The heart consists of 4 chambers, all of which contain
blood and are responsible for sending blood that is
low in oxygen to the lungs to receive more oxygen, then
sending this oxygen-rich blood throughout the body to
all the tissues in need.
A series of valves in the heart, separate the
4 chambers, and prevent blood from flowing where it
shouldn't. The heart muscle is a unique
type of muscle, different from the other muscles in
In the dog and cat, disease is mainly seen as a problem
with the valves of the heart, or in the heart muscle
itself. Click or scroll down for information on
heart disease in cats
Heart Disease in Cats
When heart disease occurs in the cat, it usually involves
the heart muscle. Unlike dogs, cats rarely develop
disease only in their heart valves. Symptoms of
heart disease usually occur when the cat's heart begins
Weakness, loss of appetite, weight loss, and difficulty
breathing are common symptoms of heart failure in the
Cardiomyopathy is the long name given to disease
of the heart muscle. It is usually divided into
two categories: thinning of the heart muscle (congestive
cardiomyopathy), and thickening of the heart muscle
(hypertrophic cardiomyopathy). In both cases,
the heart fails to "pump" blood adequately
throughout the body.
Diagnosis is made by physical examination,
X-rays, electrocardiogram, and ultrasound of the heart.
Most patients will have a heart murmur which can be
heard by your veterinarian.
Treatment is geared towards increasing the amount
of blood "pumped" by the heart per heart beat,
decreasing fluid buildup in the lungs and chest, , and
controlling any rhythm abnormalities. Certain
medications prescribed by your veterinarian are intended
to help correct these conditions.
Nutrient supplements added to the treatment plan, may
also help correct the underlying heart problem.
Taurine is an essential amino acid, and has been
found to be deficient in some cases of cardiomyopathy.
Replacement of taurine can be quite valuable in treatment
of these cases.
Heart Disease in Dogs
When heart disease occurs in the dog, most commonly
the valves of the heart become diseased . Remember,
the heart has 4 chambers, and is divided into right
and left sides. Each side has its
own set of valves. In certain breeds of dogs (Poodles,
Cocker Spaniels, Yorkshire Terriers) there is a tendency
towards developing problems with the heart valves (possibly
inherited), although any breed can be affected.
The problem is with the valve itself. It becomes
blunted, or rounded in shape, and therefore fails to
close properly. When this occurs, blood tends
to back-flow. Back-flow of blood results in an
overload of blood in the chamber receiving the back-flow.
Over time, this overload of blood can stretch out the
receiving chamber causing it to enlarge. Chamber
enlargement may in time put pressure on local structures
like the main airway in the lungs (the trachea or windpipe),
resulting in a dry, hacking cough. Stretch of
the chamber may also produce disturbances in the heart's
rhythm resulting in an arrhythmia.
Commonly, the overflow of blood can back up into the
lungs, resulting in a "wet", productive
sounding cough. When this occurs, the patient is considered
to be in "heart failure". Patients can become
weak, stop or slow down on eating, sleep a good portion
of the day, and cough. Sometimes they will "faint"
or collapse, showing signs of stiffness in the legs
and arching back of the head.
During these collapsing episodes, the patient may also
loose control of the urine, stool, or both. Clients
often refer to these episodes as "seizures",
which technically they are not.
Disease of the heart muscle is much less common
than that of valve disease in the dog. Heart muscle
disease can be inherited as well, and is seen commonly
in Cocker Spaniels, Boxers, Great Danes, and Doberman
pincers. Other breeds can also be affected.
In this disease, the heart muscle "shrinks"
or atrophies, reducing the effective "pump"
of each heart beat. Weak heart muscles fail to
pump blood adequately to the tissues of the body, and
therefore can cause similar symptoms of weakness, decreased
appetite, and cough, seen in heart valve disease.
Diagnosis of heart disease is made by physical
examination, X-rays, electrocardiogram (ECG), and ultrasound
of the heart. Most patients will have a heart
murmur which can be heard by your veterinarian. Specific
tests can determine what form of heart disease exists,
and then guide the veterinarian toward the appropriate
Reducing the backflow of blood, reducing the size of
the heart if enlarged, strengthening the heart beat
itself, correcting abnormal heart rhythms, and clearing
fluid back-up in the lungs are the goals of treatment.
Medications have been designed to accomplish these tasks
either by themselves, or working along with other medications.
Your veterinarian will chose the drugs appropriate
for your dog's situation. In some instances of
heart muscle disease, nutrient supplements may be added.
L-carnitine, and Taurine are two essential
amino acids found deficient in some cases of heart muscle
disease in the dog. Addition of these essential
amino acids in some cases may be very beneficial.