Aortic Stenosis In Dogs: Causes, Signs, Treatments

A dog’s heart is a truly impressive organ: after all, it’s built to support him as he runs, jumps, hunts, and yes, even naps. A healthy canine heart keeps up with the physical demands of even the most active puppy, but health problems within the heart and its associated support structure can lead to serious complications if they’re left unchecked. One of the most common congenital canine heart conditions is a disease called aortic stenosis, and treating it the right way can be the difference between a sudden tragedy or a long, healthy life for an afflicted dog.

What Is Aortic Stenosis In Dogs?

The term refers to a condition that affects the aortic valve of the heart, which brings oxygen-rich blood to one of the four heart chambers. When his aortic valve works as it’s intended to, his body can pump blood in and out of his heart muscle, giving him the oxygenated blood he needs to look, feel, and perform as a healthy and active dog. Stenosis refers to a narrowing of a channel – in this case, the aforementioned aortic valve – that prevents healthy flow. 

Once a pet parent knows what canine aortic stenosis is, it’s important to cover what it is not. For example, this health issue is:

  • Not typically caused by trauma, ingestion of substances, or outside influence: It most commonly presents as a congenital condition, which means that a puppy is born with it. While there are outlying cases for the vast majority of canine health problems, this specific issue can usually be traced back to genetics.
  • Not universal in the way it presents: Not all dogs with the condition will be severely affected, while in others it may immediately prove to be life-threatening. Only a vet will be able to diagnose the severity and recommend appropriate treatment.
  • Not usually idiopathic in nature: Idiopathic is a term applied to medical conditions that seem to occur randomly, without a known cause. Aortic stenosis in dogs has been found to have a strong genetic component, to the end that vets recommend dogs with the condition be neutered or spayed to avoid passing on the genetic trait to future generations of puppies.
  • Not easy to spot during a routine vet exam: While severe cases of stenosis may be noticeable during a puppy’s first examinations, if he has a mild case, it can escape notice until he’s considerably older. Unless a vet is specifically looking for signs (for example, if a dog’s dam or sire were known to have the issue), obvious red flags like a heart murmur might go undetected until more obvious symptoms emerge. 
  • Not contagious: As a congenital health problem, it exists in his genetics from birth, and cannot be passed on or “caught” by other household pets, even puppies. That being said, if he is being raised with a littermate and tests positive himself, it’s important to have the same tests performed on his sibling as soon as possible. Their mutual genetics would point to the littermate also being at risk, or at the least a genetic carrier.

Does My Dog Have Aortic Stenosis?

Just as in humans affected by serious heart issues, the only sure way to know if canine aortic stenosis is to blame for a dog’s concerning physical symptoms is testing in a medical setting. This doesn’t mean, however, that a dog’s owner should skip out on noting symptoms between routine or emergency vet visits. These questions can help a pet care professional narrow down the most useful tests and treatment for a dog suspected of struggling with heart issues:

  • What symptoms is he exhibiting? Because the heart is responsible for blood flow, any obstacles to that flow will start eventually showing in his demeanor and activity level. Even though his heart is the issue and not his lungs, pulmonary troubles are a big red flag. If he struggles to breathe after strenuous activity, or appears to be moving slowly and lethargically, compromised blood flow from a stenosis-stricken valve may be to blame.
  • When did the symptoms first emerge? Knowing the date when the visual symptoms first appeared can help veterinary teams eliminate secondary causes and determine the best testing methods to use. For example, a pet parent might not see the correlation between starting a new type of dog food and their dog’s symptoms, but a vet may spot the potential for an allergic reaction as the cause. 
  • What helps or worsens the symptoms? For example, do breathing issues taper off as he rests, or are they consistent for several minutes after “cooling down” from exercise? Pet owners should consider if weather, overall temperature, treats, food, or access to water seem to alleviate their dog’s symptoms, as true aortic stenosis will not usually be dramatically remedied by altering these factors.
  • Are there any appropriate, proactive tests available? While pet parents certainly need to weigh costs when creating a health plan for their dog, certain tests can definitively diagnose canine aortic stenosis. If he’s having x-rays done already, it might be worthwhile, for example, to request the vet examine them for heart irregularities. During a routine examination, a dog’s owner may also ask the vet or vet tech to listen specifically for a heart murmur if they suspect aortic stenosis due to breeding genetics.

How Is Aortic Stenosis In Dogs Treated?

Though all forms of this canine health concern affect roughly the same area of the heart, there are three potential positions in which it can appear. If the stenosis occurs inside the valve, it is called valvular. If it occurs above the valve, it’s called subvalvular. The third variant, subaortic stenosis or SAS, occurs below the valve. This is the most common version of canine aortic stenosis and can pose a dangerous issue as he grows from a puppy into an adult dog. The growth process puts additional strain on this subaortic area of the heart, which in turn can exacerbate symptoms and even cause fatal complications.

For mild cases of stenosis, a pet parent might remain unaware of the condition throughout their dog’s entire lifetime. Because the symptoms aren’t obvious or particularly impactful to his overall health, red flags like lethargy might be explained away by his age or other factors. Even when mild cases are diagnosed, intervention isn’t usually necessary, though the vet may recommend a low-sodium diet for him, just to be on the safe side.

For moderate to severe cases of stenosis, canine treatment follows human treatment in the form of beta blocker medications. These help alleviate the normal strain placed on the heart muscle, allowing it to pump more effectively despite the narrowing of the aortic valve. Because there is no cure for aortic stenosis in dogs, these medications will need to be administered consistently for the rest of his life in order to protect his heart. Some canine heart surgeries have been explored to repair the narrowing of the valve at the site itself, but these tend to be relatively rare, and are unlikely to be recommended in any but the most severe of cases. 

Best Practices For Aortic Stenosis In Dogs

If a dog has been diagnosed with canine aortic stenosis, he’ll need his owners to tailor his day-to-day activities accordingly. While exercise and fresh air is a must for any healthy dog, it’s important to temper high-energy activity in moderate to severe cases. That may mean limiting his interaction with particularly playful/energetic dogs, discouraging him from chasing game or prey, and keeping his running speed at a conservative pace to limit the demands on his heart. 

Excitement can also cause a strain on the heart muscle, so training him to have a calm reaction to stimuli like the doorbell or pet siblings in the house is a must. For certain energy-prone breeds, this can prove a challenge, but the health benefits of those efforts are well worth it over his lifetime.

In addition to appropriate restrained exercise, a proper diet is a must – again, much like humans with similar heart conditions, a low sodium diet is very important when it comes to protecting heart health. Certain supplements and the previously-mentioned prescription beta blockers will also help ensure a long, happy, and healthy life for him. As with any dog on a medication regimen, he’ll also need periodic visits to his vet to be sure the medication is working as intended. 

While aortic stenosis in dogs sounds like a frightening diagnosis on paper, it doesn’t have to impact his overall health and happiness. The truth is that with a few lifestyle changes, good veterinary care, and medication in more serious cases, he’ll never know his loving heart is anything less than perfect.

Sources Cited:

1)      Clark, Mike. “Aortic Stenosis In Dogs: Symptoms, Causes & Treatments.” Dogtime.com, (no publish date), https://dogtime.com/dog-health/57857-aortic-stenosis-dogs-symptoms-causes-treatments. Accessed May 26, 2020.

2)      German, Alex. “Heart (Aortic) Valve Narrowing in Dogs.” PetMD.com, March 26, 2010, https://www.petmd.com/dog/conditions/cardiovascular/c_dg_aortic_stenosis. Accessed May 26, 2020.

3)      Tou, Sandra P.; DVM, DAVCIM, North Carolina State University. “Congenital and Inherited Disorders of the Cardiovascular System in Dogs.” Merck Manual Veterinary Manual (merkvetmanual.com), June 2018, https://www.merckvetmanual.com/dog-owners/heart-and-blood-vessel-disorders-of-dogs/congenital-and-inherited-disorders-of-the-cardiovascular-system-in-dogs. Accessed May 26, 2020.

4)      “Aortic/Subaortic Stenosis.” Cornell University College of Veterinary Medicine (vet.cornell.edu), (no publish date),