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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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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.
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Coarctation of the Aorta
What Is Coarctation?
The aorta is the major blood vessel that carries blood away from the heart to the body. When someone has coarctation of the aorta, the aorta is narrowed at some point.
Here's how a healthy heart and aorta work: Blood that needs oxygen comes from all over the body and enters the right side of the heart, which pumps it to the lungs. The lungs fill the blood with oxygen, and this oxygen-rich blood returns from the lungs to the left side of the heart. The left side of the heart finishes up by pumping the blood out through the aorta. From the aorta, the blood travels through arteries that reach all of the body's organs and tissues, bringing them oxygen. Then the blood returns to the heart through veins and begins the cycle once again.
When part of the aorta is narrowed (this is a coarctation), that defect can affect the body's blood circulation because the left side of the heart has to work harder to pump blood through the narrowed aorta.
Sometimes the narrowing is minor and might not even cause symptoms. In other cases, the aorta is more constricted, placing a strain on the heart's left ventricle (the chamber that pumps blood to the aorta and out to the body).
A coarctation can occur anywhere in the aorta, but most often is found after the point where the arteries that carry blood to the upper body and head branch off from the aorta.
Coarctation of the aorta (or COA) is a congenital defect, meaning that someone is born with it. About 1 in 100 children is born with a heart problem, and coarctation represents about 8% of those cases. Doctors don't know for sure why certain people are born with this narrowing of the aorta.
Coarctation occurs more commonly in boys, but is often seen in girls with Turner syndrome, in which one of two X chromosomes is incomplete or missing. COA may occur with other birth defects or congenital heart conditions, such as a ventricular septal defect (a hole in the wall between the heart's left and right ventricles).
Coarctation also can be associated with other structures abnormalities of the left side of the heart. A common association is a bicuspid aortic valve, in which the aortic valve between the left ventricle and aorta has two leaflets instead of the normal three.
Most people with COA are diagnosed as babies or young children, although some aren't diagnosed until they're teens or even adults. Usually, in this case, the narrowing in the aorta is not severe enough to cause serious symptoms while the person is very young. But even those who do not have major symptoms usually need to be treated because the coarctation can eventually cause problems. COA will not go away on its own.
Signs and Symptoms
Often an abnormal blood pressure test is the first detected sign of COA. During a physical exam, a doctor may find that a child with a coarctation has a higher blood pressure in the arms than in the legs, and also might hear a heart murmur or notice that the pulse in the groin is weak or difficult to feel. Any person diagnosed with high blood pressure should be checked for coarctation of the aorta.
Kids who have COA often do not have any symptoms and have only mild signs that are discovered by accident during a regular visit to the doctor. A child who does have symptoms may experience some or all of these:
- cold legs and feet
- shortness of breath, especially when exercising
- chest pain
Diagnosis and Treatment
Doctors may refer a child with the signs or symptoms of COA to a pediatric cardiologist (a doctor who specializes in diagnosing and treating heart disease in kids and teens). The cardiologist will listen to the heart, feel the pulses, and check blood pressure.
The doctor probably will order an echocardiogram, a test that uses sound waves to create a picture of the heart and its circulation. Other tests that produce images of the heart, such as a chest X-ray, a magnetic resonance imaging (MRI) test, or a computerized tomography (CT) scan, also may be used to help the cardiologist look for a narrowing of the aorta.
A severe coarctation is usually diagnosed shortly after birth and repaired by surgery immediately. In an older patient, doctors often recommend that COA be treated quickly, since it can cause persistent high blood pressure and cause heart enlargement. The defect can also cause dissection or rupture of the aorta, which can be fatal in many people by the age of 40.
Coarctation of the aorta can be repaired either by surgery or other procedures. Different types of surgery can repair a narrowing of the aorta, but one of the most common ways to fix COA is to remove the narrow section and reconnect the two ends of the aorta.
In some cases, doctors may do a procedure known as balloon dilation or balloon angioplasty. They insert a tiny balloon into a blood vessel in the leg and use a very thin wire to thread it up to the aorta, across the narrow area. When the doctor inflates the balloon, the narrow area is expanded. After the area has been widened, the balloon is removed. The cardiologist also may implant a device called a stent to keep the area open after the procedure.
Once the defect has been fixed, most symptoms of COA disappear right away because the blockage that caused those symptoms is now gone. Some people will still have high blood pressure for a while and might have to take medicine to control it.
Kids and teens who have had surgery often feel completely better after a week or two, and those who have had the balloon treatment feel better even sooner, often within a couple of days.
But doctors recommend that all patients avoid some physical activities — especially lifting heavy objects or sports that could cause an impact to the chest — for several weeks or months to give the body enough time to heal. Someone whose blood pressure remains high may have to continue to limit certain activities as long as the blood pressure remains high.
Kids who've had a COA corrected will still need to be monitored over time. In some, the narrowing of the aorta can return after surgery or balloon dilation treatment. Regular visits to a cardiologist — often every year or two after recovery — let the doctor monitor blood pressure and look for signs that COA could be returning.
If your child has COA or has had a coarctation repaired, call the doctor if you see shortness of breath, chest pain, or fainting.
Overall, kids who have had coarctation of the aorta can expect to lead a normal life after treatment.
Reviewed by: Steven B. Ritz, MD
Date reviewed: May 2013