Heart Murmur in Dogs and Cats: What You Need to Know

There are options you can discuss with your veterinarian.

Heart Murmur in Dogs and Cats
A heart murmur in dogs and cats can often be heard with a stethoscope, but you might also need to bring your pet to a veterinary cardiologist. Photo: photographybycolby

Your healthy dog or cat goes in for a routine visit, and your veterinarian finds a heart murmur. What do you do?

  • You could go see a cardiologist. Check out the murmur. Get a diagnosis. Make sure it’s nothing serious.
  • But then again, a cardiology referral is expensive, usually $300–$600. Is this really necessary?

There is no simple answer.

Your vet has to run a bunch of stuff through her head and give you a qualified recommendation on how to proceed without really knowing what’s going on inside that heart without a workup.

Here are a few things your vet will consider before referring you for a cardiac workup:

  • How old is the pet?
  • What is the breed?
  • Is this a new heart murmur?
  • Is this a “typical” heart murmur, or does it sound weird?
  • Is this pet really healthy other than an “incidental” heart murmur?
  • Are there any other signs of heart disease obvious during the physical exam?

Incidental Heart Murmur in Dogs and Cats

If you and your vet decide that you have a healthy animal — not a breed at risk for heart disease, such as a Cavalier King Charles Spaniel — and there are no signs of heart disease, then the next move is your choice to make.

After this discussion, you should have reached your decision based on some important physical exam findings:

  • The murmur seems to be a minor disorder.
  • There are no serious cardiac stressors or other signs of disease.
  • Your pet is clinically normal.
  • You have no plans to breed the animal.

Typical Case

A typical scenario of an incidental heart murmur in dogs or cats goes something like this …

A healthy animal, 4 years old, comes in for a routine physical. Weight is the same, activity is the same and there are no noted changes. This animal has never had a heart murmur diagnosed.

The murmur sounds mild, and there is no evidence of any other changes throughout the chest cavity. The physical reveals a healthy, happy pet with a newly diagnosed heart murmur.

Usually, a watchful waiting approach in this situation may be appropriate.

Realize, however, that a stethoscope on the chest in no way tells you or your vet what is actually going on inside that heart.

In this video, you can hear the difference between a normal dog’s heartbeat and one with a murmur:

YouTube player

Human vs. Veterinary Medicine

If a heart murmur is detected in a person, we are referred to a cardiologist. And most folks will have their heart murmur checked out.

The physician clearly writes in the medical record that the murmur was detected and referral to a cardiologist was recommended.

In veterinary medicine, we have to do the same thing. Because so few people have pet insurance, many decline the cardiologist referral. This is where a vet’s job becomes harder.

Yes, your dog or cat’s heart murmur may not be a big deal — but it should still be checked out.

If money weren’t an issue, I’d love for every cat or dog with a heart murmur who comes through my clinic to have a cardiologist check them out.

Heart Murmur in Dogs and Cats: Cardiology Referral

If you choose to have a cardiac workup done for peace of mind, your pet will undergo some “noninvasive” diagnostic tests.

An EKG is no big deal, and an echocardiogram requires nothing more than a little fur shaved off the side of the chest cavity.

If you have a particularly rambunctious pet, sedation may be required. This is rare.

The cardiology visit determines if the heart murmur signifies heart disease. Based on these findings, the cardiologist may recommend monitoring, medication, diet changes or exercise restriction.

If you get great news that the murmur is not a worry at this time, you can go home and relax.

Final Thoughts

Try not to freak out if your vet hears a heart murmur in your pet. We can talk about it and have it checked out if necessary.

Modern veterinary medicine is there to help you and give you peace of mind.


  • Drut, A., Ribas, T., et al. (2015). Prevalence of physiologic heart murmurs in a population of 95 healthy young adult dogs. Small Animal Practice, 56(2). 112–118.


This pet health content was written by a veterinarian, Dr. Debora Lichtenberg, VMD. It was reviewed for accuracy by Dr. Pippa Elliott, BVMS, MRCVS, and was last updated Dec. 17, 2018.