Atrioventricular canal defect is a combination of heart problems causing a defect in the centre of the heart. The condition happens when there’s a hole between the heart’s chambers and problems with the valves that regulate blood flow in the heart.

Sometimes referred to as endocardial cushion defect or atrioventricular septal defect, atrioventricular canal defect is present at birth (congenital). The situation is often related to Down syndrome.

Atrioventricular canal defect allows more blood to go to the lungs. The extra blood pressures the heart to overwork, making the heart muscle enlarge.

If not treated, atrioventricular canal defects can lead to heart failure and high blood pressure in the lungs. Doctors usually recommend surgery during the first year of life to cover the hole in the heart and to reconstruct the valves.

Symptoms of Atrioventricular canal defect
Atrioventricular canal defect is divided into partial and complete. In any of the two, extra blood circulates in the lungs.

Complete atrioventricular canal defect
Signs and symptoms generally develop in the first several weeks of birth. These include:

Difficulty breathing or rapid breathing

Wheezing

Fatigue

Poor weight gain

Excessive sweating

Irregular or rapid heartbeat

Lack of appetite

Pale skin colour

Bluish discoloration of the lips and skin

Partial atrioventricular canal defect
Signs may not be noticed until early adulthood and might be related to problems that develop as a result of the defect. These signs and symptoms might include:

Abnormal heartbeat (arrhythmia)

Heart failure

Shortness of breath

High blood pull in the lungs (pulmonary hypertension)

Heart valve issues

The normal-functioning heart
The right side of your heart moves blood into vessels that go to the lungs. There, oxygen enriches the blood. The oxygen-rich blood flows back to your heart’s left side and is pumped into a large vessel (aorta) that circulates blood to every part of the body of your body.

Valves manage the flow of blood in and out of the chambers of your heart. These valves give way to allow blood to move to the other chamber or to one of the arteries, and close to keep blood from flowing backwards.

What occurs in atrioventricular canal defect
In partial atrioventricular canal defect:

There’s a hole in the wall (septum) that divides the higher chambers (atria) of the heart.

Sometimes the valve between the upper and lower left chambers (mitral valve) also has a defect that makes it leak (mitral valve regurgitation).

In complete atrioventricular canal defect:

There’s a large hole in the centre of the heart the place the walls between the atria and the lower chambers (ventricles) meet.

Instead of different valves on the right and left, there’s one large valve between the upper and lower chambers.

The abnormal valve drips blood into the ventricles.

The heart is pressured to work harder and enlarges.

Risk factors
Factors that may enlarge a baby’s risk of developing atrioventricular canal defect prior to birth include:

Down syndrome

Smoking when pregnant

German measles (rubella) or every other viral illness during a mother’s early pregnancy

Alcohol intake during pregnancy

Poorly controlled diabetes throughout pregnancy

Certain medications taken when pregnant — discuss with your doctor before taking any drugs while you’re pregnant or trying to become pregnant

Someone whose parent had a congenital heart defect

Complications
Complications of atrioventricular canal defect may include:

Enlargement of the heart. Increased blood goes with the flow through the heart pressuring it to work harder than normal, making it enlarge.

Pulmonary hypertension. When there is a hole (defect) that allows the mixing of oxygenated (red) and deoxygenated (blue) blood, the amount of blood that flows to the lungs is increased. This results in pressure buildup in the lungs, resulting in high blood pressure in the lungs.

Respiratory tract infections. Atrioventricular canal defects can cause intermittent bouts of lung infections.

Heart failure. If not treated, atrioventricular canal defect generally results in the heart’s inability to pump enough blood to meet the body’s requirements.

Complications later in life
Treatment highly improves the outlook for children with atrioventricular canal defects. Nevertheless, some children who have corrective surgery may be at risk later in life of:

Narrowing of the heart valves
Abnormal heart rhythm
Leaky heart valves
Breathing difficulties associated with lung damage

Common signs and symptoms and symptoms of these complications include:
Rapid, fluttering heartbeat

Shortness of breath

Fatigue

Prevention
Atrioventricular canal defects typically can’t be prevented.

Heredity may additionally play a role in some heart defects. If you have a family history of heart defects or if you already have a child with a congenital heart defect, discuss it with a genetic counsellor and a cardiologist before getting pregnant again.

Immunization with rubella vaccine has been one of the most effective preventive methods against congenital heart defects.