Hypertrophic Cardiomyopathy in Cats: Causes, Symptoms & Care

Hypertrophic cardiomyopathy (HCM) is the most common heart disease in cats, marked by the thickening of the heart muscle, particularly the left ventricle. This thickening reduces the heart's ability to relax and fill properly, leading to reduced efficiency and sometimes enlargement of the left atrium. Early diagnosis improves outcomes, though the condition remains serious and progressive [source].

1. Understanding Hypertrophic Cardiomyopathy in Cats

HCM causes thickened muscle walls that reduce the heart chamber volume and increase work required by the heart. This can result in rapid or irregular heartbeats and oxygen starvation of heart cells, worsening heart function. Genetic factors are key drivers, with certain breeds more predisposed to HCM due to inherited mutations [source].

2. Recognising Symptoms and Disease Progression

Many cats show no symptoms early on, masking illness well. When symptoms appear, especially in advanced stages, they may include breathing difficulties, open-mouth panting, lethargy, decreased appetite, heart murmurs, sudden limb paralysis caused by blood clots, or sudden death. Congestive heart failure with fluid in the lungs can develop in later stages [source].

3. How to Monitor Your Cat’s Breathing at Home

If your cat is diagnosed with HCM and is on medication, monitoring breathing rate while they are resting or asleep is vital. Count breaths for 15 seconds and multiply by four; it should be below 30 breaths per minute. Breathing over 50 could signal fluid in the lungs requiring veterinary attention urgently to prevent suffering.

4. Treatments and Management Options

Currently, there is no cure for HCM. However, treatment aims to manage symptoms and improve quality of life. Common treatments include diuretics and ACE inhibitors to control lung fluid buildup. In severe cases, fluid removal via catheter may be needed. Some vets suggest natural supplements like nattokinase to reduce blood clot risks, though medication is only effective once fluid accumulates [source].

5. Breeds More Prone to Hypertrophic Cardiomyopathy

Certain breeds are more genetically susceptible to HCM, including Maine Coon and Ragdoll cats, both of which have available genetic tests. Other breeds such as Persian, American Shorthair, British Shorthair, and Oriental breeds also face higher risks. Responsible breeding is essential to prevent passing on the condition. Cats diagnosed with HCM should not be used for breeding to help reduce disease prevalence [source].

6. Preventing and Reducing Risk of HCM

There is no guaranteed way to prevent HCM as it is largely a genetic condition. However, choosing cats from reputable breeders who test for the disease and avoid breeding affected cats is the best preventive measure. Routine veterinary check-ups can aid early detection, allowing timely management to slow progression and improve quality of life.

7. When to Consult Your Vet Urgently

Immediate veterinary care is paramount if your cat shows signs of distress such as laboured breathing, heavy panting, or sudden limb paralysis. Rapid intervention can reduce suffering and potentially extend a cat's life. Working closely with your vet to monitor and manage HCM ensures your feline friend receives compassionate, responsible care throughout their journey.

In summary, hypertrophic cardiomyopathy in cats is a genetic and progressive heart disease requiring early diagnosis, regular monitoring, and supportive care. By understanding symptoms, recognising at-risk breeds, and maintaining close vet communication, owners can help their cats enjoy the best possible quality of life despite this challenging condition.