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Signs and Causes of Heart Disease in Cats

SP Greaney, a cat owner for over 20 years, has given homes to stray cats and kittens. She has been around all types of cats.

There are two reasons why cat's get diagnosed with heart disease. It is either a congenital disorder that is hereditary or one that is present at birth. Heart disease could also be a condition that develops over the cat’s lifespan. However until you know the cause and the severity of the heart diseases then in the short term all you can do is wait until the tests are done to see what type of treatment can be sought.

There are three types of cardiomyopathy.

  • Hypertrophic Cardiomyopathy
  • Restrictive Cardiomyopathy
  • Dilated Cardiomyopathy

If heart disease is found in the early stages and the issue is because of an underlying medical problem, then the secondary issue can be treated and controlled. In this case, a diet change or medication could be prescribed as well as continued monitoring for the rest of the cat's life.

However while treatment might help to partially stop the problem the likelihood is that your cat will still have a reduced lifespan and the only outcome is to support them for whatever length of time they have left.

The worst case scenario is that a cat is diagnosed to late and if that is the case then unfortunately there is no cure and the cat will pass away.

How to Identify Heart Problems in Cats Early On

Heart Murmur

If your cat has a heart murmur then it could mean that your cat has an issue with its heart valve. This might be something like a leaky valve or a thickening of the valve. They might even have a hole in their heart chambers. Murmurs can also occur due to an illness, anaemia, hypoproteinaemia, or hyperthyroidism.

However sometimes a murmur in young kittens isn't necessarily a sign of something serious and as your kitten grows the murmur will disappear.

Heart Arrhythmia

If your cat has cardiac arrhythmia then they are experiencing an abnormal heart beat and your cat’s heart might be beating too fast or too slow.

This might be due to an illness, kidney disease, toxins, high blood pressure, hyperthyroidism or some kind of trauma.

It there is an underlying issue causing the arrhythmia then once this is treated the cardiac arrhythmia will correct itself.

Heart disease in cats needs to be diagnosed early if possible.

Heart disease in cats needs to be diagnosed early if possible.

A 2015 study of 780 cats aged 6 months and older found functional heart murmurs in 40.8% which could be due to anaemia. Symptoms of hypertrophic cardiomyopathy was found in 14.7% of cats.

Diagnosing Heart Disease in Cats

Heart disease is a condition that your veterinarian needs to diagnose in your cat as early as possible. If you bring your cat in for regular check-ups then your veterinarian should in all likelihood be able to spot any signs of heart disease in the early stages.

There are two things that you need to watch out for when you have a cat of any age.

  1. The first thing is excessive panting after very little activity. If your cats gets tired very easily after doing very little exercise and it isn't obese then this could be an early indication that something is wrong with it.
  2. The second thing is something that your veterinarian should spot during your cat’s check-up. When you bring your cat to the veterinarian it will listen to your cat’s heart and if they hear an irregular sound like a murmur or an arrhythmia from your cat’s heart then they will do an investigation to see what is causing this cardiac issue.

If there is an underlying condition causing the heart disease, then depending on what it is, there might be some kind of treatment.

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However if treatment is sought too late and the heart disease wasn't diagnosed in time then by the time treatment is sought, it can be too late.

The outcome even with some form of treatment could be immediate death or a reduced life span of 6 -18 months or at most 3 years.

Brachycephalic is the term used to describe Persians and Himalayans cats who have shorts head. These breeds can be predisposed to heart arrhythmias.

Types of Cardiomyopathy

There are three type of cardiomyopathy.

  • Hypertrophic Cardiomyopathy
  • Restrictive Cardiomyopathy
  • Dilated Cardiomyopathy

1. Hypertrophic Cardiomyopathy

According to American Animal Hospital Association this is the main cause of heart disease in cats. When a cat is diagnosed with this type of cardiomyopathy it is because there is thickening in the left ventricle muscle of the heart and the chambers of the heart then become too small.

The thickening can be caused by some kind of gene mutation or it could be an inherited disorder.

2. Restrictive Cardiomyopathy

This type of cardiomyopathy occurs when there is a build-up of scar tissue on the muscle and inner lining of the ventricle. This reduces the ability of the ventricle to pump blood. Scarring hardens the wall of the heart and this is what impacts its ability to pump blood.

Scarring can occur because of the lack of oxygen pumped to this part of the muscle. Another theory is that if the muscle of the heart becomes inflamed because of toxins, viruses or diseases then this can also lead to restrictive cardiomyopathy.

3. Dilated Cardiomyopathy

This type of cardiomyopathy causes the left ventricle of the heart to not dilate as efficiently as it should which then reduces its capacity to pump blood around the body. The heart becomes enlarged and the muscle walls become too thin.

The cause of this type of cardiomyopathy is blamed on a taurine deficiency which is an amino acid found in cat food. A diet rich is taurine can help to reverse this condition and fortunately all cat foods today now have this included in them.

Main Causes of Cardiomyopathy in Cats

Hypertrophic Cardiomyopathy

  • Aortic stenosis which is a condition where the aortic valve of the heart becomes narrow.
  • Hyperthyroidism is a condition that impacts older cats and causes them to have an overactive thyroid.
  • High blood pressure can also be caused by hyperthyroidism.
  • Hereditary disease.
  • Genetic defects.

Restrictive Cardiomyopathy

  • Hemochromatosis is a condition where there is a build-up of iron in the blood. A build-up of excess iron impacts the heart's ability to circulate enough blood around the body.
  • Amyloidosis is a condition that some breeds of cats can get. It leads to a build-up of a protein called amyloid in the tissue and organs. Some cats are then prone to high blood pressure.

Dilated Cardiomyopathy

  • Drugs & toxins.
  • Over secretion of acromegaly which is a growth hormone.
  • Lack of taurine in a cat’s diet which is an animal-based protein found in commercial cat food.
  • Cardiac lymphoma which is a tumour that develops in the heart muscle.

Clinical Signs of Cardiomyopathy in Cats

Hypertrophic Cardiomyopathy

  • The obvious signs that your cat has hypertrophic cardiomyopathy will be respiratory issues like panting due to issue with breathing, lack of appetite, it will become lethargic and then as it worsens your cat can get leg paralysis.
  • Cats can at a later stage develop feline ORAC thromboembolism. This occurs when pieces of a blood clot break off from the heart and travel down the iliac veins to the back legs and cause leg paralysis. If this happens then your cat's back legs will collapse.
  • If your cat does develop a blood clot it will lose control of its back legs. It will start meowing in pain and you might also notice that your cat's pads on their feet turning blue from pink and their legs and pads could be cold to the touch.

Restrictive Cardiomyopathy

  • With restrictive cardiomyopathy the signs that something is wrong with your cat will be abnormally rapid breathing, partial paralysis as well as respiratory issues like grunting, and distressing sounds from your cat as it has issue with its airways. Your cat might also have blue gums and you might notice that their chest is inflating and deflating in an abnormal manner.

Dilated Cardiomyopathy

  • If your cat has dilated cardiomyopathy then your cat’s lung and chest can fill up with fluid and make it difficult for the cat to breath and this could result in them suffocating.
  • You cat will be coughing, most likely won't be eating, will find it difficult to breath and will be in a lot of pain.
Your veterinarian will do a checkup on your cat and will determine the best treatment.

Your veterinarian will do a checkup on your cat and will determine the best treatment.

In 1980, a report carried out by The University of California, identified that a nutritional deficiency in taurine, an amino acid caused heart disease in cats.

Treatment for Cardiomyopathy in Cats

The type of treatment that will be given to your cat will be determined by the cause of the cardiomyopathy and the quickness of the diagnosis. It is always smart to have some knowledge of the clinical signs to look out for that will help you identify early on if your cat is sick.

Hypertrophic Cardiomyopathy

If this type of cardiomyopathy is caused by a secondary issue like high blood pressure or hyperthyroidism and not a congenital issue, once the secondary issue is diagnosed and treated then the condition can be stopped from advancing any further.

Restrictive Cardiomyopathy

If your cat is diagnosed with this type of cardiomyopathy then the outcome will vary between cats. There is no cure for this type of cardiomyopathy. Medication will be administered to your cat to help to eliminate or alleviate the symptoms but even then they might only live a few months to most 3 years. Each cat might also respond differently to treatment so the outcome of survival is really a wait and see approach.

Dilated Cardiomyopathy

If your cat is diagnosed with dilated cardiomyopathy then your cat will have to change its diet and maybe take medication for the foreseeable future. Also giving your cat a more meat based diet free of grain and carbohydrates might help them in the long run.

The treatment plan will depend largely on what type of cardiomyopathy your cat has.

The treatment plan will depend largely on what type of cardiomyopathy your cat has.

Veterinarian Treatment of Cardiomyopathy in Cats

The treatment that your cat will receive when you bring in to the veterinarian will depend on what is causing the cardiomyopathy issue and the severity of the condition if it hasn't been diagnosed early on.

  • Your cat will be administered oxygen to help it breath, pain medication to control the pain associated with a clot and anti-coagulation medication to help break down the blood clot.
  • Anti-coagulation medication like clopidogrel will be administered to help dissolve the clot and if that doesn’t work then surgery might be required but it can be dangerous.
  • If there is a fluid build-up in the chest cavity then the veterinarian could put in a catheter to drain this excess fluid. A diuretic medication could be prescribed for the cat to help reduce the chances of this occurring once the cat is discharged. Diuretic medication helps the cat to excrete excess fluid through its urine.
  • If the blood pressure is too high because of other issues then an ace inhibitor like benazepril, enalapril, imidapril and ramipril could be administered to help reduce the blood pressure.
  • Once the medical issue is addressed depending on what type of cardiomyopathy your cat has, the outcome will differ.

Tests That Will Be Done For Cats With Suspected Cardiomyopathy

  • An echocardiogram can help the veterinarian determine the thickness of the heart and see if it is functioning correctly. It will give the veterinarian a 3D image of the heart.
  • An x-ray can show them if there is any build-up of fluid in the chest cavity and around the heart.
  • An electrocardiogram could be carried out to monitor the heart rhythm to see if there is an issue with the muscle.


Like any condition heart disease need to be diagnosed as soon as possible. Since some heart diseases are not curable then the outcome won’t always be a positive one. While treatment can be sought, and it can help the cat to live a relatively normal life there is always the risk that they could have a setback.

Also the likelihood is that even if your cat seems like they are doing well in the short term, in the long term you need to know that eventually they will have a bad turn. Knowing what symptoms to watch for and getting medical assistance as soon as possible can help alleviate any pain that your cat might be experiencing.

But unfortunately cardiomyopathy is a ticking clock that can cause your cat to have a set back at any time and can shorten their lifespan.


This article is accurate and true to the best of the author’s knowledge. It is not meant to substitute for diagnosis, prognosis, treatment, prescription, or formal and individualized advice from a veterinary medical professional. Animals exhibiting signs and symptoms of distress should be seen by a veterinarian immediately.

© 2021 Sp Greaney


Sp Greaney (author) from Ireland on April 11, 2021:

@Pamela Oglesby, Yes I know. It is really surprising to know that they can also have similar diseases like humans. Also some of the medications used to treat cats is also ones that are used to treat humans.

@Elaine Byers, yes. I think you really have to be alert and keep an eye on their health. Also you need to have a good veterinarian who is able to spot any issues early on.

Elaine Byers on April 11, 2021:

Great article, it’s so important to seek treatment in a timely manner with any health issue.

Pamela Oglesby from Sunny Florida on April 10, 2021:

It s interesting that people with heart problems have simlar symptoms as the cats. I have had multiple cats over the years but none with heart problems. My last 2 cats died of cancer, which broke my heart. I adore cats. This is an excellent article, Sp.

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