--- sandworm90292 <erosla77@...
> My beautiful, sweet as sugar and SUPER SMART female
> short-haired tabby, Tabbatha Jean
> was diagnosed last week with cardio-myopathy. 40%
> enlarged left ventricle, arrhythmia,
> and two of her valves are slightly thickened.
> The vet has her on Atenolol, which seems to be
> having zero side-effects; she was totally
> asymptomatic when a routine yearly physical spotted
> the problem
Atenolol is doing several things for Tabby Jean that
are so important. For me understanding how it works
was important. There are andergenic receptors which
certain substances secreted by the adrenal gland fit
into. These receptors occur in the heart and the
lungs. Atenolol is a selective beta-blocker, meaning
it is like a key that fits into a certain lock. In the
case of atenolol it fits into the andergenic receptors
on the heart unlike propanolol which is not specific
and also fits into receptors on the lungs. When these
receptors on the heart are filled they are unavailable
to the substances secreted by the adrenal gland that
increase heart rate. So atenolol slows the heart rate
giving our cat's left ventricle a longer time to fill
up. Atenolol also reduces the oxygen demand of the
heart. When the heart has an increased demand due to a
fast heart rate that is not being adequately supplied
the heart muscle suffers damage. So atenolol helps to
prevent that damage. You also mentioned arrhythmia,
atenolol helps with this also.
> Question: can switching her food make a difference?
You do not want to initiate severe sodium restriction
until your cardiologist or internist tells you to.
However extremely salty people snacks are not a good
> I am wondering, once Tabby's arrhythmia is under
> control, if there is ANY kind of
> supplement to retard the myopathy so her heart does
> not continue to enlarge.
The short answer is that veterinary cardiologists are
not sure yet, but there have been intriquing reports.
According to Clarke Atkins:
"A recent report by Rush, et al. demonstrated a
reduction in wall thickness with the administration of
enalapril to cats with HCM. This suggests a potential
role for ACE-inhibitors in the treatment of HCM.
These drugs are generally safe and do play a role in
cases which are refractory or in which pleural
effusion is present. In asymptomatic patients, it is
logical that the renin-angiotensin-aldosterone system
is not pathologically activated, and hence
ACE-inhibitors would not be useful. The study
referred to argues that they may play a role, however.
Further studies are being planned. Enalapril is used
at .5 mg/kg daily."
Other therapies, including oxygen, aspirin, home
confinement, and moderate salt restriction should be
instituted as needed. Taurine supplementation is not
necessary in the treatment of HC. In asymptomatic
cats with HC, the author advises home confinement,
moderate salt restriction, Beta- and/or calcium
channel blockade, and aspirin indefinitely."
According to Dr. O'Grady of VetGo Cardiology Concepts:
"Growth hormone excess is being investigated, however
it is too early to suggest if or how common this
abnormality is involved in feline HCM.
Work in people with the identical disorder suggests
that Angiotensin II or aldosterone excess, likely at
the myocardial tissue level without elevated
circulating blood levels of angio II or aldosterone,
may activate gene expression resulting in myocyte
hypertrophy. If this also occurs in the cat, then ACE
Inhibitor therapy may reduce the local tissue levels
of Angio II or aldosterone aborting this process.
Alpha adrenoreceptor blockers may also reduce left
ventricular concentric hypertrophy.
As described above, the first prospective, randomized,
placebo-controlled clinical trial investigating the
treatment of feline HCM and CHF is underway. This
trial is investigating four treatments groups (all
groups receive furosemide as they are CHF patients):
placebo, ACE-inhibitior, atenolol (beta blocker), and
diltiazem (calcium channel blocker). We await the
results of this trial to determine the appropriateness
of these therapeutic modalities to treat feline HCM."
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