About- Atrioventricular septal defect (AVSD), also known as atrioventricular canal defect (AVCD), common atrioventricular canal (CAVC), or endocardial cushion defect (ECD), is a congenital heart defect that is present at birth. In AVSD, there is a hole or opening between the chambers of the heart, along with an abnormal development of the valves that normally separate the upper and lower chambers. These abnormalities can allow blood to flow abnormally between the right and left sides of the heart. Normally, the heart has four chambers. The atria are the two upper chambers and the ventricles are the two lower chambers. The right and left sides of the heart are separated by walls called the septum. The atrioventricular valves—the tricuspid valve on the right side and mitral valve on the left side—help control blood flow from the atria to the ventricles. In AVSD, these structures do not develop normally. Depending on the type and severity of the defect, the condition can cause increased blood flow to the lungs, enlargement of the heart chambers, leakage through the heart valves, pulmonary hypertension, and eventually heart failure. AVSD is usually diagnosed during infancy or childhood, although some less severe forms may not be identified until later in life.
Complete Atrioventricular Septal Defect- In a complete AVSD, there is a large opening in the center of the heart involving both the atrial and ventricular septa. There is also one common atrioventricular valve instead of separate mitral and tricuspid valves. This type is usually more severe and commonly causes symptoms during infancy because a large amount of blood may flow toward the lungs.
Partial or Incomplete Atrioventricular Septal Defect- In a partial AVSD, the defect usually involves the wall between the atria, along with an abnormal mitral valve. The ventricular septum may remain intact. Symptoms may be less severe and may not appear until childhood, adolescence, or adulthood.
Transitional AVSD- Some people have an intermediate form known as a transitional or intermediate AVSD, in which the abnormalities are between those seen in complete and partial defects. The severity of AVSD varies considerably from one person to another.
Atrioventricular septal defect develops while the baby’s heart is forming during pregnancy. The exact cause of most cases is not known. AVSD results from abnormal development of the structures that form the central portion of the heart, including the atrial and ventricular septa and atrioventricular valves. Genetic and chromosomal factors can play an important role. AVSD is particularly associated with certain chromosomal conditions, including Down syndrome (trisomy 21). Although genetic changes can contribute to AVSD, it is not accurate to say that every case is caused by a single gene mutation.
AVSD has a strong association with Down syndrome. Children with Down syndrome have a higher likelihood of developing congenital heart defects, including AVSD. For this reason, babies diagnosed with AVSD may undergo evaluation for associated genetic or chromosomal conditions when clinically appropriate.
The abnormal openings can allow oxygen-rich blood and oxygen-poor blood to mix or allow blood to flow in an abnormal direction. In a significant AVSD, excessive blood may flow from the left side of the heart toward the lungs. This can increase pressure and blood flow in the pulmonary blood vessels. The abnormal atrioventricular valve may also leak, causing blood to flow backward. This makes the heart work harder. Over time, these changes can lead to:
Enlargement of the heart
Increased blood flow to the lungs
Pulmonary hypertension
Heart valve dysfunction
Abnormal heart rhythms
Heart failure
If pulmonary hypertension becomes severe and remains untreated, permanent changes to the pulmonary blood vessels can develop.
The risk of complications depends on the size and type of defect, associated valve abnormalities, and how early the condition is diagnosed and treated.
A congenital heart defect may sometimes be detected during a routine pregnancy ultrasound. If an abnormality is suspected, the mother may be referred for a fetal echocardiogram, which provides a more detailed assessment of the developing baby’s heart.
Treatment depends on the type and severity of AVSD, the patient’s age, symptoms, heart function, valve abnormalities, and the presence of pulmonary hypertension or other heart defects.
Medicines do not close the heart defect, but they may be used to control symptoms or support heart function before surgery or when surgery is not immediately appropriate. Depending on the situation, doctors may prescribe medicines to:
Reduce fluid overload
Improve heart function
Control abnormal heart rhythms
Manage symptoms of heart failure
Medicines should only be taken under the supervision of a qualified healthcare professional.
Surgical repair is the primary treatment for significant complete AVSD. During surgery, the abnormal openings are closed using appropriate patches or surgical techniques, and the abnormal atrioventricular valve is reconstructed to improve its function. The timing of surgery depends on the child’s condition and the severity of the defect. Babies with significant symptoms may require repair during infancy.
Some people with partial AVSD may be monitored for a period of time if the defect is small and symptoms are absent or mild. Surgery may be recommended when there is significant blood flow across the defect, substantial valve leakage, enlargement of the heart, symptoms, or other indications.
Surgical repair can significantly improve blood flow and symptoms, but lifelong follow-up with a cardiologist is often recommended. Follow-up may include:
Regular clinical examinations
Echocardiograms
ECGs
Monitoring of heart valve function
Assessment of heart rhythm
Evaluation of heart size and function
Monitoring for pulmonary hypertension
Assessment for residual or recurrent defects
Some patients may develop leakage of the left-sided atrioventricular valve or other complications after repair and therefore require long-term monitoring.
Many people who receive appropriate treatment for AVSD can lead active and fulfilling lives. Physical activity recommendations vary depending on the individual’s heart function, rhythm, valve function, pulmonary pressure, and any residual defect. Children should follow their cardiologist’s recommendations regarding exercise, sports, school activities, and follow-up care. Good dental hygiene and regular dental care are also important because certain heart conditions may increase the risk of complications from infections. Antibiotics before dental procedures are not routinely recommended for everyone with AVSD; they are prescribed only for people who meet specific medical criteria.
There is no guaranteed way to prevent AVSD because the condition develops during fetal heart development and its exact cause is often unknown.
Women who are pregnant or planning pregnancy should receive appropriate prenatal care and discuss relevant medical or genetic risk factors with their healthcare provider. If a previous child has had a congenital heart defect or there is a significant family history, genetic counseling and/or fetal echocardiography may be recommended.
Seek medical evaluation if a child has symptoms such as:
Difficulty breathing
Poor feeding
Poor weight gain
Excessive sweating
Persistent tiredness
Bluish discoloration of the lips or skin
Recurrent respiratory infections
Rapid heartbeat
Swelling of the legs or abdomen
Adults with a known AVSD should seek medical attention for worsening breathlessness, chest discomfort, fainting, new or worsening palpitations, swelling, or a significant decline in exercise tolerance. Severe breathing difficulty, fainting, severe chest pain, or significant bluish discoloration requires urgent medical attention.
People with suspected or diagnosed AVSD may need evaluation by one or more specialists, depending on their age and condition.
Cardiologist- A Cardiologist diagnoses and manages heart conditions and monitors heart function. Children are often managed by a pediatric cardiologist, particularly when the defect is diagnosed during infancy or childhood.
Geneticist- A Geneticist may be consulted when a genetic or chromosomal condition is suspected or when genetic counseling is appropriate.
Other specialists, including a cardiothoracic surgeon or congenital heart surgeon, may be involved when surgical repair is required.
Atrioventricular septal defect (AVSD) is a congenital heart defect in which there are abnormal openings between the heart chambers and abnormalities of the atrioventricular valves.
No. Both conditions involve the septum, but they are different congenital heart defects. AVSD can involve both the atrial and ventricular septa and also involves abnormal development of the atrioventricular valves.
Symptoms may include rapid breathing, difficulty feeding, excessive sweating, poor weight gain, fatigue, recurrent respiratory infections, and signs of heart failure.
Yes. Some people with partial or less severe forms may not be diagnosed until adolescence or adulthood. Adults who have had previous repair may also require lifelong cardiac follow-up.
An echocardiogram is the main diagnostic test. ECG, chest X-ray, pulse oximetry, cardiac catheterization, MRI, or CT may be used when additional information is needed.
Surgical repair can correct the structural abnormalities in many patients, but long-term cardiac follow-up is often necessary because residual or recurrent valve problems and other complications can occur.
Not necessarily. The need and timing of surgery depend on the type and severity of AVSD, symptoms, valve function, heart enlargement, pulmonary pressures, and other clinical factors. Significant complete AVSD generally requires surgical repair.
A significant untreated defect can cause excessive blood flow to the lungs, pulmonary hypertension, heart valve problems, heart enlargement, heart failure, and other complications.
Many people who receive appropriate treatment and follow-up can have good long-term outcomes. The outlook varies depending on the severity of the defect, associated conditions, surgical results, and long-term heart function.
The original structural defect generally does not simply return, but residual openings, valve leakage, abnormal heart rhythms, or other complications can occur after repair. Regular cardiology follow-up is therefore important.
A cardiologist, preferably a pediatric cardiologist for children, manages the condition. A congenital heart surgeon or cardiothoracic surgeon may perform surgical repair when necessary. A geneticist may be involved when a genetic or chromosomal condition is suspected.
Medical Disclaimer- This information is intended for general educational purposes only and should not be considered a substitute for professional medical advice, diagnosis, or treatment. Atrioventricular septal defect can vary significantly in severity, and diagnosis and treatment should be determined by a qualified healthcare professional. If you or your child has symptoms suggestive of a heart problem, consult a doctor or qualified cardiologist. In an emergency, seek immediate medical attention.
