Health
What sleeping breath rate should worry me?
A sustained rise above your dog's own baseline, particularly past about 40 breaths a minute, warrants a same-day call.
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Myxomatous Mitral Valve Disease in the Bichon Frise
Quick answer
What sleeping breath rate should worry me?
A sustained rise above your dog's own baseline, particularly past about 40 breaths a minute, warrants a same-day call.
The problem is not the leak itself. It is what the leak does upstream, where pressure builds until fluid is forced out of the blood vessels and into the lungs.
Owners of older Bichons who have been told the mitral valve is leaking and want to understand what will actually happen, and anyone trying to work out whether a night-time cough is significant.
Important reminder
This guide is not medical advice. If your dog shows pain, sudden behavior change, or worsening symptoms, consult a licensed veterinarian.
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What this problem looks like
Myxomatous mitral valve disease is progressive thickening and distortion of a heart valve, allowing blood to leak backwards with every beat. It is the dominant acquired cardiac disease of small breeds and typically develops in the second half of life. Its clinical significance lies entirely in pressure building behind the leak, which eventually forces fluid into the lungs, so monitoring focuses on breathing rather than on the heart itself.
Common triggers
- Age, with prevalence climbing steadily past about eight years
- Small body size, the strongest structural association
- A murmur detected at a routine or pre-dental examination
- Progressive left atrial enlargement seen on follow-up imaging
- An unrelated illness or anaesthetic placing extra demand on the heart
Across small breed dogs this accounts for the large majority of acquired heart disease, and rates rise sharply with age. Because the Bichon Frise routinely lives 14 to 15 years, a meaningful proportion reach the age band where a leaking mitral valve becomes detectable. Reaching that stage is not the same as developing heart failure, which affects only a subset.
Why this happens
Breed factors
Body size is the consistent association, and the mechanism is thought to relate to how valve connective tissue is maintained rather than to mechanical load. A 12 to 18 pound Bichon sits firmly in the size band where this disease predominates. Longevity is the second factor and it works against the breed here: 14 to 15 years gives a slow degenerative process ample time to progress, whereas a shorter-lived dog may never reach the point where the leak matters.
Environment factors
No household factor causes valve degeneration, and owners should not search for one. What the environment governs is the load a compromised heart carries. Excess weight is the main lever, and it is easily missed in a dog whose curly dense coat conceals body shape entirely. Untreated periodontal disease adds a persistent inflammatory burden, and it is a documented concern in this breed. Heat and forced exertion both raise cardiac demand acutely.
What you can do at home (once it is not an emergency)
When to talk to your vet
Treat laboured breathing at rest, open-mouth breathing in a dog that is not hot, gums that appear pale, grey or blue, collapse, or an inability to settle and lie down at night as an emergency requiring same-day care, since these indicate fluid in the lungs. A sleeping breath rate that has risen well above your dog's baseline and stayed there for a day also justifies a call rather than a wait. Book within a week for a new soft cough, reduced stamina, abdominal swelling or a drop in appetite. Never adjust or stop cardiac medication without veterinary advice.
At home, alongside your vet's plan
- Establish a sleeping breath rate baseline while your dog is still well, and log it two or three times a week thereafter.
- Give cardiac medication at fixed times and use a pill organiser, since consistency affects how well these drugs work.
- Weigh your dog monthly, because unexplained gain can reflect fluid retention rather than food.
- Assess body condition by hand rather than by eye; the coat makes visual judgement unreliable in this breed.
- Keep the dog's walking routine going at its own pace, and shift it out of the heat during summer.
More Bichon Frise health & behavior issues
- Bichon Frise Bladder and Kidney Stones: A Real Breed Risk
- Bichon Frise Heart Conditions: Screening by Age
- Bichon Frise Heart Disease: Stages and What Changes
- Bichon Frise Heart Murmurs: Grades and Next Steps
- Bichon Frise Heart Problems: Congenital Defects Explained
- Bichon Frise Kidney Disease: Senior Signs and Staging
- Bichon Frise Pancreatitis: The Fat Trigger and the Warning Signs
- Liver Shunts in Bichon Frises: Signs in Puppies and Adults
- Pancreatitis and Diabetes in Senior Bichon Frises
- Bichon Frise & the POMC Obesity Gene: What the Test Result Means
- Bichon Frise Eye Disorders: Lids, Lashes & Corneal Ulcers
- Bichon Frise GI Disorders: What's Documented vs What Isn't
- Bichon Frise Hip Dysplasia: Signs, Risk and Treatment
- Bichon Frise Hypothyroidism: Signs, Testing and Treatment
- Bichon Frise Obesity: Why the Coat Hides Weight Gain
Myxomatous Mitral Valve Disease Mmvd in other breeds
- English Cocker Spaniel Myxomatous Mitral Valve Disease
- German Shepherd Myxomatous Mitral Valve Disease: Signs
- Great Dane Myxomatous Mitral Valve Disease: Signs
- Havanese Mmvd: Signs, Causes & What to Do
- Jack Russell Terrier Myxomatous Mitral Valve Disease: Signs
- Labradoodle Mmvd: Signs, Causes & What to Do
- Maltese Mmvd: Signs, Causes & What to Do
- Miniature Schnauzer Myxomatous Mitral Valve Disease: Signs
- Poodle Mmvd: Signs, Causes & What to Do
- Rottweiler Mmvd: Signs, Causes & What to Do
See all Bichon Frise health problems, which breeds are prone to myxomatous mitral valve disease mmvd, or the full Bichon Frise breed guide for temperament, exercise needs and ownership costs.
What to expect, and how you know it is working
Progression is usually measured in years. Dogs with a leak but a normal-sized heart are typically re-imaged every six to twelve months and many stay stable for a long time. Once medication begins, most dogs continue comfortably for a further period measured in months to years, with the trajectory becoming less predictable after the first episode of fluid.
A dog that eats, walks and sleeps normally, with a sleeping breath rate inside its own established range and no emergency admissions. Success is a long stable plateau and treatment that started because a scan said so, not because the dog was struggling to breathe.
Following the leak upstream
It helps to trace the consequence rather than memorise the terminology. Blood arriving from the lungs enters the left atrium, passes through the mitral valve into the left ventricle, and is then pumped out to the body.
When the valve leaks, a fraction of each beat goes backwards into the left atrium instead of forwards. The atrium responds by enlarging to accommodate the extra volume, which is why chamber size is the measurement that decides when treatment begins.
Behind the atrium are the pulmonary veins and the lungs. As atrial pressure rises, that pressure transmits backwards into the lung circulation. Eventually the pressure inside those small vessels exceeds what holds fluid inside them, and fluid seeps into the air spaces. That is congestive heart failure, and it is why a heart problem presents as a breathing problem.
This is also why counting sleeping breaths is the standard home monitoring tool. The lungs register the pressure change before the dog looks unwell, so a rising breath count is the earliest thing an owner can detect.
The enlarged atrium has one other consequence: it stretches the airway that passes just above it, which is one reason some dogs cough before any fluid appears.
What to watch for at home
Owners of dogs with a known leaking valve have a genuine monitoring role, and these are the observations that carry weight.
- Sleeping breath count. Watch the chest of a truly asleep dog and count rises for a full minute. Establish your dog's baseline while it is well.
- A soft cough that appears at night or when the dog first lies down, rather than during exertion.
- Restlessness at night: a dog that repeatedly gets up, resettles, or chooses to lie propped up rather than flat.
- Reduced stamina on a familiar route, especially a dog wanting to turn for home at the same point each day.
- Abdominal swelling or a sudden change in appetite, both of which warrant a call rather than a wait.
Thirty-four breaths on a Tuesday night
Willow was twelve, on cardiac medication for eighteen months, and stable. Her owner Ben counted her sleeping breaths most evenings out of habit; she had sat between 18 and 24 for over a year. On a Tuesday he counted 34. He counted again an hour later and got 32. She had not coughed and had eaten her dinner normally. He rang the practice first thing. Radiographs showed early fluid accumulation, and her medication was adjusted that morning. She never developed the laboured breathing that would have made it an emergency, and her breath count was back to 22 within four days.
Key takeaway: The lungs report the change before the dog does. A number counted on an ordinary evening is what turns a night-time emergency into a morning appointment.
Frequently asked questions
Is this the most common heart disease in Bichon Frises?
It is the most common acquired heart disease in small breed dogs generally, and a Bichon that develops heart disease is most likely to develop this one. That said, cardiac disease is not listed among the breed's documented concerns, which are skin allergies, patellar luxation, bladder stones, cataracts and dental disease.
How is it different from a murmur?
The murmur is the sound the leak makes; the disease is the valve degeneration causing it. Hearing a murmur tells you turbulence exists. Determining whether the heart has enlarged, which requires imaging, is what tells you whether the disease has reached the stage that needs treating.
Does every dog with a leaking valve go into heart failure?
No, and this is important. Many dogs carry a leaking mitral valve for years with a heart that stays a normal size, and a significant number die of something else entirely. Progression is variable and often slow, particularly in dogs diagnosed late in life.
What does treatment involve?
Once imaging shows enlargement, daily medication is started to reduce the workload on the heart and delay fluid accumulation. Additional medications are added if fluid does develop. It is lifelong, taken at consistent times, with periodic bloodwork to monitor kidney values.
Is the cough always from the heart?
No. In small dogs, airway irritation and tracheal problems produce coughs that sound similar. A cardiac cough is typically soft, worse lying down and at night, and comes with a rising sleeping breath rate. A dry honking cough during excitement more often points elsewhere.
Can diet or supplements slow the valve degeneration?
There is no dietary change that repairs valve tissue, and you should not alter your dog's diet or add supplements without asking your vet, particularly since some interact with cardiac medication. Keeping the dog lean and treating dental disease are the measures with genuine value.
Quick answers
View more answersHealth
Why does my dog cough at night?
Lying flat raises pressure in the lung vessels, and an enlarged heart chamber can also press on the airway above it.
Costs
What does cardiac medication cost monthly?
For a dog of 12 to 18 pounds the daily tablets are relatively modest, with periodic bloodwork and imaging as larger occasional costs.
Living
Should my dog stop exercising?
No. Gentle daily walking at the dog's own pace maintains condition. Avoid pushing through obvious tiredness or walking in heat.
Living
Does my dog need to sleep somewhere different?
Many dogs choose a propped position once fluid pressure rises. Provide a raised edge or bolster and let the dog settle as it prefers.
Related DogBreedCompass guides
- how heart disease is staged – The staging framework decides when treatment for this disease begins.
- Bichon Frise heart murmurs – Murmur grading is the finding that leads to this diagnosis.
- cardiac screening by age – Screening cadence across the lifespan sits on the overview page.
- dental disease in Bichon Frises – Untreated dental infection adds burden to a compromised heart.
- Bichon Frise cost of ownership – Long-term medication changes the ownership cost picture.
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