Mitral valve disease in dogs: what the murmur grade means, the ACVIM stages B1 to D, and what it costs in India

Signs of Mitral valve disease

The 9 signs to watch for are listed below. Any one of them is a reason to consult your nearby vet; none of them is a diagnosis.

• A new cough, worst at night or in the early morning
• Tiring on a walk the dog used to finish easily
• Faster breathing at rest, counted while the dog sleeps
• A murmur the vet hears before you notice anything
• Restlessness at night, or refusing to settle and lie flat
• Fainting or a brief collapse after excitement or exertion
• Appetite and weight falling away in a previously stable dog
• Pale or dusky gums together with laboured breathing
• A swollen belly, which points to the right side of the heart

Breeds on this site that document this condition

Each breed page below carries the figure for this condition with its denominator and its source. The 10 breeds listed are the ones on this site that document it, not a ranking of risk.

A vet heard a murmur. What that tells you, and what it does not

A heart murmur is a sound, not a diagnosis, and the grade your vet writes down measures how loud that sound is rather than how sick the heart is. In a middle-aged or older small dog a left-sided systolic murmur usually means mitral valve disease, and Cornell states plainly that veterinarians can hear a murmur months to years before an owner notices anything. The grade still decides very little on its own, and the evidence for that is a study of 578 small-breed dogs.

Start with what the sound is. The mitral valve separates the left atrium from the left ventricle, and when the ventricle contracts the valve should shut and send every drop forward to the body. A degenerated valve does not close cleanly, so some blood goes backwards into the left atrium, and the turbulence of that backward jet is what a stethoscope picks up. Cornell's cardiology service puts it in one sentence, that virtually all dogs with clinically important mitral and tricuspid regurgitation will have a cardiac murmur, and in the next sentence gives the caution nobody quotes, that most frequently early degeneration of the valve does not cause a murmur because the amount of leaking is not enough to make a sound audible at the body surface.

So the murmur arrives late, and it arrives loud or soft for reasons that are only loosely about severity. That is the part every page you will read gets wrong by omission.

The grading scale, and the fact that three authorities print three of them

Vets grade murmurs on the Levine scale, which runs from 1 to 6 by loudness and by whether the vibration can be felt through the chest wall. Vetic, an Indian clinic chain, names it as the six-point Levine scale and describes the steps. Purina India sets out the same six grades, from Grade I as barely audible to Grade VI as loud enough to be heard with the stethoscope held off the chest. Cornell's Riney Canine Health Center, writing for the same owner, says that heart murmurs are graded on a scale from 1 to 5, with 1 being mild and 5 being very loud and easily detected. Two of those three are describing the same scale and one is not, and an owner comparing a grade 5 in a Cornell article with a grade 5 at an Indian clinic is comparing different things. Ask which scale your vet used and write the answer on the file.

That table is the answer to the question Google asks as should I worry about a heart murmur in my dog, and it is built on 578 adult dogs under 20 kg with myxomatous mitral valve disease, graded by intensity and then scanned. The authors' own conclusion is careful. A four-level grouping separates clinically meaningful outcomes, soft murmurs in small-breed dogs strongly indicate subclinical heart disease, thrilling murmurs go with more severe disease, and other murmurs are less informative on an individual basis.

Read the two ends of that. A soft murmur is not nothing, because no dog with one was healthy, they simply had disease that had not yet remodelled the heart. A moderate murmur is close to uninformative, because 56 percent of the 161 dogs carrying one had a structurally normal heart. The grade tells your vet how urgently to scan. It does not tell you what stage your dog is in, and only an echocardiogram does that.

The silent dogs, which is why a clear stethoscope is not a clear heart

Auscultation misses a large share of affected dogs, and two registers measure how large. The Royal Kennel Club Heart Scheme has graded 2,279 Cavalier King Charles Spaniels since 2019 on both instruments, a murmur grade from the stethoscope and a mitral valve prolapse grade from the scan. Adding up the scheme's own seven-by-four grid, 1,313 of 2,279 dogs scored prolapse grade 1 or worse, 57.6 percent, while only 459 scored a murmur grade of 1 or worse, 20.1 percent. 895 dogs, 39.3 percent of the entire scheme, had a prolapsing valve on the scan and no audible murmur at all.

A second breed says the same thing on a smaller sample and a harder endpoint. Of 48 overtly healthy Norfolk Terriers aged six or over, 23 had murmurs and 41 had echocardiographic evidence of degenerative mitral valve disease, which leaves 18 dogs with the disease and no murmur. The authors state the conclusion directly, that echocardiographic changes consistent with mild disease can be seen in dogs without a heart murmur.

The practical consequence for an Indian buyer is in the dog breeder checks guide, and it is short. A breeder who tells you the vet listened and heard nothing has told you very little.

A murmur in a puppy is a different conversation entirely

In puppies a murmur is usually innocent and usually temporary. A Utrecht University team auscultated 584 client-owned clinically healthy puppies between 20 and 108 days old, in two surveys. In the pilot of 389 pups, 15 percent had a murmur; in the principal study of 195 pups, an innocent murmur was diagnosed in 28 percent. Those murmurs had a recognisable signature, systolic, mostly musical in character, mostly with the point of maximal intensity at the left cardiac base, and with a maximal intensity of 2 of 6.

The same study found why they fade. Hematocrit was significantly lower in the puppies with a murmur than in those without, at P = .023, and the authors conclude that physiologic anaemia contributes to the genesis of innocent murmurs in puppies and that rising hematocrit in a growing pup explains why the sound disappears. They add the caution that matters, that hematocrit did not distinguish innocent murmurs from abnormal ones. Cornell puts the timing on it, that most innocent murmurs are outgrown by 6 months of age, and that a puppy which does not outgrow one should be referred for an echocardiogram.

What mitral valve disease actually is, and how common it really is

Mitral valve disease in dogs is a slow, degenerative thickening of the mitral valve leaflets that stops them meeting cleanly, so blood leaks backwards into the left atrium with every beat. It is the commonest heart disease of dogs by a wide margin, accounting for more than 70 percent of all canine heart disease, and it is overwhelmingly a disease of small, old dogs. The numbers below all carry the population they were measured in, because the same disease reads very differently in a breed club and in a general practice.

The lesion itself is well described. The leaflets accumulate a thickened, gelatinous spongiosa layer, the collagen weave that keeps them stiff degrades, and the valve starts to balloon above the plane of its own annulus, which is the prolapse an echocardiogram measures. As the disease advances, the cords that tether the leaflets, the chordae tendineae, can stretch or snap, and a flail leaflet follows. The Hyderabad series that examined 695 geriatric Indian dogs lists exactly that set of findings on its scans, hyperechoic thickened leaflets, kinking, prolapse of one or both leaflets above the annular plane, flail and billowing, and rupture of chordae tendineae.

Nothing about that process is fast. Parker and Kilroy-Glynn describe a chronic, progressive disease whose first sign, usually a heart murmur, develops after the age of six, and note that the vast majority of the breeds at elevated risk are small or toy breeds averaging under 9 kg as adults.

How common, measured four ways, with four different answers

Prevalence depends entirely on who you counted. The largest and cleanest number comes from VetCompass, which searched the electronic records of 111,967 dogs attending 93 primary-care practices in England between January 2010 and December 2011. It found 405 dogs with a recorded diagnosis, a prevalence of diagnosed disease of 0.36 percent, and a further 3,557 dogs with a heart murmur consistent with the disease, giving 3,962 murmur cases in all, or 3.54 percent of the whole population.

Those four are not in conflict once you read the denominators. A general practice counting every dog that walks in gets 0.36 percent. A cardiologist writing about dogs over ten gets about 30 percent. An Indian hospital that pre-selected old dogs already coughing and tiring gets 61.43 percent. Any page that quotes one of those without the population attached is misleading you.

One collision is worth flagging, because it will confuse anyone who reads two of these sources side by side. Oyama writes that approximately 30 percent of dogs over age 10 possess the characteristic left-sided systolic murmur, while Parker and Kilroy-Glynn write that approximately 30 percent of dogs with the disease progress to mitral regurgitation and eventually heart failure. Those are two different 30 percents, one a prevalence in old dogs and one a progression rate among affected dogs, and they are routinely quoted as if they were the same number.

Age is the variable that dwarfs everything else

Breed gets the attention and age does the work. In the VetCompass model, adjusted for breed, sex, insurance, bodyweight and clinic, the odds of a diagnosis rose from a baseline in dogs aged one to four years to 7.03 at four to seven, 38.24 at seven to ten, 101.61 at ten to thirteen, and 150.76 in dogs of thirteen and over, with a 95 percent confidence interval of 78.11 to 290.96 on that last figure. The Hyderabad heart-failure series found the same shape from a different direction, with 51.37 percent of its 146 confirmed cases in dogs aged 10 to 14 years, 32.87 percent at 5 to 10, 10.27 percent over 14, and only 5.48 percent under 5.

Size runs the other way. Dogs of 20 kg and over had roughly half the odds of a diagnosis, 0.51 with a confidence interval of 0.36 to 0.74, which is why a large dog that coughs and tires is a different page on this site, dilated cardiomyopathy in dogs, and not this one.

What the breed studies add, which is a curve rather than a yes or no

Two breed surveys show what that age effect looks like inside a single breed. Beardow and Buchanan auscultated 394 American-bred Cavalier King Charles Spaniels and found left apical systolic murmurs in 22 percent overall, rising from 9 percent in dogs under one year to 56 percent in dogs of four and over and 100 percent in dogs of ten and over. They then re-examined 79 of those dogs a year later and found an incidence of new murmurs of 21 percent, so roughly one clear dog in five had a murmur twelve months on.

The same paper measured the head start this breed has over every other. Among 128 referral hospital cases of chronic mitral valve disease, the mean age at presentation was 6.25 years in the 17 Cavaliers against 12 years in the other breeds. That gap of nearly six years, not the eventual prevalence, is what makes the Cavalier a special case.

A smaller breed study makes the silent-dog point again from Sweden. Of 102 privately owned asymptomatic Chinese Crested dogs recruited through the breed club and scanned, mitral regurgitation was present in 39 dogs, 38 percent, while a systolic murmur was present in only 35, 34 percent, with mitral valve prolapse in 32 and tricuspid regurgitation in 29. The dogs with regurgitation were older, at a median of 9.5 years, and males were over-represented. The authors are careful about what they have shown, noting that the prevalence of regurgitation in this breed is similar to reports in other small breeds and that whether the regurgitation detected in these dogs is a sign of myxomatous disease is unknown.

The finding in that study that nobody quotes

Insured dogs had 3.56 times the odds of a diagnosis, with a confidence interval of 2.79 to 4.55, after adjusting for breed, age, sex and weight. Insurance does not damage a mitral valve. What it does is pay for the scan that turns a murmur into a diagnosis, so that figure is measuring detection, not disease. Every prevalence number on this page is a diagnosis rate in a population with a particular level of access, and in India, where access is the binding constraint, the true burden is certainly higher than anything anyone has counted.

Males also carried higher odds than females, 1.40 with a confidence interval of 1.12 to 1.74, and the Hyderabad heart-failure caseload was 66.44 percent male against 33.56 percent female. Two very different populations, the same direction.

The ACVIM stages A to D, one at a time, and what actually changes at each

The ACVIM stages are the spine of this disease, and they answer the only question that matters after a murmur is found, which is whether anything should be done today. Stage A is a dog at risk with no murmur, stage B is a structural leak with no heart failure ever, stage C is a dog that has been in heart failure, and stage D is heart failure that no longer responds to standard treatment. The line that decides treatment sits inside stage B, between B1 and B2, and it is drawn by measurement rather than by how the dog looks.

The 2019 ACVIM consensus panel, ten cardiologists chaired from North Carolina State University, revised the 2009 guidelines and describes the staging system's purpose in its own words, to develop screening programmes for dogs known to be at risk, to identify asymptomatic dogs early so they can be managed as chronic disease patients, and to identify dogs with advanced heart failure refractory to conventional treatment.

Stage A, and the one instruction that costs nothing

The consensus recommendation for stage A is a single line and it is free. Small breed dogs, including breeds with a known predisposition such as Cavalier King Charles Spaniels, Dachshunds, and Miniature and Toy Poodles, should undergo regular evaluations, meaning yearly auscultation by the family veterinarian, as part of routine health care. No drug treatment and no dietary treatment are recommended for any patient at this stage.

There is a breeding instruction attached to stage A too, and it is stronger than anything in Indian law. Potential breeding animals should no longer be bred if a murmur or echocardiographic evidence of mitral regurgitation is identified early, during the normal breeding age range of under six to eight years.

Stage B1, where doing nothing is the recommendation

Stage B1 covers a spectrum, from dogs with completely normal chamber dimensions and a normal vertebral heart score, through to dogs with visible enlargement that still does not meet the specific criteria below. For all of them the guideline is explicit, and it is worth quoting because owners find it hard to accept. Treatment is not recommended in these dogs because at this early stage progression to heart failure is uncertain, unlikely to occur within the recommended evaluation interval, and there is no evidence that medication is effective at this stage.

What B1 does buy is a date. Re-evaluation by echocardiography is suggested, or radiography where echocardiography is not available, and the point of the repeat is to catch the crossing into B2 while the dog is still well.

Stage B2, the four criteria, and the reason all four matter

Stage B2 is the whole ballgame, because it is the only stage where a drug delays the onset of heart failure in a dog that currently feels fine. The guideline names four criteria, and rates the recommendation Class I on strong evidence. The four are listed below.

• Murmur intensity of 3 of 6 or louder. The cheapest of the four and the only one available with a stethoscope alone.
• An echocardiographic left atrium to aorta ratio of 1.6 or more, measured in the right-sided short axis view in early diastole.
• A left ventricular internal diameter in diastole, normalised for bodyweight, of 1.7 or more. The normalising formula divides the measured diameter in centimetres by bodyweight in kilograms raised to the power 0.294.
• A breed-adjusted radiographic vertebral heart score above 10.5.

The panel adds the sentence that stops over-treatment. Ideally all these criteria should be met before initiating treatment, because treatment represents a lifelong commitment, and of the four, echocardiographic evidence of left atrial and ventricular enlargement is considered the most reliable way to identify dogs expected to benefit.

The normalised ventricular criterion is abstract until you convert it into a measurement for a real dog, which the guideline does in its own table. A few rows of that table are reproduced below so an owner can read their own report.

Where no echocardiogram is available, which is the ordinary Indian situation outside a handful of cities, the guideline allows a substitute. Clear radiographic evidence of cardiomegaly, meaning a general breed vertebral heart score of 11.5 or more, or a comparable breed-adjusted score where breed-specific normals exist, or evidence of accelerating enlargement across repeat films, can substitute for quantitative echocardiography to identify stage B2, rated Class I on expert opinion. A newer radiographic index of left atrial size, the vertebral left atrial size, is measured from the carina to the caudal edge of the left atrium and transposed onto the fourth thoracic vertebra, and values of 3 or more likely identify stage B2 in the absence of a scan.

The disagreement inside the panel, printed rather than smoothed over

At stage B2 the guideline recommends pimobendan on Class I strong evidence and recommends mild dietary sodium restriction on weak evidence. On angiotensin converting enzyme inhibitors it does something unusual and prints its own split. For patients in stage B2, or those whose left atrium has grown markedly across successive examinations, 5 of 10 panelists recommend treatment with an ACE inhibitor, rated Class IIa in geographic regions where these drugs are low cost, on weak evidence. Clinical trials of ACE inhibitors in stage B have shown mixed results. Beta blockade is not recommended routinely at this stage, rated Class III, because trials have shown no benefit to date.

India is precisely a geographic region where ACE inhibitors are low cost, so that half-of-the-panel recommendation is more relevant here than in the country the guideline was written in. It is still a decision for the veterinarian in front of your dog.

Stages C and D, and the words the guideline actually uses

Stage C covers every dog that has experienced an episode of clinical heart failure and is not refractory to standard treatment, and the guideline is emphatic that these patients continue to be categorised as stage C even after improvement or complete resolution of their clinical signs. A dog that coughed, was treated, and now looks entirely normal is a stage C dog, not a stage B dog, and its treatment does not stop. The one written exception is surgical, and it is the closest thing in the guideline to a reversal, that in exceptional cases which undergo successful surgical mitral valve repair, reclassification to stage B is warranted.

Stage D is defined as end-stage disease in which clinical signs of heart failure are refractory to standard treatment, where patients require advanced or specialised treatment strategies to remain clinically comfortable, and where, in the guideline's own words, at some point treatment efforts become futile without surgical repair of the valve. The panel splits both stage C and stage D into dogs needing hospital-based acute care and dogs who can be managed at home.

What to watch at home, and the breathing rate that means go today

Count the breaths, not the coughs. A sleeping dog's resting respiratory rate is the single most useful number an owner of a dog with mitral valve disease can collect, it costs nothing, and it rises before the dog looks ill. Cornell puts a normal dog at 15 to 30 breaths per minute and says that rates above 35 in a relaxed or sleeping dog signify heart problems and warrant an immediate trip to the veterinarian. Vetic, writing for Indian owners, sets its early-warning line lower, at above 30 at rest. Both thresholds are printed here because the two sources disagree and your vet will pick one.

Counting it is easier than it sounds. Watch the chest rise and fall for 15 seconds while the dog is genuinely asleep, count each rise, and multiply by four. Do it three or four evenings in a row while the dog is well, so you own a baseline rather than a single frightening number. PDSA, whose page is the best-structured owner page ranking on this query, makes the same recommendation and hosts a video of the technique, and says that one of the most helpful things an owner can do at home is to regularly record the resting breathing rate.

The symptoms of mitral valve disease that owners actually notice are listed above, and the Indian series describes the commonest of them with unusual precision. In 695 geriatric dogs presented at Hyderabad clinics, the cough was reported to be nocturnal, predominantly from late night to early morning, where the dog suddenly wakes with a cough and goes breathless for a few seconds before becoming normal, sometimes induced by physical activity. That description is worth more to an Indian owner than any list, because it is what the disease sounds like at 3 a.m. in a small flat.

The same paper records something else no other source mentions. About 30 percent of the presented dogs were reported as insomniac, standing or sitting up on their hind legs for short periods, without sleep for more than 24 to 36 hours. A dog that will not lie down flat is not being difficult. It is a dog that breathes better sitting up.

Why the cough happens, and why that matters for what you do next

The cough is usually mechanical rather than wet. Both Hyderabad papers attribute it to pressure on the left mainstem bronchus caused by left atrial enlargement, rather than to fluid in the lungs Kumar KS, Kumar VVVA. Diagnosis…. That distinction is practical. A cough from a big left atrium pressing on an airway and a cough from fluid in the alveoli look the same to an owner and need different responses, and only a radiograph separates them. It also means a cough alone does not prove heart failure, and an old small dog can cough for reasons that have nothing to do with the heart, which is why kennel cough in dogs is a real differential in a dog that has recently been boarded.

The first week after a murmur is found

Do these five things in order, in the week after your vet says the word murmur.

• Ask for the grade and the scale. Write down the number and whether it was out of five or out of six, because the two are in circulation.
• Ask where the murmur was loudest. A left apical systolic murmur in an old small dog points to the mitral valve; a murmur at the base in a young dog often does not.
• Start the breathing diary. Three or four sleeping counts while the dog is well, dated, on paper or in your phone.
• Book the echocardiogram, and ask what it will cost before you go. Indian prices for the same test differ by a factor of more than twenty-five and the cost section below has both ends of that range.
• Weigh the dog and write that down too. The stage B2 ventricular criterion is normalised to bodyweight, so the scan cannot be read without an accurate weight.

How it is diagnosed, and why the scan is the only test that settles the stage

To diagnose mitral valve disease properly a vet needs three things, a stethoscope to find the leak, a radiograph to size the heart and look for fluid, and an echocardiogram to measure the chambers and put the dog in a stage. Only the last of those decides treatment, because the stage B2 criteria that trigger a lifelong drug are echocardiographic measurements. Everything else narrows the question.

A presumptive diagnosis is genuinely easy and Oyama says so, that diagnosis is one of the easiest clinical aspects of the disease, because the hallmark finding is an adult small-breed dog with a left-sided systolic murmur, in which it is reasonable to assume the source is mitral regurgitation. The hard part is not naming the disease. The hard part is knowing which of the four stages the dog is standing in.

What the echocardiogram measures, in plain terms

An echocardiogram is an ultrasound of the heart, performed with the dog awake and lying on its side, usually with a small patch of fur clipped. VOSD describes the procedure as taking between 20 and 45 minutes depending on how cooperative the dog is, with no recovery period, and notes that sedation is rarely necessary unless a dog is particularly distressed. The cardiologist measures the left atrium against the aorta to get the ratio the staging system uses, measures the ventricle in diastole and normalises it to bodyweight, looks at the leaflets themselves for thickening, kinking and prolapse, and uses Doppler to see the regurgitant jet and estimate how much blood is going the wrong way Voice of Stray Dogs.

The guideline warns that this is not trivial on a small heart. Echocardiographic identification of mild left atrial or ventricular enlargement can be challenging, and comparisons to breed-specific normal values may be required. That sentence is the reason breed-specific reference ranges matter, and it is where India has quietly contributed something.

The Indian contribution nobody cites, which is a set of yardsticks

ICAR-IVRI Izatnagar has published breed-specific M-mode echocardiographic reference ranges for two of the breeds Indian owners actually keep. For the Indian Spitz the team measured 24 clinically healthy conscious dogs aged 3 to 5 years and weighing 7 to 18 kg from a right parasternal long axis view, and reports left ventricular dimensions, left atrial and aortic diameters and mitral valve parameters, concluding that the data can be used as breed-specific reference values for cardiac disease diagnosis. The same division published the same exercise for 24 conscious clinically healthy Labrador Retrievers, and found a significant breed effect on some parameters, which is the whole argument for doing it breed by breed.

Neither paper is a prevalence study and neither claims to be. What they are is the measuring stick, and an Indian cardiologist deciding whether a 10 kg Indian Spitz has an enlarged ventricle is better served by numbers taken from 24 Indian Spitz dogs than by a general canine reference interval. Both papers were found by the author-affiliation search and neither appears in the title search, which is covered in the India section below.

The radiograph, the vertebral heart score, and a very Indian research answer

Where a scan is out of reach, the radiograph carries the load. Cardiac size is measured as the vertebral heart score, which counts the long and short axes of the cardiac silhouette in vertebral body lengths, and above 10.5 breed-adjusted it is one of the four stage B2 criteria. Both Hyderabad series used it. The heart-failure series recorded vertebral heart scores ranging from 11.8 to 13.2 in its confirmed cases, and the geriatric mitral series recorded a mean of 12.2 in its valve-disease dogs.

The score's known weakness is that it depends on a human placing landmarks by eye, and observers disagree. An Indian review addresses exactly that. A team at Pandit Deendayal Energy University in Gandhinagar, Gujarat, searched three databases, screened 3,729 records, found 94 studies meeting the inclusion criteria and evaluated 17 in detail, on deep learning methods for automated vertebral heart score estimation, and reports that EfficientNet-B3 and EfficientNet-B7 performed most consistently for landmark regression and score prediction. The same review is honest about what is missing, that differences in dataset characteristics, annotation protocols and the limited availability of multi-centre validation continue to restrict clinical implementation. It is not a tool an Indian owner can use today. It is evidence that the measurement problem in the cheapest cardiac test is being worked on from India.

The blood test, and what it is and is not for

NT-proBNP is a blood marker that rises when heart muscle is stretched and stressed. Cornell describes it as a test that may indicate advanced heart failure when a large amount of regurgitation is present, and as a useful monitoring tool Cornell University College of Veterinary…. Both Hyderabad papers cite a combined threshold from the wider literature, that a radiographic vertebral heart score above 12 together with a plasma NT-proBNP above 1,500 pmol/L are significant markers of threatened heart failure in dogs with chronic mitral valve disease. It does not replace the scan and the guideline does not treat it as a staging test.

An ECG has a narrower job here. Cornell says an electrocardiogram may be performed to further characterise dogs with valve degeneration but that this test is usually not as important as the physical examination, the radiograph and the echocardiogram. The Hyderabad heart-failure series still found real abnormalities on it, wide or elevated P, R and QRS waves, atrial fibrillation and ventricular premature complexes, and ran the whole study on a smartphone-based single-lead device recording for 30 seconds in an unsedated dog. That is a rig an Indian district practice can actually own.

Treatment in general terms, and the stage at which starting it changes the answer

Treatment of mitral valve disease in dogs is staged, not standard, and the single most consequential decision is when it starts rather than what it is. Starting an inodilator at stage B2, before a dog has ever shown a sign, delayed the onset of heart failure or cardiac death by a median of 462 days in a 354-dog randomised trial. No dose appears anywhere on this page. What a dog needs, and how much, is a decision for the veterinarian examining it.

Four drug classes do the work. An inodilator makes the heart contract harder and opens the vessels it pumps into, a diuretic pulls fluid out of the lungs, an ACE inhibitor blunts the hormonal cascade that makes a failing heart retain salt and water, and an aldosterone antagonist blocks part of that same cascade further down. Cornell lists the same set as the drugs commonly used, diuretics, vasodilators, positive inotropes and agents for specific problems such as high pressure in the lung vessels, and stresses that the drugs selected and the doses are titrated to the need of each dog and that early disease is not treated the same as advanced disease.

The EPIC trial, which is why stage B2 exists as a treatment threshold

The EPIC study randomised 360 client-owned dogs with preclinical mitral valve disease and a left atrial to aortic ratio of 1.6 or more, a normalised left ventricular diameter of 1.7 or more, and a vertebral heart sum above 10.5, to pimobendan or to a visually identical placebo, prospective, blinded and multicentre. The per-protocol population was 354 dogs, 178 on the drug and 176 on placebo, with a median age of 9.0 years and an interquartile range of 7 to 11.

Read the difference in the first row in months rather than days. Fifteen months of ordinary life, in a nine-year-old dog, bought by starting a tablet at the right moment. The trial's own conclusion is that giving the drug to dogs with this disease and with echocardiographic and radiographic evidence of cardiomegaly prolongs the preclinical period and is safe and well tolerated. That result is the reason the 2019 guideline moved treatment earlier than the 2009 version did.

The trial population is also a useful breed census of who actually gets this disease badly enough to enrol. Of the 354 dogs, 161 were Cavalier King Charles Spaniels at 45.5 percent, 21 were Dachshunds at 5.9 percent, 13 were Miniature Schnauzers at 3.7 percent, 8 each were Poodles and Yorkshire Terriers at 2.3 percent, 98 were other pure breeds and 45 were mixed breeds at 12.7 percent.

The QUEST trial, which is what happens once heart failure has arrived

Stage C has its own trial. QUEST recruited 260 client-owned dogs already in congestive heart failure from mitral valve disease at 28 centres in Europe, Canada and Australia, excluded 8, and randomised 124 to pimobendan and 128 to benazepril, each on top of conventional therapy. One hundred and ninety dogs reached the primary endpoint, a composite of cardiac death, euthanasia for heart failure or treatment failure, and the median time was 188 days overall, 267 days in the pimobendan arm against 140 days in the benazepril arm, a hazard ratio of 0.688 with 95 percent confidence limits of 0.516 to 0.916 and P = .0099.

Two details in that paper are worth an owner's attention. A longer time to the endpoint was associated with being a Cavalier King Charles Spaniel, with needing a lower diuretic requirement, and with a higher creatinine concentration, while increases in left atrial to aortic ratio, vertebral heart scale and systolic ventricular diameter, and a worse exercise tolerance, all predicted a shorter time. The breed with the worst reputation for this disease did comparatively well once it was in failure, which is not what most owners expect.

Diet, weight and the things that are not drugs

Mild dietary sodium restriction is recommended from stage B2, with a highly palatable diet carrying adequate protein and calories to maintain optimal body condition, rated Class IIa on weak evidence. Weight matters for a mechanical reason Cornell states plainly, that obesity makes it harder to breathe, which strains the heart, and harder to exercise, and that exercise is good for the heart. Keeping a heart-disease dog lean is covered on the obesity in dogs and cats page and is not optional here.

PDSA sets the exercise rule sensibly for owners who want a number, that dogs with this disease should have regular short walks to stay fit, and that walks much longer or more strenuous than the dog is used to put the heart under a lot of pressure. The daily plan belongs to your vet, because what is safe at stage B1 is not what is safe at stage C.

Mitral valve surgery, what it achieves, and what it costs in risk

Surgical repair of the valve exists, works, and is the only intervention the guideline treats as potentially stage-reversing, since a dog undergoing successful surgical mitral valve repair may be reclassified from stage C back to stage B. The panel rates it Class IIa on moderate evidence for advanced stage B2, for clients who can afford and access repair at the few centres demonstrating acceptably low complication rates and durable results.

The largest published experience is a single Japanese centre and its numbers are the honest ones to quote. In a cohort of 2,089 client-owned dogs that underwent mitral valve repair between 2016 and 2023, the 30-day all-cause mortality rate was 4.9 percent, or 102 of 2,089. A separate long-term series from the same centre followed 1,019 dogs in ACVIM stages B2, C and D operated on between January 2017 and December 2020, and found 61 dogs reaching a composite of death, post-operative heart failure or a second repair within the first 100 days and 211 doing so between 100 and 1,400 days, at incidence rates of 19.6 and 7.1 events per 1,000 dog-months respectively. Stage D dogs carried 2.2 times the daily hazard of an early event compared with stage B2 dogs, and no dog in the series needed a second repair.

One in twenty dogs does not survive the first month, and the risk of an early event more than doubles if you wait until the disease is refractory. That is the trade, stated in numbers rather than adjectives. What it costs in India is in the next section.

How long a dog lives with it, and what the final stages actually look like

Most dogs with a leaking mitral valve die of something else. Approximately 30 percent of dogs with the disease progress to significant regurgitation and eventually heart failure, which means the majority never reach stage C at all. For the minority who do, the published median survival after a diagnosis in general practice is 25.4 months, and after a murmur alone it is 33.8 months. Those are medians in a named population, not a prediction about your dog.

Google India asks this question twice on the same day. The live People also ask box on 24 September 2026 carried both How long do dogs live with mitral valve disease? on the bare query and How many years can a dog live with a heart murmur? on the India query, which is the same worry asked from two directions. Both are answered verbatim below, and the two answers carry different figures because the two populations behind them are different.

The largest general-practice survival figures come from the same VetCompass population as the prevalence numbers. Among 116 dogs newly diagnosed during the study window, 58 died, and the median survival time for all-cause mortality was 25.4 months from detection with a 95 percent confidence interval of 20.4 to 34.4 months, at a mean age at diagnosis of 9.52 years. Among a random sample of 407 dogs with a murmur but no formal diagnosis, 121 were incident cases, 49 died, and the median survival was 33.8 months with a confidence interval of 23.7 to 43.1 months, from a mean age of 9.73 years when the murmur was first recorded.

Three things fall out of that table. The murmur-only group outlived the diagnosed group by more than eight months, which is what you would expect if a formal diagnosis tends to follow a scan that was ordered because the dog was worse. A referral population did worse than a general-practice population, 19.5 months against 25.4 Mattin MJ, Boswood A, Church DB, because referral centres see the harder dogs. And the two EPIC arms, which are the cleanest comparison because they were randomised, differed by 157 days.

What predicts a shorter time, measured rather than guessed

Borgarelli and colleagues followed 558 dogs of 36 breeds and tested which variables actually forecast death. On univariable analysis, age over 8 years, syncope, a heart rate above 140 beats per minute, dyspnoea, arrhythmias, heart failure class, diuretic therapy, an end-systolic volume index above 30 mL per square metre, a left atrial to aortic root ratio above 1.7, a transmitral E wave peak velocity above 1.2 metres per second, and involvement of both mitral leaflets were all associated with survival. When all of them were modelled together, only three survived for all-cause death, syncope, the left atrial ratio above 1.7 and the E wave velocity, and for cardiac death the only significant variable left was the left atrial to aortic ratio above 1.7.

That is worth sitting with. Of everything a vet can measure, the size of the left atrium relative to the aorta is what independently predicts a cardiac death, and it comes off the same scan that decides the stage. The authors' overall conclusion is measured and reassuring, that mild disease is a relatively benign condition in dogs while some clinical variables identify individuals at higher risk who need closer monitoring or earlier intervention.

The final stages, answered honestly

Stage D is the final stage and the guideline defines it by response rather than by a measurement. It is end-stage disease in which the clinical signs of heart failure are refractory to standard treatment, where the dog needs advanced or specialised strategies to stay clinically comfortable, and where, in the panel's own words, at some point treatment efforts become futile without surgical repair of the valve. Practically, a stage D dog is one whose fluid keeps coming back on treatment that used to hold it.

What that looks like at home is fluid, effort and exhaustion. Breathing is fast and laboured at rest, the cough does not settle, the dog cannot lie flat, appetite goes, and the belly may swell if the right side of the heart is also failing. PDSA states the outcome plainly and without softening it, that in serious cases which do not respond to medication the disease can shorten life expectancy even to a few days or weeks. The same page is equally clear that some dogs with this disease live with no symptoms for many years, sometimes their whole lives.

Surgery is the one thing that changes the trajectory at this end, and the risk of waiting for it is quantified. In the Japanese series of 1,019 operated dogs, stage D dogs carried 2.2 times the daily hazard of an early postoperative event compared with stage B2 dogs. Waiting until the drugs stop working makes the operation more dangerous, not less.

Can any of this be reversed, and the words the sources actually use

Cornell's cardiology service answers this in one sentence, that treatment of this disease is not curative but palliative, and adds that further research is really required to find an early therapeutic intervention that stops the degeneration itself. No drug cures a degenerated mitral valve Keene BW, Atkins CE, Bonagura JD, Fox PR. The only intervention the guideline treats as potentially reversing the stage is surgical repair, and even there the wording is careful, that in exceptional cases which undergo successful surgical mitral valve repair, reclassification from stage C to stage B is warranted.

So the honest answer to an owner asking whether this is curable is that the disease is not curable with medication and is sometimes correctable with surgery at a 4.9 percent thirty-day mortality in the largest published series Cornell University College of Veterinary…. For most Indian dogs the realistic goal is years of ordinary life on tablets, not a cure Boswood A, Haggstrom J, Gordon SG, Wess G.

Mitral valve disease in India: two Hyderabad series, a Rs 300 echocardiogram, and a law that never mentions the heart

India has published real evidence on this disease and almost nobody cites it, because it is not in PubMed. Two hospital series from Hyderabad, one screening 9,369 dogs and one examining 695 geriatric dogs, sit in the Indian Journal of Animal Research. The cost of finding out ranges from Rs 300 at a government veterinary teaching hospital in Chennai to Rs 3,000 to Rs 8,000 at a private specialist centre. And the only Indian rule that names inherited defects in breeding dogs names eleven of them, none cardiac.

The Hyderabad heart-failure series, 9,369 dogs

Between 2017 and 2020, the Teaching Veterinary Clinical Complex at the College of Veterinary Science, Rajendranagar, and the Veterinary Hospital at Bhoiguda, Secunderabad, saw 9,369 adult dogs presented with signs of various systemic diseases. Of those, 309 showed manifestations suggestive of heart failure, and after electrocardiography, thoracic radiography and echocardiography, 146 were confirmed. The overall prevalence of heart failure was therefore 1.55 percent of the 9,369 dogs, and 47.25 percent of the 309 suspected cases. The other 163 of 309 turned out to have respiratory disorders in 69 dogs, renal insufficiency in 57, hepatic insufficiency in 26, pyometra in 7 and anaemia in 4.

That last sentence is the most clinically useful thing on this page for an Indian owner. More than half of the dogs brought in looking like heart failure did not have it. A coughing, tiring old dog in Hyderabad was more likely to have a chest, kidney or liver problem than a failing heart, and pyometra in dogs and cats accounted for seven of them.

The counts in the third column were computed by Bonbeno from the published percentages and they add to 146, which is the study's own total. Read the table as a picture of the Indian pet population rather than as a ranking of breed risk, which is what the authors themselves say, attributing the pattern to the predominance of Labrador Retrievers and Pomeranians in that geography. The Labrador share is also inflated by the fact that this series counted all heart failure, including dilated cardiomyopathy, which is a large-breed disease and is covered on the dilated cardiomyopathy in dogs page.

Age and sex in the same 146 dogs ran as the international literature predicts. Cardiac disease was recorded in 51.37 percent of cases in dogs aged 10 to 14 years, 32.87 percent at 5 to 10 years, 10.27 percent over 14 and 5.48 percent under 5, and 66.44 percent of affected dogs were male against 33.56 percent female.

The Hyderabad geriatric series, and the inconsistency in it that you should know about

The second paper is specifically about this disease. From 1,695 geriatric dogs presented to the university clinical complex and other Hyderabad clinics, 695 were selected on the basis of exercise intolerance, poor physical activity, respiratory distress and cough, and after auscultation, chest radiography and two-dimensional echocardiography, 427 of 695, or 61.43 percent, were confirmed with myxomatous mitral valve disease. Physical examination found a grade II to IV pansystolic murmur at the mitral area on the left side of the chest, and radiography showed left atrial bulge, tracheal elevation and pulmonary congestion at a mean vertebral heart score of 12.2.

The paper is internally inconsistent about its own sampling frame and this page states that rather than hiding it. Its abstract says the dogs were presented between 2015 and 2020 and describes the selection as medium to large size breed dogs above 8 years, while its materials and methods section says 2013 to 2016 and describes the selection as small breed dogs above 9 years. The individual scans it illustrates are of a Cocker Spaniel, a Beagle, a Lhasa Apso, a Pomeranian and a Dachshund, which are small and medium dogs. Treat 61.43 percent as a figure from a pre-selected Indian geriatric caseload with an unclear date range, not as a population prevalence, and it is still the largest Indian denominator anyone has published on this disease.

The cost of echocardiography in India, which differs by a factor of more than twenty-five

Madras Veterinary College Teaching Hospital in Chennai, part of Tamil Nadu Veterinary and Animal Sciences University and listing Cardiology among the referral units of its Department of Medicine, publishes its fee structure in a column headed COST IN RUPEES. VOSD, an Indian animal welfare organisation whose page is medically reviewed, publishes a private-sector range for the same test. Both are reproduced below.

The spread between Rs 300 and Rs 8,000 is a factor of more than twenty-six for the same named test, and it is the single most actionable fact on this page for an Indian owner. Every rupee figure here was run through the exchange-rate test, divided by 84.38 and by 74, and none of them resolves to a round dollar amount, so none is a converted foreign price list. VOSD's own page names the drivers of the private range, whether the operator is a general practitioner with an ultrasound machine or a board-certified cardiologist, the equipment, whether Doppler is included and whether a written report is provided.

Where you live moves the private price more than anything else about your dog. VOSD names the pattern directly, that costs in metropolitan cities such as Mumbai, Delhi, Bengaluru, Chennai and Pune tend to be higher than in smaller cities, reflecting the infrastructure and specialist availability required. Its echocardiography page says the same thing about the scan, that clinics in metropolitan areas with dedicated cardiology units sit at the higher end of the Rs 3,000 to Rs 8,000 range. The government rate card does not move that way, which is the argument for finding out whether a veterinary college hospital is reachable before you book anywhere else.

The Chandigarh line is the other half of the Indian picture and it deserves its own sentence. The Union Territory's government veterinary fee table has no echocardiogram line, no ECG line and no ultrasound line at all, and its only imaging entry is an X-ray fee of Rs 30 per film carrying the parenthetical note that the radiology wing is not functioning. Access, not price, is what actually limits cardiac diagnosis in most of India.

Is pimobendan available in India, and what does it cost

Pimobendan is stocked and sold in India on prescription, under Indian-market brands rather than only as the original. Supertails lists Veko Petmedin pimobendan tablets for dogs and cats in a pack of 30 at Rs 1,137 against a maximum retail price of Rs 1,172, marked prescription-only. TNMEDS lists Pimoheart, marketed by Heilen Animal Health, in a pack of 30 at a maximum retail price of Rs 2,150 inclusive of all taxes, also prescription-required. The two listings differ because they are different brands at different tablet strengths, and which strength a dog needs is set by its weight and by its veterinarian, which is why no strength and no dose is printed on this page.

Both figures pass the exchange-rate test. Rs 1,137 converts to 13.47 or 15.36 US dollars and Rs 2,150 to 25.48 or 29.05 dollars at the two rates, neither of them a round foreign number, so these are Indian retail prices and not a converted list. The practical consequence is that the drug with the strongest evidence in this disease costs an Indian owner roughly the price of a month of decent dog food.

Surgery is a different order of money and VOSD publishes the only Indian figures Bonbeno could open. Its table prices heart valve repair or replacement at Rs 1,50,000 to Rs 4,00,000 and open heart surgery at Rs 2,00,000 to Rs 5,00,000, and the page labels its own table as general estimates for awareness purposes only, adding that open heart surgery is performed at very few centres in India. Those two ranges are round numbers that sit close to two thousand and five thousand US dollars at the rates of the last few years, so this page reports them as the estimates VOSD says they are rather than as a rate card.

What Indian law says about breeding a dog with a leaking valve, which is nothing

The Prevention of Cruelty to Animals (Dog Breeding and Marketing) Rules, 2017, notified as G.S.R. 496(E) on 23 May 2017, are the only Indian instrument that names inherited defects a breeding dog must be tested for. Second Schedule paragraph 8(10) reads that the dogs shall have been tested for genetic defects, including hip dysplasia, progressive retinal atrophy, night blindness, hypothyroidism, entropion, ectropion, overshot, undershot jaw, wry mouth, two or more missing teeth, unilateral cryptorchid or full cryptorchid males. Eleven defects are named and not one of them is cardiac.

Two qualifications matter. The word including makes that list illustrative rather than exhaustive, so mitral valve disease is unnamed rather than formally excluded. And the rule names no test, no threshold and no laboratory for any of the eleven, which makes enforcement against a breeder difficult in practice. Against that, the ACVIM consensus tells a breeder exactly what to do, which is to stop breeding any dog in which a murmur or echocardiographic mitral regurgitation is found during the normal breeding age range of under six to eight years. An Indian buyer's leverage is the question, not the statute, and the dog breeder checks guide sets out how to ask it.

A controlled absence: what PubMed does and does not hold on Indian mitral valve disease

Both PubMed instruments were run on 24 September 2026 with their query translations recorded. The title and abstract search, combining mitral or myxomatous or endocardiosis with dog or dogs or canine and India[tiab], returned 2 records. The author-affiliation search, identical except for India[ad], returned 5. Controls run through the identical route in the same session, substituting parvovirus for the cardiac terms, returned 40 and 84 records respectively, so both instruments were working.

All seven records were then opened through efetch, and the result is a clean demonstration of why the title search cannot be trusted alone. The 2 records it returned are both artefacts of the words India ink, a laboratory stain: a 1989 Japanese anatomy study of lymphatics in dog atrioventricular valves from the Medical College of Oita, and a 1975 American study of cardiac lymphatic obstruction in which the ventricular walls were injected with India ink. Neither has anything to do with India. The affiliation search returned one further artefact, a 1995 comparative anatomy paper from Madras Christian College that matched on dog shark, and one Indian congenital case report of Ebstein's anomaly in a French Bulldog from Guru Angad Dev Veterinary and Animal Sciences University in Punjab, which is a tricuspid malformation and not this disease.

The other three affiliation hits are the real ones, and the title search finds none of them. Two are the ICAR-IVRI Izatnagar breed-specific echocardiographic reference sets for the Indian Spitz and the Labrador Retriever Gugjoo MB, Hoque M, Saxena AC, and the third is the Gujarat deep-learning review of automated vertebral heart scoring. So the honest summary is not that India has no published work on this disease. It is that India's two largest clinical series are in the Indian Journal of Animal Research and are invisible to both PubMed searches, while the work PubMed does hold from India is about measurement rather than prevalence.

Living with a dog that has a leaking valve, in an Indian house

Living well with this disease comes down to four habits, a weekly weight, a sleeping breath count, a heat plan and a vet who auscultates the chest at every visit. None of them costs anything. Between them they catch the transition from one ACVIM stage to the next, which is the only moment at which what you do changes.

Keep the dog lean, and keep doing it. Cornell's reasoning is mechanical rather than moral, that obesity makes it harder to breathe, which strains the heart, and harder to exercise, and that exercise is good for the heart. A weekly weight on the same bathroom scale, recorded, is enough. Weight loss in the other direction is also a signal, because cardiac cachexia is a real feature of advanced disease and appetite falling away in a stable dog is worth a call.

The heat, which is the Indian variable nobody writes about

A dog with a compromised heart has less cardiac reserve to move blood to the skin and shed heat, which is why summer afternoons and pre-monsoon humidity are a bigger problem for this dog than for the one next door. The practical rules are in the heat safety for dogs in India guide and they matter more here, not less. Walk at first light and after dark, keep a fan or cooler on the dog's usual spot, and do not let a dog with a known murmur sleep in a shut room that bakes.

Exercise is not cancelled, it is capped. PDSA's guidance is that dogs with this disease should have regular short walks to keep them fit and active, and that walks much longer or more strenuous than they are used to can put the heart under a lot of pressure. What is safe changes with the stage, and the plan is your veterinarian's to set for your dog.

The monitoring log, which is the cheapest diagnostic you will ever own

Keep these five things in one place and bring them to every appointment.

• The sleeping breath count, three or four readings a week, dated. Cornell's line for an immediate visit is above 35 breaths per minute in a relaxed or sleeping dog.
• The weekly weight, on the same scale, because the stage B2 ventricular criterion is normalised to bodyweight.
• The murmur grade and the scale it was given on, dated at every visit, so a change is legible.
• The last echocardiogram's numbers, specifically the left atrium to aorta ratio and the normalised ventricular diameter, because the ratio above 1.7 is the one independent predictor of cardiac death in a 558-dog series.
• The cough diary, noting time of night, since the Indian series describes it as predominantly late night to early morning.

Anaesthesia, travel and the ordinary rest of life

A dog with a murmur is not automatically a dog that cannot be anaesthetised, but it is a dog whose anaesthetist needs the scan. Cornell makes the point about young dogs undergoing spay and neuter, that an echocardiogram gives the surgeon important information about anaesthetic risk, and the same logic applies to an eleven-year-old Pomeranian booked in for a dental. Tell the clinic about the murmur when you book, not on the morning.

Air travel and long train journeys need the same conversation in advance, and the practicalities are in the flying with pets from India guide. Insurance is worth pricing early rather than after a diagnosis, because a recorded murmur is a pre-existing condition on most Indian policies; the pet insurance in India guide covers what is and is not excluded.

The rest of the routine is ordinary senior-dog care, and the senior dog care guide covers it, with one addition. Most dogs on this page are over eight, and a vet who listens to the chest at every single visit, and writes down what was heard, is worth more than any annual package. That is the whole of stage A screening and it costs the price of a consultation.

Knowing when enough is enough

Stage D ends somewhere, and PDSA says the thing most pages avoid, that if a dog's quality of life is poor and treatment is not working or is not possible, an owner may need to discuss the difficult decision of putting the dog to sleep to prevent future suffering. The measures that matter at that point are not the echocardiogram numbers but whether the dog can breathe comfortably, sleep lying down, eat and enjoy anything. When your pet dies in India covers what follows, and it is a decision to take with the veterinarian who knows the dog, not from a page.

Most owners reading this are nowhere near that. A dog with a grade 2 murmur and a normal scan is a stage B1 dog with no treatment recommended and a repeat appointment in the diary, and roughly seven in ten dogs with this disease never progress to heart failure at all.