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Complete Common Atrioventricular Canal Defect, also known as Atrioventricular Septal Defect, is a lack of separation of the atria and the ventricles into separate right and left chambers as well as a lack of separation of the mitral and tricuspid valves. The lack of separation of these two valves results in a single atrioventricular valve.
In patients with atrioventricular canal defect, the single atrioventricular may not close properly. Therefore, the heart must pump an excessive amount of blood and this may result in an enlargement of the heart.
Surgical repair for atrioventricular canal defect is required within the first six months of life. The surgery involves sewing patches over the ASD and VSD and carefully separating the single atrioventricular valve into two valves.
How Does Atrioventricular Canal Defect Differ From
Normal Cardiac Anatomy?
If your child has atrioventricular canal defect the structure of his or her heart is different from normal cardiac anatomy.
Heart With Normal Cardiac Anatomy
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Adobe Flash Player.
When your child has a congenital heart defect, there's usually something wrong with the structure of his or her heart's structure.
The heart is composed of four chambers. The two upper chambers, known as atria, collect blood as it flows back to the heart. The two lower chambers, known as ventricles, pump blood with each heartbeat to the two main arteries (the pulmonary artery and the aorta). The septum is the wall that divides the heart into right and left sides. The atrial septum separates the right and left atria; likewise, the ventricular septum separates the two ventricles.
There are four valves that control the flow of blood through the heart. These flap-like structures allow blood to flow in only one direction. The tricuspid and mitral valves, also known as the atrioventricular valves, separate the upper and lower chambers of the heart. The aortic and pulmonary valves, also known as the arterial valves, separate the ventricles from the main arteries. Oxygen-depleted blood returns from the body and drains into the right atrium via the superior and inferior vena cavas. The blood in the right atrium then passes through the tricuspid valve and enters the right ventricle.
Next, the blood passes through the pulmonary valve, enters the pulmonary artery, and travels to the lungs where it is replenished with oxygen. The oxygen-rich blood returns to the heart via the pulmonary veins, draining into the left atrium. The blood in the left atrium passes through the bicuspid, or mitral, valve and enters the left ventricle.
Finally, the oxygen-rich blood flows through the aortic valve into the aorta and out to the rest of the body.
From Nemours' KidsHealth
- ECG (Electrocardiogram)
- Cardiac Catheterization
- When Your Child Needs a Heart Transplant
- If Your Child Has a Heart Defect
- Heart and Circulatory System
- Congenital Heart Defects Special Needs Factsheet
- Atrial Septal Defect
- A to Z: Tetralogy of Fallot
- A to Z: Atrial Flutter
- Patent Ductus Arteriosus (PDA)
- Ventricular Septal Defect
- Tetralogy of Fallot
- A to Z: Patent Ductus Arteriosus (PDA)
- A to Z: Hypoplastic Left Heart Syndrome
- Heart Murmurs
- Coarctation of the Aorta
- Congenital Heart Defects
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Ventricular Septal Defect
What Is a Ventricular Septal Defect?
A ventricular septal defect (VSD) — sometimes referred to as a hole in the heart — is a type of congenital heart defect. In a VSD, there is an abnormal opening in the wall between the main pumping chambers of the heart (the ventricles).
VSDs are the most common congenital heart defect, and in most cases they're diagnosed and treated successfully with few or no complications.
What Happens in a Ventricular Septal Defect?
The right and left ventricles of the heart are separated by shared wall, called the ventricular septum. Kids with a VSD have an opening in this wall. As a result:
- When the heart beats, some of the blood in the left ventricle (which has been enriched by oxygen from the lungs) flows through the hole in the septum into the right ventricle.
- In the right ventricle, this oxygen-rich blood mixes with the oxygen-poor blood and goes back to the lungs.
The blood flowing through the hole creates an extra noise, which is known as a heart murmur. The heart murmur can be heard when a doctor listens to the heart with a stethoscope.
VSDs can be located in different places on the septum and can vary in size.
What Causes a Ventricular Septal Defect?
Ventricular septal defects happen during fetal heart development and are present at birth. The heart develops from a large tube, dividing into sections that will eventually become the walls and chambers. If there's a problem during this process, a hole can form in the ventricular septum.
In some cases, the tendency to develop a VSD may be due to genetic syndromes that cause extra or missing pieces of chromosomes. Most VSDs, though, have no clear cause.
What Are the Signs & Symptoms of a Ventricular Septal Defect?
Whether a VSD causes any symptoms depends on the size of the hole and its location. Small VSDs usually won't cause symptoms, and might close on their own.
Older kids or teens who have small VSDs that don't close usually have no symptoms other than the heart murmur. They might need to see a doctor regularly to make sure the VSD isn't causing any problems.
Medium and large VSDs that haven't been treated in childhood may cause noticeable symptoms. Babies may have faster breathing and get tired out during attempts to feed. They may start sweating or crying with feeding, and may gain weight at a slower rate.
These signs generally indicate that the VSD will not close by itself, and heart surgery may be needed. This usually is done within the first 3 months of life to prevent other complications. A cardiologist can prescribe medicine to lessen symptoms before surgery.
What Problems Can Happen?
People with a VSD are at greater risk for developing endocarditis, an infection of the inner surface of the heart caused by bacteria in the bloodstream. Bacteria are always in our mouths, and small amounts get into the bloodstream when we chew and brush our teeth.
The best way to protect the heart from endocarditis is to reduce oral bacteria by brushing and flossing daily, and visiting the dentist regularly. In general, it's not recommended that patients with simple VSDs take antibiotics before dental visits, except for the first 6 months after surgery.
How Are Ventricular Septal Defects Diagnosed?
VSDs are usually found in the first few weeks of life by a doctor during a routine checkup. The doctor will hear a heart murmur as blood passes between the left and right ventricles. A murmur from a VSD has certain features that let a doctor know that's it's not due to other causes.
If your child has a heart murmur, your doctor may refer you to a pediatric cardiologist, a doctor who specializes in diagnosing and treating childhood heart conditions.
The cardiologist will do an exam and take your child's medical history. If a VSD is suspected, the cardiologist may order one or more of these tests:
- a chest X-ray: a picture of the heart and surrounding organs
- an electrocardiogram (EKG): a record of the heart's electrical activity. This is often the primary tool used to diagnose a VSD.
- a cardiac catheterization: this provides information about the heart's structures and the blood pressure and blood oxygen levels in its chambers. This test usually is done for a VSD only when more information is needed than the other tests can give. (It's sometimes also used to close certain kinds of VSDs.)
How Are Ventricular Septal Defects Treated?
Treatment depends on a child's age and the size, location, and severity of the VSD. A child with a small defect that causes no symptoms may only need to visit a cardiologist regularly to make sure that there are no other problems.
In most kids, a small defect will close on its own without surgery. Some might not close, but they won't get any larger. Kids with small VSDs usually don't need to restrict their activities.
Kids with medium to large VSDs likely will take prescription medicines to aid circulation and help the heart work more efficiently. Medicines alone, however, will not close the VSD, and in these cases, the cardiologist will recommend fixing the hole, either with cardiac catheterization or heart surgery.
Surgery usually is done within the first few weeks to months of a child's life. The surgeon makes an incision in the chest wall and a heart-lung machine will maintain circulation while the surgeon closes the hole. The surgeon can stitch the hole closed directly or, more commonly, will sew a patch of manmade surgical material over it. Eventually, the tissue of the heart heals over the patch or stitches, and by 6 months after the surgery, the hole will be completely covered with tissue.
Some kids with VSDs may take heart medicine before surgery to help ease symptoms from the defect. Those who have surgery for larger VSDs usually leave the hospital within 4 to 5 days after surgery if there are no problems.
Certain types of VSDs may be closed by cardiac catheterization. A thin, flexible tube (a catheter) is inserted into a blood vessel in the leg that leads to the heart. The cardiologist guides the tube into the heart to make measurements of blood flow, pressure, and oxygen levels in the heart chambers. A special implant, shaped into two disks formed of flexible wire mesh, is positioned into the hole in the septum. The device is designed to flatten against the septum on both sides to close and permanently seal the VSD.
After healing from an operation to repair the defect, a child should have no further symptoms or problems.
What Else Should I Know?
In most cases, kids who have VSD surgery recover quickly and without complications. But doctors will closely watch the child for signs or symptoms of any problems. Your child may have another echocardiogram to make sure that the heart defect has closed completely.
If your child is having trouble breathing, call your doctor or go to the emergency department immediately. Other symptoms that may indicate a problem include:
- a bluish color around the mouth or on the lips and tongue
- poor appetite or difficulty feeding
- failure to gain weight or weight loss
- listlessness or decreased activity level
- a long-lasting or unexplained fever
- increasing pain, tenderness, or pus oozing from the incision
Call your doctor if you notice any of these signs in your child after closure of the VSD.
Having your child diagnosed with a heart condition can be scary. But the good news is that your pediatric cardiologist will be very familiar with VSDs and how best to manage the condition. Most kids who've had a VSD corrected go on to live healthy, active lives.
Reviewed by: Steven B. Ritz, MD
Date reviewed: September 05, 2017