HCM ~ HYPERTROPHIC CARDIOMYOPATHY

[AdamSavage]

Copying this over from another forum, just to educate people on the illness.

Also referred to as HCM, Hypertrophic Cardiomyopathy can affect not only humans, but cats. Certain cat breeds are more prone to it than others.

What is HCM?
Hypertrophic cardiomyopathy (HCM) is a condition in which the heart muscle becomes thick. The thickening makes it harder for blood to leave the heart, forcing the heart to work harder to pump blood.

Causes:

Hypertrophic cardiomyopathy is often asymmetrical, meaning one part of the heart is thicker than the other parts. The condition is usually passed down through families (inherited). It is believed to be a result of several problems (defects) with the genes that control heart muscle growth.

Screening:

It is a good idea when purchasing a Bengal to ask the breeder if the mating cats have been tested for HCM, as it is hereditary. Many catteries are now doing HCM screening on all of their breeder cats. You can even find vets at cat shows doing HCM screening on all of the cats at a reduced rate. There are a couple of methods of screening, one of which is doppler radar (ie: a radar using the doppler effect of the returned echoes from targets to measure their radial velocity. To be more specific the microwave signal sent by the radar antenna's directional beam is reflected toward the radar and compared in frequency, up or down from the original signal, allowing for the direct and highly accurate measurement of target velocity component in the direction of the beam. Doppler radars are used in air defense, air traffic control, sounding satellites, police speed guns, and radiology.)

Symptoms:

* Chest pain
* Dizziness
* Fainting, especially during exercise
* Heart failure (in some patients)
* High blood pressure (hypertension)
* Light-headedness, especially after activity or exercise
* Sensation of feeling the heart beat (palpitations)
* Shortness of breath

Other symptoms that may occur are:

* Fatigue, reduced activity tolerance
* Shortness of breath when lying down

Some patients have no symptoms. They may not even realize they have the condition until it is found during a routine medical exam.

The first symptom of hypertrophic cardiomyopathy among many young patients is sudden collapse and possible death. This is caused by very abnormal heart rhythms (arrhythmias). Hypertrophic cardiomyopathy is a major cause of death in young athletes who seem completely healthy but die during heavy exercise.


Feline Cardiomyopathy

The most common cardiomyopathy (heart muscle disease) in cats is hypertrophic cardiomyopathy. This form has many variations and is defined by thickening of the primary heart muscle, the left ventricle. Depending on the specific variation, the problem can be primarily in the blood flowing out of or into the cat's heart. This differentiation using echocardiographic and other examination findings helps determine which medications your cat requires. With appropriate medication and early intervention, we can frequently achieve stabilization of the disease and sometimes reversal of the problems.

A genetic predisposition to develop hypertrophic cardiomyopathy has been found in Maine Coon and American shorthair cats with a suspected genetic predisposition in ragdolls and Persians. The 1 to 4 year age group of cats has a tendency toward more aggressive disease. Male cats are also over represented. [Bengal cats are alsoat risk for HCM, as it is in some of their lines]

A common secondary change in cats with cardiomyopathy is enlargement of the left atrium. This finding is particularly worrisome in cats because they are susceptible to blood clot formation. If your cat has an enlarged left atrium, we may prescribe aspirin therapy (children's aspirin twice weekly is safe in cats) or other medication to try to delay or prevent blood clot formation. Unfortunately, the development of a blood clot is unpredictable and can occur on any medication. Blood clot formation can result in a cat being paralyzed in the rear legs, limping on a front leg, exhibiting episodes of abnormal behavior, or even sudden death.

Older cats may have a thickened heart muscle due to an underlying systemic cause. In our middle aged and older cats high blood pressure, kidney disease, and hyperthyroidism are common problems that increase the workload of the heart muscle and cause secondary thickening. We always try to rule out a potential underlying cause before we make the diagnosis of hypertrophic cardiomyopathy. If your cat has another problem, the response to therapy for that primary problem usually improves and may resolve the secondary heart changes. The response to any therapy depends on the stage of disease with the best response seen when therapy is started earlier in the course of the problem.

Restrictive cardiomyopathy is another type of heart muscle disease. This form can be a late stage of hypertrophic disease or may be a primary entity. Unfortunately, restrictive cardiomyopathy presents a much greater challenge in its treatment. These cats tend to have very large left atria and are usually at high risk for the development of a blood clot and heart failure.

Both types of cardiomyopathy can cause congestive heart failure (fluid in the lungs). Sometimes, there will also be fluid around the lungs in cats with heart failure (pleural effusion) and that problem is best treated with physical removal of the fluid. If your cat has experienced an increased effort or rate of respiration, he or she may have experienced an episode of heart failure. Multiple medications are typically recommended to improve this situation and try to maintain your cat's normal lifestyle and appetite. If your cat has not been eating for several days, we may also recommend placement of a feeding tube to provide the calories and fluid your cat needs to recover.

Unfortunately, feline patients hide signs of disease instinctively and many times present with advanced forms of cardiomyopathy because they have hidden their problems so well. As with all heart disease, early diagnosis is the key to achieving the best possible clinical response

[AdamSavage]

And this article deals with some symptoms, detection and treatment:
Feline hypertrophic cardiomyopathy (HCM) is a disease affecting cats in which the walls of the heart become increasingly enlarged.

This is a compilation of information on the disease for veterinarians and pet owners, including a list of other HCM Internet resources. (Standard disclaimer applies: I'm not a vet and this is not medical advice.)

Diagnosis in early stages can be tricky, but here are the symptoms: lethargy, poor appetite, panting/troubled breathing. Often, a feline will develop a heart murmur along with HCM; while the HCM can be treated if detected early, the murmur will probably never go away (but it isn't anything to worry about).

Even after treatment, weakness or paralysis of the back legs should be watched for -- blood clots can be developed and lodged in each leg ("saddle thrombosis"). This is a grave condition and must be treated immediately (within minutes, maybe hours at best) for the feline to survive.

Prognosis is not favorable -- no cure is known at this time. In a fairly recent study, cats with HCM lived for an average of around 736 days, but I've heard of HCM-afflicted cats living for four or more years before heart failure.

If diagnosed early, medication can slow the process down. Late diagnosis is usually postmortem, or when the disease has reached an acute state.

The cause of HCM is believed to be genetic. It has been noted that an alarming increase of cats (and dogs), especially younger ones, afflicted with HCM in recent years.

The best hope for HCM, it seems, is to diagnose animals which carry the HCM gene and don't let them breed.
Who bred your HCM-afflicted cat?
7% - Pet store or other corporate breeder (11 votes)
11% - Friend, family member, or other indivdual (18 votes)
20% - Professional cattery (32 votes)
62% - Unknown (obtained from animal shelter, etc) (99 votes)
(Poll presented on 1999-11-30; 160 votes total)

Treatment is through medication to both thin the blood and retard the growth of the heart wall. Several types of vet-prescribed medications can be administered: atenolol (generic for tenorim, a beta blocker, which lowers blood pressure), lasix or other diuretic, and Cardizem. Baby aspirin (normally fatal to cats) can be given twice a week to thin the blood.

It can be a struggle getting the medication down the hatch, and few cats seem to be easily "tricked" into eating food laced with meds. The best technique is to kneel on the ground with your feet crossed, the cat held between your knees. Open the jaw with one hand and insert the medication with the other. It can also help to give meds before they eat their first meal of the day, to reduce the chance of vomiting it up.

It may be appropriate, later down the line, to take the cat off diuretics (which act as an appetite supressant and can also dehydrate the cat).

Other treatment is focused on encouraging strength and optimum health by giving the feline the best living conditions possible; this also happens to be sound advice even for cats who aren't sick -- a diet of name-brand, commercial pet food is probably worse for cats than a human on a diet of fast food:

* Feed high-taurine, quality foods. Commercial cat foods that seem to meet standards include Bench & Field, Nature's Recipe, Wysong, Katz-n-flocken. Other healthy foods reported to be liked by some cats include plain, cooked oatmeal; steamed broccoli; cooked liver. Avoid salt and salty foods. (Proper diet for HCM-afflicted cats is of utmost importance.)
* Exercise should be with caution (feline should not be stressed), but is also important.

[AdamSavage]

HCM Awareness group on Facebook: https://www.facebook.com/groups/HCMAwaraness/

Here is the newest version of the HCM list. It is good for us to familiarize ourselves with it and check pedigrees before purchasing a kitten. Not all HCM cats are included in the list..

https://docs.google.com/file/d/0B3YLzW- ... sp=sharing