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Heart Murmur in Cats

Knowing the signs of a heart murmur can help you identify that your feline friend may have a cardiovascular problem that needs to be treated by your vet. In this blog post, our Dallas vets list the signs and stages of heart murmurs in cats. 

What is a feline heart murmur?

A heart murmur is an abnormal heart sound your vet may hear when listening to your cat's heart with a stethoscope. A heart murmur is caused by turbulent blood flow in the heart or the large vessels exiting the heart. This triggers an abnormal noise that your vet will be able to hear. 

This may leave you wondering if stress can cause a heart murmur in cats and what your feline friend's life expectancy might be if they are diagnosed with a heart murmur. If your cat is scheduled to have surgery when the heart murmur is discovered, you may also question whether there are any concerns regarding heart murmurs in cats and anesthesia. 

Before we get into that, let's explore the basic facts surrounding heart murmurs in cats. 

The Heart Murmur Grading System 

Veterinary cardiologists use specific criteria to assess and grade heart murmurs. Grades 1 – 6 are recognized, with Grade 1 being the mildest and Grade 6 the most severe. This grading system is based primarily on how loud the heart murmur is. However, other factors such as the area over which the heart murmur is audible are also considered. 

Grade 1: Essentially inaudible 

Grade 2: Readily but softly heard. Always focal. 

Grade 3: Readily heard; the heart murmur is moderately intense. Regional. 

Grade 4: Readily heard, loud and typically wide radiation. 

Grade 5: Readily heard, loud and with a precordial thrill. 

Grade 6: Readily heard, loud and with a precordial thrill. Can be heard when your vet cardiologist lifts the stethoscope one centimeter from the thorax. 

The grade of the heart murmur does not necessarily relate to the degree of severity of the underlying heart problem. While some severe heart conditions may not be associated with a heart murmur at all, some quite loud murmurs may develop with relatively small defects. 

Symptoms of Heart Murmurs in Cats

The most common symptoms that are observed with a cat that has a clinically significant heart murmur are poor appetite, weight loss (or stunted growth in a kitten), breathing problems, pale gums, lethargy, or weakness.

The Potential Causes of Heart Murmurs in Cats

While the presence of a murmur generally implies an underlying heart condition, murmurs can sometimes have other causes.

In young kittens, ‘innocent’ heart murmurs may be heard as an incidental finding. These are usually no longer present when the kitten is older. Anemia is another cause of heart murmurs in cats, but the cats often show other signs of lethargy and anorexia as well.

Occasionally cats are reported to have incidental murmurs as adults, which is when the blood flow within the large vessels exiting the heart may occasionally be heard as a murmur.

Can stress cause a heart murmur in cats?

Some heathy adult cats may develop an intermittent heart murmur when stress causes their heart rate to increase. This type of physiologic murmur vanishes when the heart rate returns to normal, and it does not impact the cat's health. 

Heart Murmurs in Cats: Treatment Options

When a heart murmur is first discovered in a cat, an investigation will be performed to find out the underlying issue. This may involve further tests such as an X-ray of the heart or a cardiac ultrasound examination.

If however the cat is showing no other signs of a problem and is exercising normally, then your vet may suggest you come back for a second examination in a few months to reassess the heart murmur and see if it has changed.

Sometimes if the cat is well and the heart murmur is unchanged, a periodic examination will be recommended.

The only way to determine if there is any disease within the heart itself that may be causing the murmur is to perform a detailed ultrasound examination of the heart. This is completely painless and is normally performed in a fully conscious cat.

Life Expectancy of a Cat With a Heart Murmur

Even cats with a more severe murmur who have been diagnosed with hypertrophic cardiomyopathy (a cardiac disease characterized by thickening of the heart's left ventricle) can live for many years if medical treatment is effective. If a cat with a heart murmur develops congestive heart failure, they are typically expected to live between 6 and 18 months. 

Veterinary Cardiology in Dallas

While your primary care veterinarian will be able to diagnose and treat a variety of health issues very well, some conditions require specialized diagnostics and care so your pet will have the best chance at a positive outcome. 

This includes heart murmurs and related illnesses or diseases, congestive heart disease, congenital heart disease, cardiac tumors, arrhythmias, and more. 

If your cat or dog has been diagnosed with a heart condition or you'd like one of our board-certified veterinary cardiologists to assess your pet's heart problem, feel free to contact us. While we accept referrals from primary care veterinarians, we do not require them. 

Note: The advice provided in this post is intended for informational purposes and does not constitute medical advice regarding pets. For an accurate diagnosis of your pet's condition, please make an appointment with your vet.

Is your cat displaying signs of heartworm disease? Contact our Dallas vets today to book an appointment.

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New Patients Welcome

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