What to Know About Heart Murmurs in Cats

Does your cat have a heart murmur, or are you concerned that they might? What does a heart murmur mean for cats, and is it a life-threatening condition?

If you are a cat owner dealing with a heart murmur in your cat, you may find yourself asking a variety of questions. In the article below, we’ve put together some basic information to help you find out more about what a heart murmur could mean for your pet. Read through this information for the basics and be sure to talk to your veterinarian for specific guidance about your individual pet, too.

heart murmurs in cats

Causes of Heart Murmurs in Cats

There are a few different causes of heart murmurs in cats, here are a few.

Rapid Growth

Kittens that grow quickly may experience heart murmurs, just like young human children sometimes might. In this situation, it is common for kittens to outgrow the heart murmur as they get older and bigger.


Some heart murmurs in adult cats may occur as a result of stress and anxiety. While this type of heart murmur is typically not too serious, it’s important to have your cat medicated if their anxiety is too severe.

Structural Heart Issues

Holes in the heart, leaky valves, and other problems with the structure of the heart can lead to a heart murmur. These problems can be birth issues for some cats, and they may be related to illness in other cats.

Functional Heart Issues

These types of feline heart murmurs occur in cats who have issues like anemia, obesity, or severe malnutrition. Sometimes, the heart murmur improves if the condition is resolved. However, in many cases, heart murmurs like these are irreversible when caused by an illness of health condition.

Types of Heart Murmur in Cats

There are four types of heart murmurs that can affect a cat, innocent, structural, extracardiac, and grading system.

1. Innocent

Innocent heart murmurs are also sometimes called physiologic heart murmurs. These refer to stress-based heart murmurs or those that occur when kittens are aging normally. They are the least concerning type of heart murmur a cat can experience, and they may even go away on their own with time.

2. Structural

Structural heart murmurs are those related to issues with the structure of the heart. They may occur in any of the parts of the heart, or in the heart as a whole. They are typically much more severe than the other types, and they can pose significant health risks for some cats depending on the specific instance, too.

3. Extracardiac

Extracardiac heart murmurs are those caused by illness or health conditions. They can be mild, moderate, or severe, and the severity of the heart murmur depends on the cat’s individual situation. Your veterinarian will give you more information about your cat’s heart murmur and its severity.

4. Grading System

Heart murmurs in cats are graded from I to VI. Grade I murmurs are the least concerning and are very quiet when the vet listens to your cat’s heart. Grade VI murmurs, on the other hand, are very loud when the vet listens and can be felt even when just petting your cat.

Cat Heart Murmur Treatment Options

Once your cat has been diagnosed with a heart murmur your veterinarian could recommend any of these treatment options.

Mild Heart Murmur

A mild heart murmur may require no treatment. If your cat is still young or is easily stressed, your vet may simply advise you to keep having them checked regularly, but otherwise will not recommend any treatments.

Moderate Heart Murmur

Moderate heart murmurs can typically be treated with the help of a special diet or a certain type of medication. They may or may not need treatment at all, depending on where they fall on the scale and what your vet thinks is best for your specific cat’s needs.

Severe Heart Murmur

Severe heart murmurs will require medical intervention. They may require medication or potential surgery, but they may also be so severe that no treatment can really help. In this case, your cat will be provided with supportive assistance instead, and you will be advised on how best to care for your pet regarding their heart murmur.


The prognosis of a heart murmur in cats depends entirely on the underlying cause and the severity of the murmur. In most instances, cats will live out the rest of their natural lives with a heart murmur, especially if you catch it early enough. However, this may not always be the case.

Talk to Your Vet About Heart Murmurs in Cats

With the help of this information, you should be ready to talk to your vet for more help regarding your cat’s heart murmur. Your vet is your best resource when it comes to helping your cat navigate this condition, and it’s important to always follow veterinary guidance and recommendations for cats with heart murmurs, too.

Keep this information in mind the next time you find yourself wondering about the basics about your cat’s heart murmur. And if you suspect your pet may be dealing with this problem, have them examined as soon as possible to find out more.

Book an appointment online today with your Heart + Paw veterinarian at any of our locations!

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Heart + Paw was founded in 2018 by Chief Veterinary Officer Dr. George Melillo, who currently serves the Mid-Atlantic area. Heart + Paw offers a combination of veterinary care, pet grooming, and dog daycare to help be a resource in your pet parenthood journey.

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