Issue Description Heart failure is a clinical syndrome that
describes the end result of severe heart disease. Heart disease is
always present when heart failure is present; however, heart disease
can be present and never lead to congestive heart failure.
Congestive heart failure (CHF) occurs when high diastolic pressures in
the heart "back up" into the veins and capillaries causing fluid to
leak out of these vessels (edema).
Heart failure is the
end-result of many different cardiac and pericardial (the sac that
surrounds the heart) diseases.
These include, but are not
Decreased myocardial contractility (a weak heart muscle) which is
commonly seen with dilated cardiomyopathy.
Valvular regurgitation (leak in one of the four heart valves) as
seen with mitral and tricuspid regurgitation.
Increased myocardial stiffness impairing the heart's ability to
fill with blood as seen in feline hypertrophic cardiomyopathy.
Other Names Congestive Heart Failure
Causes There are many causes of heart failure in dogs,
Birth (congenital) defects of the heart
Degeneration of the heart valves
Heart muscle disease (cardiomyopathy)
Diseases of the pericardium (the lining around the heart)
Irregular electrical rhythms of the heart (arrhythmia)
Dogs of any age and any breed can develop heart failure. There is
certainly a predisposition for heart failure caused by cardiomyopathy
in giant canine breeds.
Symptoms Although some of the early stages of heart
failure in dogs have no visible signs, heart failure can be diagnosed
through a clinical evaluation by a veterinarian. Dogs with mild to
moderate heart failure typically experience heart enlargement,
coughing, lethargy and difficulty breathing. Severe heart failure is
characterized by difficulty breathing (even at rest), fainting,
profound intolerance to exercise, loss of appetite and weight loss.
Diagnosis Veterinarians diagnose canine congestive heart
failure with electrocardiograms to detect heart abnormalities. An
ultrasound may also be useful to show the enlarged size of the heart.
A chest x-ray will also be useful in diagnosis.
Treatment The primary goal of treating CHF is to manage
the clinical signs by reducing the formation of edema and effusion and
to increase cardiac output (delivery of blood to the tissues). A
variety of therapies are available and will be tailored to meet your
pet's current needs.
The most commonly prescribed
medications include digitalis glycosides, diuretics, and ACE
inhibitors. Different medications may also be prescribed depending on
your pet's underlying heart disease and severity of the heart failure.
A sodium restricted diet may also be recommended along with restricted
exercise. Please keep in mind that heart failure therapy is dynamic
and will necessitate regular checkups with your veterinarian to ensure
your pet's needs are being met.
Prognosis As stated earlier, dogs in the early stages of
canine congestive heart failure will show no symptoms. By the time the
dog starts to show symptoms, the condition will be in the later
stages. Dogs in the later stages of canine congestive heart failure
rarely live longer than a year. Many dogs will pass away within six
months of diagnosis.