Cardiomyopathy in cats – signs and vet care

Updated 2026-09-30 · 1 sources

Based on: International Cat Care (iCatCare)

Book a vet visit

Book a vet appointment if you think your cat has this – a vet needs to confirm it and plan the treatment. Cardiomyopathy is a disease that affects the heart muscle.

What to do now

What you can do now

Contact your vet
Note when it started, how often it happens and what else you see
Take a photo or short video to show the vet
Keep fresh water available
Let your cat rest somewhere calm

Don't

Do not give any human medicine
Do not wait if it gets worse

What it is

Cardiomyopathy is the name given to any disease affecting the heart muscle.^[1] It is the most common form of heart disease seen in cats and the most common cause of heart failure.^[1] Cats may seem to develop signs very suddenly because they may not show signs of illness until it is very severe.^[1]

Signs

A heart murmur
A gallop rhythm
An abnormal heart rate
Cardiac rhythm disturbances

sudden

Causes and risk factors

Overactive thyroid glands (hyperthyroidism)
High blood pressure (hypertension)
Excessive growth hormone production (acromegaly)
Taurine deficiency, including in cats fed nutritionally incomplete diets
Growth in the heart muscle, such as lymphoma
Some drugs may have secondary effects on the heart
Genetic defects recognised in Maine Coon, Ragdoll and other breeds

How a vet finds out

Blood tests
X-rays
Ultrasound
An ECG
An echocardiogram
Blood pressure measurement

How vets treat it

A diet change

Breeds prone to this

Veterinary charities list these breeds as more likely than others to get this condition. Each breed page lists the inherited conditions documented in the breed.

What the experts say

“Genetic defects have been recognised in Maine Coon and Ragdoll cats and other breeds which may contribute to the development of cardiomyopathy (in some breeds a genetic test is available and advised before breeding).”
— International Cat Care (iCatCare) [1]

If your pet is struggling to breathe, has collapsed, is having a seizure or can't stand up: go to the nearest vet now.

Not sure how serious it is?

OkPaw asks a few quick questions about your pet and tells you in 30 seconds whether it can wait. Free on Google Play for Android.

OkPaw is on Android now – an iPhone version is on its way.

Common questions

What is cardiomyopathy?

Cardiomyopathy is any disease affecting the heart muscle.^[1]

Can signs appear suddenly?

Cats may seem to develop signs very suddenly because they may not show signs of illness until it is very severe.^[1]

What signs can cardiomyopathy cause in cats?

Signs can include a heart murmur, a gallop rhythm, abnormalities in heart rate and cardiac rhythm disturbances.^[1]

Sources

International Cat Care (iCatCare)

How this page was made: written with the help of AI from the sources below, then checked claim by claim against those sources. Urgency levels follow OkPaw’s fixed safety rules. It is guidance, not a diagnosis. How we write our pages