Pulmonary Stenosis in Dogs: Symptoms, Diagnosis and Treatment

Written and verified by the biologist Ana Díaz Maqueda

Last update: 27 December, 2022

Pulmonary stenosis in dogs is a congenital heart disease. Animals born with this pathology won’t show clinical signs until they’re older or until the condition worsens. However, the dogs that suffer from it will have heart disease from birth, even though the disease takes years to detect.

Despite being congenital and depending on the breed at all times, a dog with pulmonary stenosis can live for many years and, in addition, undergo restorative surgeries that are usually successful in many cases. Next up, we’ll tell you more about this congenital heart disease.

What’s pulmonary stenosis in dogs?

A dog’s heart, just like a human’s, is divided into four chambers, two atria that receive blood from the body or the lungs, and dog ventricles that send blood to the whole body or only to the lungs for its oxygenation.

Between the atria and the ventricles, there are valves that prevent blood from flowing backwards. Similarly, other valves are located at the outlet of the ventricles for the same purpose.

These last 2 valves, called pulmonary and aortic – because they’re in the pulmonary artery and the aorta  – are the ones that are atrophied in this congenital pathology.

When the ventricles contract, all the blood should go out to the body or lungs and, thanks to these valves, the blood doesn’t return to the heart. In pulmonary stenosis in dogs, one or both valves, mainly the pulmonary one, are poorly designed and return blood to the heart.

Clinical signs of the disease

As already mentioned, even if animals have a heart defect from birth, they often won’t show any clinical signs during the first months or years of their life. Because of this, in most cases the diagnosis occurs late.

In mild cases of pulmonary stenosis in dogs, the clinical signs may not be noticeable throughout the animal’s life. However, in moderate or severe conditions, there may be clinical signs, such as the following:

• Lethargy or apathy
• Weakness
• Exercise intolerance: the dog gets tired very quickly during walks and isn’t too keen to walk
• Heart failure
• Arrhythmia

These clinical signs are usually common to many other cardiac pathologies, and so the breed the dog belongs to can be key to its diagnosis. Although any dog can suffer from the disease, there are breeds with a greater predisposition. These are the following:

• English bulldogs
• French bulldogs
• Jack Russell terriers
• Boston terriers
• Newfoundlands
• Labradors
• Boxers
• Samoyeds

How to diagnose pulmonary stenosis in dogs?

If it’s suspected that the pet could have a heart problem because it has one or more of the aforementioned clinical signs, then make an appointment with the veterinarian. With the help of a stethoscope, the vet will be able to hear any strange noises coming from the heart, such as murmurs.

A heart murmur can be totally related to this disease. Its detection is one more step towards the diagnosis of heart disease. After that, an echocardiogram is highly recommended —to observe the valves and all the structures that support them, as well as blood flow.

These and some other tests, such as an X-ray or EKG, are sufficient to diagnose pulmonary stenosis in dogs. Although some of the tests can be somewhat expensive, they’re absolutely necessary for diagnosis.

Available treatments

Treatment will depend at all times on how serious the pet’s condition is. If the congenital heart disease is very severe and the animal’s life is in danger, the best solution is an aortic valvotomy or aortic valvuloplasty.

This surgical procedure involves widening the opening through which the valve allows blood to pass. A surgical balloon is placed which gives the valve greater flexibility and makes it work more efficiently.

On the other hand, in cases where surgical treatment isn’t possible or the animal doesn’t need surgery, pharmacotherapy is chosen. The vet can prescribe specific drugs that help the valves with their task.

Whether opting for one treatment or another, long-term veterinary supervision is absolutely necessary. Even if the dog is medicated or has undergone surgery, it will have heart disease for life. These animals need more veterinary checks to detect any changes more effectively, but they can lead normal lives.