, epilepsy, or other conditions, to optimize medicines before conception.
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Avoiding alcohol, smoking, and illicit drugs during pregnancy, which are linked to many birth defects.
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Taking folic acid before and during early pregnancy to reduce some congenital malformations, as advised by obstetric guidelines.
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Prompt treatment and, when possible, prevention of maternal infections such as rubella.
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Avoiding known teratogenic medicines in early pregnancy, after discussion with doctors.
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Regular antenatal care and ultrasound scans, which may detect the defect and allow planned delivery in a specialist center.
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Early postnatal screening when there is a family history of congenital heart disease or Down syndrome.
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After birth, preventing lung infections (vaccines, smoke-free home, good hygiene) to avoid extra stress on the heart.
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Ensuring timely surgery when recommended, to prevent irreversible lung vascular damage.
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Maintaining lifelong follow-up with a congenital heart specialist to catch late complications early.
When to see a doctor or go to emergency care
Children with complete atrioventricular canal defect should be seen urgently if there is:
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Fast, difficult breathing or ribs pulling in while breathing
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Bluish colour of lips, tongue, or face
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Poor feeding or refusal to eat, especially with sweating or breathing trouble
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Very poor weight gain or weight loss
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Unusual sleepiness, irritability, or low energy
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Fever with breathing problems or vomiting
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Swelling of legs, face, or belly
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Any chest pain or fainting in older children
If any of these occur, parents should contact the cardiology team or local emergency service immediately.
What to eat and what to avoid
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Offer small, frequent feeds with calorie-enriched breast milk or formula as advised, rather than large feeds that tire the baby.
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As the child grows, aim for a balanced diet with fruits, vegetables, whole grains, and lean protein to support general health and healing.
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Limit high-salt processed foods (chips, instant noodles, salty snacks) if the cardiologist recommends salt restriction.
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Avoid sugary drinks and excessive sweets, which give calories without good nutrients and may worsen weight problems later.
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Make sure the child gets enough iron-rich foods (meats, beans, fortified cereals) if anemia is a concern, as guided by the doctor.
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Encourage safe fluids as advised; in some cases, total fluid may need to be limited, so parents must follow the cardiology plan.
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Avoid giving herbal or over-the-counter supplements without approval, as they can interact with heart medicines or cause harm.
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After surgery, follow specific post-operative diet instructions, such as soft foods if the child is tired, and gradually return to normal eating.
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For older children and teens, avoid energy drinks and high-caffeine drinks, which can speed up the heart and disturb rhythm.
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Work regularly with a dietitian linked to the cardiac team to adjust calories and nutrients as the child grows, especially if appetite is poor.
Frequently asked questions (FAQs)
1. Can complete atrioventricular canal defect close by itself with medicines?
No. This defect involves a large central hole and valve malformation. Medicines can improve symptoms and growth but cannot close the hole or rebuild the valves. Only surgery can repair the structure of the heart.
2. What is the usual age for surgery?
Most centers aim to perform complete repair in early infancy, often between 3 and 6 months of age, before high pressure in the lungs becomes permanent. The exact timing depends on symptoms, lung pressure, growth, and the presence of other conditions such as Down syndrome.
3. Will my child need medicines for life after surgery?
Some children need only short-term medicines after surgery, while others may stay on diuretics, ACE inhibitors, or low-dose aspirin for longer, depending on valve function and lung pressure. Regular follow-up decides when medicines can be reduced or stopped.
4. What is the long-term outlook after repair?
Many children live active lives after successful repair, attend school, and play with some limits. Some may need further valve surgery or treatment for rhythm problems later in life. Lifelong follow-up with a congenital heart specialist is essential to keep track of these issues.
5. Is this condition always linked to Down syndrome?
No. It is strongly associated with Down syndrome, but it can also occur in children with normal chromosomes or other syndromes. Genetic testing can help clarify the cause and guide other health checks.
6. Can my child play sports?
After full healing and with cardiologist approval, many children can take part in light or moderate physical activity. Contact or very intense competitive sports may be limited, depending on valve function, lung pressure, and rhythm. The cardiologist will give personalized advice.
7. Will future pregnancies have the same heart problem?
The risk is higher than in the general population but not 100%. Cardiac and genetic counselling can give more precise estimates and discuss screening options such as detailed fetal echocardiography in future pregnancies.
8. Are stem-cell therapies available to avoid surgery?
At present, stem-cell treatments for this defect are experimental only and not approved for routine care in infants. Surgery remains the standard and proven treatment. Any offer of stem-cell cure outside a controlled trial should be discussed carefully with the cardiology team.
9. Why does my baby sweat so much when feeding?
Feeding is like exercise for a baby. Because the heart is working very hard and the lungs have too much blood flow, feeding increases heart rate and breathing. Sweating is a sign that the baby is using a lot of energy. Medicines, high-calorie feeds, and timely surgery help reduce this.
10. Can my child get all routine vaccines?
Yes, and they are very important. Children with heart defects can become more seriously ill from infections like flu or pneumonia. The cardiologist may also recommend extra protections, such as RSV prevention in high-risk infants.
11. Do we always need antibiotics before dental visits?
Not always. Some children with certain heart repairs or valve problems do need antibiotics before high-risk dental work, but others do not. The cardiologist will provide a written plan. Good daily tooth brushing is the most important part of prevention.
12. How often will my child need check-ups?
In infancy, visits may be frequent, sometimes every few weeks. After surgery and stabilization, visits may move to every 6–12 months. In adulthood, regular reviews at an adult congenital heart clinic will continue for life.
13. What are signs that medicines are not enough anymore?
Warning signs include faster breathing, new or worse sweating with feeds, poor weight gain, swelling, or more hospital admissions for lung infections or heart failure. These may mean surgery or medicine adjustment is needed.
14. Is pregnancy possible later for a girl with this repair?
Many women with repaired complete atrioventricular canal defect can have healthy pregnancies, but they need careful evaluation before becoming pregnant and close monitoring during pregnancy in a high-risk cardiac-obstetric center.
15. What should we do day-to-day at home?
Give medicines exactly as prescribed, keep all appointments, watch for breathing or feeding changes, keep vaccinations up to date, maintain good nutrition and sleep, and avoid smoke and sick contacts. Ask the cardiology team whenever you are unsure. These simple actions, together with surgery and medical care, give your child the best chance for a healthy life.
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.
