Acting Early to Help Dogs With Aortic Stenosis

Aortic stenosis (AS) is a congenital heart defect affecting dogs, meaning they’re born with it. It narrows the aortic valve, the gateway through which blood leaves the heart for the rest of the body.

A more common form, subaortic stenosis (SAS), involves narrowing just below the valve. For simplicity, we’ll refer to both as AS throughout this post, which the team at Coast to Coast Cardiology is hoping will help any dog owners in need of clarity regarding the condition.

Read on to learn the basics of AS and what you can do to manage it.

How AS Affects the Heart

With a narrowed valve, the heart’s left ventricle must work harder to pump blood through the obstruction. If severe, this extra effort can lead to complications like:

  • Congestive Heart Failure, in which blood backs up, causing fluid buildup in the lungs.
  • Fainting Episodes, which can cause reduced blood flow to the brain and lead to fainting.
  • Arrhythmias, since thickening of the heart muscle can disrupt the heart’s electrical system.
  • Endocarditis, in which bacteria can become trapped on the abnormal valve, leading to a potentially life-threatening infection.

Diagnosis of AS

A heart murmur detected during a routine checkup might be the first clue. From there, veterinarians rely on an echocardiogram (ultrasound of the heart) to diagnose AS.

  • This provides detailed images of the heart’s structure and blood flow, revealing specific signs of AS like thickened valve cusps or an enlarged left ventricle.
  • Chest X-rays and electrocardiograms (ECGs) may also be used for a broader picture of the heart and lungs and to check for arrhythmias.

Treatment Options

While surgery (balloon valvuloplasty) is an option, it doesn’t significantly improve lifespan, although it can manage symptoms.

Any treatment approach depends on the severity:

  • Mild AS: If your dog shows no symptoms and has minor echocardiogram changes, medication might not be necessary.
  • Moderate or Severe AS: Beta-blockers like atenolol are commonly prescribed. These medications help the heart relax more fully, allowing the valve to open more and reducing abnormal thickening of the heart walls. They can also have anti-arrhythmic properties.
  • Severe Complications: Hospitalization might be required. Diuretics may be used to remove excess fluid in cases of heart failure. Antibiotics are used to treat endocarditis.


It’s essential to understand how AS affects long term outlook and daily life for your dog. Its severity can progress until a dog reaches full size, and as always, early diagnosis allows for regular monitoring to determine treatment needs.

  • With mild AS, dogs typically live average lifespans without needing treatment.
  • With moderate or severe AS, dogs may experience symptoms and have an increased risk of sudden death.
  • In severe cases, lifespan is often reduced, with an average of around 2 years.

Management Methods

  • Since AS is hereditary, breeding dogs with this condition is not recommended.
  • Littermates of affected dogs should be screened for heart murmurs and undergo echocardiograms if necessary.
  • Exercise, especially strenuous activity, should be restricted in dogs with AS, as it can increase the risk of sudden death.

If you have any concerns about the cardiovascular health of your pet, the best thing you can do is come see us! At Coast to Coast Cardiology, we have ten different locations, but we deliver on one goal no matter what: treating the patient, not just the signs. To make an appointment, contact us online or call 844-582-3827 today.