Dog Heart Murmurs: What to Monitor Between Vet Visits
A heart murmur is a sound, not a diagnosis. Learn which breathing, activity, sleep, and symptom trends can help your veterinarian between visits at home.
BVMS MRCVS
Medically reviewed by Dr. Pippa Elliott, BVMS MRCVS · Last reviewed
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Dog heart murmurs are sounds caused by turbulent blood flow, not diagnoses by themselves. Between veterinary visits, monitor your dog's resting respiratory rate, breathing effort, activity, sleep, cough, appetite, and any weakness or fainting. These observations can help your veterinarian judge whether the pattern is stable or whether your dog needs a sooner recheck, but they cannot identify the cause or stage of a murmur.
Maven Pet's respiratory rate tracker can collect resting breathing trends while a dog is quiet or asleep. It also tracks heart rate, rest, and activity, giving families a consistent record to share with a veterinarian. Maven Pet does not listen to the murmur, grade it, perform an echocardiogram, or replace the follow-up schedule your vet recommends.
For a closer look at the service itself, see Petful's Maven Pet Smart Collar review.
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 a heart murmur tells your veterinarian
A veterinarian hears a murmur through a stethoscope when blood flow creates an extra sound during the heartbeat. Murmurs are commonly described by timing, location, sound quality, and loudness. In dogs, intensity is often graded from 1 to 6.
The grade describes how readily the sound can be heard. It is only one piece of the clinical picture. As the MSD Veterinary Manual explains, some mild valve leaks can produce prominent sounds, while diagnostic testing is needed to determine the underlying abnormality and its importance.
Is it serious for a dog to have a heart murmur? It can be, but the sound alone cannot answer that question. A soft murmur may need follow-up because of its cause, while a louder murmur does not by itself prove heart failure. Age, symptoms, breed, pulse quality, heart size, blood pressure, and echocardiographic findings help the veterinarian judge significance. Establishing a baseline while feeling well and noting respiratory, activity, rest, and appetite changes gives the clinic useful context without predicting seriousness from home.
Possible causes include:
- Myxomatous mitral valve disease, especially in older small-breed dogs
- Congenital heart defects
- Dilated cardiomyopathy or another disease affecting heart function
- Temporary innocent or physiologic murmurs, most often in young puppies
- Changes in blood flow associated with anemia, fever, or other systemic illness
Your vet may recommend chest radiographs, blood pressure, an electrocardiogram, blood tests, or an echocardiogram. An echocardiogram performed by a veterinary cardiologist shows heart structure, chamber size, valve movement, and blood flow. Home data cannot supply those answers.
Murmur grade and the testing question it cannot answer
| Murmur description | What the grade communicates | What may still require testing |
|---|---|---|
| Grade 1 or 2 | A soft sound that may be heard only in a focused area | Whether it is innocent, structural, or related to another illness |
| Grade 3 or 4 | A readily heard to loud murmur, sometimes over a wider area | The exact valve or defect, chamber size, and effect on blood flow |
| Grade 5 or 6 | A very loud murmur, often with a palpable chest vibration called a thrill | Disease stage, heart function, pulmonary edema, rhythm, and treatment need |
The table is a conversation guide, not a risk score. Murmur grade can change with heart rate, body position, chest shape, and the examiner's technique. Your veterinarian may repeat the examination and use an echocardiogram, chest radiographs, electrocardiogram, blood pressure, or blood tests to answer different questions.
Build a normal baseline while your dog feels well
Many dogs with an early murmur act completely normal. That makes the quiet period between appointments useful: you can learn what your dog's ordinary breathing, sleep, and movement look like before anything changes.
Record a few consistent measures rather than trying to monitor everything at once:
- Resting or sleeping respiratory rate
- Breathing effort and sleeping position
- Daily activity and exercise tolerance
- Nighttime restlessness or repeated position changes
- New cough, gag, or throat clearing
- Appetite and body-weight changes
- Weakness, collapse, or fainting
Ask your veterinarian how often each item should be checked. A puppy with a soft murmur and an older dog with documented chamber enlargement will not have the same plan.
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 between-visit murmur monitoring worksheet
Establish the baseline while your dog is feeling well, then use the same fields when something changes. Most murmur explainers describe causes and grades, but they do not give owners a non-diagnostic worksheet for respiratory, activity, rest, and appetite changes between appointments. Dog heart murmur symptoms are not unique to the heart, so this worksheet records a baseline while feeling well and repeatable changes without labeling their cause. The surrounding explanation keeps the section substantive even when a reader cannot use every field in the table.
| Observation | Baseline while feeling well | Change to record | What to share with the clinic |
|---|---|---|---|
| Resting respiration | Usual sleeping range and easy effort | Sustained higher range or visible effort | Counts, time, sleeping state, and short video if safe |
| Activity | Normal walk length, pace, and recovery | Lagging, stopping early, or slower recovery | Date, weather, distance, and whether the pattern repeats |
| Rest and sleep | Usual position and ability to settle | Pacing, repeated position changes, or sleeping upright | When it began and whether cough or fast breathing occurs too |
| Appetite and weight | Ordinary meal interest and stable weight | Skipped meals, gradual loss, or unexpected gain | Amount eaten, scale used, medication timing, and other signs |
| Cough or weakness | None, or an established pattern the vet knows | New cough, more frequent cough, wobbliness, collapse, or fainting | Trigger, duration, recovery, and whether emergency signs occurred |
Review the worksheet weekly during a stable period and sooner when a change appears. The purpose is to make the next veterinary conversation specific. It cannot determine murmur grade, heart size, disease stage, or whether medication is indicated.
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Resting respiratory rate: the most useful home trend
Measure respiratory rate when your dog is asleep or resting quietly. Do not count during panting, active dreaming, recent exercise, stress, or heat exposure. One rise and fall of the chest equals one breath.
The important comparison is your dog's own stable baseline. A sustained increase can be more meaningful than one outlying count. Recheck an unexpected reading when your dog is truly settled, then contact your veterinarian if the rate remains elevated or the dog has other signs.
The ACVIM consensus guidelines for canine mitral valve disease support home respiratory monitoring as part of follow-up for dogs at risk of heart failure. The guidelines also make clear that staging depends on clinical evaluation and evidence such as heart enlargement or CHF, not a home breathing number alone.
Do not wait for a threshold if your dog is visibly struggling to breathe. Appearance and effort outrank the app.
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 36-dog murmur analysis can and cannot show
Maven Pet published a July 2026 analysis of dogs with reported heart murmurs. The company compared 36 dogs whose onboarding information explicitly mentioned a murmur with 1,376 dogs reported as healthy and a broader cohort of 471 dogs with heart conditions.
The murmur group had a median resting respiratory rate of 15.1 breaths per minute, close to the 14.4 median in the reported-healthy group. The result is a helpful reminder that a murmur does not automatically mean a dog is breathing abnormally at rest. It also reinforces why a personal trend can be more useful than assuming every murmur should produce a high number.
The limitations matter. Thirty-six dogs is a small sample. Murmur status and health conditions came from owner onboarding information rather than a standardized cardiology examination, and the analysis did not establish murmur cause, grade, ACVIM stage, treatment, or outcomes. Maven appropriately describes the findings as directional rather than population-level. The analysis cannot show that the tracker diagnoses murmur progression or predicts CHF.
A customer experience, with the right context
In a July 2026 Trustpilot review, a customer named Nichole said her dog had an enlarged heart associated with a murmur and that she needed to monitor his respiration rate. She reported that setup was easy and that the device handled that monitoring along with additional tracking.
That experience is closely aligned with the practical burden many families describe: remembering to collect consistent resting counts. It remains one person's report. It does not verify medical accuracy for every dog or show that Maven can determine when medication is needed.
For a broader look at the signals and veterinary tests used in canine cardiac care, see Maven Pet's dog heart disease resource.
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.
Track the pattern behind activity and sleep
Activity data is most useful when it is interpreted in context. A quiet day after a busy outing is different from a steady loss of stamina across several weeks.
Note changes such as:
- Stopping earlier on the usual walk
- Lagging behind or refusing stairs
- Taking longer to recover after mild exercise
- Sleeping much more than usual
- Pacing or being unable to settle at night
- Choosing an upright or neck-extended sleeping position
Weather, joint pain, weight, medication, anxiety, and many noncardiac conditions can change activity. Share the pattern with your vet rather than labeling it as heart disease.
If your dog is older, WebVet's senior dog health guide can help you consider mobility, cognition, dental pain, vision, and other reasons daily behavior may change.
Know when a cough needs attention
A new cough deserves a veterinary call, but a murmur does not prove that the cough comes from heart failure. Airway disease is common in many small older dogs that also develop mitral valve disease.
Record when the cough occurs, how it sounds, how long it lasts, and whether it follows exercise, drinking, excitement, or sleep. A short video can be helpful when it is safe to make one. WebVet's guide to a dog coughing with heart failure explains why imaging is often needed to separate pulmonary edema from airway problems.
Never suppress a worsening cough with an over-the-counter human medication unless a veterinarian specifically directs you to use it.
Red flags that should not wait
Contact your veterinarian promptly for a persistent rise in resting respiratory rate, a new cough, reduced exercise tolerance, appetite loss, or an obvious change in sleep. The clinic can tell you whether the next planned recheck should be moved sooner.
Seek emergency care for:
- Open-mouth breathing at rest
- Blue, gray, or very pale gums
- Pronounced abdominal effort with breathing
- 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 Maven Pet or another tracker to confirm an emergency. Keep your dog calm and minimize exertion during transport.
Questions to ask at the next appointment
Bring your trend summary and ask specific questions:
- What is the most likely cause of this murmur?
- What grade is it, and has the grade changed?
- Does my dog need an echocardiogram or cardiology referral?
- Is the heart enlarged on imaging?
- What resting respiratory range should prompt a call for my dog?
- How much exercise is appropriate right now?
- Which symptoms should trigger an urgent or emergency visit?
- When should the murmur and heart size be reassessed?
Write down the answers. A clear plan reduces anxiety and prevents a wearable's routine variation from being treated as a diagnosis.
Frequently Asked Questions
Does a heart murmur mean my dog has heart failure?
No. A murmur is a sound, and many dogs with a murmur do not have CHF. Veterinary testing determines the cause, whether the heart is enlarged, and whether treatment or monitoring is appropriate. Follow the recheck plan and report new breathing, cough, activity, sleep, appetite, weakness, or collapse changes rather than assuming the murmur has progressed.
Can a dog live normally with a heart murmur?
Many dogs live active, comfortable lives with stable murmurs, especially when the underlying condition is mild or progresses slowly. Prognosis depends on the cause and stage, so follow the recheck plan your veterinarian provides. A baseline while your dog feels well makes later changes easier to describe, but home observations cannot predict an individual lifespan.
Should I limit exercise after a murmur is found?
Ask your veterinarian. Do not impose strict rest on an otherwise stable dog unless directed. The appropriate level depends on diagnosis, heart size, symptoms, age, fitness, and other health conditions. Track walk pace, distance, recovery, cough, and comfort so the clinic can adjust advice using the dog's response rather than a generic restriction.
Can Maven Pet grade my dog's murmur?
No. Murmur grading requires listening to the heart, and diagnosis may require imaging. Maven Pet records home trends that can add context between veterinary visits. It cannot identify the valve involved, measure chamber enlargement, detect pulmonary edema, or determine whether treatment is needed. Share the trend with the veterinarian who knows the clinical findings.
Is one high respiratory reading an emergency?
Not always. Verify that your dog was truly resting and recheck calmly. Note recent heat, exercise, stress, panting, or active dreaming that could affect the value. A sustained rise or any visible breathing difficulty requires prompt veterinary guidance, and labored breathing is an emergency regardless of the number or app result.
Is it serious for a dog to have a heart murmur?
It can be serious for a dog to have a heart murmur, but seriousness depends on the cause and its effect on the heart, not the sound alone. Many dogs with murmurs remain comfortable and active. A veterinarian uses the examination plus testing such as echocardiography or chest imaging when indicated. Meanwhile, a baseline while feeling well and clear respiratory, activity, rest, and appetite observations can help the clinic recognize meaningful change.
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
Mitral Valve Disease in Dogs: Tracking Respiratory Rate, Heart Rate, and Rest Between Vet Visits
Tracking a Dog’s Respiratory Rate Over Time: What a Rising Trend Can Tell Your Vet
Congestive Heart Failure in Dogs: How At-Home Trends Support Veterinary Care
