A ventricular septal defect (VSD) is a type of heart defect (congenital heart disease) in which there is a hole in the wall (septum) between the heart's lower chambers (ventricles). It is the most common congenital heart defect.

VSDs vary in size, from a mere pinpoint to the almost total absence of septum. Also, they may occur in isolation or as part of a more complex series of congenital defects. The symptoms and severity of a VSD depend on how large it is. The vast majority are small, without symptoms and spontaneously close within the first three years of life.

Larger VSDs, however, can be dangerous. Because the pressure in the left side of the heart is greater than the pressure in the right side, the hole allows blood to seep from the left ventricle into the right ventricle. This results in too much blood volume in the right side of the heart and lungs. The more blood that is diverted to the right side of the heart, the harder the lungs and right ventricle must work. Eventually, the stress on the right ventricle can cause it to weaken and/or enlarge (dilate) to compensate for the increased workload, resulting in symptoms associated with heart failure.

Also, the lungs can become congested upon receiving more blood than is needed, which can result in either infection of the lungs and/or pulmonary hypertension (high blood pressure in the lung’s blood vessels). Additionally, VSD may raise the risk of the formation of blood clots (which could lead to stroke), and the development of abnormal heart rhythms (arrhythmias).

For VSDs that remain open, most physicians agree that no matter how small the hole is, it should be treated sooner rather than later – especially if other defects are present. However, in some cases, the VSD may actually encourage the mixing of blood from the left and right sides of the heart, which can be beneficial in the setting of complex heart defects that do not allow blood to travel through the heart in a normal fashion. In this case, the VSD may actually be beneficial, and surgeons will wait to treat the VSD until the more serious congenital defects can be corrected. Treatment usually involves surgery.

A ventricular septal defect (VSD) is a type of heart defect (congenital heart disease) in which there is a hole in the wall (septum) between the heart’s lower chambers (ventricles). The hole may be as small as a pinpoint, or as large as the space where the entire septum should be (i.e., the total absence of the septum). 

VSD is the most common congenital heart defect, occurring in as many as 1 percent of newborns. VSDs may occur in isolation or as part of a more complex series of congenital defects. The vast majority of VSDs are small and spontaneously close on their own during the first years of life, without any symptoms or harmful effects.

Although larger VSDs are more dangerous than smaller ones, most physicians agree that all VSDs that do not close on their own should be treated, no matter how small they are. This is because even small VSDs carry a risk of the formation of blood clots that may be carried to the brain and cause a stroke. VSDs can also increase the risk of a person developing infective endocarditis (infection within the heart). 

Larger VSDs, however, may result in a dangerous left-to-right shunt. This occurs when some of the oxygen-rich blood in the left ventricle is diverted (shunted) through the VSD and into the right ventricle, where it mixes with oxygen-poor blood. Left-to-right shunts, which also include atrial septal defect (ASD) and patent ductus arteriosus (PDA), account for over half of all heart diseases that are present at birth (congenital heart disease).

Because of the left-to-right shunt, the right ventricle of the heart receives blood from two different places: from the right atrium, as it should, and from the left ventricle (through the VSD). This results in too much blood flow to the right side of the heart and lungs. The more blood that is diverted to the right side of the heart, the harder the lungs and right ventricle must work to compensate for the problem.

Eventually, the stress on the overworked right ventricle may cause it to weaken and/or enlarge. Also, the lungs can become congested from constantly receiving more blood than is needed. Eventually, the congestion and overwork could lead to arrhythmias (abnormal heart rhythms) or heart failure.

There are a number of different types of VSDs, which include the following:

A VSD may be present by itself, or it may be one of a number of heart conditions, including:

• Tetralogy of Fallot. A complex congenital abnormality characterized by four anatomical defects.
  
  
• Double outlet right ventricle. This occurs when both the aorta and the pulmonary artery attach to the right ventricle, instead of the left and right ventricles, respectively.
  
  
• Transposition of the great arteries. In this congenital defect, the positions of the aorta and pulmonary artery are switched.
  
  
• Atrial septal defect (ASD). This defect refers to a hole in the septum between the upper chambers of the heart (atria).
  
  
• Patent ductus arteriosus. This occurs when the ductus arteriosus, a normal connection between the aorta and pulmonary artery that should seal within a few days of birth, remains open.
  
  
• Heart valve disorders. The position of the VSD may affect the tricuspid valve, mitral valve or aortic valve.
  
  
• Anomalous pulmonary venous connection. Instead of the pulmonary veins connecting with the left atrium, as they should, they connect to the right atrium, vena cavae or hepatic veins. The condition may be partial or complete. The associated ASD is usually at a high position in the atrial septum.

In the case of some complex congenital heart defects, the presence of a VSD may actually be beneficial. For example, if a patient is born with a defect that prevents blood from flowing normally through the lungs, into the left side of the heart and out to the body, a VSD may allow an alternative path for oxygen-rich blood to reach the body. In these cases, the VSD may actually be life-saving, and physicians will not attempt to correct the VSD until they have addressed the more serious heart defect.

Although a physician can often find a VSD by listening for a heart murmur (abnormal heart sound), the majority of VSD patients have no symptoms at birth. Therefore, the defect may be found when a person is three or four years old, or when a person is 30 or 40 years old. If symptoms do appear, they may include frequent chest colds and infections that, if severe enough, can stunt a young child’s growth and may even be fatal. Furthermore, the more congested the lungs become, the more susceptible a person is to pulmonary hypertension – a condition in which blood pressure in the lung’s blood vessels is high.

Symptoms of pulmonary hypertension include the following:

Eisenmenger syndrome is the name given when a VSD is present along with other conditions such as displacement of the aorta and enlarged muscles (hypertrophy) in both the right ventricle and pulmonary artery.

Because children with a VSD often have no symptoms, the VSD is usually first noticed during routine testing or medical check-ups. Most commonly, it is found when a physician uses a stethoscope to listen for a heart murmur. However, not all heart murmurs are signs of a VSD. Therefore, the physician will often listen to the patient’s heart a number of times over a 6- to 12-month period before ordering further testing.

An echocardiogram of the heart and major arteries is often the next test to find a possible VSD. This test uses sound waves to visualize the structure and function of the heart. A moving image of the patient’s beating heart is played on a video monitor, where a physician can study the heart’s thickness, size and function. The image also shows the motion pattern and structure of the four heart valves revealing any potential leakage (regurgitation). During this test, a Doppler ultrasound may also be done to evaluate blood flow in the coronary arteries, the blood vessels of the arms and legs, and the carotid arteries in the neck. The technique can also measure pulmonary artery pressure as well as the volume of blood being pushed through the defect.

Other tests that may be performed include:

Researchers are testing a new diagnostic tool, a combination of an MRI (magnetic resonance imaging) and x-ray, called XMR. This measures blood flow and heart structure and function in three-dimensional imaging.

Physicians may wish to wait long enough to see if the ventricular septal defect (VSD) will close on its own, particularly if it is a membranous VSD (which has the highest chance of self-closing). A VSD that does not close on its own after birth will need treatment. The physician may wish to try to treat the VSD with medications, which may include the following:

If the medications are not working, or the VSD is too large, or the child has already passed the age at which the VSD would have closed, the physician will often choose to do surgery. Most often this surgery involves a sternotomy, an operation in which the breastbone (sternum) is divided in two to open the chest and expose the heart. The strategy for closing a defect during surgery depends on the size of the hole and its location. Smaller holes are closed by stitches (sutures). Larger holes are patched with a large “swatch” made of either a synthetic material or the patient’s own tissue (often from the fluid–filled sac around the heart called the pericardium). When a VSD occurs along with other defects, the surgery becomes more complicated. However, the surgery to treat a VSD alone has a relatively low risk, high rate of success and short hospital stay (three to five days).

Minimally invasive techniques are being tested to repair septal defects. Researchers are evaluating a method to squeeze a patch into a catheter and snake it through the body up to the heart. Once in place, the physician can place the patch over the hole, sealing it. The patch eventually becomes covered with the body’s tissues. Catheter closure of VSDs are limited by the nature of individual VSDs. If, for example, the VSD involves the heart valves, it may not be possible to access the defect without causing damage to structures associated with the valves.

While certain types of congenital heart disease may be diagnosed in-utero, the reason for their developing in the first place is frequently unknown. In general, women are urged to avoid exposure to conditions such as infection and certain drugs. The U.S. Food and Drug Administration (FDA) recently issued a warning about the use of the drug Paxil by pregnant women. New studies suggest an increased risk of heart defects, particularly VSD, in women who use Paxil during pregnancy.

As genetic research advances, however, it is hoped that DNA testing will allow for early diagnosis (and, therefore, early treatment) for many types of septal defects. Genetic research continues to make progress in identifying proteins involved in heart structure and function, and how abnormal (mutated) forms of those proteins influence congenital heart defects. For example, scientists have uncovered mutations in genes responsible for a normal heart septum.

Preparing questions in advance can help patients to have more meaningful discussions with their physicians regarding their conditions. Patients may wish to ask their doctor the following questions related to a ventricular septal defect (VSD):

1. Does a VSD cause any pain or discomfort?
   
   
2. What size VSD does my child have?
   
   
3. Do you expect my child's VSD to close on its own?
   
   
4.  What type of VSD does my child have?
   
   
5. How dangerous is my child's VSD?
   
   
6. What type of treatment do you plan to use to treat my child's VSD?
   
   
7. Will my child need surgery?
   
   
8. Do you plan to conduct further testing in order to be sure of a diagnosis?
   
   
9. What was my child's VSD caused by?