Hypertrophic Cardiomyopathy – or HCM – is the most common form of heart disease in cats.
Cats with HCM develop a significant increase in the thickness of their heart muscle. This not only stops the heart from functioning correctly, but it ultimately leads to heart failure.
What causes HCM?
The left ventricle – one of the four chambers of the cat’s heart – becomes exceedingly thick. This limits the ability of the left ventricle to accept blood as the muscle wall restricts the space available.
The left ventricle muscle also becomes very rigid. It is Increasingly unable to relax and the amount of blood pumped out to the body when the heart muscle contracts is severely reduced.
The cat’s heart rate increases dramatically to compensate for the lower volume of blood being plumped out to the body. However this response cannot adequately maintain the blood supply to the body.
Over time the thickened left ventricle muscle also outgrows Its own blood supply. This results in the death of some of the left ventricle’s muscle cells.
The exact triggers of HCM are unknown. Genetic factors may play a role.
In some cats, HCM develops as a result of another disease such as hyperthyroidism (excessive levels of thyroid hormones) or high blood pressure. When these underlying diseases are properly treated, a cat’s HCM may improve and sometimes disappear altogether.
How do I know if my cat suffers from HCM?
The most noticeable signs in cats suffering with HCM include:
- lethargy
- abnormally fast heart rate
- rapid and/or difficult breathing
- low appetite
- fainting or collapse
In some cases there may be a sudden onset of weakness or paralysis of the back legs. This is caused by a blood clot that blocks the major blood vessels supplying the cat’s back legs. This is a delicate condition that is difficult to treat.
If left untreated, HCM can result In sudden death.
Your veterinary surgeon will be able to detect other signs of HCM when listening to your cat’s heart rate. If you become concerned about your cat’s health and welfare, you should consult your veterinary surgeon immediately.
Many cats show no symptoms of the disease
The perceived “no stress” lifestyle of a cat might often conceal the onset of a heart condition. As a result, many cats with HCM may not show any obvious signs of the disease to their owners. Only when a veterinary surgeon has had a chance to property listen to a cat’s heartbeat will any abnormality be detected.
Unfortunately, some cats conceal their HCM until their heart has become severely damaged. These cats will suddenly develop a weakness of the back legs, severe heart failure or sudden death.
Early diagnosis and monitoring can prevent this.
How will my veterinary surgeon diagnose HCM?
Firstly, your veterinary surgeon will listen to your cat’s heartbeat with a stethoscope. He/She may detect further signs associated with the condition:
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- a faster heart rate
- a heart murmur caused by a turbulent
- flow of blood through the heart
- an abnormal heart rhythm
Your veterinary surgeon will also want to confirm the diagnosis by performing some further tests that may include:
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- radiography – x-ray of the chest
- echocardiography – use of an ultrasound to examine the heart
- electrocardiography (ecg) – to assess the hearts electrical currents
- blood tests – to identify any underlying cause for the disease
- blood pressure measurement
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