In the developing embryo, the heart initially has four chambers that are not separated from one another. As the fetal heart develops, walls called septums form to divide the heart into four separate chambers. Occasionally the walls separating the heart chambers will develop incompletely, thus not properly dividing the chambers from each other. This congenital birth defect is sometimes referred to as a 'hole in the heart.' In reality there is no hole in the heart, but rather a hole between the heart chambers. Most commonly this septal defect occurs between the right and left ventricles, hence the name ventricular septal defect (VSD).

What are the symptoms?

Because the left ventricle is stronger than the right, blood is forced backward into the right ventricle. With any backward flow of blood, an additional stress is placed on the affected structures. In the heart this can possibly lead to heart failure. Additionally, with VSD, the body tissues receive an inadequate quantity of oxygenated blood.

Puppies may not have any outward signs. On a routine exam, veterinarians using a stethoscope may hear the heart murmur associated with VSD. In severe septal defects, a decrease in stamina and retarded growth rates occur.

What are the risks?

Many dogs with minor septal defects live normal lives even though a heart murmur is detectable. Sometimes the septal defect closes spontaneously in dogs as old as two years of age. Dogs with large septal defects typically have a shortened life span, generally succumbing to heart failure.

What is the management?

In minor septal defects, treatment is generally not recommended. In severe cases, heart surgery to correct the defect can be performed.

More Information Aortic Stenosis Heart Attacks Mitral Valve Insufficiency Patent Ductus Arteriosus (PDA) Persistent Right Aortic Arch (PRAA) Pulmonic (Pulmonary) Stenosis Ventricular Septal Defect (VSD) Main Menu