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Heart Murmurs in Cats
Written By hannah hollinger
Published: 09/16/2016Updated: 11/19/2021
Veterinary reviewed by Michele K.
What are Heart Murmurs?
If your vet discovers a heart murmur, that alone is not an actual diagnosis. Rather, it can lead to the discovery of an underlying problem. Not all heart murmurs affect the health of your cat, but if heard, it may be best to still have your cat fully assessed.
When your veterinarian uses a stethoscope to listen to your cat's heart, an abnormal sound, known as a heart murmur, may be heard. Typically, the heart makes two distinct noises as the heart valves closes. Murmurs are heard between these normal beats. The more severe murmurs are capable of drowning out the average heartbeats.
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Symptoms of Heart Murmurs in Cats
Symptoms of a heart murmur can vary widely depending on several characteristics. Some cats may not exhibit any signs at all. However, there are a few clinical signs to lookout for:
  • Pale gums
  • Lethargy
  • Weakness
  • Abnormal or congested breathing
  • Rapid or difficult breathing
  • Loss of appetite (anorexia)
  • Weight loss
  • Coughing
  • Collapse
Types
Heart murmurs are classified as congenital, acquired, and innocent/physiologic.
  • Congenital: This type is present at birth, and is commonly caused by heart defects or diseases.
  • Acquired: Cats with this type develop it later in life. It is the most common type of murmur.
  • Innocent/Physiologic: This has no impact on a cat's health, and is commonly found in young kittens.
Causes of Heart Murmurs in Cats
There are a number of conditions that can disrupt blood flow, thus causing heart murmurs. Common causes include:
  • Hypertension (high blood pressure)
  • Hypoproteinemia (low protein levels in the blood)
  • Hyperthyroidism (excess thyroid hormone)
  • Hypertrophic cardiomyopathy (heart walls thicken and restrict blood flow)
  • Anemia
  • Blood clots in the heart
  • Increased heart rate in nervous cats
  • Obesity
  • Pregnancy
  • Emaciation
Diagnosis of Heart Murmurs in Cats
Heart murmurs are mainly discovered during a physical examination as your veterinarian listens to your cat's heart. Once the abnormality is found, your vet will further assess your cat. Initially, you will be asked about your cat's health as well as whether they have presented any clinical signs.
The vet will also grade the intensity of the heart murmurs while listening with the stethoscope. This grade is placed on a scale of I to VI. Grade I is barely audible, and it is heard on only one side of the chest. By Grade VI, the loudness has intensified. It can be heard in more than one location, and the vibration of it can be easily felt through the cat's chest wall.
If your cat presented no symptoms and was instead nervous during the physical examination, your vet may simply wish to re-evaluate them at a later date when they are calmer as the murmur could have simply been innocent. Likewise in young kittens that have a low-intensity murmur, the vet will just propose a re-evaluation in a few weeks.
In the case that your cat presents symptoms or the murmur appears to be caused by an underlying problem, your vet may order several diagnostic tests. Blood tests such as a CBC (complete blood count) is used to detect anemia or infections, and blood pressure tests are used to check for hypertension. Chest X-rays will also be ordered to look at the lungs and the vessel size and shape of the heart. An EGG (electrocardiogram) will be used to examine any irregular heart rate or rhythm.
Further, your vet may perform an ultrasound to exam the heart, a procedure known as an echocardiogram. An echocardiogram may be accompanied by a Doppler examination which detects the speed and the direction of blood flow the heart valves and chambers. This particular assessment is highly useful in determining the exact location of the cause of the heart murmur.
Treatment of Heart Murmurs in Cats
Any type of treatment always depends on what exactly is the underlying cause of the heart murmurs.
Monitor
In the event that heart murmurs are innocent, then your vet may wish only to monitor your cat. Regular monitoring ensures that no complications arise, and your cat remains relatively healthy. This periodic re-examination may occur every few weeks to every few months.
Medication
Depending on the cause, specific medication may be given to treat whatever condition that has been discovered. Medicine is useful in cases such as hyperthyroidism and high blood pressure. Nutritional supplements are also useful in treating cases of anemia. In the case of hypertrophic cardiomyopathy, some medication such as blood thinning drugs and beta blockers to relax muscles may be useful in providing some relief. Even so, cardiomyopathy is mainly treated with supportive care.
Surgery
If the murmurs are caused by a congenital disease, then your vet may recommend surgery. Any specific surgery will depend on the exact nature of the disease.

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Recovery of Heart Murmurs in Cats
Depending on the cause of the heart murmurs, the outlook ranges. Those diagnosed with innocent murmurs live healthy and normal lives, and require no recovery and minimal management beyond routine examinations. If your vet has prescribed any medication, then it is best to take it as directed even if your cat appears to be in good health.
Depending on the diagnosis, lifestyle changes may be of good help to manage your cat's condition. These changes include managing diets as well as exercise. Also, be sure to still follow-up with your vet as only they can check whether or not a murmur has been resolved or may have worsened.
Heart Murmurs Average Cost
From 600 quotes ranging from $200 - $2,000
Average Cost
$800
Top
Heart Murmurs Questions and Advice from Veterinary Professionals
Feline
⁶weeks

20 found this helpful

20 found this helpful

My pet has the following symptoms:
Coughing
I was told she has a heart murmur will she grow out of it
Aug. 5, 2020
Answered by Dr. Michele K. DVM
20 Recommendations
Thank you for your question. Heart murmurs in cats are not common, even as kittens. She may have what is called a physiologic murmur, that will go away as she gets older, but those are uncommon in cats. It would be best to have rechecks for her so that your veterinarian can listen to her heart and lungs, and monitor the cough. She may need a cardiac ultrasound to assess the function of her heart. I hope that all goes well for her.
Aug. 5, 2020
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Persian
Little Karma
22 Days

1 found this helpful

1 found this helpful

My pet has the following symptoms:
Heart Flutter
My 22 day old kitten has been passing out and when we felt it's heart it will slow down to almost stopping and it will speed up and it will jolt up screaming and trys to run. It's like it's forgot to suckle so we've been bottle feeding it. My cousin says it could be a murmur but I don't have no money to take it to the vet and I'm afraid I'll lose him
April 19, 2018
1 Recommendations
Without examining Little Karma I cannot say what the specific cause is and you should consider visiting a charity clinic to have Little Karma seen so that at least a diagnosis can be made. Heart arrhythmias can be painful and can cause loss of consciousness, but without an examination I cannot give any guidance. Regards Dr Callum Turner DVM
April 19, 2018
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Black and white
Moonbay
16 Years

10 found this helpful

10 found this helpful

My pet has the following symptoms:
Shaking
My cat is 16 years old and was just diagnosed with hart murmur. The cat’s appetite is good and she still active. One of the symptoms is that the cat will shake at times when she wakes. The vet who check it out suggested a more expensive examination provided by a larger facilitated vet hospital in Portland Maine. The doctor said she is healthy in all aspect except the unknown cause of the hart murmur. Question: At the cat’s age of 16 what effective treatment can be down to correct the described problem.
July 26, 2017

10 Recommendations
There is no one-fit all treatment for heart murmurs, the treatment (if any) would be dependent on the actual cause of the heart murmur (heart murmur is a symptom, not a condition). Some animals live their whole life with a heart murmur and some develop a murmur as they age. Echocardiography can be performed to examine the structure of the heart and to look for valve anomalies and other pathologies. Regards Dr Callum Turner DVM
July 26, 2017
Has the cat been screened for hyperthyroidism? It is common in elderly cats and can cause heart murmur. Also it can cause seizures which exhibit as head shaking.
July 26, 2017
Beth C.
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domestic short hair
Paris
22 Years

0 found this helpful

0 found this helpful

My pet has the following symptoms:
Sneezing Sleeping Not Eating
Paris is at least 22 years old. She has had a murmur since 2001. She has become a bit frail. Paris sleeps a lot. I use wipes to groom her. And keep her brushed. The years have been good to her. Now she sleeps all the time and is totally deaf. When Paris sees me she cries wildly to greet me. I’m worried about the new symptom of sneezing. She becomes very upset and paws at her nose as if it burns after she has sneezed multiple times in a row. I’m worried that she is near the end.
Himalayan
Zeltz
3 Years

0 found this helpful

0 found this helpful

My pet has the following symptoms:
Coughing
Not Eating
Heart Flutter
Urinated Tract Deceise
Not Drink
We have a 3 & 1/2 Persian/Himalayan mixed cat. He was brought to the hospital because he has feline urinary tract decease & had almost a full blockage. The vet inserted a cathider & started him on iv fluids and kept him 2 nights. The cathider was in 36 hours as he developed crystals in his bladder. During this time, they did a separate test for feline asthma and the test came back positive for asthma. At the same time the vet doctor said that he developed a heart murmur with the iv fluids. So my question is, did he develop the heart murmur because of the iv? Also could it be heart problems and not asthma as they diagnosed? Can human asthma inhalers be used on cats? We bought the inhaler chamber.
Siamese
hansel
7 Years

0 found this helpful

0 found this helpful

My pet has the following symptoms:
Rapid Breathing
My cat was diagnosed with a grade 2 mumur at vet consultation prior to tooth extraction surgery. The vet advised blood tests be taken but not a pro BNP test? His Blood results came back with no red flags and surgery went ahead. Two day's later I found my cat collapsed with rapid breathing and drooling. I rushed him to Emergency and vet diagnosed CHF secondary to heart disease. He recovered after fluid drainage and oxygen and 2 days later I took him home with diuretics. Two day's later he collapsed again and vet said cardiac arrest was likely and it was kindest to send him to sleep. I am devastated and cannot understand how his heart condition lay undetected and whether the BNP test would have shown some issue?
Domestic shorthair
Simon
4 Years

0 found this helpful

0 found this helpful

My pet has the following symptoms:
Weight Loss
Increased Thirst
Frequent Urination
Vomiting
I brought my cat to the vet this past November 2019 and was told he has a slight heart murmur! I have been bringing him to the vet for yearly vaccinations and wellness exams since adopting him in 2014. We go back for tests early 2020. I feel like his symptoms are becoming more frequent and am worried if this murmur can become worse before getting it fully checked. My husband and I recently adopted another kitten June 2019, can the stress of the kitten cause a heart murmur?
tabby
Nina
5 Months

0 found this helpful

0 found this helpful

My pet has the following symptoms:
Murmur
Hi, I rescued a 5 month old kitten a couple of weeks ago, and when I took her to get spayed the vet discovered she had a grade 5 heart murmur (and didn´t spay her). I then took her to a cardiologist who told me he couldn´t perform the echo because she was too restless, but just from hearing her heart he said she only has a few months to live. I´m going to look for a second opinion, although if this is true, I really don´t want to put her through more stress than absolutely necessary. She seems perfectly healthy, active and has an excellent appetite, although she is two pounds lighter than my other (male) kitten. The vet says she is too small to medicate (4.6 pounds). Is there any hope for her? What should I do?
Heart Murmurs Average Cost
From 600 quotes ranging from $200 - $2,000
Average Cost
$800

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