Canine Congestive Heart Failure: The symptoms, causes and treatment

Canine congestive heart failure is very serious illness with the symptoms often difficult to spot. It has recently been estimated that over 3 million dogs a year suffer from congenital heart disease, so to equate that in real terms it is equal to 1 in 10 dogs developing the condition.

For your vet to discover what causes heart disease he or she may need to listen for a heart murmur with a stethoscope and depending on the symptoms and how advanced the condition is it may involve the affected dog being hospitalized.

The Facts about the condition…Canine congestive heart failure develops when the heart muscle starts to weaken. Every dog needs the heart to pump a certain amount of blood around the body, and if it starts to struggle this is when heart failure is diagnosed.

To help compensate for the lack of blood pumping around the dog’s body the heart may start to beat faster, which will also cause more and more damage.

So in a nutshell canine congestive heart failure occurs when the heart doesn’t pump the blood efficiently enough to meet your dogs needs. Thus Heart failure is the result of the body not being able to compensate for the decreased cardiac function.

As previously mentioned congenital heart failure in dogs affects about 1 in 10 dogs, which equates to about 3 million dogs every year being diagnosed with the condition. Although humans suffer from heart attacks, in dogs they do not tend to suffer from an attack but are more prone to developing heart failure.

The term failure does not mean that the heart has stopped working it refers to the fact that it is suffering and beginning to slowly fail. This means that your dog will need very urgent attention from a vet. Another difference between dogs and humans is that heart failure in humans is often caused by a build up of fat in the arteries. This is not the case with dogs as they don’t get the fat build up.

Unfortunately canine congestive heart failure is not normally curable. However, if your dog manages to get the best treatment and medications there is no reason why he can’t have a relatively good quality of life. Canine congestive heart failure will slowly get worst over a period of time as the heart gets weaker and weaker. This will of course put more pressure on the rest of your dog’s organs which will eventually cause more and more health problems.

Symptoms of Canine Congestive Heart Failure – As mentioned previously, it is sometimes difficult to spot the symptoms of heart failure in your dog but below we have provided a guide to some of the symptoms.

Canine congestive heart failure (CHF) produces various symptoms depending whether it has affected the right or left side of the heart.

CHF – Symptoms on the Left Side:

– Your dog may become intolerant to exercise (this is because there is a lack of oxygenated blood in the dogs body).

– Rapid breathing is a common symptom.

– Sometimes a difficulty in breathing may develop.

– Your dog may faint.

– Coughing is another common symptom. The cough may appear wet, this is due to the build up of fluid in the lungs.

Left sided heart failure will increase the amount of pressure in the blood traveling from the lungs. This will lead to small amounts of blood being deposited in the lungs. This will then start to affect how carbon dioxide and oxygen are exchanged.

CHF – Symptoms on the Right Side:

– Your dog’s limbs may begin to swell (this is because there is a lack of blood circulating properly which will then start to back-up in the veins).

– Coughing may develop.

– Rapid breathing may also develop.

– The dog may experience a difficulty when breathing.

– Your dog may have a swollen abdomen, this is due to a build up of fluid.

Right sided heart failure (due to the heart muscle failing) will lead to blood not being able to travel effectively around the dogs body. So as a consequence of a lack of blood traveling around the body this will leave the body’s tissues poorly nourished. Right sided heart failure is often caused by an inherited heart defect, lung disease or due to heartworm.

These symptoms don’t always mean that your dog has heart failure as they maybe an indication of another problem. However if your dog is exhibiting any of these symptoms get him to the vet immediately.

How is heart failure diagnosed and treated…? It is important to mention that canine congestive heart failure is not actually a ‘diagnosis’. In fact it is simply a term that is used by vets to describe what happens inside a dog’s body when the heart is unable to effectively pump blood.

A pretty good way of determining whether your dog has heart disease is for the vet to listen with a stethoscope (auscultation) for a heart murmur as this is one of the most common ways to diagnose Mitral Valve Disease. The vet may also undertake radiography, ECG’s (electrocardiograms) and even an ultrasound (known as an echocardiography).

The vet will grade your dog’s heart murmur from 1-6, with the higher the number the more serious the condition. It is actually relatively common for a young puppy to have a heart murmur, but if it continues for 12 – 15 weeks then your puppy will need further tests. Dog’s that are very athletic also sometimes have a heart murmur, the sound that your vet will hear will be the rush and surge of blood from an active heart. If your dog has an enlarged heart known as a DCM it is very difficult to diagnose as it does not produce a heart murmur.

Treatment for Canine Congestive Heart Failure…The treatment your vet gives to your dog depends on what has caused the heart failure but it may include some of the following treatments and medications…

– The affected dog may need to be Hospitalized (depending on how serious the condition is).

– Nitroglycerine paste maybe administered.

– Your dog maybe given diuretics to help encourage him to eliminate fluids.

– The vet may perform a Thoracocentesis which basically entails your vet removing the fluid from the lungs with a needle. This will help your dog breath easier.

– Angiotensin onverting enzyme inhibitor drugs maybe given to your dog, these help to inhibit any sodium retention and also control any hormone imbalances.

– Your dog maybe given a low sodium diet and even nutritional supplements.

– Digoxin medication may also be prescribed.

– The vet may also prescribe drugs that help the blood vessels dilate (called venodilators). Although these can help to reduce congestion they do not enable the heart to pump more effectively.

– To enable the heart to pump more efficiently the vet may prescribe drugs called digitalis (these help increase heart muscle contraction). By using Positive Inotropes this increases cardiac contraction and slows the heart rate. There are side effects to the drugs though so you should take this into account when using them.

Did you know…? It’s very important to keep your dog’s teeth clean. Experts are now starting to realize that a dog with bad teeth and bad gums can indicate that they may have heart disease.

The reason for this is that the bacteria present in bad teeth and gums start to circulate around the body in the bloodstream and then settle in the heart valve. If this continues for a sufficient amount of time (five to six years) it can actually start to damage the heart valve on a permanent basis.


Ackermann, L. 1995. Owners Guide to Dog Health.

Bleby, J and Bishop, G. 1986. The Dogs Health from A-Z.

Bordwell, S. 1994. The American Animal Hospital Association Encyclopedia of Dog Health and Care.

Campbell, K. and Eldridge, D. 2005. The Everything Dog Health Book.

Hoffman, M. 1996. The Doctors Book of Home Remedies for Dogs and Cats. Rodale Press.

Useful Links:

Huston, L. Causes of Heart Disease in Dogs.

Congestive Heart Failure in Dogs:

A Guide to Heart Disease in Dogs…

Heart disease comes in two forms: Congenital and Acquired. With Congenital heart disease the condition is present from the moment the puppy is born. With Acquired heart disease this develops over time due to the affects of everyday life. This can be due to injury, trauma or infection.

With congenital heart disease diagnosis will normally occur around the age of five to eight years of age. A common cause of the condition is due to a genetic defect that is passed from the parents to the offspring.

It is far more common for pure bred puppies to develop congenital heart defects than in mixed breeds. In fact 81% of congenital heart defects are due to one of the following conditions:

  1. Patent ductus arteriosus
  2. Pulmonic stenosis
  3. Aortic stenosis
  4. Vascular ring anomaly
  5. Ventricular septal defects

Out of the list above Patent ductus arteriosus is by far the most common congenital heart defect to affect puppies. It is more common in Poodles, Pomeranians, Shetland Sheepdogs, German Shepherds, Pembroke Welsh Corgies and Maltese.

The Heart in more detail…

The canine heart works as a pump and is actually very similar to the human heart. The Heart is split into four chambers (the left and right atrium and the left and right ventricle). The right sided chambers are responsible for receiving blood from the body and then sending it to the lungs which helps to enrich the blood with oxygen.

The blood will then return from the lungs on the left side where the left ventricle will pump the oxygen enriched blood around the body.

If a puppy is born with defects to the heart the puppy will either have chambers in the heart which are missing or not formed properly. Other defects may include the heart blood vessels being to small or the heart valves between the chambers not formed correctly.

Below are some healthy hints for a healthy heart…

1. Regular exercise is a great way to keep the heart and lungs healthy. For optimum health you should try and take your pooch out twice a day for a minimum of 15-20 minutes.

2. Ask your Vet about giving your dog low doses of Aspirin. Low doses can help thin the blood and prevent blood clots.

3. Vitamins are also great for keeping the heart healthy. Low doses of Vitamin C, Vitamin E and Beta-carotene are excellent at helping to neutralize potentially harmful oxygen molecules in the cells that can sometimes lead to heart damage. There is some evidence that antioxidants can slow the progression of heart disease.

4. As a responsible dog owner you should also aim to reduce the level of salt in your dog’s diet. Try to choose pet food that is low in salt (especially for the breeds that are prone to heart disease).

5. Rather than feeding your dog one large meal once a day try and spread the meals throughout the day (large meals can put more stress on the heart).

6. Ask your Vet about giving your dog fish oils. There is some evidence that Omega-3 fatty acids can reduce the chances of blood clots developing and may even lower your dog’s blood pressure.

7. As discussed on the oposite page bad teeth can be a sign of heart disease. A really good healthy way to keep the teeth clean and bacteria free is to give your dog raw carrots as this helps to reduce tartar build up.

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