What Is a Heart Murmur in Cats? – (Tests Suggested by Vet)

Have you ever noticed your cat losing weight, becoming weak, and developing breathing problems? If yes, your cat might have a heart murmur. What is a heart murmur in cats? A heart murmur is an abnormal sound produced by the heart when turbulent and high-velocity blood flows through it that can be heard through a stethoscope.

Cats help you deal with stress and make you a better person as you learn how to cope. Therefore, you should always take care of your cat’s health in return and visit the vet as soon as you notice any red-flagged symptoms. We have provided all the information about cat heart murmur and what is the treatment for it. So keep scrolling for your cat’s speedy recovery.

what is a heart murmur in cats

What is a heart murmur in cats?

As mentioned above, a heart murmur is an abnormal sound produced by the heart that is audible through a stethoscope. Usually, two heart sounds (‘lub’ and ‘dub’) are heard on a stethoscope by the vet. However, an additional ‘whooshing’ sound is a heart murmur produced due to disturbance in blood flow through the heart.

Heart murmurs can be ‘physiological’, ‘innocent’, or ‘pathological’. ‘Pathological’ heart murmur in cats signifies a severe underlying heart disease. Therefore, cat heart murmur requires immediate attention, and the vet will perform various tests to find the specific cause of heart murmur in cats.

Cat heart murmurs are ranked from 1-6, with 1 being the lowest intensity murmur heard in one area of the chest and 6 being the loudest heart murmur that can even be felt by the hand placed on the cat’s chest. However, this doesn’t mean that the loudest heart murmur correlates with very severe underlying heart disease.

Following are the symptoms of feline heart murmur that are often missed;

  • Weakness
  • Difficulty in breathing
  • Rapid breathing
  • Loss of appetite
  • Weight loss
  • Pale gums
  • Stunted growth in kittens

What causes heart murmurs in cats?

The first step after identifying a feline heart murmur is to specify the cause of it. The causes of heart murmur in cats are divided into extracardiac and structural cardiac causes.

The extracardiac causes of heart murmur in cats are;

  • Anemia (low hemoglobin levels that decrease the capacity of the blood to deliver adequate oxygen to the body’s organs.)
  • Fever
  • Hypoproteinemia (low levels of protein in the blood)
  • Hyperthyroidism
  • Pregnancy
  • Obesity
  • Severe dehydration
  • Stress
  • Hypertension (high blood pressure).

The structural cardiac causes of feline heart murmur are;

  • Congenital structural heart defects such as; ventricular septal defect and atrial septal defect
  • Hypertrophic Cardiomyopathy that causes blood clots, lethargy, and congestive heart failure
  • Heart wall defects.

What is an innocent heart murmur in cats?

An innocent heart murmur is an asymptomatic and low-intensity heart murmur (usually of Grade 1-2). Innocent heart murmur in kittens has no significant value as it doesn’t affect the cat’s health.

Normally, an innocent murmur appears at 6-8 weeks of age in kittens and disappears in 4-5 months. It is caused in kittens that grow rapidly. Therefore, an innocent heart murmur in kittens is not dangerous.

Another type of safe murmur, the ‘physiological’ murmur, develops in adult cats. It is due to pregnancy or stress and disappears when stress or pregnancy ends. Therefore, physiological murmur in adult cats is also not considered dangerous as it has no impact on cat’s health.

Cat heart murmur treatment

The first step to treat cat heart murmur is to book a visit to the vet. The vet will take a history of the symptoms and perform a cat’s general examination to find pale gums and other signs.

In addition, the vet will also listen to the heart murmur with a stethoscope and identify its grade. Only then will more tests be performed to specify the cause of heart murmur in your cat. The next step will be the treatment of the cat heart murmur according to its cause.

For example, if the heart murmur is of low grade (Grade 1-2) and diagnosed in a 4-6 weeks old kitten, the vet will only recommend a re-examination after weeks to check if the ‘innocent’ murmur has disappeared or not. If it still persists, additional tests will be performed to diagnose underlying structural heart disease.

Likewise, an asymptomatic murmur doesn’t need any treatment; instead, the vet will only observe for any symptoms over the course of few weeks. If new symptoms develop, further testing will be performed to find the cause.

If signs and symptoms are present along with a murmur, treatment is given according to the cause of the feline heart murmur. For example, if the murmur is caused by dehydration, the murmur will fully resolve with hydration without additional medications.

Yet structural heart diseases require surgery to resolve the heart murmur. In other cases, the heart murmur may persist for life which can only be managed by medications that will increase the longevity of cats.

Usually, physiological murmurs resolve over time without any treatment.

Tests performed for heart murmur in cats?

After the general examination, specific tests will be performed by the vet to find the cause of heart murmur in cats, such as;

  • X-rays and ultrasound
  • ECG for cardiac problems
  • Complete blood count
  • Thyroid tests
  • Urinalysis


Can stress cause a heart murmur in cats?

Stress can cause a physiological murmur in cats that resolves when stress end. Fortunately, cat murmur caused by stress has no adverse effects on your cat’s health.

What is a grade 3 heart murmur in cats?

Cat murmurs are divided into grades of 1-6. Grade 3 murmur is a relatively loud murmur that can be caused by a severe cardiac or extracardiac problem.

How long will a cat live with a heart murmur?

It depends on the cause of the heart murmur. Mostly untreated cat heart murmur can progress over time and cause heart problems. In this scenario, the cat can live up to 12-18 months after the diagnosis of a heart murmur.

What is the most common cause of a heart murmur in cats?

Hypertrophic cardiomyopathy is the most common structural cardiac cause of a heart murmur in cats.

When should I worry about a heart murmur in my cat?

When your cat has accompanying symptoms such as difficulty and rapid breathing, only then should you worry about a heart murmur in cats.

What do you feed a cat with a heart murmur?

You can give any cat food to your fuzzball, even if it contains meat.

What causes heart murmurs in older cats?

Hypertension, hypoproteinemia, etc., causes heart murmurs in older cats.

More Articles


Never take the breathing problems of your cat lightly. Instead, visit the vet as your cat might have a heart murmur. Structural heart diseases and extracardiac problems cause a heart murmur in cats. Don’t worry, as cat heart murmur can be treated by correcting the underlying cause.

The vet will perform various tests to specify the cause of the heart murmur. We hope that your cat’s heart murmur resolves quickly without affecting its life.

Leave a Comment

Your email address will not be published.

Scroll to Top