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My dog has a level 4 heart murmur. Is it serious if she seems fine?

Updated on September 23rd, 2025

Pet's info: Dog | Shih Tzu | Female | spayed | 10 years and 7 months old

My dog has a level 4 heart murmur. What does this mean? Can she die from this? She seems perfectly fine otherwise.

4 Answers

Most Helpful Answer

Answered By Andrea M. Brodie, DVM

Veterinarian

Published on April 23rd, 2016

Old dogs often suffer from endocardiosis, a condition where the heart valves do not close properly any more and the heart needs to work much harder to pump oxygenated blood to all the regions of the body. When the valves do not close properly the swirling blood makes a noise and depending on the volume of the noise we assign it grades. A grade or level 4 heart murmur on a scale of 5 would be a serious heart murmur, on a scale of 6, not quite so serious. Here is some excellent information: http://www.vcahospitals.com/main/pet-health-information/article/animal-health/heart-murmurs-in-dogs/3912

33Pet Parents found this answer helpful

Related Answers from Veterinarians

Answered By David Elbeze, DVM, MRCVS
Veterinarian
Some heart murmurs are found by accident, if your dog doesn't show any symptoms of heart failure she might be fine. having said that, grade 4 heart murmur can definitely be life threatening if your dog starts showing heart failure symptoms.
32Pet Parents found this answer helpful
Answered By Dr. Melanie, BVSc MS
Veterinarian
Published on June 13th, 2019
If the vet feels she could live a healthy happy life, I would trust that assessment. Do be prepared there could be problems with the murmur down the line, but have regular vet checks for her and be sure to have an emergency veterinary fund just in case. Best of luck.
1Pet Parents found this answer helpful
Answered By Anna M., DVM
Veterinarian
Published on May 1st, 2019
Hello, and thanks for your question. If you're not comfortable with the input the vet gave you, then I recommend seeking a second opinion. However, a heart murmur does not necessarily suggest symptomatic congestive heart failure. Many dogs live normal, active lives with heart murmurs for years - and that murmur may never cause Immy any problems. But, if present, it's important to note a murmur, and know the signs to watch for. So, yes, in short I would say it's very common and "normal" to find a murmur in an otherwise healthy dog.

The best second opinion you could seek, to better evaluate what's going on with Immy's heart, would be from a cardiologist who could perform an echocardiogram of the heart - if you wanted a "final answer" of sorts.

hope this helps!
1Pet Parents found this answer helpful

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