Healthy hearts in dogs: what you need to know

Nine signs of heart disease in dogs

The heart is one of the most important organs in you and your dog. Every time the heart beats it is pumping vital oxygen rich blood to every part of the body through vessels called arteries. Unfortunately, dogs can get heart disease just like humans, making it very important to keep the heart healthy.

Pet parents should monitor their dogs for the following signs of heart disease:

1. Difficulty breathing
Heart disease causes fluid to accumulate in the lungs which causes breathing difficulty, primarily fast or laboured breathing. Breathing difficulty is different from panting - if your dog is panting, they are more likely to be excited or too warm than have heart disease.

2. Coughing 
Coughing is caused by the build up of fluid in the lungs. When the heart is not working properly, it compensates by increasing in size. This increase in size causes the heart to push up against the windpipe, which also causes a cough.

3. Exercise intolerance
When the heart is unable to pump oxygen around the body effectively, dogs do not have the energy to exercise. Dogs with heart disease often get tired on walks or when playing, so look out for any of these signs.

4. Fainting
Syncope is another word for fainting and is caused when not enough blood is delivered to the brain. Syncope can range from full loss of consciousness to weakness or having to sit down on the back legs for a few seconds.

5. Blue gums
Caused by poorly oxygenated blood being delivered to the gums, this is when fluid accumulates in the chest and the blood is unable to become oxygenised as it passes through the lungs.

6. Enlarged abdomen
The increased blood pressure can cause fluid to be squeezed out of the vessels into spaces where it should not be found, commonly the abdomen, creating a pot-bellied appearance.

7. Swollen limbs
Increased blood pressure can also cause fluid to collect in the limbs, so keep an eye on their legs.

8. Reduced appetite
Poor blood supply to the intestines and accumulation of fluid in the abdomen causes a poor appetite.

9. Weight loss
A combination of reduced appetite and loss of muscle causes weight loss.

The types of heart disease in dogs

The two most common heart diseases in dogs are Mitral Valve Disease (MVD) and Dilated Cardiomyopathy (DCM).

The first type: Mitral Valve Disease (MVD)

Inside the heart there are four valves that prevent the blood travelling the wrong way through the heart. One of these valves is called the Mitral valve. When MVD is present the Mitral valve does not work properly, which causes blood to travel backwards through the heart instead of forwards. This causes two problems. Firstly, less blood is pumped forwards to supply oxygen to the body. Secondly, the backflow of blood causes a build up of blood pressure in the veins behind the heart, which then causes fluid to leak into the lungs or other parts of the

Dogs predisposed to MVD include:
- Small to medium sized dogs
- Dogs over 5 years of age
- Cavalier King Charles Spaniels (especially males)
- Cocker Spaniels
- Toy and Miniature Poodles
- Dachshunds
- Shih Tzus
- Pomeranians
- Chihuahuas
- Miniature Schnauzers
- Pekingese

The second type: Dilated Cardiomyopathy (DCM)

Dilated Cardiomyopathy. DCM is when the heart muscle is weak and cannot pump blood around the body effectively. In a similar way to MVD, this causes two problems. Firstly, there is a reduced blood supply to the body and secondly, a build up of blood pressure within the heart and veins behind the heart. The heart muscle compensates by dilating, which further weakens it.

Dogs predisposed to DCM include:
- Large to giant sized dogs.
- Dogs over 5 years of age
- Dobermans
- Great Danes
- Newfoundlands
- Irish Wolfhounds
- Portuguese Water Dogs

Other less common types of heart disease also exist such as rhythm abnormalities and birth defects. This is why it's very important that all new puppies are physically examined by a vet and adult dogs attend their yearly check-ups. If your dog has heart disease, there is no substitute for investigation and monitoring at your local veterinary practice.


Best diets for your dog's heart

Just like in humans, a good diet is important for heart health. The diet should contain balanced levels of the following ingredients:

- Taurine and Carnitine: These two amino acids are important for heart muscle function, and deficiencies can lead to heart disease.
- Omega 3 fatty acids: Omega 3 fatty acids are found in fish oil and protect the heart in many ways such as reducing abnormal heart rhythms and inflammation.
- Calories: The diet should be high in proteins and carbohydrates to maintain body weight in dogs with heart disease.
- Salt: Dogs with heart disease should have a diet low in sodium to reduce high blood pressure and fluid accumulation.

For the average canine, feeding a high quality commercial dog food will provide your dog with all the nutrients it needs to have a healthy heart. Home-cooked diets are not recommended because they are unlikely to contain the correct amount of nutrients for optimal heart health. Supplements are available, but you should consult a veterinary professional before adding these to the diet as the dosing is difficult to get right.

Grain free pet foods have become increasingly popular in recent years. Whilst these diets can be beneficial for a small percentage of dogs with skin or gastrointestinal problems, recent evidence has shown that grain-free diets and diets high in legumes can cause heart disease. You should consult a veterinary professional before starting your dog on a grain-free diet. If your dog suffers from skin or gastrointestinal problems, there is likely a more suitable food available for them than some of the grain-free diets commonly available.

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