How Ventricular Septal Defects Occur and Who Is Generally Affected

November 12, 2012

How Ventricular Septal Defects Occur and Who Is Generally Affected

A ventricular septal, which is a common congenital heart defect in newborns, is a hole on the wall between the heart’s left and right ventricles.

What is a ventricular septal defect? It’s when there’s a hole in the wall between the heart’s right and left ventricles. It’s an abnormality that develops before birth and is generally found in infants.

Ventricular Septal: The Anatomy Of The Heart

The ventricles are the two lower chambers of the heart. The wall between the two is known as a septum. The hole is called a septal defect. Should the holes be between the atria (upper chambers), it’s known as the atrial septal defect. Infants born with either one or both of the defects, they’re called “holes in the heart”.

Usually, the un-oxygenated blood from the body goes back to the right part of the heart, which is the right atrium and then to the right ventricle. It then pumps blood to the lungs so that oxygen is absorbed. After the air leaves the lungs, the oxygenated blood comes back to the heart’s left side which is the left atrium and the left ventricle, pumped out to give oxygen to the areas of the body.

1 – A ventricular septal defect allows new oxygenated blood to flow out of the left ventricle, which is where you can find higher pressures, to the right ventricle, which is where you can find lower pressures. This oxygenated blood will mix together with un-oxygenated blood. The mixed blood within the right ventricle circulates into the lungs. Thus, both the left and right ventricles are working much harder, pumping out a greater amount of blood than they typically would.

2 – In time, the left ventricle will work itself so hard that it can begin to fail, meaning it doesn’t pump blood like it should or did. Blood that comes from the blood vessels to the heart will back up into the lungs, which cause pulmonary congestion and backs up more into the body such as:

  • Fluid retention

  • Weight gain

  • Congestive heart failure

3 – If the ventricular septal is large and not corrected surgically, the pressure can excessively build up in the lunge, which is known as pulmonary hypertension. The higher the pressure, the greater the possibility of blood flowing from right to left ventricle, meaning backwards. This causes the un-oxygenated blood to be pumped to the body along with cyanosis (or blue skin).

4 – The risk for the above problems will depend on the hole’s size in the septum and who good the lungs of the infant functions.

It’s possible that the ventricular septal defect won’t be heard through a stethoscope for several days after the child is born. The reason is that the circulatory system of a newborn changes in the first week with a drop in the pulmonary pressure, which creates greater pressure differential between the two ventricles.

These types of defects are the most common congenital heart defects in newborns, usually occurring in 25 percent of all newborns and generally seen in more premature births.

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