What is hypertrophic cardiomyopathy?

Hypertrophic cardiomyopathy (HCM) is the most common heart disease of cats,
whether they are random bred or pedigreed. It is a heart muscle disease in which the papillary muscles (the muscles in the left ventricle that anchor the mitral valve) and the walls of the left ventricle become abnormally thickened.
HCM is often a progressive disease, and a proportion of affected cats develop
heart failure if the muscle hypertrophy and subsequent scarring of the heart muscle significantly affects heart function.

For more information on HCM, see:
http://members.aol.com/jchinitz/hcm/index.htm

What causes HCM in cats?
This is currently unknown in most cats although familial (hereditary) HCM has been
observed in several breeds, such as the Maine Coon and American Shorthair.
Anecdotal information suggests there is familial HCM in many other breeds.
Heart muscle hypertrophy in cats can be caused by other diseases,
such as systemic hypertension (high blood pressure) and hyperthyroidism.
HCM is a primary disease of the heart muscle. Hypertension and hyperthyroidism cause secondary thickening of the left ventricle and so are not causes of HCM (although it is possible that they may exacerbate the disease if they become present in a cat with mild to moderate HCM).
HCM is diagnosed when these other causes are ruled out.

Is HCM genetic?
In Maine Coons and American Shorthairs,
HCM has been confirmed as an autosomal dominant inherited trait,
as it is in humans where over 130 gene mutations in 10 genes
have been found to cause the disease. The disease has variable expression;
meaning some cats are severely affected,
others are only mildly to moderately affected, and some cats may not have
evidence of the disease yet produce affected offspring.
While a specific feline gene mutation has not yet been identified,
research is underway in the Maine Coon cat.
However, since few veterinary cardiologists and geneticists have the expertise to study genes, it is unlikely that the responsible gene or genes for each affected
breed will be found at any time in the near future. If a gene is identified as a cause of HCM in Maine Coon cats, it may not be the same gene responsible for HCM in other breeds. HCM will require investigation in each breed individually.
Can HCM have a nutritional cause?
There is no evidence in cats, humans or other species of animals that
HCM can have a nutritional cause.

How is HCM diagnosed?
HCM is diagnosed using ultrasound of the heart – an echocardiogram.
Echocardiography is a good way to detect moderate to severely affected cats.
However, it may not always detect the mildly affected cats where
changes in the heart can be minimal.
In addition to an echocardiogram, other tests may also be useful in assessing cats with HCM. For example, a chest x-ray is necessary to detect heart failure in cats with severe HCM. An electrocardiogram is useful in cats that have an abnormal heart rhythm. Blood pressure measurement and blood testing for hyperthyroidism is indicated to rule out other diseases that mimic HCM, especially mild to moderate HCM. Ideally, an echocardiogram to test cats for HCM should be performed by a
board-certified radiologist or cardiologist.

Should my cats be tested for HCM and how often should they be tested?
In clinical practice, the most common patients tested for HCM with echocardiography are cats with suggestive clinical signs of heart disease,
such as a heart murmur.
Testing cats used in a pedigreed breeding program is a more difficult endeavor.
Echocardiography is not a perfect tool for diagnosis of HCM – some affected individuals will escape detection and access to good quality ultrasound services may be difficult and expensive for some breeders. At the very least, breeding cats should be ausculted (examined by a vet with a stethoscope)
for heart murmurs or arrhythmias once yearly.
Any cat with an abnormality should have an echocardiogram.
A significant percentage of cats with HCM will not have a heart murmur, however.
Since HCM can occur at any age, a single normal echocardiogram does not guarantee a cat is free of disease. Breeding cats should probably have an echocardiogram yearly during their breeding years.
Examining retired cats periodically is also advantageous as this may allow the identification of affected cats that have offspring in a breeding program.

At what age should a cat be tested for HCM?
HCM can affect cats at any age. It has been seen in kittens only a few months of age and in cats over the age of 10. In Maine Coons, most affected male cats have evidence of disease by 2 years of age, and most affected females have evidence of disease by 3 years of age although instances have been documented where the disease has not shown up until 7 years of age.
Ragdolls with severe disease seem to develop it earlier in life,
often at under 1 year of age.
Guidelines for other breeds have not yet been developed.
It is therefore hard to recommend a specific age to start testing.
It may make sense to test most breeding cats for the first time by the age of 2 years.

What do I do if my cat is diagnosed with HCM?
The cat should be removed from the breeding program and all offspring should be
watched closely for the development of HCM. Statistically, 50% of the cat’s offspring would be expected to have the gene that causes HCM if one parent was a heterozygote.
However, the most prudent approach may be not to use any of the
offspring in a breeding program.
The parents of an affected cat should also be examined with ultrasound,
as one of them likely carries the gene mutation for HCM.
In some cases, identification of the affected parent may be difficult,
especially if the disease is mild. In these cases, the most prudent
approach may be to remove both parents from the breeding program.
It is possible for a cat to develop a spontaneous mutation that causes
HCM during embryonic development but this is an unlikely cause in a breed
known to have the problem.
All breeders that are using cats related to an affected cat should be notified that a cat has been diagnosed with HCM. Similarly, pet owners should be notified that a relative has been diagnosed with the disease. Echocardiographic examination of cats related to the affected cat should be performed.

Will we ever eliminate HCM from my breed?
The tools we currently have to diagnose HCM
(i.e., echocardiography and necropsy)
are not perfect and will not allow us to totally eliminate this disease.
However, echocardiographic screening will be able to reduce the incidence of
HCM within a breed if enough breeders are involved.
Breeders should use all the information they can gather about HCM in family lines,
including pedigree analysis based on accurate identification of affected cats.
Any cat that dies suddenly or dies from HCM should have a necropsy
(i.e., post mortem examination).
Most cats with HCM will have a heart that weighs more than 20 grams and
most cats with severe HCM will have a heart that weighs more than 30 grams.
Myocardial fiber disarray, the hallmark microscopic heart muscle abnormality seen in humans with familial HCM is seen in all Maine Coon cats with HCM. Unfortunately, most veterinary pathologists are not trained to recognize this lesion.
In the long term, we will need a genetic test for HCM in each breed. A genetic test would allow us to identify affected cats before they were bred and do so accurately. Since the disease is inherited as an autosomal dominant trait, once a mutation is identified, if all breeders cooperated by testing their breeding cats for the mutation the disease could be eliminated from the breed within several generations. However, the money and resources necessary to identify the gene or genes and to develop a genetic test for each breed are scarce in veterinary medicine. Breeders and cat fanciers can help by supporting research
through organizations such as the Ricky Fund established
by the Winn Feline Foundation.

Can two normal parents produce a kitten with HCM?
Since HCM is known to be an autosomal dominant trait in the breeds where the
inheritance is known, each affected cat must have one affected parent.
However, there are possible situations in which an affected cat may come from
two apparently normal parents.
The first possibility is that one of the parents has been misdiagnosed.
This can happen due to inexperience of the ultrasonographer or poor quality equipment.
It can also happen if a cat’s status is decided on the basis of only one or two ultrasounds early in life. Since HCM can develop at any age, a cat that is normal on ultrasound one year could still have HCM and show signs later in life.
Since the trait has variable expression, not every affected cat will have echocardiographic evidence of HCM. It is therefore possible for a cat to test negative for HCM on ultrasound, and yet still carry the defective gene and pass it to offspring. Finally, it is possible for spontaneous mutations to occur in cats from normal parents. These cats may then pass on their mutation to offspring.
We do not know how often spontaneous mutations causing HCM occur in cats. Statistically, spontaneous mutations are more likely to occur in random bred cats than in pedigreed cats.

What does “HCM free cattery” mean?
There is no universally agreed upon definition of an HCM free cattery. The terminology is currently unclear, as different breeders mean
different things when they use this term.
Ideally, each breed should develop a specific definition and guidelines for use of this designation for catteries.

What is Feline Immunodeficiency Virus?

Known as FIV or cat AIDS, FIV is an infectious disease caused by a  retrovirus belonging to the lentivirus family. It is in the same family as the FeLV virus, and is similar to the HIV virus in humans. FIV infects both domesticated cats, lions, tigers, pumas & cheetahs. 

FIV attacks the cells of the immune system, leading to FAIDS (feline acquired immune deficiency syndrome). This compromises the cat's ability to fight off infections.

It was first discovered in 1986 in a colony of cats in California, and is found worldwide.

What is a virus?

A virus is a ultramicroscopic infectious agent which consists of either DNA or RNA wrapped in a protein coat. It is only able to replicate inside living cells. The phrase "a piece of bad news wrapped in protein" is a very well known saying regarding viruses.

Viruses are not living organisms, they don't respirate, process nutrients or generate waste products. 

What does FIV do & what are the symptoms?

FIV attacks the cat's immune system which makes it vulnerable to secondary bacterial, viral, fungal & protazoal infections. 

Stage 1: Once inside the body, FIV is carried to the regional lymph nodes where it replicates in the white blood cells known as T lymphocytes (CD4+ lymphocyte). It then spreads to other lymph nodes throughout the body. At this time there may be an acute illness which is characterised by fever, leukopenia, anaemia, malaise & swollen lymph nodes, lasting a few weeks. During this initial stage it may go unnoticed that the cat is unwell.

Stage 2: This is the asymptomatic phase which can last for many years. During this stage cat appears healthy & is able to lead a normal life.

Stage 3: As we've already discussed, FIV destroys the T lymphocytes, these cells are required for the proper functioning of the immune system.  Eventually when enough T lymphocytes have been destroyed, the immune system loses it's ability to fight off opportunistic infections & signs of immunodeficiency develop. 

Cats show a range of symptoms in this stage, these symptoms may vary from cat to cat. Some of which may include:

• Weight loss

• Poor coat condition

• Anaemia

• Gastroenteritis

• Gingivitis & stomatitis

• Diarrhoea

• Chronic or recurrent infections of the skin, eyes, urinary tract, respiratory tract etc.

• Cancer

How is FIV transmitted?

The virus is present in large quantities in the cat's saliva, and the most common mode of transmission is via bite wounds. Free roaming, entire male cats are at greater risk as they are more likely to become involved in territorial fighting. 

Occasionally FIV is passed onto kittens who's mother is FIV positive. This may happen either in utero or via infected milk.  

Cats don't become infected via mutual grooming, nor will the act of mating, although the biting that goes along with mating may pass on the virus.

How is FIV diagnosed?

FIV is diagnosed based on history, clinical signs & a blood test known as ELISA (enzyme-linked immunosorbent assay), which detects antibodies to FIV. It is possible to get false positive or false negatives from these results for the following reasons: 

False positive: 

If a cat has received the FIV vaccine it will have a positive test result. 

Kittens born to FIV infected mothers may have received antibodies from their mothers milk. This doesn't mean that the kitten has FIV, just that it's received antibodies to FIV. Kittens who test positive should be re-tested at a later date. 

False negative: 

It usually takes several weeks for antibodies to FIV to appear in the blood, if the cat is tested prior to this it will show a negative result. 

If the cat is in the later stages of infection it may not be producing antibodies. 

A FIV PCR (polymerase chain reaction) test is available in some commercial laboratories. PCR detects the presence of the FIV virus in the blood.

Western blot test or IFA (Immuno-Fluorescent Antibody Test): If a cat has tested positive to FIV it is sometimes recommended to follow up with either a Western Blot Test or an IFA test.

If your cat has tested positive to FIV but you are not sure if it has had the vaccine, or want to be sure it does/doesn't have the virus then you may be able to request a PCR (polymerase chain reaction) test, which will be able to detect the presence of FIV DNA in the blood.

How is FIV treated?

There is no cure for FIV, once a cat has it, it's for life. The goal is to provide supportive care to the infected cat. This may include; 

• Regular veterinary check ups.

• Maintaining proper parasite control. 

• Ensuring that prompt veterinary attention is sought at the first sign of illness.

• Feed a high quality diet. 

• Limiting their exposure to disease by keeping them indoors & away from neighbourhood or stray cats.

• The use of anti bacterial & anti fungal drugs 

• Maintain a proper vaccination regime to protect your cat from other infectious diseases.

• Blood transfusions may be necessary in stage 3. 

• High calorie supplements may be necessary in stage 3.

• There are other drugs available such as interferon & AZT which have been used in some cats, but it is best to speak to your veterinarian about these. 

Should I have my FIV positive cat euthanised?

No, this isn't necessary. FIV positive cats can live for many years, especially if they are given prompt medical attention when necessary & supportive care. 

Prevention of FIV:

Desexing of all pets, not allowing them to free roam & testing all cats used for breeding.

There is now an FIV vaccine which is available, it isn't 100% effective. Cats given the vaccine will test positive to FIV which may result in confusion, especially in the case of a cat being picked up by a shelter or council. For further information on the vaccine, read here...

Which cats are most at risk of FIV?

Un-neutered, free roaming males are at the greatest risk of FIV. Any cat allowed to free roam is at risk of catching FIV.

Can FIV positive & FIV negative cats live in the same household?

The general opinion is yes, this is okay as long as there isn't any fighting between the cats. As FIV positive cats are more susceptible to opportunistic infections it is important to ensure the health & vaccination status of ALL cats in the household. 

Others suggest either keeping FIV positive cats isolated from FIV negative cats or rehoming the FIV positive cat in a single cat household. Your veterinarian is the best person to speak to in this regard. 

Can I catch FIV from my cat?

No it is not possible to catch FIV from your cat, nor is it possible for your cat to catch HIV from a human. While both viruses come from the same family, they are species specific.

Please note:

The medical articles on this site have not been written by a veterinarian & should not be considered a replacement for a veterinarian visit. The articles are provided for informative purposes only.

Always seek immediate veterinary advice for any problems (health or behavioral) in your pets. 

While great care has been made in the creation of these articles, we cannot guarantee the accuracy or omissions on these pages. If in any doubt whatsoever, seek professional medical advice. 

Flat Chested Kitten Syndrome is a deformity of a kitten's ribs and sternum (breastbone). The medical term for this is Pectus Excavatum and it is also known as Funnel Chest. The term 'Swimmer Kitten' is sometimes used when a kitten with FCK crawls with both front legs out to the side of the chest in a paddling motion.

What are the symptoms?

The kitten's chest is flat, rather than rounded and the ribs bow out more than normal, along the kitten's sides. The sternum may also collapse inwards as the kitten breathes. In more severe cases, the sternum is permanently curved inward, creating a furrow along the kitten's chest.

As well as the flat or furrowed chest, the kitten may:

The flat chest means that the kitten cannot expand his lungs properly with each breath. The muscles between the ribs and the muscles of the diaphragm do not contract and relax properly, so the kitten must make an effort to get enough oxygen to his body. It will often look as if the kitten has a problem with his airway, such as a blockage or infection but on closer examination, the cause is found to be FCK. A heart murmur sometimes accompanies FCK as the heart is also affected by the lack of space within the chest.

What causes it?

It is not really known why some kittens develop FCK and others, even in the same litter, don't. There are several suggestions on why FCK occurs:

These are just some of the theories on what causes FCK. Experts such as vets, professionals and breeders still don't know exactly what causes it.

Treatment

The prognosis for these kittens is often uncertain. If the FCK is mild, the kitten may grow out of it without intervention and eventually have a normal, rounded chest. Twice daily physiotherapy, where the kitten's legs are gently flexed and massaged into the normal position, may help. This loosens and lengthens the muscles and tendons in the legs, allowing them to gradually develop into the correct position.

If a kitten has splayed legs and prefers to lie on his back or flat on his stomach, turning him to lie on his side and gently holding him that way for a few minutes, several times a day, often helps. The kitten may need supplemental feeding with a kitten formula such as KMR or Just Born, to help maintain his weight and good condition, as kittens with FCK sometimes have trouble nursing from the mother-cat.. When the kitten is old enough, encourage him to walk, as this helps the chest return to a more normal shape.

Another treatment for FCK is surgical correction, which has proven to be successful. The most common surgical method used, is to fix the ribs and sternum to an external splint which moves them into the correct position. The earliest a kitten can have this surgery is at 8 weeks old.

If you suspect a kitten has FCK, it is best to take him to a vet for a full evaluation. In cases where the FCK is severe, the kitten may have to be euthanized if he is suffering or there is no hope for his recovery. If the FCK is mild or moderate, the kitten may grow up to be a normal, healthy cat.

This is Vegemite, who was born with moderate FCK, as well as a heart murmur. She has grown up into a happy and perfectly healthy cat.