What is feline
hypertrophic cardiomyopathy & what does it do?
Feline
hypertrophic cardiomyopathy (HCM) is the most common heart
disease seen in felines. Hypertrophic cardiomyopathy is a term
used when there is no known cause, however secondary, is brought about by
other conditions such as
high blood pressure,
hyperthyroidism etc. Cats with secondary hypertrophic
cardiomyopathy tend to be older.
The main feature
of hypertrophic cardiomyopathy is excessive thickening of the
left ventricular wall, papillary muscles & septum. This enlargement
causes stiffening & prevents the heart from expanding (to
receive blood) properly. It may also reduce the ability of the valves to work
properly, and in some circumstances obstruct the flow of blood
out of the heart.
Arrhythmias,
irregularities of the heart beat & conduction disturbances are
also common complications of hypertrophic cardiomyopathy.
The thickened
wall sometimes distorts one leaflet of the mitral valve, causing
it to leak.
Fluid can leak
into the lungs causing heart failure.
Blood clots can
form in the left atrium & be carried into the systemic arterial
system, most often lodging in the terminal artery, causing
paralysis of the hind legs.
Cardio=heart,
myopathy=muscle disease & hypertrophic=thickened.
Hypertrophic cardiomyopathy tends to affect cats one to five
years of age, and male cats are more commonly affected.
What are the
symptoms of hypertrophic cardiomyopathy?
A cat with
hypertrophic cardiomyopathy may display no symptoms at all, but
die suddenly & unexpectedly. Symptoms may include;
Are some cats more
prone than others?
In humans HCM can
be inherited as an autosomal manner. It appears Maine Coons &
American Shorthairs also have a predisposition towards HCM.
How is
hypertrophic cardiomyopathy diagnosed?
A physical
examination may reveal abnormal heart or lung sounds, irregular
or gallop heart rhythm or heart murmur, this may well be the first
indication that your cat has HCM.
Echocardiogram
(heart ultrasound) is the best diagnostic tool for HCM. Your
veterinarian will evaluate the size, shape & functioning of the
heart.
X-Ray can show if
there is fluid in the chest & heart enlargement.
Electrocardiogram
Blood tests
including a complete blood count & chemistry panel. These can
help provide information on the function of other organs. This
information is important when determining methods of treatment.
Thyroid function
test to determine if the cause is due to hyperthyroidism.
Arterial blood
pressure to check for hypertension.
How is
hypertrophic cardiomyopathy treated?
Asymptomatic cats
may require no treatment, but your veterinarian will want to
monitor him/her closely.
It is not possible
to cure HCM, treatment is aimed at controlling symptoms &
preventing complications.
The thick ventricles of HCM contract and
relax abnormally, and to assist the relaxation phase some drugs
may be necessary. Beta blocking drugs & calcium blocking
channels may be prescribed to assist.
If the cat has
congestive heart failure, diuretics may be prescribed.
Controlled
doses of blood thinning drugs such as aspirin for cats who have
a high risk of clot formation.
Restricting
activity also reduces the strain on the heart & your
veterinarian may prescribe a period of cage rest.
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.
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