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Medical Author:

John Mersch, MD, FAAP

John Mersch, MD, FAAP

Dr. Mersch received his Bachelor of Arts degree from the University of California, San Diego, and prior to entering the University Of Southern California School Of Medicine, was a graduate student (attaining PhD candidate status) in Experimental Pathology at USC. He attended internship and residency at Children's Hospital Los Angeles.

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Medical Editor:

William C. Shiel Jr., MD, FACP, FACR

William C. Shiel Jr., MD, FACP, FACR

Dr. Shiel received a Bachelor of Science degree with honors from the University of Notre Dame. There he was involved in research in radiation biology and received the Huisking Scholarship. After graduating from St. Louis University School of Medicine, he completed his Internal Medicine residency and Rheumatology fellowship at the University of California, Irvine. He is board-certified in Internal Medicine and Rheumatology.

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In this Article

• What is a ventricular septal defect (VSD)?
• How common is a VSD?
• What is the normal design of the heart?
• How do VSDs cause problems?
• How is a VSD diagnosed? What are the symptoms of a VSD?
• What if the VSD is small?
• How is a small VSD treated?
• What if the VSD is large?
• How is a large VSD treated?
• What types of surgery are available to correct a VSD?
• What is the outlook (prognosis) after a VSD is repaired?
• What are complications of VSD surgery?
• What about unusual cases of VSD?
• What are long-term precautions with VSDs?
• Ventricular Septal Defect At A Glance
• Find a local Cardiologist in your town
• Ventricular Septal Defect Index

Small defects (less than 0.5 square cm) are common. With a small VSD, there is minimal shunting of blood and the pressure in the right ventricle remains normal. Since the right ventricular pressure is normal, there is no damage to the lung arterioles. The heart functions normally. A prominent murmur heard through a stethoscope is usually the only sign that brings the VSD to attention. This murmur is commonly noted during the first week of life.

One-third to one-half of all small VSDs close spontaneously (on their own). This seemingly miraculous event occurs most often before the baby is 1 year old, almost always before age 4 (75% by 2 years of age). The closure is due to the small VSD being located between heart fibers that increase in size in time, thus encroaching upon the opening in the ventricular septum.

Even if a small VSD does not close spontaneously, surgical repair is usually not recommended. However, long-term follow-up is required.

With a large VSD (usually one greater than 1 cm²), there is significant shunting of blood from the left ventricle into the right ventricle. Thus extra blood volume puts a strain on the right ventricle and causes an increase in the blood pressure of the lungs called "pulmonary hypertension." The child may have labored breathing, difficulty feeding, grow poorly, and have pallor.

Ultimately, the patient with a large VSD will need surgery to "patch the hole" in the ventricular septum. The timing of the surgery is an individualized decision based upon several factors. These include

1. The extent and duration of increased pulmonary artery pressure. Chronic pulmonary arteriolar pressure may become irreversible and put a strain on the right ventricle. These side effects may be treated with medications until surgery is appropriate.



2. A child with a large VSD often will not grow as robustly as his peers. The work of increased metabolic demands often requires additional calories when compared to children without such a cardiac defect. High-calorie dense supplements may be added to formula. Some infants may require nighttime continuous feedings using a tube that is passed through the nose to the stomach (nasogastic tube) to maximize growth. It is very rare to restrict fluid volumes in these children.



3. Infants with iron-deficiency anemia should receive iron supplements to maximize the oxygen carrying capacity of their blood. Blood transfusions to address such an anemia are rare.