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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
- Cardiac Catheterization
- ECG (Electrocardiogram)
- If Your Child Has a Heart Defect
- A to Z: Atrial Flutter
- A to Z: Tetralogy of Fallot
- A to Z: Patent Ductus Arteriosus (PDA)
- Heart and Circulatory System
- Patent Ductus Arteriosus (PDA)
- A to Z: Hypoplastic Left Heart Syndrome
- Coarctation of the Aorta
- Congenital Heart Defects
- Congenital Heart Defects Special Needs Factsheet
- Tetralogy of Fallot
- Atrial Septal Defect
- Heart Murmurs and Your Child
- When Your Child Needs a Heart Transplant
- Ventricular Septal Defect
Trusted External Resources
A to Z: Patent Ductus Arteriosus (PDA)
A to Z: Patent Ductus Arteriosus (PDA)
May also be called: PDA
More to Know
The ductus arteriosus (DA) is a normal blood vessel that connects two major arteries — the aorta and the pulmonary artery — that carry blood away from the heart in a developing fetus. The DA diverts blood away from the lungs, sending it directly to the body. The lungs are not used while a fetus is in the amniotic fluid because the baby gets oxygen directly from the mother's placenta. When a newborn breathes and begins to use the lungs, the DA is no longer needed and usually closes during the first 2 days after birth.
If the DA fails to close, a patent (meaning "open") ductus arteriosus is the result. Oxygen-rich blood from the aorta mixes with oxygen-poor blood in the pulmonary artery, and too much blood flows into the lungs.
Babies with a PDA may have poor feeding, poor growth, difficulty breathing, excessive sweating, fatigue, or a bluish color to the skin. A larger PDA puts a strain on the heart and increases blood pressure in the pulmonary arteries. A smaller PDA may not cause any symptoms.
Keep in Mind
In the vast majority of babies who have a small PDA but otherwise normal heart, the PDA will shrink and go away on its own in the first few days of life. Other PDAs may close on their own within the first year of a baby's life.
Large PDAs are rare, but can strain the heart and cause other problems. Medications, catheter-based procedures, or surgery may be used to close these PDAs.
All A to Z dictionary entries are regularly reviewed by KidsHealth medical experts.
Date reviewed: April 28, 2017