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Degenerative Mitral Valve Disease in Dogs: Symptoms & Treatment

Mitral valve disease in dogs can cause breathing problems, collapse, and long-term cardiovascular issues. Our Long Island veterinarians discuss signs and treatment options for this serious heart condition. 

What is degenerative mitral valve disease? 

Degenerative mitral valve disease (also sometimes referred to as a leaky heart valve) is a serious condition that can cause a dog's blood to leak during heart muscle contractions. It can lead to further issues such as heart murmurs and severely impact your dog's long-term health. 

Dogs who are older than eight years old are susceptible to this highly prevalent disease. Small dog breeds, such as Cavalier King Charles Spaniels, Chihuahuas, Cocker spaniels, dachshunds, miniature schnauzers, 

What causes mitral valve disease in dogs?

The mitral valve is one of the heart's four valves, and it divides the left ventricle from the left atrium. In a healthy dog, this valve closes when the heart contracts, preventing blood from "backing up" or regurgitating back into the atrium. 

A leaky mitral valve can cause a host of other issues, including accumulation of fluid in the lungs, an enlarged atrium, and damage to the heart's structures. 

What are symptoms of mitral valve disease in dogs? 

Because many young dogs will exhibit very few symptoms, or so few that the most doting owner may mistake it for the inevitable slowing down that comes with aging. However, there are a few common signs of mitral valve disease in dogs to watch for: 

  • Coughing 
  • Exercise intolerance
  • Increased respiratory rate 
  • Trouble breathing
  • Weakness
  • Collapse 

Since symptoms of a leaky heart valve in dogs can sometimes be vague, it's important to contact your veterinarian and book a physical exam if you see any of these or other concerning signs of health issues in your dog. 

How is mitral valve disease diagnosed? 

This condition can only be diagnosed by a veterinarian or veterinary specialist. Your veterinarian may refer you to our board-certified veterinary cardiologist for diagnosis and treatment. A veterinary cardiologist can check for any heart murmurs, which are often one of the first clues your dog may have this disease. Recommended diagnostic tests may include: 

  • Radiography: X-rays can reveal more information about your dog's internal condition, including whether there is any fluid in the lungs. 
  • Echocardiography: This diagnostic tool can help us better understand the structure of the heart and valves, and how they're functioning. 
  • NT-proBNP: This blood test can reveal whether your dog's heart is failing, especially if there is a large amount of 'regurgitated' blood. 

Your dog may require further testing to check how their internal systems are working, so your veterinary cardiologist will know which, if any, medications can be prescribed to treat the condition. 

How is mitral valve disease in dogs treated? 

There are a large number of drugs that can be used to address mitral valve disease in your pooch, meaning that it's critical for the type and dosage of medications must be carefully calculated for each unique case.

Because this is a progressive disease, your dog's condition will require different medications at different times. The following are some of the medications that are most frequently used to treat this illness in dogs:

  • Diuretics (e.g. furosemide)
  • Vasodilators (e.g. enalapril, benazepril, pimobendan)
  • Positive inotropes (e.g. pimobendan, digoxin)

Depending on your dog's case, they may be prescribed other drugs to deal with health issues like high pressure in the vessels of the lungs. Sadly, there is no known cure for this disease at this time, and the medications are palliative to ensure your dog's comfort and extend their life as much as possible. 

What is the life expectancy for dogs with mitral valve disease? 

Your dog's prognosis will depend on how far the disease has progressed by the time it's diagnosed. Some dogs with symptoms of mitral valve disease may only live a few months. However, if the condition is detected early on, others may live for many more years. A veterinarian's diagnosis can identify the presence and stage of mitral valve disease, and allow for the proper course of treatment for your dog. 

Note: The advice provided in this post is intended for informational purposes and does not constitute medical advice regarding pets. For an accurate diagnosis of your pet's condition, please make an appointment with your vet.

Has your dog been diagnosed with mitral valve disease or another heart problem? Ask your vet for a referral to our veterinary cardiologist in Long Island. We can diagnose and treat complex cardiovascular diseases in cats and dogs.

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