How is Mitral Valve Disease diagnosed?

Several tests can be used to diagnose and understand more about your dog’s heart complaint. We will explain why each of these tests is important and why your vet may choose to perform them to manage your dog’s care more effectively.

Click or tap on the tests below to expand and read more

A physical examination

In most cases, this is the point at which MVDD is first suspected by your vet.

  • Demeanor and gum colour

    Your vet will check the colour of your dog’s gums and assess their mentation (are they bright and happy, or quiet and depressed?).

  • Listening with the stethoscope

    They will listen to your dog’s chest with a stethoscope. It is important to remain quiet at this point and allow the vet to listen carefully, as some sounds can be very subtle. Your vet will listen to your dog’s heart, noting the murmur and assigning it a grade.

  • Rate and rhythm

    They will also record your dog’s heart rate and rhythm.

  • Listen to lungs

    They will assess your dog’s lungs to check for any crackles which could indicate fluid buildup, and note the respiratory rate and effort.

  • Check abdomen and pulses

    They will check your dog’s abdomen for any signs of swelling, and feel your dog’s pulses to check they are normal and not weakened.

  • Record weight

    Monitoring your pet’s weight is important as part of their exam too, as weight loss can be seen in dogs with advanced heart disease.

Blood Pressure

All dogs with suspected or confirmed mitral valve disease should have their blood pressure checked. Many of these dogs will have high blood pressure, which can make it even harder for the left side of the heart to pump correctly. High blood pressure can also damage other organs, such as the kidneys.

Radiographs

Taking radiographs (X-rays) of your dog’s chest is needed to assess your dog’s heart for changes in size and shape. The images can also be used to look for any signs of fluid in the lungs (pulmonary oedema), which can occur in congestive heart failure. Your dog will usually be sedated or anaesthetised so that good-quality images can be safely taken.

Echocardiography

An ultrasound scan of the heart is called ‘echocardiography’, usually just shortened to an ‘echo’. It’s a good way to look in depth at the heart, including the valves, but also gives more information about how well the heart is functioning.

Echo can help us to definitively diagnose the cause of the murmur. However, it cannot diagnose pulmonary oedema – which is why x-rays will still be needed alongside this. Unlike x-rays (radiographs), some dogs can be scanned while conscious, with gentle restraint in a darkened room.

Electrocardiography (ECG)

An ECG is a recording of the electrical activity of the heart, which is what causes the muscle to ‘beat’. This is usually performed by placing sensors on locations on the surface of the body. The results come out as a continuous ‘trace’ printed on paper or appearing on a screen. This gives the vet a record of your pet’s heart rate, but also rhythm, allowing problems like skipped beats to be noted.

The recording looks at whether all of the normal electrical activity is occurring, or whether there are defects. Animals with a poor rhythm (arrhythmia) may require specific medications to help their heart beat more effectively again.

Haematology

This blood test looks at your dog’s red and white blood cells. It is often performed to rule out other conditions such as anaemia, and to look for markers of infection or inflammation. It is usually run alongside biochemistry.

Biochemistry and electrolytes

This blood test assesses liver and kidney function, as well as looking at other things like protein and blood sugar levels. This allows other health conditions to be ruled out but also ensures that your pet can start medication for their heart safely. Your vet will need to monitor your pet’s kidneys and electrolytes on certain drugs used to manage MMVD.

Heart-specific blood tests

Blood tests are available to look at certain ‘biomarkers’ within the blood which can be released if the heart muscle is under abnormal strain. They can be useful in cases where it is unclear whether a dog’s breathing problems are due to an underlying heart issue, or something else.

The two most common markers are cardiac troponin-I and N-terminal pro-B-type natriuretic peptide (pro-BNP). Pro-BNP is released into the blood when a heart is stretched, dilated, or thickened, so raised levels suggest a problem that needs further investigation. High levels of troponin are also a sign that there’s heart disease to be investigated.

Summary

Your vet will need to perform an examination of your pet initially and take a clinical history from you. They will then be able to recommend tests based on their findings. While a murmur can make them suspicious of heart disease, it is not diagnostic. Further tests are needed to say exactly what is causing the abnormal sound and whether there are other issues such as fluid build-up in the lungs or underlying organ function issues which could affect your dog’s treatment options. Your vet will talk you through the results and recommendations for your pet.

Key takeaway

Your vet’s physical examination will give them a lot of information, but not the complete picture, so further diagnostics are usually required.