Aortic stenosis is a heart defect that some dogs have from birth. Often, affected dogs show no signs and the condition is picked up when a vet detects a heart murmur at a routine puppy examination. However, some dogs with aortic stenosis may have problems with exercise or difficulty breathing. Your vet will be able to advise on whether your dog needs treatment to support their heart.

What is aortic stenosis?

In aortic stenosis, there is a narrowing around the aortic valve of the heart. This valve sits at the beginning of the aorta, which is the main artery that carries blood around the body. In the following animation, the aorta is the red vessel leading out of the heart, and the aortic valve is the little barrier at the bottom of this that opens when blood flows through.

Animation of normal anatomy and blood flow:

The following animation is a 'top down' view of the aortic valve, and this shows a narrowing just above the valve as is seen in aortic stenosis.

Animation of abnormal aortic valve function:

When there is a narrowing at the base of the aorta, this can restrict blood flow to the body. This means the heart has to work harder to pump blood around the body, especially when the demands on the heart are greater such as in exercise or stress.

What are the signs of aortic stenosis?

If the obstruction to blood flow is only mild, dogs may show no signs at all, but a heart murmur may be picked up on a routine vet examination. This heart murmur develops because the blood flow is disrupted around the stenosis. The murmur may not be obvious when the puppy is very young, as the stenosis may develop more as they grow up.

If the obstruction to blood flow is more severe, the heart will struggle and dogs may show various symptoms. They may be less able to cope with exercise, and they may show shortness of breath. Sometimes dogs may faint when exercising or excited due to restricted blood flow to the brain.

If the disease is severe and not treated, dogs may develop heart failure, with increased breathing effort and coughing. Occasionally, the heart rhythm can be disrupted because the heart muscle has to work so hard that it thickens markedly and the electrical signals are not conducted properly. This raises a risk of sudden death.

What breeds are most affected by aortic stenosis?

Aortic stenosis can occur in any breed, but some are particularly predisposed. These include:

  • Golden Retrievers
  • German Shepherds
  • Newfoundlands
  • Rottweillers
  • Boxers

How is aortic stenosis diagnosed?

If you notice that your dog has any of the signs described above such as struggling with exercise or shortness of breath, it's best to take them to your vet for a check-up. However, many dogs with aortic stenosis will show no signs before a heart murmur is picked up on a routine vet check.

There are many reasons for heart murmurs though, and some puppies can have a murmur with a perfectly healthy heart. So, if your vet detects a murmur, they may suggest further investigation to establish the cause.

Investigation will usually involve an ultrasound of the heart. Depending on the situation and whether your dog is showing any symptoms, your vet may also advise other tests such as X-rays or an ECG.

How do you treat dogs with aortic stenosis?

Dogs with mild aortic stenosis may not require treatment at all, but those with more severe disease will need treatment to support the heart. Your vet may advise long-term medication with drugs such as beta blockers, and may add in additional medication if your dog develops heart rhythm problems or heart failure. Surgery is recommended for some cases but these specialist procedures are not widely performed.

The prognosis for aortic stenosis depends on how severe the condition is, and your vet will be able to advise on the outlook for your pet. Since aortic stenosis can be hereditary, breeding from affected animals is not advised.

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