Cavalier King Charles Spaniel & Heart Disease
Cavalier King Charles Spaniels are disproportionately affected by MMVD, developing the disease earlier and more severely than any other breed. The mitral valve degenerates over time, causing it to leak blood backward into the left atrium. While many Cavaliers live comfortably for years with a murmur, the disease is progressive and will eventually require treatment in most cases.
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Heart conditions in Cavalier King Charles Spaniels
Myxomatous Mitral Valve Disease (MMVD)
Extremely High riskApproximately 50% of Cavaliers develop a heart murmur by age 5, and nearly 100% are affected by age 10. The most severely affected breed for MMVD.
Screening recommendations
Start screening at
1 year old
Frequency
Annually (echocardiogram + auscultation)
Recommended tests
Echocardiogram, Cardiac auscultation
Genetic factors
MMVD in Cavaliers is polygenic (multiple genes involved). The MVD Breeding Protocol recommends breeding only dogs over age 2.5 with no murmur, ideally from parents who were murmur-free at age 5+. However, the prevalence is so high that eliminating the trait entirely is not currently feasible without severely narrowing the gene pool.
Common medications
Medications are determined by your veterinarian based on your dog's individual condition. This list represents commonly used medications for this breed's typical cardiac conditions.
Prognosis
Highly variable. Many Cavaliers with Stage B1 MMVD remain stable for years without treatment. Once reaching Stage B2, the EPIC study showed pimobendan delayed CHF onset by ~15 months. After CHF onset (Stage C), median survival with treatment is 9–18 months, though some dogs do much better.
Recommended reading
Other breeds at risk
Disclaimer:This content is for educational purposes only. It is based on published veterinary research and community experience, but is not written by a veterinarian and does not constitute medical advice. Every dog is different. Always consult your veterinarian or a board-certified veterinary cardiologist before making any changes to your dog's care, diet, or treatment plan.