Dog Myxomatous Mitral Valve Disease: Monitoring and Care

Myxomatous mitral valve disease (MMVD) is the most common heart disease in dogs, particularly cavalier King Charles spaniels, causing progressive heart failure if untreated.

Key Facts

MMVD accounts for approximately 75% of all cardiac disease in dogs
Cavalier King Charles spaniels are the most severely affected breed, with nearly all developing MMVD by age 10
The mitral valve leaflets degenerate, causing leakage and progressive volume overload of the heart
Pimobendan medication has been shown to delay onset of heart failure in preclinical MMVD
Regular auscultation by a veterinarian can detect the characteristic murmur before clinical signs develop

Welfare Considerations

MMVD causes a gradual decline in cardiac function that, without treatment, leads to congestive heart failure with symptoms including exercise intolerance, coughing, and breathing difficulty. The disease is often detected incidentally as a murmur before the dog shows any signs of discomfort, allowing early intervention. Treatment with pimobendan in preclinical cases significantly delays heart failure onset. In advanced stages, dogs experience breathlessness and reduced quality of life. Breeding recommendations exist for cavaliers to reduce disease prevalence.

What You Can Do

Have dogs with heart murmurs assessed by a veterinary cardiologist
Follow breed club health screening protocols when breeding cavalier King Charles spaniels
Monitor dogs with known MMVD for signs of deterioration including cough or reduced exercise tolerance
Advocate for responsible breeding programmes that test and reduce MMVD prevalence