Dog Health & CareWhat is Myxomatous Mitral Valve Disease in Dogs: Symptoms, Causes And Treatments

What is Myxomatous Mitral Valve Disease in Dogs: Symptoms, Causes And Treatments

Myxomatous Mitral Valve Disease (MMVD), also known as degenerative mitral valve disease or endocardiosis, is a prevalent cardiac issue in dogs. This condition affects the heart’s mitral valve, which separates the left atrium from the left ventricle. Normally, this valve ensures that blood flows in one direction — from the atrium to the ventricle. MVD arises when the mitral valve deteriorates, causing improper functioning. This malfunction leads to blood leakage into the left atrium, increasing the heart’s workload and potentially resulting in congestive heart failure over time.

Stages of Myxomatous Mitral Valve Disease (MMVD)

Myxomatous Mitral valve disease in dogs progresses through distinct stages. At A stage , dogs are at high risk for developing MVD but do not show detectable signs of the condition.Then at B stage some changes in heart is present, yet symptoms are not apparent. At B1 sub-stage there will not be heart enlargement. Controversially at B2 level , heart enlargement is present. At stage C dogs exhibit clinical signs of heart failure, which may necessitate hospitalization and supplemental oxygen depending on severity. The most advanced stage of MVD is stage D. This stage is characterized by severe symptoms of congestive heart failure despite treatment. Management at this stage involves aggressive treatment strategies and intensive care to improve the dog’s quality of life.

Symptoms of

Myxomatous Mitral Valve Disease

Symptoms of MVD in dogs can range from being asymptomatic in the early stages to more advanced as the disease progresses. Early detection can be challenging without regular veterinary check-ups. Common symptoms of Mitral Valve disease include:

  • Coughing
  • Difficulty breathing or increased respiratory effort
  • Decreased exercise tolerance
  • Lethargy
  • Loss of appetite
  • Rapid breathing (tachypnea) or panting
  • Fainting spells
  • Weight loss

As the disease advances, signs of congestive heart failure may appear, such as fluid accumulation in the abdomen (ascites) or lungs (pulmonary edema). A heart murmur, caused by turbulent blood flow through the compromised valve, is often detected by veterinarians during physical examinations.

Causes of MMVD

MMVD disease primarily affects aging dogs, as their valve deteriorates over time. The exact cause of this degeneration remains unclear, but genetics plays a significant role. Certain breeds, including Cavalier King Charles Spaniels, Dachshunds, Poodles, Chihuahuas, and other small breeds, are predisposed to MVD, indicating a hereditary component.

Research suggests that by age 13, around 85% of small-breed dogs will develop degenerative mitral valve disease. However, MVD can affect dogs of all sizes, particularly as they age. In addition to age and genetics, poor dental health may contribute to the condition, as bacteria from the mouth can enter the bloodstream and affect the heart valves. While the evidence is largely anecdotal, other underlying health conditions, such as high blood pressure, can exacerbate MMVD by placing additional strain on the heart.

To diagnose MMVD, your veterinarian will conduct a thorough physical examination, focusing on abnormal heart sounds like murmurs. Diagnostic tests, including chest X-rays, echocardiograms (ultrasound of the heart), and electrocardiograms (ECGs), are essential for assessing the heart’s condition and the extent of mitral valve degeneration. These non-invasive tests are crucial for accurate diagnosis and effective management of your dog’s condition. Blood tests may also be recommended to evaluate overall health and rule out other conditions.

Treatments for

Myxomatous Mitral Valve Disease

While there is no cure for degenerative mitral valve disease, various treatment options can help manage the condition and enhance your dog’s quality of life. Treatment strategies depend on the disease stage and specific symptoms:

  • Medical Management: In early or mild cases of MMVD, immediate treatment may not be necessary, but regular monitoring is essential. As symptoms develop or worsen, your veterinarian may prescribe medications such as ACE inhibitors (benazepril, enalapril), diuretics (furosemide), and pimobendan to reduce heart workload, control blood pressure, and prevent fluid buildup.
  • Lifestyle Changes: Adjusting your dog’s diet and exercise can be beneficial. Low-sodium diets help reduce fluid accumulation, while regular, moderate exercise supports heart health. It’s important to schedule exercise routines to your dog’s capacity, avoiding excessive exertion.
  • Surgical Intervention: In cases that do not respond well to medical management, surgical options like mitral valve repair may be carried out. This procedure, though promising, is typically performed in specialized veterinary surgical centers and can be cost-prohibitive.

Early detection through regular veterinary check-ups is crucial for effective management of MMVD. If you notice any symptoms or if your dog belongs to a breed at higher risk, consult your veterinarian promptly. While MMVD is a lifelong condition, early and appropriate treatment can manage symptoms and potentially extend your pet’s quality of life.

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