“She’s doing really well, thank you!” Sid* beams, as he carefully put the cat carrier down on the vet’s table. “She’s just in for her annual check-up and vaccinations.” He opens the carrier and peers inside. “Come on out now Daisy, there’s a good girl.” Daisy* cautiously pokes her head out of the carrier. She’s a 5-year-old Maine Coon, a beautiful tabby with shiny coat and a curious nature. Daisy is Sid’s only pet, and his pride and joy. 

The vet chats to Sid about Daisy’s appetite, toileting habits, mobility and general health as she starts her examination. She gives Daisy a full examination from head to tail, and then turns to Sid for a chat. She explains that Daisy has a quiet heart murmur and an increased heart rate, which hasn’t been mentioned in any of her previous medical notes, and checks that Sid hasn’t been told about a heart murmur before. He hasn’t, and is concerned. 

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The vet explains that it is impossible to tell from using the stethoscope alone what is causing the murmur. 

Heart murmurs in cats

A heart murmur is a swishing sound that can be heard over the normal heart sounds when a vet listens to their chest with a stethoscope. Murmurs are caused by turbulent and abnormal blood flow within the heart. Some murmurs can be completely innocent, especially in young cats under 6 months and pregnant cats, and not be indicative of a health problem. However, murmurs can also be caused by various medical problems, including heart disease, high blood pressure, an overactive thyroid, anaemia and any illness which causes dehydration and a high fever. 

Daisy is bright and active, is it important?

She’s able to exercise well and not showing any symptoms of heart failure; but at her age the murmur is less likely to be innocent. The vet recommends a heart scan, blood tests and an electrocardiogram (ECG) for Daisy to discover the underlying cause of the murmur. She gives an estimate of costs, and asks Sid if he would like to go ahead. 

Sid is a pensioner and this is an unexpected expense

Daisy appears to be so well that he was only prepared for the cost of the vaccinations and some flea and worm preventatives. However, Daisy is his special girl and he’s very worried about her. Luckily, Daisy is insured and so he doesn’t have to make a decision based on cost. He agrees to the investigations. 

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Hearts scans and ECGs 

A heart scan (echocardiogram) is an ultrasound scan of the heart. It is non-invasive, not painful, and can usually be done while a pet is conscious. An ECG (electrocardiogram) uses special monitors to assess the heart’s rate and rhythm. 

Daisy’s day trip to the vets goes well, and the vet calls Sid in to discuss the results

Daisy has a thickened heart muscle, which means it is having to work harder than normal to pump blood around the body. This is likely due to Hypertrophic Cardiomyopathy (HCM), a commonly diagnosed heart condition in cats. Maine Coons are one of the known breeds with a genetic link to the condition, which makes the diagnosis even more likely. A thickened heart muscle can also be the consequence of an overactive thyroid, or high blood pressure. Daisy tests negative for hyperthyroidism, but her blood pressure is on the high end of normal range.

Hypertrophic Cardiomyopathy

HCM is a common feline heart condition. It causes the heart walls to thicken, meaning the heart has to pump harder to ensure adequate blood flow around the body. It can also predispose to clot formation. Many cats will not show any symptoms of HCM until the condition is very advanced, so regular check-ups are important. 

Symptoms can include:

  • Lethargy, unwillingness to exercise
  • Changes to normal breathing, including breathlessness, rapid breathing and open-mouthed breathing
  • Collapse
  • Sudden paralysis of the back legs due a clot
  • Sudden death – sadly, some cats will die very suddenly from HCM without displaying any symptoms

HCM has a genetic link in some cat breeds, including the Maine Coon, Ragdoll, Persian, Bengal and British Shorthair. It can also be ‘idiopathic’ (when a cause is unknown) or secondary to an overactive thyroid or high blood pressure. It is diagnosed using an echocardiogram – an ultrasound scan of the heart.

A few weeks later, Sid has got over his initial shock and is focused on caring for Daisy

He is monitoring her breathing rate at home, and Daisy is booked in for another scan in 6 months’ time to check progression of her heart thickening, as well as regular check-ups for blood pressure. As Daisy is not displaying any symptoms of heart disease, Sid and the vet are both hoping that Daisy will continue to do well for some time yet. Sid knows what signs to look out for that would warrant an urgent trip back to the vet. Daisy is on some anti-clotting medication to help prevent a thrombus forming, which can be an unpleasant complication of feline heart disease. 

Treating HCM

There is no cure for HCM, and treatment will depend on the stage of the condition. If the patient is showing no symptoms, the advice may be to monitor only, with regular check-ups. Anti-clotting medication is commonly used, as affected patients often form clots which can do a lot of damage and carry a poor prognosis. If the cat is showing signs of heart failure, medication may be prescribed to support the heart, and diuretics (fluid tablets) used if there is any fluid buildup in the lungs or abdomen. 

The future is sadly uncertain for Daisy

HCM carries a very variable prognosis: some cats with no symptoms can do well for years without displaying any signs of heart failure. Others develop progressive heart failure, and some sadly die very suddenly and unexpectedly. Sid is aware that Daisy won’t be around forever, but with his pet insurance covering the costs of scans, check-ups and medications, after simply paying the initial excess, he’s determined to do everything he can to keep his precious girl happy at home for as long as he can. 

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*Names and some details have been changed

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