Maine Coon Hypertrophic Cardiomyopathy

Maine Coon hypertrophic cardiomyopathy is a feline health issue prone to the Maine Coon cat breed.

Maine Coon HCM is a genetic illness that thickens the heart walls, deteriorates the heart function, and causes the cat’s body to receive a very poor blood flow. Symptoms include breathing difficulties, pulmonary edema, and limb paralysis. No cure exists, but early detection will improve the cat’s prognosis significantly.

As one of the most popular cat breeds in the world, it is therefore surprising that many owners do not know how this particular heart disease develops.

This is especially true since this sickness is very common in this breed and it reduces the cat’s lifespan. It can also deteriorate the quality of a Maine Coons life.

There are attempts to get rid of the mutated gene that causes Maine Coon HCM by selecting which cats not to breed. However, since there are other unknown causes for this sickness, these procedures might not be very effective.

What Is Maine Coon Hypertrophic Cardiomyopathy?

Hypertrophic Cardiomyopathy, or HCM, is a common heart disease in cats and a lot of Maine Coons tend to have it.

In this illness, the heart wall thickens to the point where it creates complications in the heart functions. The amount of blood that the heart can pump will be severely reduced.

Also, the heart will become stiffer, contract harder, and relax less between contractions. This will diminish the amount of oxygenated blood that the cat’s body will receive.

This illness can be obstructive or non-obstructive.

When it’s non-obstructive, the blood can leave the left ventricle of the heart without problems.

When it is obstructive, the valve of the left ventricle cannot close properly and some of the blood returns to the heart.

HCM is one of the diseases that can cause Maine Coon heart murmurs, which are unusual sounds detected between heartbeats.

HCM can lead to:

  • Heart failure
  • Sudden death
  • Pulmonary edema
  • Paralysis in one or more legs (in some cases)

This illness is considered to be genetic, but the fact that the cat has this mutated gene does not mean that it will actually have HCM.

There can be several causes for this illness, like a taurine deficiency in the cat’s diet. Most of them are still unknown, but it is believed that it is mostly a genetic disease.

Normally the sickness goes undetected in the early mild stages because cats tend to hide the symptoms until the disease becomes very severe.

Symptoms Of Maine Coon Hypertrophic Cardiomyopathy

The symptoms of HCM vary a lot depending on the severity of the sickness. Cats with mild disease will probably not show any symptoms at all.

However, when the disease is severe and the cat does not hide it, the common symptoms of HCM are:

  • Tiredness, dizziness, fainting, and loss of appetite
  • Shortness of breath
  • Weak pulse and heart murmur
  • Loss of movement in legs

This Maine Coon heart disease changes the behavior of the cat. It produces lethargy, due to the lack of oxygenated blood in the body.

Instead of exercising as a normal cat does, a Maine Coon with HCM will be lying around instead of running and jumping.

Sometimes it can even start hiding in secluded areas, or even feel dizzy and faint occasionally due to blood clots in the brain. It will also show a loss of appetite.

A Maine Coon will also manifest the illness with respiratory distress, caused by congestive heart failure.

It is hard to distinguish, but it makes a slight effort when breathing and sometimes it will even open its mouth or pant.

Normally, if respiratory problems are caused by HCM, the cat will not make any noises when breathing.

The heart of a Maine Coon with HCM will not work properly and this will manifest in a weak pulse and heart murmur.

A weak pulse is caused by the diminished quantity of blood used by the sick heart and the constant rigidness of the heart muscles.

A Maine Coon heart murmur sounds like a vibration or a whoosh and it is caused when the blood flow passes through a narrow or a leaking valve.

Occasionally, this illness can paralyze the movement of one or more legs of the Maine Coon.

This is caused by blood clots that diminish the blood flow in the limbs.

The temperature of the affected legs will decrease, the cat will feel a lot of pain, and some owners have reported a slightly bluish color in the footpads.

Diagnosis Of Maine Coon Hypertrophic Cardiomyopathy

The thickening of the heart wall can be verified with an Electrocardiogram Test, X-ray of the cat’s chest, blood pressure measurement, and Echocardiogram Test.

This last test is the most accurate in determining if the Maine Conn has HCM because it shows the thickened heart walls very clearly.

This type of thickening of the heart wall can be caused by several different illnesses, like:

  • Hypertrophic Cardiomyopathy
  • Hyperthyroidism
  • System Hypertension

In order to diagnose Maine Coon Hypertrophic Cardiomyopathy the other illnesses have to be ruled out.

How To Care For A Maine Coon With HCM

There is no cure for Maine Coon Hypertrophic Cardiomyopathy.

However, there are treatments that can slow down the disease and sometimes even improve the quality of life of the cat.

The treatment varies in each particular case, depending on the severity of the disease.

  • Diagnose as soon as possible
  • Give the cat the proper medication
  • Feed the cat with a proper diet

The sooner you start the treatment with your cat, the better the prognosis.

Although cat’s tend to hide the symptoms of HCM, as soon as you detect the sickness, take it to the veterinarian for a checkup.

In certain situations, the cat has to be administered a type of medication to reduce the heart rate and relax the heart muscles.

In other instances, the Maine Conn is given other kinds of medication to avoid the formation of blood clots by thinning the blood.

Sometimes diuretics have to be used to diminish fluid buildups if they are necessary. Oxygen therapy and pain medication may also be applied.

Check with your veterinarian to see if your cat needs a particular diet. Sometimes a meat-based diet, with fewer grains and carbohydrates can work well and help the cat feel better.

However, each case is different.

Life Expectancy Of Maine Coon With Hypertrophic Cardiomyopathy

The life expectancy for a Maine Coon with HCM varies a lot.

In some cases where the cat responds well to the treatment, it can live for several years with a good quality of life.

However, Maine Coon Hypertrophic Cardiomyopathy is a progressive sickness and usually, t reduces the cat’s life span significantly.

Is Heart Failure Painful For Cats?

A cat with Maine Coon Hypertrophic Cardiomyopathy feels tired and has trouble breathing.

The extreme pain comes from blood clots.

When the limbs get paralyzed, the cat is definitely in extreme pain.

At the end of the illness, the cat goes through terrible distress as it gets pulmonary edema because the lungs and chest are filling up with fluid and it starts suffocating.

Maine Coons Genetics

About 1/3 of the Maine Coon population has Hypertrophic Cardiomyopathy.

This illness is mostly caused by a mutated gene that can be detected with a DNA test.

For reasons that remain unknown, some Maine Coons that possess this mutated gene do not get sick.

If the DNA test is negative and the cat develops HCM, the disease was caused by something different than the mutated gene.

How To Reduce Risk Of Maine Coon Hypertrophic Cardiomyopathy

There is no way of preventing Maine Coon HCM.

The only things that you can do to avoid this sickness are:

  • Check the cat’s diet
  • Check the cat’s parents DNA test

Some people claim that a cat whose diet lacks enough taurine can also develop HCM. However, these cases are extremely rare because cat food already contains enough taurine to avoid this.

In case a cat has HCM because of taurine deficiency, it can be cured with a regular diet that includes it.

In the case that HCM is developed for genetic reasons, taurine will not help in curing the disease. You can reduce the cat’s risk of developing this illness by checking that it has a healthy diet.

Responsible breeders are trying to detect the sick Maine Coons by giving them a DNA test and only breeding the cats that are free of that mutated gene.

When you buy a Maine Coon cat, the breeder should give you a health statement that determines that the parents of the Maine Coon you are buying were given a DNA test and do not have the mutation of the gene that causes this illness.

It is important to notice that testing the cat you are buying may not be effective because HCM cannot be detected in cats younger than one year.

“Breeding Out” Maine Coon Hypertrophic Cardiomyopathy

There are many people and organizations that are trying to get rid of this illness.

Some of these associations, like International Cat Care and the Veterinarian Cardiology Society in the UK, recommend that the cats get tested to detect this gene before they are bred.

In case that they do present the mutated gene, they should not be bred with the intention to keep the mutated gene from passing on to further generations of Maine Coons.

They hope that with these measures, the Mains Coon breed will stop having that gene.


Maine Coon Hypertrophic Cardiomyopathy is an illness that thickens the heart walls and causes many major problems in the cat’s health.

It can create major problems in the cat’s health if it is not treated adequately.

It is believed to be mostly a genetic sickness, but there are other causes that are still unknown.

A DNA test of the cat’s parents can tell you if the Maine Coon has the mutated gene, but that does not eliminate the possibility of the cat getting the disease for some other reason.

There is no real prevention or cure for this HCM, but if it is treated in the early stages, the cat can have a better prognosis.

Maine Coon Central

Hello! My name is Katrina Stewardson, and I’m a CRAZY CAT LADY! I've been in love with the Maine Coon cat breed ever since we welcomed an adorable male Maine Coon kitten into our home 10 years ago. We called him 'Pippin', but he also goes by the name ‘Pipsteroo’! Our enormous, kind-hearted cat genuinely thinks he's a dog and has convinced me that cats are Man's True Best Friend! UPDATE: We recently adopted two 4-year-old male Maine Coon cats. They are named Mika and Bali.

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