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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.
From Nemours' KidsHealth