Mitral Valve Disease in Dogs: Tracking Respiratory Rate, Heart Rate, and Rest Between Vet Visits
Mitral valve disease often changes gradually. Learn how resting breathing, activity, sleep, and symptom trends can support veterinary follow-up at home.
BVMS MRCVS
Medically reviewed by Dr. Pippa Elliott, BVMS MRCVS · Last reviewed
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Mitral valve disease in dogs often progresses gradually, which makes consistent home observations valuable between veterinary visits. Resting respiratory rate is usually the most actionable home trend, while heart rate, sleep, activity, cough, appetite, and comfort add context. These signals can help your veterinarian decide when to reassess your dog, but they cannot stage the disease or replace an examination, chest radiographs, or an echocardiogram.
Maven Pet's respiratory rate tracker records breathing during quiet rest and displays longer-term trends alongside heart rate, activity, and rest. Used within a veterinarian's plan, that record can make a subtle change easier to describe. Maven Pet should not be used to diagnose heart failure or change pimobendan, a diuretic, or any other medication without veterinary guidance.
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A collar-mounted sensor and app for activity, rest, sleep, respiratory rate, heart-rate trends, itch behaviors, and more.
- Builds a personalized baseline over time
- Tracks trends between veterinary visits
- Generates a month-long shareable report
Health monitoring for dogs and cats
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What happens in mitral valve disease
The mitral valve sits between the left atrium and left ventricle. In myxomatous mitral valve disease, also called MMVD, MVD, degenerative mitral valve disease, or chronic valvular disease, the valve leaflets thicken and lose their normal shape. The valve begins to leak, allowing some blood to move backward each time the heart contracts.
The heart may compensate for years. Many dogs are diagnosed after a veterinarian hears a murmur during a routine examination, before the dog has any outward symptoms. As leakage and chamber enlargement progress, some dogs eventually develop congestive heart failure, but the timeline varies widely.
Small, older dogs are affected most often. Cavalier King Charles Spaniels have a strong predisposition, and Dachshunds, Chihuahuas, Miniature Poodles, Papillons, Shih Tzus, and small mixed-breed dogs are also commonly represented. A breed tendency does not replace screening or diagnosis.
Understand the ACVIM stages
The ACVIM consensus guidelines organize MMVD into stages that guide follow-up and treatment:
- Stage A: The dog is at risk because of breed or age but has no current structural disease.
- Stage B1: A murmur and valve disease are present, but heart enlargement does not meet Stage B2 criteria.
- Stage B2: The heart has enlarged because of MMVD, but the dog has not developed clinical signs of CHF.
- Stage C: The dog currently has or previously had clinical CHF caused by MMVD.
- Stage D: Heart failure is refractory to standard treatment.
An echocardiogram and chest imaging help distinguish these stages. Murmur grade, a breathing count, or a wearable result cannot do that alone. Follow the recheck interval your veterinarian or veterinary cardiologist sets for your dog's documented stage.
What are the stages of mitral valve disease in dogs? In plain language, Stage A means risk without current structural disease, Stages B1 and B2 mean disease is present without clinical heart failure, Stage C means current or previous CHF, and Stage D means heart failure that is difficult to control with standard therapy. Only the veterinary team can assign or change the stage.
| ACVIM stage | Veterinary finding that defines it | Useful home observation without staging the dog yourself |
|---|---|---|
| A | Risk based on breed or age, without identified structural MMVD | Keep routine wellness visits and note new exercise, cough, or breathing changes |
| B1 | MMVD is present without enlargement meeting B2 criteria | Establish normal resting respiration, activity, rest, and appetite patterns |
| B2 | MMVD with defined cardiac enlargement but no clinical CHF | Follow the cardiologist's recheck and respiratory-monitoring instructions closely |
| C | Current or previous clinical CHF | Record resting breathing, effort, weight, cough, medication context, and comfort as directed |
| D | CHF that is refractory to standard treatment | Follow the specialist's individualized plan and emergency instructions exactly |
The home-observation column does not create a separate set of stage criteria. It shows how the same calm record can serve different veterinary plans. A Stage B2 mitral valve disease dog may have no obvious symptoms, which is precisely why scheduled imaging and a reliable baseline matter.
A collar-mounted sensor and app for activity, rest, sleep, respiratory rate, heart-rate trends, itch behaviors, and more.
- Builds a personalized baseline over time
- Tracks trends between veterinary visits
- Generates a month-long shareable report
Health monitoring for dogs and cats
Webvet may earn a commission when you click through to Maven Pet, at no extra cost to you.
Resting respiratory rate: establish the baseline first
Measure respiratory rate only when your dog is asleep or resting quietly. Panting, recent activity, heat, stress, and active dreaming can raise the number. One complete chest rise and fall is one breath.
Ask your veterinarian for a personalized call threshold. A sustained sleeping or resting rate above 30 breaths per minute is commonly used as a concern point in dogs at risk of left-sided CHF, but the pattern relative to your dog's own baseline also matters.
The most useful record includes:
- Date and time
- Respiratory rate and whether the dog was asleep
- Any increased breathing effort
- Cough, restlessness, appetite, and activity changes
- Medication doses and any missed doses
- Notes about heat, excitement, pain, or another possible influence
If a reading is unexpectedly high and your dog appears comfortable, wait until your dog is fully settled and count again. Contact your veterinarian when the increase persists or appears with other changes. Treat labored breathing as an emergency regardless of the number.
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Heart rate, rest, and activity add context
Heart rate varies with size, stress, movement, pain, medication, and rhythm. A wearable heart-rate trend is not an electrocardiogram and cannot identify an arrhythmia. It can still give your vet useful context when a sustained shift occurs alongside changes in breathing, energy, or sleep.
Compare heart rate only under similar conditions. A sleeping value and a value recorded after climbing stairs answer different questions. If the trend changes, note whether the dog was asleep, awake, restless, coughing, painful, warm, or recently active. A persistently unusual rate or irregular pulse should be discussed with the clinic, but a device cannot determine the rhythm responsible.
Rest deserves its own note rather than being treated as the absence of activity. Record whether your dog settles in the usual place, changes position repeatedly, wakes to cough, chooses to sleep upright, or seems comfortable lying flat. A dog resting more because of arthritis or a hot day may show a different pattern from a dog that cannot settle because breathing is uncomfortable. The veterinarian needs that context.
Watch for a cluster of changes rather than assigning meaning to one value:
- A gradual loss of stamina on the usual walk
- Longer recovery after mild activity
- More nighttime pacing or position changes
- Reluctance to lie flat or settle
- A new cough, especially during rest or overnight
- Reduced appetite or unexplained weight loss
- Weakness, wobbliness, collapse, or fainting
Joint pain, airway disease, anxiety, hot weather, and many other conditions can produce similar changes. The record helps your veterinarian ask better questions, not skip diagnostic testing.
A collar-mounted sensor and app for activity, rest, sleep, respiratory rate, heart-rate trends, itch behaviors, and more.
- Builds a personalized baseline over time
- Tracks trends between veterinary visits
- Generates a month-long shareable report
Health monitoring for dogs and cats
Webvet may earn a commission when you click through to Maven Pet, at no extra cost to you.
What Maven Pet's 2,533-dog analysis contributes
Maven Pet reports a June 2026 internal analysis related to mitral valve disease using resting respiratory data from 2,533 dogs monitored at home. The company compared reported-healthy dogs with dogs whose onboarding information indicated cardiac conditions while excluding reported airway comorbidity from the cardiac cohort.
Maven Pet reported that small dogs in the cardiac cohort had modestly higher resting respiratory rates than reported-healthy peers, while the same pattern was not significant in large and giant dogs. The size-specific observation is biologically plausible because MMVD is concentrated in small dogs and large breeds have a different cardiac disease mix.
This was an observational company analysis, not a peer-reviewed diagnostic trial. Health status came from onboarding declarations, individual MMVD stage was not established by standardized echocardiography, and residual confounding is possible. The results do not show that Maven Pet detects MVD, predicts progression for an individual dog, or distinguishes cardiac from respiratory disease. They are best treated as hypothesis-generating support for tracking a personal trend.
What independent longitudinal research shows
The EPIC temporal-variable study followed dogs with Stage B2 MMVD and cardiomegaly. It compared 135 dogs that developed CHF with 73 that did not during the study period. Heart rate, clinic respiratory rate, owner-measured resting respiratory rate, body weight, temperature, and radiographic heart size were evaluated over time.
Dogs approaching CHF showed increases in heart rate and respiratory measures, while the largest absolute and rate changes were in clinic and resting respiratory rate. The study supports frequent serial observation rather than reliance on one clinic snapshot.
It does not mean every small increase signals CHF. The population already had Stage B2 disease, group averages cannot set a personal alert threshold, and the study's conflict-of-interest statement reports industry relationships. Veterinary evaluation remains necessary to determine whether a change represents pulmonary edema, airway disease, pain, stress, or another problem.
A real customer experience, not clinical proof
In an August 2026 Trustpilot review, Jessica McWeeny described caring for a senior Papillon with a leaky mitral valve. She said keeping up with the resting respiratory information requested by the veterinarian had been difficult, and that Maven made the task feel manageable.
That account illustrates an adherence benefit: automatic collection may reduce missed observations. It is one person's experience. It does not establish measurement performance for her dog, prove a medication effect, or show improved clinical outcomes.
A collar-mounted sensor and app for activity, rest, sleep, respiratory rate, heart-rate trends, itch behaviors, and more.
- Builds a personalized baseline over time
- Tracks trends between veterinary visits
- Generates a month-long shareable report
Health monitoring for dogs and cats
Webvet may earn a commission when you click through to Maven Pet, at no extra cost to you.
A weekly MVD trend report
How can you help a dog with mitral valve disease? Give medications exactly as prescribed, keep scheduled examinations and imaging, support veterinarian-approved activity and comfort, and provide a concise weekly record of resting respiratory and heart rate plus rest and activity changes. Many MVD pages explain stages and prognosis, but they do not translate respiratory rate, heart rate, rest, and activity into one repeatable between-visit report. This report supports veterinary decisions without diagnosing stage progression or replacing testing.
| Weekly field | What to record | Why the veterinarian may find it useful |
|---|---|---|
| Resting respiratory rate | Typical sleeping range, highest repeatable value, and breathing effort | Shows whether quiet breathing has shifted from the personal baseline |
| Resting heart rate | Comparable asleep or quietly resting values and any sustained change | Adds context alongside respiration, medication, activity, and clinical rhythm testing |
| Rest and sleep | Ability to settle, sleeping position, nighttime waking, and cough | Describes comfort and whether rest has become disrupted |
| Activity | Usual walk, pace, recovery, stairs, and play interest | Shows functional change without assuming it is cardiac |
| Appetite and weight | Meal interest, body weight on the same scale, vomiting, and diarrhea | Helps interpret energy, medication tolerance, hydration, and other illness |
| Medication context | Every dose, missed or vomited dose, and recent prescription change | Prevents a trend from being separated from the treatment timeline |
Use one row or short summary per week while your dog is stable. If a meaningful change appears, do not wait for the weekly review. Follow the clinic's call threshold and emergency plan.
Do not send every raw point unless the clinic requests it. Summarize what changed and when.
Include:
- The usual resting respiratory range and the new range
- Whether the change is sustained across several rest periods
- Breathing effort, cough, sleep, and activity changes
- Heart-rate trend if your device collects it
- Appetite, body weight, water intake, and bathroom changes
- Current medications, doses, and adherence
- A short video of cough or breathing when safe to record
The Maven Pet MVD resource describes downloadable trend reports. Ask your clinic whether screenshots, a PDF, or a simple written log is easiest for its team to review.
Never use a trend report to adjust a cardiac drug on your own. Diuretics can affect kidney values and electrolytes, while other heart medications have their own monitoring needs.
When a change needs prompt veterinary care
Call your veterinarian promptly for a sustained respiratory increase, new or worsening cough, reduced appetite, marked fatigue, nighttime restlessness, or declining exercise tolerance. The clinic may advise an earlier examination or imaging.
Seek emergency veterinary care for:
- Open-mouth breathing at rest
- Blue, gray, or very pale gums
- Pronounced abdominal effort with each breath
- Collapse or fainting
- Severe weakness or inability to stand
- Coughing up pink or foamy fluid
- Distress that prevents lying down or sleeping
Do not wait for a tracker alert when your dog looks distressed. Keep your dog quiet and minimize exertion during transport.
If coughing becomes part of the picture, WebVet's guide to dog coughing with heart failure explains why chest imaging may be needed to distinguish pulmonary edema from common airway disorders. Our senior dog health guide can help you track mobility, cognition, dental pain, and other age-related factors that may affect rest and activity.
Keep monitoring calm and sustainable
A monitoring routine should give you clarity, not require constant vigilance. Choose one daily time to review breathing and one weekly time to summarize the broader trend. Observe your dog as a whole: comfort, appetite, connection with family, sleep, and enjoyment still matter.
Keep medication and recheck schedules in one place. Save the cardiologist's normal range and emergency instructions where every caregiver can find them. If your dog's baseline changes after a medication adjustment or illness, ask when to establish a new comparison period.
Frequently Asked Questions
Is mitral valve disease the same as a heart murmur?
No. A murmur is a sound caused by turbulent blood flow. MMVD is a structural disease and is a common cause of murmurs in older small dogs. An echocardiogram can confirm the valve disease and assess its effects. The murmur may prompt testing, but its grade alone cannot establish ACVIM stage, heart enlargement, or CHF.
Does every dog with MVD develop congestive heart failure?
No. Progression varies, and some dogs remain in a preclinical stage for years. Stage, heart size, age, breed, and individual disease behavior influence prognosis. Keep the imaging and recheck schedule even when your dog appears well, and report meaningful respiratory, rest, activity, cough, appetite, weakness, fainting, or collapse changes promptly.
What is the best number to monitor at home?
Resting or sleeping respiratory rate is generally the most useful home measurement for dogs at risk of left-sided CHF. Follow the method and threshold provided by your veterinarian. Heart rate, rest, activity, cough, appetite, weight, and medication context can strengthen the report, but none of those signals should be interpreted alone as a stage change.
Can Maven Pet diagnose progression from Stage B2 to Stage C?
No. Maven Pet can display trends that prompt a veterinary conversation. Diagnosis of CHF and stage progression requires clinical assessment and often imaging. A Stage B2 to Stage C transition is a veterinary diagnosis, not an app threshold. Contact the clinic about sustained breathing or comfort changes and seek emergency care for respiratory distress.
Should I change pimobendan or furosemide based on a rising trend?
Only if your veterinarian has already provided exact written instructions for that situation. Otherwise, call the clinic with the trend, current symptoms, and complete medication record. Do not start, stop, or change cardiac medication on your own. Diuretics and other cardiac drugs can affect blood pressure, hydration, kidney function, and electrolytes.
How often should a dog with MVD see a cardiologist?
The interval depends on stage, heart size, symptoms, test results, and treatment. Ask the cardiologist for a written recheck schedule and the specific changes that should move the appointment sooner. A calm home trend can help explain what happened between visits, but a stable trend does not replace scheduled imaging, bloodwork, or examination.
How can I help my dog with mitral valve disease?
You can help your dog with mitral valve disease by keeping veterinary and cardiology appointments, giving each medication exactly as prescribed, maintaining veterinarian-approved activity and a comfortable routine, and reporting meaningful changes promptly. A weekly record of resting respiratory and heart rate plus rest and activity changes can make those conversations more specific. It cannot stage the disease, diagnose CHF, or justify changing treatment without the veterinarian.
What are the stages of mitral valve disease in dogs?
The stages of mitral valve disease in dogs are ACVIM Stage A for dogs at risk, B1 for MMVD without qualifying enlargement, B2 for MMVD with defined enlargement but no clinical CHF, C for current or previous CHF, and D for heart failure refractory to standard treatment. Echocardiography, imaging, clinical history, and examination determine the stage. A home trend or murmur grade cannot assign it.
Sources
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Editor
The Webvet Editorial Team is the in-house group of pet-care editors and writers behind Webvet, operated by Smart Pet Collective. The team researches, writes, and maintains Webvet's pet health, behavior, and medication content. Every article follows a defined editorial process: research from reputable veterinary and scientific sources, careful drafting, mandatory review of medical content by a credentialed veterinarian, and dated publication. Health and medication articles are medically reviewed by a licensed veterinary professional before they go live and are kept current over time.
Veterinarian · BVMS MRCVS
Dr. Pippa Elliott, BVMS, MRCVS, is a veterinarian with nearly 30 years of experience in companion animal practice. Dr. Elliott earned her Bachelor of Veterinary Medicine and Surgery from the University of Glasgow. She was also designated a Member of the Royal College of Veterinary Surgeons. Married with 2 grown-up kids, Dr. Elliott has a naughty Puggle named Poggle, 3 cats and a bearded dragon.
Related reading
Tracking a Dog’s Respiratory Rate Over Time: What a Rising Trend Can Tell Your Vet
Dog Heart Murmurs: What to Monitor Between Vet Visits
Congestive Heart Failure in Dogs: How At-Home Trends Support Veterinary Care
