Heart Murmurs

[Elaine]

Just found and read the following, was actually looking for my dogs benefit but thought it might be useful for all us cat owners too.

Heart Murmurs in Dogs and Cats

What is a heart murmur?
Lots of people assume that a ‘heart murmur’ is a disease or a diagnosis. This is not true – a heart murmur is simply a noise that your vet has heard through the stethoscope. It tells us that blood is not flowing smoothly through the heart for some reason and is making more noise than normal.

What causes heart murmurs ?
There are lots of different reasons why a cat or dog might develop a heart murmur. Some are caused by birth defects in the heart – e.g. ‘Hole in the heart’, and are often heard first in puppies or kittens when they have vaccinations. Diseased valves in the heart tend to leak, and they make a noise which is heard as a heart murmur. This is quite common in older dogs and cats. Heart muscle disease ( so called ‘Cardiomyopathy’ ) can occur at almost any age in cats and dogs, and it tends to deform heart valves making them leak. This will, in turn, cause a heart murmur. Some heart murmurs are termed ‘innocent’ or ‘flow’ murmurs. They are usually quite quiet and are not caused by any disease process, but are a variation of normal. The murmur is just the sound of blood flowing through the heart which in some individuals can be louder than others – particularly in thin fit animals such as greyhounds and lurchers. Finally, heart murmurs can be caused by disease elsewhere in the body. For example, if a cat or dog does not have enough red blood cells ( anaemia ) then the blood can become very thin, and this can make more noise as it flows through the heart, causing a murmur to be heard.

What happens if my vet finds a heart murmur in my pet?
It is common for cats and dogs to have heart murmurs but no other signs at all. In this situation it is advisable to find out what is causing the murmur.
If the cause of the murmur can be found, then your vet can give you the best advice about management of any heart problem. Pets with heart murmurs often need no medication, especially if they are not showing any outward signs of disease.
Sometimes they do require treatment that can help prevent worsening of any disease process that is going on. For an accurate diagnosis, it is usually necessary to perform ECHOCARDIOGRAPHY – which is a complicated way of saying an ultrasound scan of the heart, which is the same sort of scan that humans have for pregnancy diagnosis. It is harmless to your pet, and only involves a little clipping of hair on either side of the chest low down so that the ultrasound probe can contact the skin. In most dogs sedation is not needed. Many cats can be successfully scanned without any sedative,
but they tend to be a bit more wriggly, and we sometimes find that a low dose of a sedative drug enables the cardiologist to get much more information from the scan.
Ultrasound means that we can look right inside your pets heart. We can see the valves, heart muscle, blood vessels etc, and we can even measure blood flow in areas of the heart and see blood flowing in colour. This means that we can find the cause of the heart murmur in most cases, and the cardiologist can give you the best advice on management.

What other tests might my pet need?
Depending upon your individual pet, the heart rate, rhythm, pulse, loudness of murmur, breed, age etc, the cardiologist may advise other tests including:
1. Blood pressure – usually in older dogs, or cats with heart muscle disease, kidney problems, diabetes or thyroid problems. 2. E.C.G. – short for electro-cardio-gram. This looks at the electrical impulses that pass through the heart muscle as it beats and can be very useful for helping work out if there is any problem with the heart rhythm. 3. Blood tests – various tests can be useful – it is often useful to check that the rest of the body is working well, especially the kidneys and liver, before we dispense any drugs, and we can even find out if the heart muscle has been damaged. 4. X-rays - these are sometimes useful especially if there is evidence of coughing or breathing problems.

Does my pet have to have these tests?
No, not if you don’t want to. Our job is to give you the best advice that we can and to try and make sure that we treat your pet with the correct drugs (or preferably no drugs if they are not necessary!). To do this, we need information. We get a lot of information from examining your pet in the consulting room, but often we need more. This is what these tests can provide, in a similar way to the advice you would be given if you went to see your GP who wanted to refer you to see a consultant for more tests.

What if I don’t get the tests done?
Lots of pets can have a heart murmur for long periods of time, and some of them may never have any problems that relate to the heart murmur. If your pet is lucky, it may fall into this category and never have any problems. Unfortunately, we cannot always tell you this when we see your pet, simply because we don’t have enough information to be able to tell. This is especially true in cats, as they can often seem absolutely fine one day, and suddenly go into a crisis in a very short space of time.

If you would like to speak to our cardiologist about your pet, please let your vet know, and they can arrange for him to contact you. That way, if you have any questions relating to your pet and any tests that we might have suggested, you can speak to him directly to answer your queries.

We hope this information leaflet helps!

[angieh]

I'm so sorry to hear about Rayne Elaine. I remember the awful feeling I had when we took Monty to the vet for the first time as a newly acquired puppy and was told that he had a heart murmur. Of course being a new owner I had no idea that heart murmurs in puppies is not uncommon and often clears, which, thank goodness Monty's did.

That doesn't help you and Rayne of course but I do understand the reaction of dread that you must have experienced, especially with Rayne and the other health problems she has had.

Virtual hugs are really all I can offer.

[Elaine]

thanks Angie.
Just re-reading that article and have been reading several others as well as talking to people more informed than I am.

Particularly this part...

The murmur is just the sound of blood flowing through the heart which in some individuals can be louder than others – particularly in thin fit animals such as greyhounds and lurchers.

Rayne is really fit and had been out running before we went to the vets which makes me question whether she has a murmur or not. She is back at the vets in 4 weeks, will make sure she is rested before we go and ask them to check her again because it does seem really odd to me that she all of a sudden has this.

[farthing]

I have quite a few animals with heart murmurs, cats and particularly Levi the lab, I think you might remember him.
He is a totally hyper dog who has vaso-vagus disorder. He has had an ECG and bloods done, as well as x-rays and nothing is abnormal.
He went in for a dental and lump removal a few months ago and at the age of 9, the vets could hear no murmur.
I think it is often down to the day, how nervous the animal is and the situation.
I think the time I worry now is if they develop a murmur when they get older.

[Elaine]

Thanks for that Farthing. I will ask them to check again when I go back in 4 weeks.