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HEART DISEASE

3.  Congestive Heart Failure

What is congestive heart failure?

When the heart fails to pump sufficient blood around the body it tries to compensate by changing the rate and sometimes the strength of contractions.  This sometimes improves the situation and symptoms virtually disappear.  However without treatment the condition will slowly get worse.  Pooling of  blood in the organs and tissues of the body leads to signs.   The animal will be said to have 'decompensated' and to have developed congestive heart failure.

Clinical signs vary depending on whether the dog has left or right sided heart failure.  This usually involves failure of the valves of the heart although sometimes the muscle can be involved.

What is the difference in the signs?

With right sided heart failure there is a 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 and thus blood is unable to be cleared from the systemic circulation which consequently becomes congested.  Accumulations of fluid occur in the abdomen and/or the chest cavity, interfering with the function of the organs in these areas.   The abdomen may become enlarged due to fluid and this is called ascites, or dropsy.   Sometimes fluid also leaks from the thin walled veins and swelling may appear in the limbs in severe cases.

When CHF involves the left ventricle blood is not moved into the systemic circulation and therefore builds up in the lungs which causes fluid to seep out into the lung tissue resulting in  pulmonary oedema.  This causes coughing and breathing difficulties.

Is congestive failure due mainly to valvular disease of the heart?

No.  There are may other causes.   Disease of the heart muscle, (cardiomyopathy), irregularities of rhythm and narrowing of some of the major blood vessels can also cause the condition.

What  signs should I expect?

CHF usually results in coughing, ascites, exercise intolerance, general lethargy, weakness and often weight loss although the dog may develop a big abdomen due to the ascites or dropsy.  The normal pink colour of the mucous membranes (for example inside the lips or under the eyelids) , may become pale or even a bluish colour.

How is the condition diagnosed?

As with any heart problem, diagnosis involves what is known as a 'full work-up' which includes blood and urine tests to establish that there is not a problem in other organs, particularly the liver and kidneys; auscultation which is listening to the heart with a stethoscope, which will detect abnormalities of the valves (murmur) and also irregular rhythms, x-rays which will give an indication of changes in the heart size or shape as well as the state of the lungs;  and ultrasound examinations which allow us to examine the heart in motion and, if necessary, take measurements which gives a very accurate diagnosis of heart function.

Are these tests likely to be expensive?

Unfortunately a full work up can cost several hundred pounds but, depending on the condition, and its severity, sometimes only selected tests are necessary.

Is it not possible to treat my dog without these tests since surely it is better to spend the money on treatment?

Accurate diagnosis gives us a much better guide to the type and extent of treatment necessary.  Today there are a wide selection of drugs that can be used to treat congestive heart failure and treatment regimes have to be tailored for each animal.

With correct treatment, although this is not curative but merely stabilises the dog, many animals are able to live a normal life often for months or years.  If you would like to discuss this further, please do not hesitate to contact us.