Heart Murmurs in Cavalier King Charles Spaniels: Causes & Care

The Cavalier King Charles spaniel is a charming small dog breed grouped in The Kennel Club’s toy group. These affectionate companions are popular across the UK for their friendly nature and moderate exercise needs, often considered a great choice for first-time dog owners as well as those seeking a personable, quieter canine friend.

However, one of the most significant health concerns for this breed relates to heart murmurs, primarily caused by mitral valve disease (MVD). Heart murmurs vary in severity, and understanding their implications is essential for any current or prospective Cavalier owner.

What is a Heart Murmur?

A heart murmur is an unusual sound detected when a vet listens to the dog’s heart with a stethoscope, caused by turbulent blood flow during the heartbeat. Murmurs can differ based on their location, timing within the heartbeat cycle, and cause.

They may be congenital (present from birth) and sometimes diminish as the pup matures, or acquired later in life. Murmurs are classified as systolic or diastolic depending on when they occur within the heart’s cycle, and graded on a scale from 1 (very mild) to 6 (severe) to express their intensity and potential impact on health.

In the Cavalier King Charles spaniel, murmurs often indicate the presence of mitral valve disease (MVD), a hereditary and progressive disorder where the mitral valve degenerates and leaks, causing the heart to work harder and potentially leading to heart failure over time.

Why Are Cavalier King Charles Spaniels More Prone to Heart Murmurs?

Like most pedigree breeds, Cavaliers have a predisposition to certain hereditary conditions, with MVD being one of the most common and serious. The exact genetic cause remains unidentified, but it is well established that the condition is inherited.

The prevalence of MVD in Cavaliers is approximately twenty times greater than in other breeds, with around 50% affected by age five and nearly all showing murmurs by age ten, demonstrating its progressive nature.

Breeding dogs with heart murmurs increases the risk of passing these defects to their puppies, especially if both parents are affected. This hereditary risk underlines the importance of responsible and informed breeding practices.

Recognising the Symptoms of Heart Murmurs in Cavaliers

Heart murmurs themselves are generally undetectable without veterinary examination, so annual vet check-ups are vital. Early stages may show no clinical signs, but as the disease advances, symptoms like exercise intolerance, a persistent soft cough, fatigue, fainting, or breathing difficulties may arise.

If you notice these symptoms or suspect something is wrong, a prompt veterinary visit is essential for timely diagnosis and management.

How Are Heart Murmurs Diagnosed?

Your vet will listen carefully to your dog's heart with a stethoscope during routine exams or if symptoms are present. If a murmur is detected, referral to a veterinary cardiologist for advanced testing such as echocardiography (heart ultrasound) may be recommended. This helps assess the severity of mitral valve degeneration and guides treatment plans.

The UK Kennel Club Heart Scheme encourages breeders to screen dogs regularly with clinical exams and echocardiograms every two years, plus interim checks, to monitor cardiac health when breeding Cavaliers.

Can Heart Murmurs Be Treated or Prevented?

There is no surgical cure for mitral valve disease, but medications like pimobendan can be prescribed to help manage heart function and delay heart failure, particularly when murmurs reach a grade IV severity or higher. Other supportive treatments might include diuretics and ACE inhibitors as the condition progresses.

Prevention focuses mainly on responsible breeding: selecting breeding dogs confirmed free from significant heart disease through regular screening and removing affected dogs from the breeding pool. Prospective puppy buyers should always seek Cavalier King Charles spaniel puppies from breeders who provide health testing proof and participate in the UK Kennel Club Heart Scheme.

Why Annual Vet Checks Matter

Given the progressive nature of heart murmurs in Cavaliers and the importance of early detection, annual veterinary examinations with heart auscultation are indispensable. Early diagnosis allows more effective management, improving quality of life and potentially extending lifespan.

Summary and Responsible Ownership

Cavalier King Charles spaniels have a notable predisposition to heart murmurs primarily caused by mitral valve disease, a progressive inherited condition. While symptoms may be subtle initially, regular veterinary screenings can detect murmurs early, guiding appropriate treatment and care.

Prospective owners should choose puppies from reputable breeders who carefully screen for heart issues, supporting the health of future generations. Responsible breeding, regular health checks, and attentive care are key to helping Cavaliers live happy, healthy lives despite this common hereditary concern.