3. Congestive Heart Failure
What is congestive heart failure?
Congestive Heart Failure (CHF) is a
term that refers to the heart’s inability to pump adequate blood to
the body. There are many causes of CHF in dogs. The two most common
causes are mitral valve insufficiency (MVI) and dilated
Clinical signs vary depending on
whether the dog has left- or right-sided heart failure. The most
common symptoms are decreased stamina, coughing or difficulty
is the difference in the signs?
Right-sided congestive heart
failure causes poor venous return to the heart. In other words, when
the heart contracts instead of the right ventricle pushing the blood
through the lungs for oxygenation, some returns to the right
auricle. This blood is unable to be cleared from the systemic
circulation and consequently becomes “congested”. Fluid accumulates
in the abdomen and/or the chest cavity, interfering with the
function of the organs in these areas. The abdomen may become
enlarged with fluid called ascites. Fluid may also leak from
veins and swelling may appear in the limbs (peripheral edema).
When CHF involves the left
ventricle, blood is not pumped into the systemic circulation and
builds up in the lungs. Fluid then seeps into the lung tissue
resulting in pulmonary edema. This causes coughing and difficulty
CHF due mainly to heart valve disease?
CHF is most commonly caused by
valvular insufficiency. It is estimated that 80% of the canine CHF
cases are caused by MVI. However, there are many other causes.
Disease of the heart muscle (cardiomyopathy), irregularities of
rhythm and narrowing of some of the major blood vessels can also
clinical signs should I expect?
CHF usually results in coughing,
ascites, exercise intolerance, general lethargy, weakness and weight
loss despite having an enlarged abdomen due to ascites. The normal
pink color of the mucous membranes may become pale or bluish color.
How is CHF diagnosed?
As with any heart problem,
diagnosis involves several tests:
or listening to the heart with a stethoscope is the first step in
diagnosing heart disease. Pulse quality and heart rhythm are also
assessed during auscultation.
x-rays are then used to
determine the size and shape of the heart and the presence of fluid
in the lungs.
and urine tests are
performed to give an indication of any other disorders in the body.
Liver and kidney function are often impaired in patients with heart
An electrocardiogram (ECG)
will also be run. This measures the electrical activity of the heart
and allows accurate determination of both heart rate and rhythm. Any
abnormal rhythms (arrhythmias or dysrhythmias) can be detected and
utilizes sound waves to evaluate the heart’s contractions and to
measure the amount of blood pumped by the heart.
you treat my dog without these tests?
Accurate diagnosis gives us a much
better guide to the type and extent of treatment necessary. Today
there is a wide selection of drugs that can be used to treat
congestive heart failure and treatment regimes have to be tailored
for each patient. Without these tests, we are unlikely to provide
the best care for your pet loved one and may inadvertently cause
more harm than good.
With correct treatment, many dogs are able to live a normal life for
months to years. If you would like to discuss this further, please
do not hesitate to contact us.