Heart murmur grading

[borderdawn]

Kay has made a good post. I have experience with dogs and Cats with heart murmurs and issues. If an apparently "normal" Cat (or dog) suddenly develops a murmur, and a big one, its usually down to a disease like cardiomyopathy. Some dog and Cat breeds have this in their breeds and it will pass down genetically. my 5yr old Dobermann was working in trials, he was "normal" until 5yrs, they said he had a murmur, six months later he was dead with Dilated Cardiomyopathy. This affects cat breeds like the Persian too.

Old animals that develop murmurs can be said to have issues associated with old age, congestive heart failure can be managed and animals can live a long time on meds. My 18yr old Cat has this, he is well and happy having been on meds for 3yrs.

Murmurs can also affect animals by way of infection or virus. I have a Border who had Pneumonia as a result of severe Kennel Cough, this left him with a murmur, never changed in 11yrs and has never given him a moment worry.

Grading is 1-6, and as said before 1 is the best, 6 is the worst.

[Kay]

While Dilated Cardiomyopathy (DCM) is possible in cats it isn't as common as it is in dogs. Abyssinians, Burmese, Siamese are a breed that have shown, in the past, a greater risk to DCM. This was general before better food with taurine was introduced and it is thought that there is a possibility that these breeds need a higher level of taurine.

Hypertrophic Cardiomyopathy (HCM) AND restrictive Cardiomyopathy (RCM) are the most common forms in cats.

A genetic DNA test has been developed to detect HCM in Maine Coons and Ragdolls but as yet is not available for other breeds as the gene mutation has not been isolated in any other breed. This doesn't mean it doesn't occur in other breeds as it does. While the DNA test is good it only indicates the genetic cause. A negative cat can still go on to develop a non-genetic case of HCM.

There is shown to be a possible breed predisposition to HCM in the following breeds:- British Shorthair, Cornish Rex, Devon Rex, Norwegian Forest, Persian, Scottish Fold, Siberian, Sphynx, Turkish Van. Although no gene has been detected as yet in any of these breeds therefore it cannot be said that 'it will pass down genetically'.

[borderdawn]

Originally Posted by Kay

While Dilated Cardiomyopathy (DCM) is possible in cats it isn't as common as it is in dogs. Abyssinians, Burmese, Siamese are a breed that have shown, in the past, a greater risk to DCM. This was general before better food with taurine was introduced and it is thought that there is a possibility that these breeds need a higher level of taurine.

Hypertrophic Cardiomyopathy (HCM) AND restrictive Cardiomyopathy (RCM) are the most common forms in cats.

A genetic DNA test has been developed to detect HCM in Maine Coons and Ragdolls but as yet is not available for other breeds as the gene mutation has not been isolated in any other breed. This doesn't mean it doesn't occur in other breeds as it does. While the DNA test is good it only indicates the genetic cause. A negative cat can still go on to develop a non-genetic case of HCM.

There is shown to be a possible breed predisposition to HCM in the following breeds:- British Shorthair, Cornish Rex, Devon Rex, Norwegian Forest, Persian, Scottish Fold, Siberian, Sphynx, Turkish Van. Although no gene has been detected as yet in any of these breeds therefore it cannot be said that 'it will pass down genetically'.

Thats interesting Kay, and in direct contradiction to what Ive read.

Ive read that they think HCM is genetic, and probably inherited.

Bottom line though, until things are certain, NO Cat that has HCM, either itself or either of its parents or siblings should be bred from, that way the disease stands a chance of limitations before tests are available.

[Kay]

Originally Posted by borderdawn

Thats interesting Kay, and in direct contradiction to what Ive read.

Ive read that they think HCM is genetic, and probably inherited.

Bottom line though, until things are certain, NO Cat that has HCM, either itself or either of its parents or siblings should be bred from, that way the disease stands a chance of limitations before tests are available.

The only breeds that a gene has been detected in are Maine Coons and Ragdolls and they have a DNA test now but as I said there are other non-genetic cases of HCM and therefore the DNA test only rules out the genetic HCM. The cat can still develop a non-genetic HCM.

They do think there is a possible genetic and therefore possibly heriditary HCM but until a definite gene is isolated this cannot be proved. The DNA test does not work on other breeds as this gene mutation has only been found in Maine Coons and Ragdolls.

Please read the following from the Animal DNA website about the test and HCM:-
'
Hypertrophic Cardiomyopathy (HCM) is the most common form of heart disease in cats. Onset of clinical symptoms usually occurs in middle age however, cats as young as one have been described. Cats with severe HCM and heart failure usually only live for a few months.
The inherited form of HCM is autosomal dominant, which means that carriers or heterozygotes (ie, those having one copy of the gene) will be affected. Although all cats with the mutation will be affected, the age of clinical onset and severity can vary considerably.
It is important to note that there are many forms and causes of HCM. HCM leads to a thickening of the heart wall, particularly on the left side. This in turn, can lead to heart failure, embolism and death.
Two specific mutations at different sites on the MYBPC3 gene have been found to be associated with HCM in Maine Coon and Ragdoll cats, respectively. The MYBPC3 gene is partly responsible for the heart’s ability to contract. These specific mutations result in the production of faulty proteins, which the heart tries to compensate by producing more. This overproduction can result in thickening or hypertrophy of the heart.

A Positive Result ?

A positive test result means that the cat will be effected in its lifetime.However the DNA test cannot predict the age at which clinical onset occurs nore the diseases severity. Some have found that males may get the disease at an earlier age and may have a more severe form.
A Negative (Clear) Result ?

A “clear” result means that the cat does not have the specific mutation that has been found to be associated with HCM in the breeds mentioned. As the test does not detect other causes of HCM, a “clear” result does not mean the cat will never develop HCM.
Breeding outcomes.

The table below summaries the probability of affected offspring by various matings.

Percentage of Offspring expected to be affected.

Unaffected Clear

Positive Heterozygous

Positive Homozygous

Unaffected Clear

0%

50%

100%

Positive Heterozygous

50%

75%

100%

Positive Homozygous

100%

100%

100%

Two DNA tests are available that identify the specific mutations that have been associated with HCM in Maine Coon and Ragdoll cats. They identify mutations that were described by Drs Meurs and Kittleson and published in the scientific journals Genomics & Human Molecular Genetics1.

The tests are able to be performed on a simple cheek swab sample.
To get your cats tested, simply request a sample collection pack and submission form and mark either HCM-Maine Coon or HCM-Ragdoll.

1. Genomics, 2007, 90;261-264. Human Molecular Genetics,2005, 14;3587-3593.

As for breeding from a cat with HCM, whether it be a genetic version or not, no breeder should breed from these cats primarily because the cat would more than likely die from the excessive exertion involved with mating, . That was my reason for not using Tate after his heart murmur was detected. This heart murmur was probably down to HCM but no kitten of his has ever shown any signs of a murmur and I am in touch with all his kittens. This proves there are other forms of HCM other than heriditary ones.

[Phoenix]

Thanks Kay and borderdawn.

Here's a picture of her: (taken today)

(mid yawn - the camera woke her up)