Pediatric Heart Disease Ventricular Septal Defect

Ventricular septal defect, or VSD, occurs when a child is born with an opening in the wall, or septum, dividing the two lower heart chambers (the ventricles). Affecting 0.1 percent to 0.4 percent of all births, ventricular septal defect is among the most common pediatric heart defects. If the ventricle wall hole is very small, VSD may close over time. However, larger cases of ventricular septal defect can cause serious heart conditions if left untreated, including congestive heart failure.

How Ventricular Septal Defect Affects the Body

The heart has four chambers:

  • two lower chambers (the left and right ventricles)
  • two upper chambers (the left and right atria).

Oxygen-rich blood is pumped to the body through the left ventricle while oxygen-depleted blood is pumped to the lungs through the right ventricle.

In cases of ventricular septal defect, oxygenated blood in the left ventricle passes through the septal defect into the right ventricle. This blood, already oxygenated, is then pumped back to the lungs. If the ventricular septal defect is large, significant amounts of blood are redirected through the hole.

To compensate for ventricular septal defect, the heart pumps harder to ensure the body receives enough oxygenated blood. An overworked heart may develop thicker muscle tissue, causing the entire heart to become enlarged. This puts patients at risk for congestive heart failure.

Another complication of VSD is that blood redirected through the ventricular septal defect increases blood pressure in the lungs. The resulting high blood pressure in the lungs slowly causes permanent damage to the lungs’ blood vessels.

Causes of Ventricular Septal Defect

Like many congenital heart defects, the exact causes of ventricular septal defect are unknown. However, genetics is thought to play a role. Parents with congenital birth defects are more likely to have children with ventricular septal defect (or other congenital heart disorders) than parents without such defects.

Ventricular Septal Defect Symptoms

Although a child with a small ventricular septal defect may have no apparent symptoms, doctors may detect a heart murmur, an unusual sound heard when listening to the child’s heartbeat, during routine physicals. Small ventricular septal defects rarely cause serious health complications unless they occur in tandem with other heart problems.

Yet, an infant with a large ventricular septal defect can develop congestive heart failure within weeks of birth. While symptoms of congestive heart failure due to ventricular septal defects can appear in older children or adults, they can also occur as early as two months after birth.

Common symptoms of congestive heart failure include:

  • delayed growth
  • fast heart rate
  • fatigue
  • low energy levels
  • rapid breathing
  • slow weight gain.

Diagnosing Ventricular Septal Defect

Detection of a heart murmur during routine physical examination is usually the first step in diagnosing ventricular septal defect. Ironically, small ventricular septal defects often produce louder heart murmurs than mid-size to large-size VSDs: Larger ventricular septal defects place less resistance on blood flowing through the hole and, therefore, produce a quieter heart murmur.

A physical exam may also reveal unusually labored or rapid breathing and/or an unusually rapid heart rate. In combination with a heart murmur, such findings suggest the possibility of ventricular septal defect and the need for diagnostic testing. Common diagnostic tools used to detect VSD include:

  • Cardiac catheterization is generally used as a last-resort diagnostic tool because it is a more invasive procedure than the other techniques. During a cardiac catheterization, a catheter (a thin tube) is inserted into an artery in the groin or arm. Doctors then inject dye into the blood through the catheter. At this point, the doctor then takes X-rays on which the dye is visible. The doctor can then trace the blood’s path through the heart and detect any possible defects or obstructions.
  • Echocardiograms use sound waves to construct an image of the heart on a monitor. An echocardiogram may be required during ventricular septal defect diagnosis if VSD is thought to be accompanied by other heart defects. Similarly, your doctor may call on an echocardiogram if electrocardiogram results are inconclusive.
  • Electrocardiograms use electrodes (placed on the patient’s chest) to measure the heart’s electric impulses. Electrocardiograms can detect the presence of enlarged heart chambers, suggesting that a ventricular septal defect is forcing the heart to work harder. Enlarged hearts put patients at risk of congestive heart failure. Keep in mind that enlarged hearts take years to develop. As a result, regular follow-up electrocardiograms may be necessary to check if a large ventricular septal defect is contributing to the presence of congestive heart failure symptoms.

VSD Complications

Left untreated, mid- to large-size ventricular septal defects can cause a number of serious complications. Because excessive blood pressure tends to force unoxygenated blood through the VSD into the left ventricle, insufficient oxygen reaches the body.

The most common complaint is the progressive worsening of congestive heart failure symptoms. Eisenmenger’s syndrome, a result of untreated congestive heart failure and ventricular septal defect, results from long-term oxygen-deficient blood. Symptoms include:

  • breathlessness
  • cyanosis (bluish lips and fingers)
  • difficulty feeding (which can impair brain growth in some infants)
  • hemotysis (coughing up blood)
  • increased susceptibility to infection, especially lung infections.

Treating Small Ventricular Septal Defects

Treatment is not often required for small ventricular septal defects, presuming no other heart conditions are present. A ventricular septal defect will not enlarge over time, and small VSDs will often grow smaller or close completely as the child grows.

If a heart murmur is the only symptom of ventricular septal defect, regular observation by a pediatric cardiologist (a specialist in childhood heart disease) may be the only treatment required.

Non-Surgical Ventricular Septal Defect Treatment

Doctors may also observe, rather than treat, mid-size to large ventricular septal defects. If the doctor starts noticing symptoms of congestive heart failure, medications to help reduce symptoms’ severity may be prescribed. Some of these medications may include:

  • digoxin to improve heart contractions
  • diuretics to remove fluid from the lungs
  • hypertension medication to lower blood pressure and reduce strain on the heart.

Infants who have difficulty gaining weight due to ventricular septal defect symptoms may need prescription, high-calorie formula. Breast-fed babies may benefit from fortified mother’s milk. However, babies that have extreme difficulty feeding due to VSD may need a nasogastric tube to deliver food directly to their stomachs.

The goals of non-surgical treatment for ventricular septal defect are twofold. Ideally, the VSD will close or the hole will narrow enough during treatment so surgery and medication are no longer needed. Failing this, non-surgical treatment controls symptoms long enough for the child to grow and become a more suitable candidate for surgery.

Surgery and Ventricular Septal Defect

Large ventricular septal defects require surgical correction, either to prevent congestive heart failure or to prevent other heart conditions from developing later in life. While ventricular septal defect surgery can be performed in adolescents and adults, it is usually performed in the first two days of life.

During VSD surgery, surgeons seal the septum hole with an artificial patch. As the heart tissue grows, the patch is slowly embedded within the tissue, making the patch a permanent part of the heart.

The prognosis for VSD surgery is good: Few people require follow-up surgery. Along with repairing the hole in the heart, surgery for VSD usually corrects abnormal blood circulation, preventing the possibility of congestive heart failure.

Endocarditis Prevention

Endocarditis is an infection of the heart tissue. Children with ventricular septal defect require prophylactic antibiotics to reduce the risk of developing this type of heart infection. Once the VSD is corrected, preventative antibiotics can be discontinued after six months.

If a child with a small VSD is under observation, preventative antibiotics are required prior to dental work or surgery to lower the risk of developing endocarditis.

Post-Surgical Complications

Generally, ventricular septal defect has few complications. In some cases, congestive heart failure has caused pulmonary hypertension (high blood pressure in the lungs) prior to surgery. This may require additional treatment, and the child may need to restrict his or her physical activity.

The patient may also have to restrict his activity after surgery. If the post-surgical heart continues to have impaired contractions, diuretics, blood pressure medication and contraction regulating medication may be required.

Resources

American Heart Association (n.d.). Ventricular septal defect (VSD) Retrieved September 14, 2007, from the AHA Web site: www.americanheart.org/presenter.jhtml?identifier=11066.

Cincinnati Children’s Hospital Medical Center (n.d.). Ventricular septal defect. Retrieved September 14, 2007, from the Cincinnati Children’s Hospital Medical Center Web site: www.cincinnatichildrens.org/health/heart-encyclopedia/anomalies/vsd.htm.

National Heart, Lung, and Blood Institute (n.d.). Ventricular septal defect. Retrieved September 14, 2007, from the NHLBI Web site: www.nhlbi.nih.gov/health/dci/Diseases/vsd/vsd_what.html.

Medlineplus Medical Encyclopedia (2004). Ventricular Septal Defect. Retrieved September 14, 2007, from the U.S. National Library of Medicine Web site: www.nlm.nih.gov/medlineplus/ency/article/001099.htm.