Pet Wellness Guides > Heart Murmurs in Cats: Are They a Serious Concern?

Heart Murmurs in Cats: Are They a Serious Concern?

Posted: 11/06/2023 | BY: Erin Cain | Categories: Uncategorized

It’s not uncommon for a cat to have a heart murmur. More than one-third of all cats will experience a heart murmur at some point. But what does that mean for your cat’s health? Are heart murmurs something you should be concerned about? This article will discuss the causes and symptoms of murmurs in cats and treatment options, and when your cat should see a veterinarian.

A cat hangs over the back of a chair.

What is a heart murmur?

When a veterinarian listens to your cat’s heart, they may hear an abnormal heart sound called a murmur. This condition occurs because of turbulent blood flow in the heart and or the larger vessels exiting the heart. An abnormal heart sound is similar to a “swishing.” Veterinarians grade heart murmurs in levels from one to six. Barely audible murmurs rank as one, while the loudest varieties, which veterinarians can hear in various areas of a cat’s body, rank as six.

If your cat has a heart murmur, that doesn’t mean it’s time to panic. The murmur might indicate an underlying cause, such as congestive heart disease, heart valve deficiencies, structural heart disease, or heart defects. The vet will perform additional diagnostic testing to determine what’s going on with your cat and how to treat him best.

A beautiful cat sits on a chair.

What causes a heart murmur?

Several different factors can cause feline heart murmurs. Some will not affect your cat’s health, while others may bring about severe complications and lead to death if left untreated.

Here are some reasons behind murmurs in cats:

  • congenital heart disease
  • cardiomyopathy
  • fever
  • infection
  • anemia
  • hyperthyroidism (thyroid disease)
  • increased heart rate and high blood pressure
  • stress
  • obesity
  • pregnancy
  • emaciation
  • old age

Whether your cat has innocent heart murmurs or underlying heart disease, any murmur, no matter how slight or quiet, requires veterinary attention and examination.

Heart murmurs in kittens

For young kittens, most heart murmurs are classified as physiologic murmurs or innocent heart murmurs. This low-level murmur is typically benign and asymptomatic. First, it appears when a kitten is six to eight weeks old. The heart murmur should be gone by the fourth and fifth months of the kitten’s life.

Heart murmurs in middle-aged and older cats

Middle-aged and senior cats can experience heart murmurs for different reasons, such as excitement or underlying heart disease or health problem (acquired heart disease). Hypertrophic cardiomyopathy is the most common heart disease in older cats, and this condition causes heart murmurs to occur. This disease can lead to congestive heart failure and additional complications like hypertension or arrhythmia.

A tabby kitten sits on a blanket.

Symptoms of heart murmurs in cats

It is essential to know the symptoms of a cat with a heart murmur. The clinical signs may be subtle and not noticeable until it becomes advanced. Here are the symptoms of heart murmurs in cats:

  • weight loss
  • stunted growth (in a young kitten)
  • lethargy
  • pale gums
  • exercise intolerance
  • open mouth breathing
  • limping or loss of the use of the back legs
  • poor appetite

Unfortunately, some cats who have heart murmurs do not display symptoms of the condition. That’s why preventative care for your cat, primarily through a pet health insurance policy and annual veterinary exams, is vital to your cat’s future health.

A Russian blue cat lies near flowers.

How is a cat’s heart murmur diagnosed?

A veterinarian will notice a heart murmur when checking your cat’s heart rate during a physical examination. Suppose the murmur is heard for the first time and your cat has no symptoms. In that case, the veterinarian may schedule a re-evaluation within weeks.

If, however, your cat has a murmur and symptoms, the vet may recommend additional diagnostic tests if the cat’s symptoms or heart murmur seem to be caused by an underlying issue. These tests include:

  • chest x-rays
  • complete blood tests
  • urine tests
  • blood pressure tests
  • electrocardiogram
  • NT-proBNP blood test

Suppose the veterinarian suspects a murmur is causing your pet’s heart problems. In that case, they might also perform an echocardiogram, a cardiac ultrasound that includes a Doppler examination. The Doppler examination helps pinpoint the underlying cause of the murmur.

Treatments for feline heart murmurs

Some cats will need to be treated for their heart murmur, but it depends on the cause and severity. Cats with physiologic heart murmurs don’t need treatment, but regular monitoring will help to ensure that no other problems develop. Murmur treatment depends on the cause, severity, symptoms, and how far advanced the condition is.

Several underlying problems can cause murmurs, and the veterinarian’s treatment plan will depend on this diagnosis. Treatment may include specialized diets or medications as well as supportive care.

A fluffy black cat lies on a blanket.

Life expectancy and long-term outlooks

The prognosis for a murmur depends on its cause. A physiologic murmur or innocent murmur generally does not require treatment, and the life expectancy is quite good. It might resolve over time if the murmur is caused by a functional problem that a veterinarian can treat or an extracardiac disease.

The long-term prognosis for cats with heart murmurs caused by cardiac disease depends on the specific type of heart condition they suffer from. Suppose you notice any of the above heart murmur symptoms in your cat. In that case, it is important to contact the veterinarian immediately. Most murmurs can be treated and managed, but early detection helps prevent future problems. Each case is different for each cat, and preventative care can give your cat the best chance at treatable heart murmurs.

A gray and white cat stands on a table.

Plan for chronic health conditions with a pet insurance plan.

If you have a cat, it’s essential to take him in for checkups with the vet. A heart murmur can lead your furry friend to need medications and treatment, which may be costly without proper health insurance coverage.

Are you interested in finding the best cat health insurance? Pet Insurance Review has got you covered! You can choose from several providers and plans, all designed for your cat. Get a free quote today, and keep your cat’s health a priority.


  1. Cats Protection. (n.d.). Heart murmurs and heart disease. Retrieved from
  2. Kelley, T. (2022). If Your Vet Hears Your Cat Has a Heart Murmur, Here’s What It Might Mean. Retrieved from
  3. estaff, (2015). Feline Heart Murmurs. Retrieved from
  4. Collins, S. (2016). Managing heart disease in cats – part 2. Retrieved from



The information contained on this blog is intended for informational and educational purposes only and should not be construed as medical advice. It is not a substitute for professional veterinary care. Always consult with your veterinarian before making any changes to your pet's health care or treatment plan.

The authors of this blog are not veterinarians and do not claim to be experts in pet health. The information provided here is based on our own experiences and research, as well as information from reputable sources. However, we cannot guarantee the accuracy or completeness of this information.

We encourage you to do your own research and consult with your veterinarian before making any decisions about your pet's health.

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