Pulmonic stenosis is a congenital heart defect (one present since birth) that causes a narrowing of the heart’s pulmonic valve. The pulmonic valve connects the right ventricle heart chamber to the pulmonary artery, which carries blood from the heart to the lungs.
When the pulmonic valve is narrowed, it blocks the flow of blood from the heart to the lungs, and the right ventricle must work harder than normal to push blood through. In many cases, pressure builds up behind the obstructed pulmonic valve, resulting in fluid accumulation in the abdomen or chest that leads to congestive heart failure. The heart’s overwork can also cause a heart murmur (abnormal heart sound) and arrhythmias (abnormal heart rhythm).
Pulmonic stenosis is one of the most common congenital heart defect in dogs, but it is rarely seen in cats.
Causes of Pulmonic Stenosis in Dogs and Cats
Pulmonic stenosis is a congenital heart defect, which means that it is present at birth. It is known to be inherited in certain breeds, including the Beagle, Chihuahua, and English Bulldog. It is also commonly seen -- though not necessarily inherited -- in Labrador Retrievers, Newfoundlands, and West Highland White Terriers.
Pulmonic stenosis can range from mild to severe. In some cases, a pet may function normally or have only a benign heart murmur. In other cases, the narrowing of the pulmonic valve may result in serious health consequences, including congestive heart failure or sudden death due to arrhythmias.
Symptoms of Pulmonic Stenosis in Dogs and Cats
Most pets affected by pulmonic stenosis do not show any symptoms when they are young. The defect is usually discovered when a heart murmur is detected during a routine check-up, warranting further investigation.
In moderate or severe cases, the pet may show symptoms of congestive heart failure, including:
- Difficulty breathing/shortness of breath
- Exercise intolerance
Diagnosing and Treating Pulmonic Stenosis in Dogs and Cats
If your veterinarian suspects that your pet is suffering from a heart defect, they will most likely perform a physical examination, chest radiograph, and echocardiogram. An echocardiogram is a heart ultrasound, and the only test that can definitively diagnose pulmonic stenosis. An echocardiogram allows the veterinarian to see the heart’s activity in real time, revealing the severity of the defect and any other heart abnormalities that may impact treatment.
Treatment for pulmonic stenosis will ultimately depend on the severity of the defect. Pets with mild forms may live normally without the need for intervention. Pets with moderate to severe defects, however, are usually treated with a minimally invasive procedure called balloon valvuloplasty. Balloon valvuloplasty is a catheterization procedure in which a balloon is guided to the narrowed part of the valve and then inflated, causing the valve to stretch and blood flow to improve. In many cases, this procedure alleviates symptoms and prolongs the pet’s life.
If congestive heart failure is present, the pet will need to be stabilized before undergoing balloon valvuloplasty. In cases wherein the procedure is not possible for one reason or another, medications such as beta-blockers may be prescribed to reduce symptoms.
Talk to your veterinarian about what else you can do to help your pet. Many vets recommend limiting exercise to avoid overwork of the heart and low-sodium diets to reduce fluid buildup.
Since the defect may be inherited, affected pets should not be bred.
More on Heart Health
How To Treat Heart Disease In Pets
What Is A Heart Murmur In Dogs
4 Common Causes Of Heart Failure In Dogs