Mitral valve disease (MVD) is the most common health problem of the Cavalier King Charles Spaniel and the leading cause of death in the breed. It is a degenerative disease of a heart valve that progresses over years, and in Cavaliers it occurs about twenty times more often than in other breeds and considerably earlier in life.
This article explains what the disease looks like, how it is recognised, how it is monitored and — perhaps most importantly for a future owner — what a responsible breeder does to reduce the risk.
What mitral valve disease is
The mitral valve separates the left atrium from the left ventricle and prevents blood from flowing backwards. In MVD the valve tissue degenerates and thickens over time, so the valve no longer seals. With every beat, part of the blood flows back into the atrium.
At first the heart compensates without any outward signs. That is why the disease is almost always discovered before the dog shows any symptom — usually as a heart murmur that the vet hears during a routine examination.
Why Cavaliers in particular
MVD occurs in other small breeds too, but in the Cavalier King Charles Spaniel it is pronounced to a degree that sets the breed apart. Veterinary literature reports the following course:
- about 50 percent of Cavaliers show signs of the disease by the age of five
- about 70 percent by the age of seven
- nearly all dogs that reach the age of ten
It is important to understand what these numbers mean and what they do not. They do not mean that every Cavalier will die of heart disease, nor that the disease necessarily shortens life — many dogs live for years with a mild form and never develop serious trouble. They do mean that regular cardiac check-ups are obligatory in this breed, not optional.
Stages of the disease
Veterinary cardiology uses an international classification (ACVIM) with four stages. Knowing these labels helps you understand the report you receive from your vet.
- Stage A: the dog belongs to a predisposed breed but has neither a murmur nor changes in the heart. Every Cavalier is by definition in this stage from birth.
- Stage B1: a mild murmur is present but the heart is not enlarged. The dog has no symptoms and treatment is usually not started; instead the condition is checked once a year.
- Stage B2: the murmur is louder and the heart is measurably enlarged. The dog still has no outward symptoms, but at this point medication is started that is proven to delay the onset of heart failure.
- Stage C: heart failure has developed with visible symptoms. It is treated with a combination of medicines.
The transition from stage B1 to B2 is the key moment, because that is when the most time can be gained. That transition cannot be noticed at home — only a cardiac ultrasound reveals it.
Signs the owner should watch for
In the early stages there is nothing to notice, and that is precisely why check-ups exist. When the disease progresses to heart failure, the following signs appear:
- coughing, especially at night or after lying down
- faster breathing at rest and tiring on the usual walk
- poorer appetite and loss of condition
- fainting in more severe cases
A practical tip worth knowing: the number of breaths taken during sleep is one of the most reliable signs an owner can monitor themselves. A healthy dog takes fewer than thirty breaths per minute while asleep. A persistently raised breathing rate at rest is a reason to contact your vet, and it is exactly the kind of data a cardiologist welcomes.
Diagnosis
An examination by a veterinary cardiologist usually includes listening to the heart with a stethoscope, a cardiac ultrasound measuring enlargement and the amount of backflow, and a chest X-ray if needed.
For Cavaliers a cardiac examination once a year is recommended, starting from two to three years of age, and before any sign of disease appears.
Treatment
MVD cannot be cured and a degenerated valve cannot be restored to its original state. What modern therapy can do is significantly delay the onset of heart failure and extend a good quality of life.
In stages A and B1 no medicines are given; the condition is only monitored. From stage B2 a therapy is introduced that relieves the heart, and in stage C medicines are combined to remove accumulated fluid and support cardiac function. The specific choice and dosage is determined solely by the vet on the basis of the findings.
What a responsible breeder does
This is the part a future owner rarely hears, and the part that matters most. The risk of early-onset MVD cannot be eliminated, but it can demonstrably be reduced by the choice of parents.
The internationally recognised breeding protocol for this breed sets out the following:
- both parents at least two and a half years old at the time of mating
- both parents examined and free of heart murmur, with a report signed by a specialist cardiologist
- and their own parents, that is the puppy's grandparents, examined at the age of five or older and likewise free of murmur
The reason for the age limit is simple: a one-year-old dog almost certainly has no murmur yet, so a report from that age tells you nothing. Only an examination at a more mature age has value. Where this protocol is applied consistently, the onset of the disease shifts to later years.
What to ask the breeder before buying
If you are choosing a puppy, three questions give you the most information:
- How old are the parents and when were they last examined by a cardiologist?
- May I see the reports on paper, with the cardiologist's name and signature?
- Have the puppy's grandparents also been examined, and at what age?
A breeder who cares about the health of the breed will have these answers ready and will show the reports without hesitation. Avoiding the question, or claiming that the dogs have no heart problems, is a reason for caution — in this breed such a claim without reports means nothing.
Conclusion
Mitral valve disease is a reality of this breed and there is no sense in glossing over it. What an owner can do is choose a puppy from a litter with tested parents, take the dog for an annual cardiac examination from an early age, and monitor breathing at rest. MVD detected early at stage B2 is treated today in a way that gives the dog additional years of good life — but only if it is found in time.
Note: this article is informational and does not replace examination and advice from a veterinarian. For diagnosis and treatment consult your vet, preferably a specialist in cardiology.
Related
- Heart murmur in Cavaliers: what it means and when it is a cause for concern
- Syringomyelia and Chiari-like malformation in Cavaliers
- Why Cavaliers scratch their neck and shoulder — when it is a sign of illness
- Which health tests are required for the parents of a Cavalier litter
- The expected lifespan of the Cavalier and what affects it
- A schedule of veterinary check-ups by the age of a Cavalier
- Eye problems in Cavaliers: what occurs and how to recognise it
- Patellar luxation in Cavaliers: the slipping kneecap of small breeds
- Ear problems in Cavaliers — why drop ears need more care
- How to read a Cavalier cardiology report
- MRI screening for syringomyelia: when, how and what the report means
- Cavalier vaccination and deworming: schedule by age
- Living with a Cavalier diagnosed with MVD
- Health of the Cavalier King Charles Spaniel — an overview of all topics
- Puppies for sale from a kennel with health-tested parents
