Healthy Heart Function
Normal blood flow through the heart begins with deoxygenated blood (depicted as blue) passing through the vena cava, from the body tissues, and into the right atrium of the heart. From there, atrial contraction pushes the blood through the tricuspid valve into the right ventricle (figure B). Blood then moves with low pressure through the pulmonary valve and to the pulmonary artery (figure C) which transports blood to the lungs where it becomes oxygenated. Oxygenated blood (depicted as red) now flows to the left atrium (figure D), and then, with atrial contraction, continues through the mitral valve to the left ventricle. Ventricular contraction pushes the blood through the aortic valve, into the aorta, and out to the body (figure E).
Ductus arteriosus- in a fetus, there is a passageway at the top of the descending aorta that connects it to the pulmonary artery. This allows blood to bypass the lungs, which are not yet operational, and continue on to circulate throughout the body. |
Complete Atrioventricular Canal Defect
What is it?
A complete Atrioventricular canal defect (AVCD) occurs when the endocardial cushions fail to form properly. This leads to a large hole in the center of the heart where the right and left atria meet the ventricles. Now, rather than the chambers of the heart being separated by septal walls, they are all open to one another. The tricuspid and mitral valves do not form properly, and instead one large valve spans the heart and separates the atria from the ventricles. What causes it?
The causes of AVCD are widely unknown, though it is a very common defect among children born with Down syndrome. |
Retrieved from https://www.cincinnatichildrens.org/patients/child/encyclopedia/
defects/avsd |
How does it effect the body?
Without septal walls separating the chambers of the heart, oxygenated and deoxygenated blood are allowed to mix, sending a mixture of oxygenated and deoxygenated blood to both the lungs and the body. Because of decreased pressure in the pulmonary arteries compared with the aorta, increased blood tends to flow to the lungs, and increases the work of the heart, and especially the pulmonary vessels which may be permanently damaged without rapid intervention. Blood may also build up in the lungs causing pulmonary congestion. |
How can I assess for it?
Infants born with AVCD may not have symptoms other than a heart murmur in the first few weeks of life that is associated with blood passing from the left ventricle to the right. Symptoms on congestive heart failure will typically develop over the first few weeks of life and include:
Infants born with AVCD may not have symptoms other than a heart murmur in the first few weeks of life that is associated with blood passing from the left ventricle to the right. Symptoms on congestive heart failure will typically develop over the first few weeks of life and include:
- Difficulty breathing or rapid breathing
- Wheezing
- Fatigue
- Lack of appetite
- Poor weight gain
- Excessive sweating
- Irregular or rapid heartbeat
- Swelling in the legs, ankles and feet
How is it treated?
AVCDs will not close up on their own, unlike some other septal defects and will require surgical repair. In the meantime, medications such as ACE inhibitors and diuretics may be used to control symptoms of congestive heart failure. Surgery for infants with complete AVCD is typically done when the infant is between 3 and 8 months of age, and includes patching the septal walls of the heart and repairing the valves between the atria and ventricles. |