Puppies can be born with virtually the same birth defects of the heart that affect human babies. Treatment of some congenital abnormalities is possible in dogs however it pales in comparison to the sophistication that is available for treatment of children with congenital heart disease.
Types of Congenital Heart Disease of Dogs and Children (birth defects of the heart)
Abnormalities range from so-called “hole in the heart” where the defect is an opening between the left and right sides of the heart, to abnormalities of the valves or combinations of both. A defect between the ventricles is called an Interventricular Septal Defect and between the atria is called an Interatrial Septal Defect. Congenital defects can also occur between great vessels such as the aorta and the pulmonary artery; the most common of which is called a Patient Ductus Arteriosus.
Over time in severely affected dogs and children, the blood flowing between the stronger left side to the right side may result in heart enlargement and eventually heart failure. Lessor affected patients may be able to live with these defects for extended periods of time.
Congenital defects of the heart valves are the most common cardiac birth defects in both dogs and humans. Narrowing of the Aortic Valve or Aortic Stenosis or SubAortic Stenosis (SAS) results in increased work to force the blood through a smaller opening. Thus the left ventricle becomes progressively thickened proportionate to the severity of the narrowing. If the narrowing is severe the thickening will be so severe that the dog or child will die if untreated.
Pulmonic Stenosis is a narrowing of the Pulmonic Valve resulting in similar process to Aortic Stenosis but of the right side of the heart. The result is a decrease blood flow to the lungs and thickening of the right side of the heart (right ventricle). Unless the condition is severe many dogs live with this disease without clinical signs for many years or even for their entire life.
Tricuspid Valve Dysplasia is not uncommon particularly in Labrador Retriever dogs. It may be unnoticed thought the entire live of the dog but in the most severe cases may eventually cause right heart failure.
Mitral Valve Stenosis, though common in children is a relatively rare disorder in dogs.
Many other defects have been recognized and are typically combinations of the above abnormalities or other complex, the most notable of which is Tetralogy of Fallot.