Complete Atrioventricular Canal Defect (CAVC): Symptoms, Diagnosis, And Treatment

Complete Atrioventricular Canal Defect (CAVC) is a heart defect present at birth. CAVC is characterized by a hole in the middle of the heart that causes damage to all four chambers of the heart, which are normally separated. 

What happens when you have CAVC?

The chambers of the heart are normally separated — one part of the heart contains oxygenated blood that needs to go out to the body, while another part houses deoxygenated blood which needs to go to the lungs to receive oxygen. When patients have CAVC, that causes the blood from these different regions of the heart to become mixed up. Additionally, the heart's chambers and valves may not work properly to ensure adequate blood flow.

What is the cause of CAVC?

What happens to the heart when there is a hole in it, such as in CAVC?

In patients with CAVC, a hole in the heart wall causes blood to travel from the left to the right side of the heart, where it is sent out to the blood vessels of the lungs. This extra volume of blood causes the lungs, as well as the heart, to work harder, thus damaging both organs. This also causes high blood pressure within the lungs, eventually leading to permanent damage to the blood vessels of the lungs. Additionally, in some infants, the valves don’t close normally, causing blood to leak back into the lower part of the heart from the upper ones. Again, this phenomenon, which is known regurgitation, causes the heart to work harder.

What are the symptoms of CAVC?

Symptoms in children with CAVC may not develop until many weeks after they have been born. In other cases, symptoms can develop within days of being born. Symptoms in children with CAVC include:

• Breathing faster and harder than normal. Having difficulty breathing in general.
• Not growing at a normal rate and trouble gaining weight.
• High blood pressure in the lungs.
• A bluish tint within the lips, skin and nails due to cyanosis or lack of oxygenated blood.
• A heart murmur, an abnormal sound emitted by the heart when blood flows through.

Unlike CAVC, partial atrioventricular canal defects are associated with fewer symptoms. Thus, the condition often goes undiagnosed until the child has reached adulthood. On average, these children are diagnosed when they are in their twenties or thirties. At that time, they may start developing symptoms associated with heart defects, such as arrhythmia (irregular heartbeat), leaky valves or other defects.

How is CAVC diagnosed?

Doctors may suspect that your baby has CAVC if they hear a heart murmur or notice other symptoms indicative of a heart defect. There are several ways to diagnose CAVC, including:

• A fetal ultrasound, an ultrasound technique conducted when the mother is still pregnant.
• An echocardiogram, a technique in which sound waves are used to create a moving image of the heart.
• An electrocardiogram, a test that measures the heart's electrical activity.
• A chest X-ray to create a picture of the structures of the chest, including the heart and lungs.
• Pulse oximetry, a non-invasive technique that uses a clip on the finger to measure blood oxygen levels.
• Cardiac catheterization, which involves threading a thin tube through a blood vessel and guided it to the heart to create a detailed picture of the heart
• Cardiac MRI, which creates a three-dimensional image of the heart and is able to show any abnormalities.

How is CAVC treated?

Usually, CAVC is treated using surgery, which needs to be carried out within the first few months of the baby’s life. Essentially, the surgeon cpnducts a procedure to close the hole of the heart using one or two patches. These patches are attached to the muscles of the heart using stitches. As the child gets older, tissue will grow on top of the patches. Additionally, the surgeon will fix the valves by separating one big valve into two valves. The exact treatment will depend on the child’s anatomy.

Partial atrioventricular canal defects will also require surgical treatment, regardless of whether they are diagnosed during childhood or adulthood. The surgeon will use a patch or stitch the hole together until it is closed. They will also fix the valve or replace it with an artificial valve or one from a donor so that the heart can function as normally as possible.

Conclusion

A child with CAVC who undergoes surgery will, in most cases, recover completely and will not need any extra surgery or procedures. The child will go on to lead a productive life, while being followed by a cardiologist periodically. This is because in some cases, patients may develop some issues, such as an irregular heartbeat or leaky valves, that may require extra procedures. However, overall, the outlook for patients with CAVC is, thanks to modern medicine, good.