Dilated Cardiomyopathy (DCM)
DCM is a disease that affects the heart muscle. DCM typically affects young to middle-aged dogs, and it is most common in medium and large sized dogs.
Susceptible breeds
Whilst DCM can affect all breeds of dog, including cross-breeds, it is often hereditary and some breeds are at a higher risk of developing DCM, such as Dobermans, Cocker Spaniels, Springer Spaniels, Boxers, Irish Setters, German Shepherds, Great Danes, St Bernards and Irish Wolfhounds.
Enlarged heart
Dogs with DCM have an enlarged heart, and the walls of their heart (the heart muscle) stretch, making them thin, weakened and floppy. This means that the heart can’t contract properly and is unable to pump blood around the body as well as it used to.
The two stages of DCM
There are two distinct stages of DCM:
The first is a long silent stage in which a dog with DCM appears healthy and shows no outward symptoms that there is a problem with their heart. This is called the asymptomatic or preclinical stage.
The second is a shorter stage in which the heart can no longer cope and the dog shows symptoms of their heart disease. This is called the heart failure stage or congestive heart failure (CHF).
First stage: asymptomatic or preclinical
A dog with asymptomatic DCM will appear outwardly healthy and show no visible symptoms to suggest there is a problem, even though the changes to their heart have already begun. The lack of symptoms can make diagnosing DCM difficult. However, early identification of dogs with asymptomatic DCM is really important, to ensure they are monitored closely and given treatment as soon as they need it.
It is recommended that if you have a larger breed dog (weighing 20 kg or over) and they are three years of age or older, then you should talk to your vet about keeping a close eye on their heart.
DCM does slowly progress and get worse over time. Eventually the heart will no longer be able to cope with the additional strain and will be unable to pump enough blood around the body. This is known as congestive heart failure.
Second stage: congestive heart failure (CHF)
Symptoms of heart failure can initially be quite subtle. However, as the heart disease progresses, the symptoms become more severe and more noticeable. Sadly in DCM, the disease tends to progress quite quickly once a dog reaches the heart failure stage.
Symptoms of heart failure can include:
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Increased breathing rate
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Difficulty breathing
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Tiredness
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Difficulty exercising
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Coughing
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Fainting/collapse
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Weight loss
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Poor appetite
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Swollen abdomen
How is DCM diagnosed by my vet?
When your vet examines your dog, there are a few changes that may suggest your dog has heart disease. Listening to your dog’s heart with a stethoscope will allow your vet to pick up a murmur if it is present, and also assess the heart rate and rhythm.
If your vet is suspicious that your dog has DCM, they may recommend further tests or they may refer your dog to a heart specialist.
The tests may include:
Blood test
A blood test may be taken to rule out other diseases. The vet may also recommend a blood test called Pro-BNP, which helps indicate whether heart disease is present or not.
ECG
Electrocardiograms (ECGs) look at the electrical activity in the heart. They can be used to diagnose abnormal heart rhythms, which are sometimes seen in dogs with DCM.
X-ray
A chest X-ray enables your vet to assess the overall size of your dog’s heart as well as enabling them to check for any fluid in the lungs. If their heart is bigger than normal, this may suggest your dog has DCM. Fluid in the lungs isn’t present in the asymptomatic stage of the disease, but it is often present when a dog is in heart failure.
Ultrasound
An ultrasound scan of the heart allows your vet to assess the inside of your dog’s heart. By performing an ultrasound scan, your vet can take measurements of the heart chambers and this helps them to confirm whether the heart is enlarged. They can also measure how well the heart is contracting. You may hear your vet refer to the ultrasound scan as an ‘echo’.
Why do I need to find out if my dog’s heart is enlarged?
Finding out whether your dog has DCM is very important, as it will allow your vet to:
- Identify whether your dog will benefit from Vetmedin®
- Provide you with an accurate prognosis
- Monitor the progression of your dog’s disease
It is important to remember that if DCM isn’t diagnosed, your vet may recommend that your dog is checked annually if they are at risk of developing DCM.
For more information about DCM, please speak to your vet.
How to help your dog
Most importantly, visit your vet to determine whether your dog would benefit from starting on Vetmedin®. There are also changes you can make at home to help your dog:
Diet
Your vet may recommend a change in diet. It’s important that dogs with heart disease aren’t overweight as this can put more strain on their heart, and so your vet may suggest a diet that helps to prevent weight gain or helps with weight loss. Your vet may also discuss a diet for your dog that is low in salt to prevent them from retaining excess water. You shouldn’t make changes to your dog’s diet without consulting your vet first.
Exercise
It is very important to seek your vet’s advice about whether exercise is suitable for your dog and to what level.
Generally, for dogs with asymptomatic DCM and no abnormal heart rhythm, exercise can continue as normal. If your dog has mild symptoms of heart failure, regular light exercise is thought to be beneficial; however, if your dog seems tired, stop exercising and allow them to rest.
Keeping a diary
Try to keep a diary of your dog’s activity level, appetite and demeanour; this will help your vet understand how well they are responding to treatment and how their condition is progressing.
Monitoring breathing rate
Your vet may suggest that you monitor breathing rate if they have been diagnosed with DCM. Click below for more information on how to do this. Should you have any further questions on whether or not your dog would benefit from monitoring, or how and when to monitor your dog, please contact your vet.
