Mitral Valve Disease in Dogs: Symptoms and Diagnosis

What is It?

Mitral valve disease is a condition in which the barrier between the two chambers in the left side of the heart decreases in efficiency.

What Causes It?

The heart is made up of 4 chambers, right and left atrium and right and left ventricle. Blood flows one way. The flow of blood is maintained by valves between each chamber. In mitral valve disease, the valve thickens and shortens. This makes the seal between the two chambers less effective, allowing blood to leak backwards.

The leaking of blood causes a heart murmur and requires the heart to increase pumping pressure to move blood through. Over time MVD can lead to congestive heart failure.

This condition is not uncommon. Around 10% of dogs will experience heart disease during their lives, and of those affected with heart disease, around 80% of those cases will be MVD.

Genetics plays a role as these breeds are most prone to MVD:

The general cause is somewhat unclear. The left ventricle uses a great amount of pressure to pump blood out to the body, so overtime the force begins to wear on the mitral valve. Endocarditis is also a concern. This condition is a heart valve infection and can come from blood-borne infections or as a secondary condition from chronic oral infections.

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What Are The Symptoms?

  • Heart murmur
  • Low energy
  • Reluctance to walk
  • Labored breathing
  • Coughing
  • Fainting
  • Poor appetite
  • Swollen belly

Is it Life Threatening?

Yes, if left untreated mitral valve disease can develop into congestive heart failure and death.

Are You Covered When Your Pup Gets Sick?

How is It Diagnosed?

A vet will give your dog a full physical examination and a medical history questionnaire. An echocardiogram can diagnose MVD and measure the pressure in the lungs and any other secondary changes to the heart.

  • Stage A – no symptoms, but dog is high risk for developing MVD
  • Stage B – heart murmur, no signs of heart disease
    • B1: no heart enlargement
    • B2: heart enlargement, dog is still asymptomatic
  • Stage C – signs of heart disease present
  • Stage D – heart failure, medication will no longer help

What Are The Treatments?

The stage of MVD will dictate the treatment required. Medication is not typically prescribed until stage B2. Repeated echocardiograms will be necessary to monitor the progress of the condition.

In stage B2 and C, angiotensin converting enzyme inhibitors and furosemide will slow the progression of the disease. The supplement coenzyme Q-10 has also shown some evidence of assisting.

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 pup’s condition, please make an appointment with your veterinarian. Or, consult a virtual vet here.