Maine Coon Heart Problems

If you have just gotten a Maine Coon, heart problems may not be very high on your list of concerns.

However, despite Maine Coons being a healthy breed, they are still prone to some health problems, and they can suffer from a variety of heart conditions.

The most common Maine Coon heart problem is Hypertrophic Cardiomyopathy, a deadly condition that cannot be cured. Since HCM is genetic, good breeders will test for this condition before allowing the kitten to go to a new home. Cats can also develop heart conditions due to injury or natural causes as they age.

Nobody wants to think of what might happen if their cat is diagnosed with a heart problem.

However, it is a good idea to learn about potential heart problems early on, so you can keep an eye out for symptoms and be prepared if the unthinkable should happen.

Read on to find out what kinds of heart problems Maine Coons are prone to, and what you can do to prevent them.

Maine Coon Heart Problems

The Maine Coon is a rugged breed that originated naturally in the snowy state of Maine.

These cats developed independently, and they have a wild-looking face that many people mistake for a wildcat rather than a domestic cat.

Maine Coons are hardy and well-muscled, and their natural development makes them one of the healthiest cat breeds in the world.

Sadly, even Maine Coons can suffer from health problems.

Although heart disease in cats is less common than in humans and dogs, it can still prove deadly without proper treatment.

Below are the heart problems that Maine Coons can experience.

Congenital Heart Issues

Here are three congenial heart issues that Maine Coon cats are prone to:

1. Hypertrophic Cardiomyopathy

Hypertrophic Cardiomyopathy, also known as HCM, is one of the most common Maine Coon health issues.

Although cats with Hypertrophic Cardiomyopathy are born with this condition, its symptoms typically do not appear until adulthood.

This type of congenital heart disease causes the walls of a cat’s heart to slowly thicken over time, until blood can no longer pass through, leading to death.

Sadly, there is no way to cure this condition, but since it can be tested for, responsible breeders will not sell kittens who have tested positive for HCM.

These are the other Maine Coon health tests that can be purchased.

2. Malformed Valve

Cats can be born with a malformed heart valve, leading to irregular blood flow. This condition can range from mild to severe.

In some cases, the affected cat will live a long and healthy life, while other cats may die prematurely from the condition.

3. Septal Defect

Although rare in cats, kittens can be born with a hole in their heart, typically between the left and right ventricles, known as a ventricular septal defect.

Cats with a large ventricular septal defect are likely to have shortened lifespans, but cats with a small septal defect can live, mostly unaffected, for many years.

This is the average lifespan of a Maine Coon cat.

Heart Issues That Might Develop

Below are five heart issues that your Maine Coon may develop:

1. Restrictive Cardiomyopathy

Restrictive Cardiomyopathy is most common in senior cats. This condition causes the heart to fill or squeeze poorly, or both.

If this condition is caused by an underlying problem then it can at times be treated.

However, treatment of this condition usually involves managing symptoms and keeping the cat as healthy as possible.

2. Dilated Cardiomyopathy

This condition is much rarer today than it was in the past, as it can be caused by a lack of taurine in a cat’s diet.

However, most of the underlying causes of Dilated Cardiomyopathy in cats today are unknown.

Also known as DCM, Dilated Cardiomyopathy causes the left ventricle of the cat’s heart to contract poorly, and it can also cause the heart’s atria to enlarge.

3. Unclassified Cardiomyopathies

Cats can also suffer from other cardiomyopathies of unknown causes.

4. Heart Murmur

A heart murmur is a catch-all term that refers to any abnormal sound that the cat’s heart makes.

Heart murmurs can range from Grade 1 (soft) to Grade 6 (loud).

Many cats can live long, unbothered lives with a heart murmur, while others may die early from heart-related problems.

5. Secondary Diseases

Conditions that affect the function of the heart include anemia, high blood pressure, and hyperthyroidism, among others.

These conditions will cause more wear and tear on the heart, which can cause more serious complications later in life (source 1,2,3,4,5).

What Is HCM In Cats?

HCM, also known as Hypertrophic Cardiomyopathy, is the most common form of heart disease found in cats.

This condition is usually genetic, but even cats who test negatively for the gene associated with HCM can develop the condition.

HCM causes the left ventricle of a cat’s heart to thicken with scar tissue over time.

As the tissue thickens, the ventricle becomes narrower and narrower.

If a cat with HCM develops a blood clot, it can stop the left ventricle from working at all, leading to sudden death.

Hypertrophic Cardiomyopathy is a progressive condition that only gets worse over time.

Some cats live long lives and pass away due to natural causes rather than from HCM, but many cats with HCM die as young as four years old (source 1).

What Causes HCM In Cats?

Hypertrophic Cardiomyopathy is often a genetically inherited disease.

Cats carry two genes which can be either N or HCMmc.

If the gene is N, it means there is no mutation associated with Hypertrophic Cardiomyopathy, while a gene labeled HCMmc indicates Hypertrophic Cardiomyopathy.

Cats who test N/N for Hypertrophic Cardiomyopathy are not at an increased risk for developing the condition, and cannot pass on this condition to their offspring.

Cats who test N/HCMmc for Hypertrophic Cardiomyopathy are more likely to have longer lifespans than cats who test positive for both copies of HCMmc.

But, even one copy of this gene can cause HCM to develop.

Finally, cats who have both copies of HCMmc are at a much higher risk of developing this condition.

While cats who test N/N for Hypertrophic Cardiomyopathy don’t have a genetic predisposition towards this condition, it can still develop independently as a cat ages (source 1).

Maine Coon HCM Symptoms

HCM symptoms in cats are usually mild at first and progress over time.

In some cases, however, a cat might not show any outward symptoms until the disease kills them.

Here are some of the Hypertrophic Cardiomyopathy Maine Coon symptoms, ranging from mild to severe:

Elevated Heart Rate

A cat’s heart rate can range from 140 to 220 beats per minute.

It is normal for cats to have a heart rate that is much higher than a human’s.

But, if your cat’s heart rate is regularly at the higher end of that range, even while at rest, it is a potential sign that your cat has Hypertrophic Cardiomyopathy.

Decreased Activity

One of the first clinical signs of HCM in cats is a decrease in activity.

Your cat may not be able to play for as long as it once was, or it may run more slowly or jump less.

Labored, Rapid, Or Open-Mouthed Breathing

If your cat’s breathing has become fast or heavy, or if your cat pants regularly, it is a sign that serious heart problems are going on.

While some faster breathing is expected after playing or running, cats should not be breathing quickly or panting while at rest.


Chronic coughing is a sign that your cat’s HCM has advanced to congestive heart failure when extra fluid begins to gather in the chest cavity around the cat’s lungs.

Exercise Intolerance

If your cat is no longer able to exercise at all, it is time to go to the vet immediately.

A cat that is unable to exercise may have reached a more advanced stage of heart failure.

Decreased Appetite

Your cat’s appetite is one of the most important things to monitor. Therefore, if you notice that your Maine Coon has stopped eating, this is a sign that something is seriously wrong.

If your cat has stopped eating altogether, take it to the emergency vet straight away.


If your cat faints or collapses suddenly, you need to take your cat to the vet straight away.

Although this is not always a symptom of HCM, any cat that has just fainted requires emergency care.

Pain Or Paralysis In Hind Limbs

If your cat experiences sudden acute pain or paralysis in its hind limbs, it is likely suffering from thromboembolism, also known as a blood clot.

Cats with HCM are most likely to get a blood clot in the aorta, where it splits to travel through each hind leg.


Sadly, in some cases, cats do not show any symptoms of HCM until it is too late.

That is why it is incredibly important to bring your cat in for regular checkups, so your vet can keep an eye on your cat’s heart and let you know if anything has changed (source 1,2).

How to Test For HCM In Cats

Maine Coon heart screening is incredibly important among Maine Coon breeders.

Organizations like UC Davis and Basepaws send genetic testing kits directly to your door.

Once you provide a sample of your cat’s DNA (typically via cheek swab), you can send the kit back and receive a thorough genetic profile of your cat soon after.

You can specifically order a kit just to test for Hypertrophic Cardiomyopathy.

If your cat tests N/N for the condition, then it is not genetically predisposed to HCM.

However, if your Maine Coon cat tests N/HCMmc or HCMmc/HCMmc, your cat is a carrier of the condition and is more likely to suffer from it.

Diagnosing Hypertrophic Cardiomyopathy is a bit trickier, and vets will usually focus on ruling out conditions like high blood pressure or a heart murmur before diagnosing HCM.

Vets can use X-rays, blood tests, and echocardiography to determine if your cat has Hypertrophic Cardiomyopathy (source 1).

Maine Coon HCM Treatment

Sadly, Hypertrophic Cardiomyopathy is incurable.

This progressive condition will only get worse over time, but there are a few treatments vets can use to slow and manage your cat’s symptoms.

Treatment options for Maine Coon hypertrophic cardiomyopathy include:


The most common form of treatment for HCM is medication.

Your vet may prescribe blood thinners to prevent a blood clot.

Many other medications work to slow the affected cat’s heart rate, relax the heart muscle, and decrease the amount of work that the heart has to do.

While this will not stop the progression of HCM, it can slow it and keep your cat’s heart stronger and healthier.


If your cat is experiencing more serious symptoms of heart failure, your vet may recommend hospitalization for a time.

This will give the vets the opportunity to monitor your cat’s symptoms and keep your cat stable in case of a blood clot.

Fluid Draining

Hypertrophic Cardiomyopathy can cause fluid to build up around the lungs, which increases the cat’s risk of congestive heart failure.

This can be treated by draining the fluid (source 1).

How Long Do Cats With Hypertrophic Cardiomyopathy Live?

When it comes to HCM in cats, life expectancy is sadly shortened in many cases. 

A cat with HCM may die as young as four years old.

However, some cats with Hypertrophic Cardiomyopathy can live completely normal lives and may live out their entire lifespan before dying to natural causes.

What Is Heart Failure In Cats?

The two main jobs of the heart are to fill with blood and pump it back out.

Heart failure in cats means that the heart is having difficulty fulfilling one or both of these jobs.

Sadly, when a cat experiences heart failure, it means the heart has to work even harder to keep up so it can make enough oxygen for the body.

This in turn wears out the heart even further.

Congestive heart failure refers to heart failure that has begun to affect the lungs, as well. Congestive heart failure requires more immediate and aggressive treatment (source 1).

Early Signs Of Heart Failure In Cats

The first stage of heart failure in cats is asymptomatic, which means that you cannot detect it without the help of a medical professional.

Symptoms that are observable by the cat’s owner do not begin until the second stage of heart failure.

Here are some of the first symptoms that you might notice in your cat:

1. Shortness Of Breath

Since the heart’s main job is to provide oxygen for the body, cats suffering from heart failure are likely to experience shortness of breath.

They might breathe more quickly, more heavily, or with their mouth open to get enough oxygen.

2. Decreased Activity

Cats with heart problems will feel more tired, as their heart cannot fill with or pump blood as easily as it needs to provide oxygen.

Your cat may stop halfway through a play session, or spend less time walking around.

3. Coughing

If your cat’s heart failure has also had an impact on its lungs, it may begin to cough more frequently.

4. Swelling

If your cat’s heart is having a hard time pumping blood throughout the body it may result in swelling, particularly in the legs.

Your cat’s legs or paws may be more sensitive to the touch, or your cat may walk more slowly.

5. Weight Gain

If your cat has begun exercising less, it is more likely to gain weight.

Sudden weight gain should be a cause for concern regardless of whether your cat is experiencing heart problems (source 1).

Stages Of Heart Failure In Cats

Heart failure in cats can fall under one of three stages:

1. Asymptomatic

This stage means that your vet has been able to detect heart disease in your cat, but your cat has not shown any outward symptoms of the condition.

This stage can also refer to cats who have been diagnosed with arrhythmia or a heart murmur.

2. Mild To Moderate Heart Failure

The second stage of heart failure is when symptoms of heart problems can be observed outwardly, both when the cat is active and resting.

3. Advanced Heart Failure

The final stage of heart failure results in serious symptoms like:

  • Inability to exercise
  • Fluid in the chest cavity
  • Respiratory Distress

At this stage, the cat’s prognosis is worse, and much more aggressive treatment is required to keep the cat alive.


While this breed is generally known to be healthy, there are some Maine Coon heart problems your cat may be susceptible to.

The most common heart condition found in Maine Coons is Hypertrophic Cardiomyopathy, a progressive, incurable condition that causes the walls of the heart to thicken.

Maine Coons can also suffer from congenital birth defects that affect the heart, such as a ventricular septal defect or a malformed heart valve.

Other conditions like high blood pressure or anemia can put more stress on the heart, leading to an increased likelihood of heart disease.

While there is little veterinarians can do to reverse the damage of heart disease, it can often be managed through medications.

It is important to bring your cat in for yearly checkups so your vet can monitor your cat’s heart and inform you of any changes.

Related Questions

Maine Coon Sudden Death

If your cat has died suddenly, it is most likely due to heart failure. This is because some heart problems can go on undetected for some time until a blood clot occurs.

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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