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SeverePrevalence: Very common — affects the majority of senior individuals

Mitral Valve Disease in Cavalier King Charles Spaniels

Mitral valve disease (MVD) is the most common heart condition in Cavalier King Charles Spaniels and the leading cardiac cause of death in small breeds. The mitral valve gradually thickens and degenerates, allowing blood to leak backward with each heartbeat. Nearly all Cavalier King Charles Spaniels will develop a murmur in their senior years — the key is catching it early and starting medication at the right time.

Prevalence

Very common — affects the majority of senior individuals

Typical Onset

5-8 years (murmur), 8-12 years (heart failure)

Severity

Severe

Symptoms to Watch For

If your Cavalier King Charles Spaniel shows any of these signs, monitor closely and consult your veterinarian.

heart murmur detected at routine checkup
cough that worsens at night or with excitement
increased breathing rate at rest (over 30 breaths/minute)
exercise intolerance progressing over months
fainting during exertion or excitement
restlessness at night, inability to settle

Risk Factors

  • strong breed predisposition to valve degeneration
  • small breed body type
  • male sex (slightly higher risk)
  • dental disease and chronic bacterial exposure
  • untreated progression — delay in starting pimobendan

Diagnosis

Heart murmur on auscultation (left apex, systolic). Echocardiogram confirms valve thickening, regurgitation, and chamber enlargement. Chest radiographs show heart enlargement and pulmonary changes. Resting respiratory rate monitoring at home (count breaths while sleeping — normal is under 30/minute).

Treatment

Stage B1 (murmur, no enlargement): monitor every 6-12 months. Stage B2 (murmur + enlargement): pimobendan starts — proven to delay onset of heart failure by 15 months. Stage C (heart failure): pimobendan + furosemide + ACE inhibitor. Stage D (refractory): add spironolactone, increase diuretics. Mitral valve repair surgery is now available at specialized centers with excellent outcomes.

Prevention

Choose breeders who cardiac-screen with echocardiography (especially Cavaliers). Maintain dental health — dental bacteria enter the bloodstream and can worsen valve disease. Keep body weight lean. Monitor resting respiratory rate at home weekly in senior small breeds.

When to See a Vet

See your vet if sleeping respiratory rate exceeds 30 breaths/minute, or if you notice new coughing, exercise intolerance, or fainting. If already diagnosed, any sudden breathing change is an emergency.

Other Health Conditions in Cavalier King Charles Spaniels

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