A ventricular septal defect (VSD) is a hole in the heart. It's a common heart problem present at birth (congenital heart defect). The hole occurs in the wall that separates the heart's lower chambers (ventricles).

A VSD changes how blood flows through the heart and lungs. Oxygen-rich blood gets pumped back to the lungs instead of out to the body. The oxygen-rich blood mixes with oxygen-poor blood. These changes may increase blood pressure in the lungs and require the heart to work harder to pump blood.

A small ventricular septal defect may cause no problems. Many small VSDs close on their own. Babies with medium or larger VSDs may need surgery early in life to prevent complications.


Symptoms of serious heart problems present at birth (congenital heart defects) often appear during the first few days, weeks or months of a child's life.

Symptoms of a ventricular septal defect (VSD) depend on the size of the hole and if there are any other heart problems. A small VSD may never cause symptoms.

In general, VSD symptoms in a baby may include:

  • Poor eating
  • Slow or no physical growth (failure to thrive)
  • Fast breathing or breathlessness
  • Easy tiring
  • Whooshing sound when listening to the heart with a stethoscope (heart murmur)

Symptoms of a ventricular septal defect in adults may include:

  • Shortness of breath, especially when exercising
  • Whooshing sound when listening to the heart with a stethoscope (heart murmur)

When to see a doctor

Call your health care provider if your baby:

  • Tires easily when eating or playing
  • Is not gaining weight
  • Becomes breathless when eating or crying
  • Breathes rapidly or is short of breath

Call your provider if these symptoms develop:

  • Shortness of breath
  • Rapid or irregular heartbeat
  • Fatigue or weakness


Ventricular septal defect (VSD) occurs as the baby's heart is developing during pregnancy. The muscular wall separating the heart into left and right sides doesn't form fully, leaving one or more holes. The size of the hole or holes can vary.

There's often no clear cause. Genetics and environmental factors may play a role. VSDs can occur alone or with other heart problems present at birth. Rarely, a ventricular septal defect can occur later in life after a heart attack or certain heart procedures.

How the heart works

To understand more about ventricular septal defect (VSD), it may be helpful to know how the heart typically works.

The typical heart is made of four chambers — two upper chambers (atria) and two lower chambers (ventricles).

  • The right side of the heart moves blood to the lungs.
  • In the lungs, blood picks up oxygen.
  • The lungs pump the oxygen-rich blood to the heart's left side.
  • The left side of the heart pumps the oxygen-rich blood to the rest of the body.

A ventricular septal defect changes the direction of blood flow in the heart and lungs. The hole lets oxygen-rich blood go back into the lungs, instead of going out to the body. Oxygen-rich blood and oxygen-poor blood now mix together. If the ventricular septal defect is large, the blood pressure in the lung arteries may increase. The heart then must work harder to pump blood. A large VSD can also increase the amount of blood flow in the lung arteries, causing congestion.

Risk factors

Risk factors for ventricular septal defect include:

  • Premature birth
  • Down syndrome and other genetic conditions
  • Family history of heart problems present at birth (congenital heart defects)

A baby born with ventricular septal defect may have other heart problems, such as:

  • Atrial septal defect
  • Coarctation of the aorta
  • Double outlet syndrome
  • Patent ductus arteriosus
  • Tetralogy of Fallot

If you already have a child with a congenital heart defect, a genetic counselor can discuss the risk of your next child having one.


A small ventricular septal defect (VSD) may never cause any problems. Some medium or large VSDs may be life-threatening. Treatment can help prevent many complications.

Complications of ventricular septal defect can include:

  • Heart failure. In a heart with a medium or large VSD, the heart works harder and the lungs have too much blood pumped to them. Without treatment, heart failure can develop.
  • Eisenmenger syndrome. An unrepaired hole in the heart can lead to this complication after many years. Irregular blood flow causes the blood vessels in the lungs to become stiff and narrow. Blood pressure rises in the lungs' arteries (pulmonary hypertension). This syndrome permanently damages the blood vessels in the lungs.
  • Endocarditis. This is a rare complication of VSD. An infection causes life-threatening inflammation of the inner lining of the heart's chambers and valves.
  • Other heart problems. These include heart valve disease and irregular heart rhythms (arrhythmias).


Because the cause is unclear, it may not be possible to prevent ventricular septal defect (VSD). But getting good prenatal care is important. If you have a VSD and are planning to become pregnant, schedule a visit with your health care provider and follow these steps:

  • Get early prenatal care, even before you're pregnant. Talk to your provider before you get pregnant about your health and discuss any lifestyle changes that your doctor may recommend for a healthy pregnancy. Also, be sure you talk to your doctor about any medications you're taking.
  • Take a multivitamin with folic acid. Taking 400 micrograms of folic acid daily has been shown to reduce birth defects in the brain and spinal cord. It may help reduce the risk of heart defects as well.
  • Avoid alcohol. Drinking alcohol during pregnancy increases the risk of congenital heart defects.
  • Don't smoke or use illegal drugs. If you smoke, quit. Smoking during pregnancy increases the risk of a congenital heart defect in the baby. Avoid using illegal drugs as they may harm a developing baby.
  • Get recommended vaccinations. Be sure you're up to date on all of your vaccinations before becoming pregnant. Some infections can be harmful to a developing fetus. For example, having rubella (German measles) during pregnancy can cause problems in a baby's heart development. A blood test done before pregnancy can determine if you're immune to rubella. A vaccine is available for those who aren't immune.
  • Keep diabetes under control. Careful control of blood sugar before and during pregnancy can reduce the risk of congenital heart defects in the baby. Diabetes that develops during pregnancy (gestational diabetes) generally doesn't increase a baby's risk. If you have diabetes, work with your provider to be sure it's well controlled before getting pregnant.
  • Check with your provider before taking any medications. Some medications can cause birth defects. Tell your provider about all the medications you take, including those bought without a prescription.

If you have a family history of heart problems present at birth, consider talking with a genetic counselor and a heart doctor (cardiologist) before getting pregnant.

Oct. 21, 2022
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