HCM in cats

What is HCM in cats?
HCM stands for Hypertrophic Cardiomyopathy. That means; abnormal enlargement of the heart muscle. In humans, for example, intense exercise can strengthen the heart muscle, but this is normal and useful. In the case of HCM, enlargement is not normal, much less practical.

HCM is a common condition in cats and can lead to heart failure (fluid in the lungs), thrombus and sudden death.

As the heart muscle gets thicker, the space in the left ventricle (left ventricle) gets smaller. As a result, there is not enough space for all the blood and less blood is pumped through the body per beat. Also, less blood travels from the lungs to the heart, causing blood to pool in the lungs.

Can every cat get HCM?
In principle, any cat can develop HCM. However, veterinarians observe the disease more frequently in certain breeds, e.g. Maine Coon, Ragdoll, Norwegian Forest Cat, British Shorthair and the Sphynx.

Age is also very variable, with some cats developing HCM at a young age (even as young as 6 months) and some cats later in life.

Inheritance of HCM
In some breeds, the condition is hereditary and a blood test can determine if your cat is a carrier of the abnormality that can cause HCM. However, this test is inconclusive. A cat that tests positive for the abnormality does not necessarily develop HCM, and cats that test negative can still develop HCM. A cat needs to have two abnormal genes to know for sure that she will develop the disease and there is no way to test for that. The reason breeders still want to test for the anomaly is because they don't want to cross two carriers. This makes it very likely that many (or all) offspring will have two abnormal genes and therefore develop HCM.

What are the symptoms?
In many cases, you will not notice much of your cat at the beginning of the illness. If you do not go to the vet for a long time, reduced stamina can become noticeable. In many cases, however, a less active cat is attributed to old age. Even cats are not always active by nature. If heart failure is imminent, your cat may start coughing. However, not all cats cough due to fluid in their lungs.

The vet may hear a heart murmur (heart murmur) early on, or notice an irregular heartbeat. Shortness of breath and paralysis often only occur at a later stage. Some cats have no symptoms at all.

How is the diagnosis made?
The veterinarian often suspects HCM based on all observations. A true diagnosis can only be made by an ultrasound scan of the heart. An X-ray is not sensitive enough. It takes a certain amount of experience to perform a good ultrasound scan of a cat's heart. In many cases, your vet will therefore refer your cat to an ultrasound specialist. An ultrasound scan is performed when the cat is awake, so your cat will not need anesthesia.

There is also a test on the market that can be performed using blood. This test is only reliable in severe forms of HCM and not in the early stages.

Can I do something about HCM in cats?
It's always up to you what you want once the diagnosis is made. In many cases, treatment is not necessary and even superfluous if the disease is detected early. As a rule, treatment is only given when the disease has already reached a more advanced stage. It is therefore important to have regular ultrasound examinations of the heart to monitor the progression of the disease. There is no cure for HCM, so treatment consists only of medications that support your cat's heart and circulation.

My cat has a heart murmur and needs surgery. is this safe?
In principle, every anesthetic carries a risk, even in healthy animals. However, if your cat has HCM, it is very important to know at the time of anesthesia if this is a problem for your cat. This can really only be determined correctly with an ultrasound. If the HCM does not present a cardiovascular problem, anesthesia is just as safe as in a healthy animal. However, if there is a problem, your vet will have to make a decision. He/she will always do this in consultation with you.

This text was translated by a translation machine