Ventricular Septal Defect Overview
Ventricular septal defect is a hole in the wall between the right and left ventricles of the heart. This abnormality usually develops before birth and is found most often in infants.
- The ventricles are the 2 lower chambers of the heart. The wall between them is called the septum. A hole in the septum is called a septal defect.
- If the hole is located between the upper chambers or atria, it is called an atrial septal defect.
- Infants may be born with either or both types of defects. These conditions are commonly known as "holes in the heart."
Normally, deoxygenated blood from the body returns to the upper chamber of the right side of the heart called the right atrium. It passes through the tricuspid valve into the right ventricle, which pumps the blood to the lungs to absorb oxygen. After leaving the lungs, the oxygenated blood returns to the left side of the heart, to the left atrium. It then passes through the mitral valve into the left ventricle, where it is pumped out to provide oxygen to all the tissues of the body.
- A ventricular septal defect can allow newly oxygenated blood to flow from the left ventricle, where the pressures are higher, to the right ventricle, where the pressures are lower, and mix with deoxygenated blood. The mixed blood in the right ventricle flows back or recirculates into the lungs. This means that the right and left ventricles are working harder, pumping a greater volume of blood than they normally would.
- Eventually, the left ventricle can work so hard that it starts to fail. It can no longer pump blood as well as it did previously. Blood returning to the left side of the heart may back up into the lungs, causing pulmonary congestion, and blood returning the right side of the heart may further back up into the body, causing weight gain and fluid retention. Overall, this is called congestive heart failure.
- If the VSD is large and surgically uncorrected, pressure can build excessively in the lungs, called pulmonary hypertension. The higher the lung or pulmonary pressure, the greater the chance of blood flowing from the right ventricle through the VSD to the left ventricle, causing deoxygenated blood to be pumped out to the body by the left ventricle, causing cyanosis (blue skin).
- The risk for these problems depends on the size of the hole in the septum and how well the infant’s lungs function.
The ventricular septal defect may not be heard with a stethoscope until several days after birth. This is because a newborn's circulatory system changes during the first week, with a drop in the lung or pulmonary pressure creating the greater pressure differential between the 2 ventricles, which may increase the left-to-right shunt and produce an audible murmur.
Ventricular septal defects are the most common congenital heart defects in infants
- The condition occurs in about 25% of all infants born with a heart defect.
- These defects are more common in premature infants.
Ventricular Septal Defect Causes
No one knows what causes ventricular septal defects, but they probably come from a malformation of the heart that occurs while the infant is developing in the womb.
- There may be just one hole or several holes in the septum.
- The septum itself is divided into multiple areas, including the membranous part, the muscular part, and other areas called the inlet and outlet. Any or all of these parts can have a hole.
- The location of the hole depends on where the malformation takes place during fetal development.
The most common type of ventricular septal defect is the membranous variant. In this type, the hole is located below the aortic valve, which controls flow of blood from the left ventricle into the main artery of the body, the aorta.
Ventricular Septal Defect Symptoms
Small holes in the ventricular septum usually produce no symptoms but are often recognized by the child's health care provider when a loud heart murmur along the left side of the lower breast bone or sternum is heard. Large holes typically produce symptoms 1-6 months after an infant’s birth. The left ventricle begins to fail, producing the following symptoms:
- Fast breathing
- Very fast heartbeatsDecreased feeding
- Poor weight gain
When a ventricular septal defect is not detected early in life, it can cause more severe problems and more severe symptoms as time goes on. The biggest concern is development of high pressure in the lungs (pulmonary hypertension). If the ventricular septal defect is not surgically closed, irreversible pulmonary hypertension can develop, and the child may no longer benefit from surgery. The following are typical symptoms of pulmonary hypertension:
- Shortness of breath
- Chest pain
- Bluish discoloration of the skin (cyanosis)
The skin turns faintly bluish when the tissues are not receiving quite enough oxygen. This condition is often termed "hypoxemia" or "hypoxia."
When to Seek Medical Care
Any of the following should be reported to your child's health care provider:
- Poor weight gain or slowing of weight gain in the first months of life
- Unusual behavior
- Any of the other symptoms noted in the previous section
An immediate visit to the nearest hospital emergency department is warranted if you notice any of the following in your infant:
- Shortness of breath, breathing difficulty of any type, or worsening of an existing breathing problem
- Bluish color of the skin, lips, or under the nails
- Unusual or unexplained sweating
Exams and Tests
If a ventricular septal defect is noted before your baby leaves the hospital, several tests may be ordered before discharge.
A ventricular septal defect is detected on physical examination by a systolic murmur audible with a stethoscope along the lower left sternal or breast bone border. It is related to the oxygenated blood “swishing” through the hole or VSD into the right ventricle.
The presence of a hole in the heart can be confirmed by echocardiogram. This painless test uses ultrasound waves to construct a moving picture of the heart. It can quantitate the size of the left-to-right shunt by enlargement of the left ventricle, pressure in the lungs, and actually estimate the degree of shunting by an empirical formula.
Chest X-ray is useful to see if the overall heart size is enlarged, and may demonstrate evidence of fluid in the lungs or pulmonary congestion. An electrocardiogram is helpful to evaluate the sizes of the left and right ventricle. If right ventricular hypertrophy is indicated, this may suggest pulmonary hypertension.
Cardiac catheterization may be performed in certain circumstances.
- In this procedure, a very thin plastic tube called a catheter is inserted into the skin in the groin, arm, or neck (under local anesthesia with minimal pain) and advanced to the heart under X-ray observation by the cardiologist.
- Pressures are measured inside the heart, especially if any concern was previously raised over the degree of pulmonary hypertension and therefore operability. If the lung pressures are very high and won’t drop with oxygen and additional vasodilating drugs, the patient may not be operable.
- If additional abnormalities are possible, a dye study may be performed to visualize the anatomy of inside the heart. But the echocardiogram may accomplish this goal in the majority of patients.
Ventricular Septal Defect Treatment
In some children with ventricular septal defect, the defect will close on its own as the child grows.
If a larger ventricular septal defect is causing symptoms, your child's health care provider may prescribe medication.
- Which medication is prescribed depends on the severity of symptoms.
- The goal of therapy is to reduce the symptoms of congestive heart failure, such as poor growth and development, weight loss and/or poor weight gain, excessive sweating, and fast breathing. An older patient typically develops fluid in the lungs, liver, and legs.
- Routine antibiotic use is warranted for dental surgery and any invasive procedure if any VSD is still present after closure.
- Vasodilators: Angiotensin-converting enzyme inhibitors or angiotensin-receptor blockers are used to decrease the work load on the left ventricle.
- Digoxin (Lanoxin) increases the strength of the heart muscle to deal with the greater blood volume.
- Diuretics such as Lasix (furosemide) or spironolactone help remove excess fluid from the body so the heart doesn't have to work as hard and the patient feels much better.
Larger ventricular septal defects do not close as the child grows. If it does not close, closing the heart surgically is necessary.
- Surgical closure is typically done before the child begins preschool.
- Surgery is indicated if medications do not work in the first few months or years of life, especially if the child is not growing adequately even with medications.
- Surgery is more urgent if evidence of pulmonary hypertension has developed.
- The most used operation involves placing a Gore-Tex patch over the hole. This prevents shunting (the movement of oxygenated blood from the left to the right ventricle).
Surgery is not usually performed in newborns because small defects will close spontaneously in 20%-25% of cases. The surgery also is more risky in the first few months of life; the risk of death from the operation is higher in the first 6 months of life.
Researchers are testing devices that cover the defect, performed in the cardiac catheterization laboratory, not by open heart surgery.
Next Steps - Follow-Up
- Regular office visits and echocardiograms are required to continually reassess the ventricular septal defect.
- The child's weight and length/height will be checked often. Feeding and activity levels should be assessed routinely.
- Routine antibiotic use is warranted for dental surgery and any invasive procedure.
Women can do nothing during pregnancy to prevent their babies from developing a ventricular septal defect.
During the growth of a child, the defect may become smaller and close on its own.
- Twenty to 25% of all ventricular septal defects close by age 3 without medical intervention.
- Children who show no symptoms and are being monitored by a primary care provider do not have to restrict their activities. Children with mild-to-moderate shunting of blood may have to reduce their levels of activity.
- Once a defect is repaired, there are no restrictions on activity.
Several other conditions may result from ventricular septal defects.
- Aortic regurgitation: Blood flowing backward from the aorta into the left ventricle.
- Endocarditis: An infection of the heart valves due to abnormal blood flow. Because endocarditis is always possible, medical professionals may recommend that children with certain types of ventricular septal defects receive antibiotics before undergoing dental procedures or surgery.
- Pulmonary hypertension: An increase in pressure in the right side of the heart and in the arteries of the lungs. This is caused by the shunting of blood from the left to the right ventricle, which increases the pressure in the right ventricle.
For More Information
American Heart Association
7272 Greenville Avenue
Dallas, TX 75231
Synonyms and Keywords
ventricular septal defect, atrial septal defect, congenital heart defect, heart murmur, hole in the heart, leaking heart, left to right shunt, shunting, VSD, aortic regurgitation, endocarditis, pulmonary hypertension