Breed Club Testing for Aortic Stenosis in Dogs

Aortic stenosis is a heart condition characterised by a narrowing of the heart’s aortic valve, restricting blood flow out of the heart. This places extra strain on the heart as it must pump harder to circulate blood through the body, which in severe cases can lead to heart failure or the need for corrective surgery.

While aortic stenosis can affect any breed, it is notably more prevalent in certain dog breeds due to hereditary factors and conformation. This poses challenges not only for owners but also for breeders aiming to prevent propagation of the condition within breed populations.

Since aortic stenosis cannot be reliably diagnosed through DNA testing, breed clubs and canine health organisations often manage screening programmes using specialised cardiac examinations. These tests aim to identify affected dogs early, guiding responsible breeding decisions and helping reduce disease prevalence.

In this article, you will learn about the breeds at risk, how aortic stenosis presents, details of the testing processes, and the role of breed clubs in health screening.

Understanding Aortic Stenosis

Aortic stenosis causes narrowing at the aortic valve, which reduces efficient blood flow out of the heart. The severity varies from mild cases with no health impact to severe cases that may cause heart failure. The condition tends to have a hereditary component, meaning affected dogs are more likely to produce offspring susceptible to the disease. However, a specific gene mutation has not been identified, so it cannot be detected by simple genetic screening.

Breeds That Should Be Tested for Aortic Stenosis

Some breeds have a notably higher risk of developing aortic stenosis. This risk is often related to breed conformation and bloodlines. Breed clubs in the UK have implemented screening programmes particularly for the following breeds:

• The Boxer
• The Bull Terrier
• The Newfoundland

Of these, the Boxer has the most established risk and the aim is for recommended health tests to be performed before breeding. Kennel Club Assured Breeders are strongly urged to have their entire breeding stock screened.

How the Test for Aortic Stenosis Works

There are three primary methods used for testing aortic stenosis, with the choice depending on breed club guidelines and the individual dog:

1. Echocardiography (Cardiac Ultrasound): This non-invasive ultrasound scan provides a clear image of the heart, allowing measurement of blood velocity through the aortic valve to identify the degree of narrowing. It is performed by veterinary cardiologists or specialised vets. Doppler echocardiography helps classify severity based on blood flow velocities.
2. ECG (Electrocardiogram): This tests the heart’s electrical activity and can detect abnormalities associated with aortic stenosis but is usually supplementary to echocardiography.
3. Auscultation: Listening to the heart with a stethoscope to detect murmurs characteristic of aortic stenosis. This is often a first screening and may lead to further diagnostic imaging if a murmur is present.

Most vets can provide immediate results from auscultation and ECG. Echocardiogram results may require review by a specialist and results are registered with the breed club if part of an official screening programme.

Classification System for Test Results

Test results are categorised based on Doppler velocities and murmur presence:

• Unaffected: No murmur at rest, Doppler velocity less than 2.0 m/s, normal heart structure
• Equivocal: Very soft murmur at rest or murmur only post-exercise, Doppler velocity between 2.0 and 2.5 m/s without structural changes
• Affected: Murmur audible at rest, Doppler velocity of 2.0 m/s or higher, possible structural changes indicating stenosis severity

Importance of Breed Club Testing

Breed clubs play a vital role in managing aortic stenosis by:

• Coordinating and overseeing testing programmes tailored for at-risk breeds
• Educating breeders and owners about the condition and importance of screening
• Maintaining health records and registers to monitor prevalence within breeds
• Guiding breeding decisions to reduce incidence and improve overall breed health

For example, the Boxer breed club recommends cardiac screening as part of responsible breeding and discourages using affected dogs for breeding to minimize passing on the condition.

FAQs About Aortic Stenosis and Breed Club Testing

Can a puppy be tested for aortic stenosis?

Quick Answer: Puppies usually can be screened, but more reliable results are generally obtained in dogs older than 1 year.

Testing very young puppies is difficult because their heart structures are still developing, and mild murmurs might not be detected accurately. Breed clubs typically recommend testing before breeding age to ensure accurate health status.

Is aortic stenosis genetic?

Quick Answer: Aortic stenosis has a hereditary component but isn’t linked to a simple gene mutation.

The condition is believed to be polygenic and complex, involving multiple genes and factors, which is why DNA tests cannot currently identify it. Responsible breeders rely on cardiac screening to assess individual dogs.

What should I do if my dog tests positive?

Quick Answer: Breeding affected dogs is strongly discouraged. Veterinary advice on managing health is essential.

If your dog is diagnosed with aortic stenosis, you should not breed from it to prevent passing on the condition. Your vet will advise on management and monitoring to support your dog’s health and quality of life.

Conclusion

Breed club testing for aortic stenosis in dogs is crucial for maintaining the health of predisposed breeds like Boxers, Bull Terriers, and Newfoundlands. Since genetic testing is not yet available, cardiac screening involving auscultation, ECG, and echocardiography plays a central role in identifying affected dogs.

Responsible breeders who undertake recommended screening can make informed mating decisions that help reduce the incidence of this serious heart condition. Owners are encouraged to discuss testing with their vets if their dog belongs to or is a cross of any at-risk breed.