Heart Murmurs in Older Pets: The Early Warning Sign You Could Be Missing

Every year, on World Heart Day, we’re reminded just how crucial cardiovascular health is – not just for people, but for our four-legged friends too. At Petgevity, we believe that compassionate and proactive care makes all the difference, especially as pets age.

Today, we’re focusing on one of the most common findings in older dogs and cats: heart murmurs, which can be a symptom of other heart issues. Working with veterinary expert, Dr Rebecca MacMillan BVetMed BSAVA PGCertSAM MRCVS to share guidance on how to keep your pet’s heart healthy and ticking for as long as possible.

What is a heart murmur?

A heart murmur is often a symptom of more serious heart issue, meaning there’s something interrupting the normal flow of blood through your pet’s heart. This can happen if blood is being pushed through a narrow area, if it’s leaking in the wrong direction, or if the blood itself has changed in thickness (for example, in severe anaemia).

What can cause a heart murmur in dogs and cats?

Heart murmurs in dogs and cats can be caused by conditions that affect the heart itself, such as congenital abnormalities present from birth or age-related problems like mitral valve disease. They can also develop due to other illnesses, including anaemia or infections, and even during pregnancy. In young puppies and kittens, it’s not unusual for ‘innocent’ flow murmurs to be heard. These are harmless and usually disappear by the time the animal is 4 to 6 months old.

Heart murmurs are relatively common in pets, with roughly one in 30 dogs (3.33%) seen by a veterinarian has a heart murmur, with this being more likely in small-breed and older dogs.

Studies also show that more than one third of cats have a heart murmur. Although a murmur may signify a problem with the heart or its blood vessels, approximately fifty percent of healthy cats with a heart murmur don’t have an underlying disease – and of those that do, many live quite normally without ever developing any signs of disease.

What are the most common heart problems in dogs and cats?

In dogs, the most frequently diagnosed heart problem is mitral valve disease (MVD). Over time, the mitral valve thickens and no longer seals properly, which means some blood leaks backwards instead of flowing in the right direction – and the extra strain can gradually affect the heart’s overall function.

The most common heart problems in cats is hypertrophic cardiomyopathy (HCM). This condition causes the walls of the heart muscle to thicken abnormally, making it harder for the heart to pump efficiently.

In the UK, heart murmurs are a relatively common finding in dogs, especially in older and smaller breeds. Large practice data shows that 1 in 30 dogs seen by a vet has a murmur, with degenerative MVD being the leading cause. 

Certain breeds such as Cavalier King Charles Spaniels and Chihuahuas are more likely to be affected than crossbreeds, and in one large study, about 10% of dogs with recorded murmurs were confirmed as DMVD. 

Insured dogs were also more likely to have a murmur recorded, reflecting greater access to diagnostic care. 

For dogs over six years of age and under fifteen kilograms, a newly diagnosed grade IV murmur carries a significant risk of progressing to congestive heart failure, with studies showing that 56% of untreated cases developed heart failure within five years, compared with 34% of treated cases. 

How do I know if my pet has a heart murmur?

In most cases, a heart murmur in dogs and cats is only picked up when your vet listens to your pet’s chest with a stethoscope – one of the main reasons why regular check-ups matter so much. If the heart condition is more advanced, you might also notice changes at home, such as reduced activity, coughing, difficulty breathing or general weakness.

Can heart murmurs be treated or cured?

Treatment for a cat or dog’s heart murmur depends on the underlying condition. Some birth defects can be repaired surgically, while many conditions that develop later in life cannot be cured and require ongoing medical management. Medications can help the heartbeat more effectively and prevent fluid build-up, helping your pet live longer and maintain a good quality of life.

What can I do to increase the chances of my pet’s heart staying healthy?

While there’s often nothing you can do to stop your pet from developing acquired heart conditions like mitral valve disease or hypertrophic cardiomyopathy, you can still support their overall heart health. Keeping your pet at a healthy weight, feeding them a high-quality diet and ensuring they get regular exercise all play an important role.

What changes can I make at home to support my pet with heart problems?

If your pet has a heart condition, the best thing you can do is follow your vet’s advice closely, especially around diet and exercise. If medication is prescribed, it’s vital to give it regularly and as directed. One of the most important things you can do is to observe your pet carefully – keeping track of their breathing rate and watching for new symptoms, such as a cough, so you can report any changes to your vet promptly.

Can I get pet insurance if my cat or my dog has a heart murmur?

Here at Petgvity, we offer lifetime dog and cat insurance, including pets with pre-existing medical conditions. We’re proud to offer pet insurance for older dogs and older cats cats, where heart murmurs can be a common issue.

If a heart murmur is diagnosed prior to taking out pet insurance, many insurance companies won’t cover it, but will sometimes cover a newly diagnosed murmur as long as it’s detected after the policy has begun. However, we provide ourselves in offering fair and flexible options where possible. As such, we could cover heart murmurs and any injuries that may offer because of the condition, subject to acceptance*.

In summary

This World Heart Day is a great reminder that heart health matters for all members of the family – including our senior pets. Heart murmurs are a common symptom in older dogs and cats often pointing to a serious heart condition, but with regular vet-check-ups, careful observation and following advice on diet, exercise and medication, you can help support your pet’s heart for years to come.

Staying proactive and informed gives your furry friend the best chance of keeping their heart healthy, happy and ticking for years to come.

If you have a pet with a heart murmur, or any other pre-existing medical condition, get a quote with Petgevity to see if we can cover you.

*Cover for pre-existing medical conditions is subject to acceptance. They will not be covered unless you have declared them and they are shown on your Confirmation of Cover.