Issue Description Dilated cardiomyopathy usually affects both
the left and right sides of the heart with either side being more
severely affected. Typically, both the ventricle (lower chamber) and
the atria (upper chamber) enlarge and the ventricle loses its ability
to contract and pump blood out to the body or the lungs. The
consequence of the heart failing in its ability to pump blood can be
compared to a simple mechanical pump. If the sump pump in your
basement fails, water backs up into the basement; if the left heart
fails, fluid backs up into the lungs and if the right heart fails,
fluid backs up in the abdomen or space surrounding the lungs. Other Names Dilated Cardiomyopathy
Causes The disease usually afflicts larger breeds of
dogs such as the Doberman Pinscher, Scottish Deerhound, Boxer,
Newfoundland, Golden Retriever, Labrador Retriever, and the Irish
Wolfhound. However, it can also affect both the English and American
Cocker Spaniel and rarely, other small breeds of dogs. The occurrence
of dilated cardiomyopathy increases with age and typically has an age
of onset between 4 and 10 years. The cause of DCM in dogs is still
unknown; however, many factors suggest a genetic cause.
Symptoms Symptoms of DCM usually appear between 4 and 10
years of age. As the chambers of the heart enlarge and the heart loses
its ability to pump blood properly, heart failure occurs.
Shortness of breath.
Tiring on exercise.
Deep, dry coughing.
Heavy, labored breathing.
Restlessness or lethargy.
Enlarged abdomen and/or swollen, puffy legs.
Cyanosis-blue discoloration of the tongue and lips.
Diagnosis During physical examination, your veterinarian
may hear heart murmurs and muffled heart sounds, feel abnormal fluid
accumulation in the abdomen, feel an enlarged liver, and discover
signs of impaired circulation. X-rays of the chest and abdomen are
useful for diagnosing heart enlargement and fluid accumulations. EKGs
usually show conduction disturbances and arrhythmias. Ultrasound of
the heart helps confirm the diagnosis. Urinalyses and blood tests are
commonly performed to assess the effects of heart failure on other
Treatment Treatment of dilated cardiomyopathy is aimed at
both improving the heart's function and controlling the signs of
congestive heart failure. Drugs such as Lanoxin (Digoxin, Digitalis)
are used to help the heart contract better and to slow the heart rate
down if certain arrhythmias exist. Once your dog is started on
Lanoxin, watch for signs of digoxin toxicity that, although uncommon,
include loss of appetite, vomiting, diarrhea, and lethargy. These
adverse signs can hopefully be avoided by having a blood test run by
your regular veterinarian 7 to 14 days after the drug is initiated. To
check for appropriate levels of Lanoxin in the bloodstream, a blood
test must be drawn 6 to 8 hours after your dog's morning dose of the
Diuretics are also used to help both control and prevent accumulation
of fluid in or around the lungs. Lasix (Furosemide) is usually the
drug of choice. Potential side effects of diuretic use include
increased thirst and potentially increased urination. Another
essential drug that is used in the treatment of dilated cardiomyopathy
is termed a balanced vasodilator. This helps the heart pump more
effectively against the pressures of the arteries and veins. Examples
of this drug include Vasotec, Enacard, Zestril, Prinavil, and
Lotensin. These drugs are usually started gradually with a low dose
and then building up to your dog's required dosage. These drugs can
occasionally interact with the kidneys. Please see your regular
veterinarian in 7 to 10 days, in 4 weeks, and then every three months
to have a chemistry blood panel checked to assure that kidney function
Other drugs utilized in the treatment of
dilated cardiomyopathy are aimed at controlling cardiac arrhythmias
(electrical disturbances in the heart). Arrhythmias can be very
problematic in some cases of DCM and can even be life threatening.
Certain breeds are more predisposed to this additional problem. If
possible, it is a good idea to buy an inexpensive stethoscope to
monitor your dog's heart rate and rhythm. Keep a journal of these
records and if you are seeing a progressive increase or decrease in
your dog's heart rate or hear an irregular heartbeat, please call your
It is also important for you to
monitor your dog's overall attitude and outward signs. If you notice
any heavy/labored breathing, coughing, fainting spells, restlessness,
or profound lethargy, please see your regular veterinarian as soon as
Prognosis Long term prognosis for dilated cardiomyopathy
varies considerably. Unfortunately, most dogs with signs of heart
failure at the time of diagnosis die as a result of the disease within
6 months to two years. Unfortunately, some dogs, especially certain
breeds with a more severe form of the disease may survive only weeks
to a couple of months.