Heart Murmurs in Dogs

heart murmur in dogs

Heart murmurs are found when a veterinarian listens to a dog’s heart and hears a whooshing sound. It’s not constantly a reason for concern, however it can be. In dogs, common causes consist of heart valve issues, heartworm disease, heart problems, growths, or weakening of the heart muscle. If your dog has problem breathing, sounds busy or coughs, has a pot tummy, passes out, or suddenly collapses, he could have a heart condition. Treatments can include surgery or addressing any underlying problems that might be causing the murmur.

What Is It?

A heart murmur is an abnormal sound that a veterinarian hears when listening to a dog’s heart through a stethoscope. Normally, a veterinarian hears 2 noises, a “lub” and a “dub,” which are the sounds of the heart valves closing as blood circulates through the heart. An additional “whooshing” sound or other noise, called a heart murmur, is generally associated with a disturbance of the generally smooth flow of blood through the heart.

Vets rank the intensity or volume of a heart murmur in grades from one to 6, with one being hardly audible and six being the loudest. There is also a one-to-five ranking system that works the exact same method. These grades do not necessarily associate with the seriousness of the heart condition; they are merely one of several ways that veterinarians attempt to characterize the murmur.

Though it’s not considered normal, a heart murmur is not constantly a cause for concern. It may, nevertheless, be an indication of a heart problem. Depending upon your dog’s condition, the veterinarian might wish to carry out additional diagnostic tests to figure out the cause of the murmur.

Symptoms of Heart Murmurs in Dogs

Heart murmurs are brought on by any number of conditions that can produce turbulence in the circulation of blood through the heart. In dogs, typical causes for heart murmurs consist of:

  • Heart valve shortages or obstructions
  • Flaws in the heart walls
  • Dilated cardiomyopathy (weakening of the heart muscle walls).
  • Heartworm disease.
  • Endocarditis (an infection of the heart valves).
  • Tumors.

Sometimes, a vet finds a heart murmur in a young pup. Though this might suggest the existence of a hereditary heart condition (a defect the puppy was born with), in most cases it is what is called an innocent murmur, indicating that it is not associated with a heart problem. These murmurs usually vanish by the time the animal has to do with 4 months of age. If a murmur does not solve, your veterinarian might recommend diagnostic screening to investigate it further.

Not all dogs with a heart condition show outward signs. However, if you have been told that your dog has a heart murmur, you should expect signs such as:

  • Coughing.
  • Hard or rapid breathing.
  • Congestion or “loud” breathing.
  • Exercise intolerance (hesitation to workout).
  • Weakness or lethargy (exhaustion).
  • Passing out episodes.
  • Gray or blue gums.
  • Stomach distention (a pot-bellied appearance).
  • Collapse.

If your dog displays any of these signs, call your veterinarian for recommendations or to set up an examination.

Small Puppies

Soft heart murmurs (grade 1/6 to 2-3/6) can take place in young animals and are of no effect to them. These kinds of murmurs are called “innocent” murmurs. They are soft and generally go away by 14 weeks of age.

A cardiologist should evaluate Loud heart murmurs (Grade 3-4/6 to 6/6) in a new young puppy or cat. This may indicate that genetic (present at birth) heart problem is present. The cardiologist will perform an echocardiogram along with other tests (EKG, blood pressure, etc.) to assess the heart and figure out if congenital heart disease is present. Depending on the disease present, some hereditary diseases can be fixed or made better with an interventional catheter procedure.

Older, Small Breed Dog

Heart murmurs in these dogs might suggest that these dogs have leaking mitral valve (the heart valve in between the left atrium and left ventricle). The mitral valve’s task is to enable blood to flow from the left atrium to the left ventricle but not permit blood to flow backward from the left ventricle to the left atrium. This valve degenerates as a dog’s age, and when it does, the older valve permits blood to leakage in reverse. We describe this disease as chronic valve disease, endocardiosis or degenerative mitral valve disease.

Mild chronic valve disease that leads to small leakages across the mitral valve generally does not create an issue for a dog. The disease is gradually progressive most of the times, and the leak will continue to intensify over months to years. If the disease ends up being severe, the dog is at danger for establishing congestive heart failure. Heart disease indicates that the leak across the heart valve overwhelms the heart and fluid goes from the heart backward into the lungs (instead of from the heart forward to the body). Signs of congestive heart failure consist of cough (particularly a cough at rest), a fast breathing rate, problem breathing, fainting, weakness, sleepiness, workout intolerance, and stomach distension.

A cardiologist can perform an echocardiogram and determine the stage of chronic valve disease present. The presence or lack of heart disease is then detected by X-ray of the chest. If heart disease exists, oral medications can be recommended and some dogs can do well with these medications for 1-2 years.

Middle-aged to Older Big Breed Dog

…especially a Doberman Pinscher, Irish Wolfhound, Great Dane, Boxers, St. Bernards, Newfoundlands, Cocker Spaniels, Dalmatians or Portuguese Water Dogs.

Heart murmurs in these dogs might indicate that they have a disease called dilated cardiomyopathy (with a subsequent leaky mitral valve). Dilated cardiomyopathy is a disease of the pumping chamber (ventricle) of the heart where the muscle becomes weakened and the contraction of the heart is reduced. When the ventricle is not able to pump blood to the body, fluid goes from the heart backward into the lungs (instead of from the heart forward to the body). This is called congestive heart failure. Signs of congestive heart failure include cough (particularly a cough at rest), a quick breathing rate, problem breathing, fainting, weak point, lethargy, exercise intolerance and stomach distension. Also, since the heart is not pumping efficiently, these dogs can establish extensive weak point, lethargy, workout intolerance and fainting. Regrettably, they can likewise die unexpectedly from unusual heartbeats from the diseased heart chambers.

A cardiologist can perform an echocardiogram and identify if dilated cardiomyopathy is present in susceptible breeds. Oral medications can be started in the preclinical (asymptomatic) phase of dilated cardiomyopathy and sometimes, these medications can delay the progression of the disease to the development of heart disease. If a dog establishes scientific symptoms of heart disease, X-rays are used to confirm the presence and identify the seriousness of the heart disease. If heart disease exists, oral medications can be prescribed and some dogs can do well with these medications for 1-2 years.

Causes of Heart Murmurs in Dogs

When your vet has described what kind of murmur your dog has, and its grade of strength, your next concern will probably be “what is causing my dog’s heart murmur?

There are several types of heart diseases and flaws that can cause heart murmurs. Determining the cause is something your veterinarian will try to do based on your dog’s age, breed, and test results.

In general, the causes of heart murmurs in dogs can be broken down into a few classifications of blood circulation disturbances.

  • Disturbances triggered by irregular valves or vibrations
  • Disruptions brought on by blockage, infected valves, or dilated vessels
  • Disturbances caused by regurgitant flow

Various diseases can likewise cause heart murmurs. Your veterinarian will examine these diseases based upon the type of murmur.

Causes of Systolic Murmurs in Dogs

A lot of heart murmurs are systolic. The most typical cause of systolic murmurs is pulmonic stenosis or subaortic stenosis, which is a constricting of the capillary that triggers obstruction of the blood circulation.

Other conditions that can trigger systolic murmurs include:

  • Anemia
  • Heartworm disease
  • Hyperthyroidism
  • Cardiomyopathy
  • Aortic valve insufficiency
  • Mitral and tricuspid cardiac arrest
  • Systolic anterior mitral motion (SAM)
  • Endocarditis of the mitral and tricuspid valve

Causes of Diastolic Murmurs in Dogs

Diastolic heart murmurs are unusual in dogs. The most typical condition associated with diastolic murmurs is aortic insufficiency, which is when the aortic valve does not close firmly, and therefore leakages. Mitral and tricuspid valve stenosis, and aortic and pulmonic valve endocarditis can also trigger diastolic murmurs.

Causes of Continuous Murmurs in Dogs

Constant murmurs are most commonly brought on by PDA, but aortic regurgitation caused by a ventricular septal defect, and aortic stenosis with aortic regurgitation, can also cause a continuous murmur.

Innocent Murmurs in Dogs

Heart murmurs sound serious, and typically are, but often a heart murmur is categorized as an innocent heart murmur. These heart murmurs are not serious and typically resolve with time. They are most typically found in young dogs and are usually a grade III or less.

Canine Heart Murmur Grade

Another tool vets utilize to assist identify the cause of the murmur is grading.

Heart murmurs in dogs are graded on a scale of one to 6.

  • Grade I murmurs are the least severe and are barely detectable with a stethoscope.
  • Grade II murmurs are soft, but your vet can hear them with the help of a stethoscope.
  • Grade III murmurs have a volume that falls in the middle of grades II and IV. Most murmurs that trigger serious problems are at least a grade III.
  • Grade IV murmurs are loud and can be heard on either side of the chest.
  • Grade V murmurs are very loud and can be heard with a stethoscope without problem, and can likewise be felt by holding a hand against the dog’s chest.
  • Grade VI murmurs, like grade V murmurs, are very loud and can be felt through the chest wall, and are the most severe of the heart murmurs.

As your physician listens to your dog’s heart murmur, you might likewise hear her discuss the configuration of the heart murmur. This describes the method the heart murmur sounds.

Diagnosis for Heart Murmurs in Dogs

To figure out the cause of a heart murmur, your vet may advise a variety of tests, such as:

  • Blood tests, consisting of heartworm tests.
  • Chest radiographs (X-rays) to examine the heart, blood vessels, and lungs.
  • An electrocardiogram (ECG).
  • An echocardiogram (an ultrasound exam to assess heart structure and function).
  • Blood pressure tests.

Treatment for Heart Murmurs in Dogs

Treatment depends on the cause of the heart murmur and your dog’s condition. If your dog is disappointing any signs of heart problem other than the murmur, your vet may choose to monitor your dog and provide treatment only if signs happen.

In many cases, such as when a heart murmur is caused by heartworm disease, treatment may solve the heart murmur totally. If the murmur is brought on by a congenital condition, surgery may be advised. In other cases, the heart murmur might remain, however medications can assist make your dog more comfortable and enhance your pet’s longevity.

Not all heart murmurs need treatment. Just keeping the dog slim and active, is all that’s needed for grades 1&2.

With louder murmurs, there are medications which can support how the heart pumps and lengthen a good quality of life. These drugs include angiotensin-converting enzyme inhibitors, diuretics, and positive inotropes.

An especially important medication is pimobendan (TM Vetmedin.) This heart medication is unusual because it’s been clinically proven to extend life when it’s started even prior to the dog ends up being sick. However, it’s best started at a particular stage, where the heart is enlarged however the dog isn’t showing signs of heart disease.

To hit this sweet spot involves dogs with peaceful murmurs being scanned every 6-12 months. This enables the cardiologist to detect the heart enhancement early to start the dog on pimobendan.

Prognosis or Dog Heart Murmur Life Expectancy

When a heart murmur is determined in your healthy dog, do not panic. There’s every possibility the dog may never establish full-blown heart problem.

Your veterinarian will tape-record the grade of the heart murmur in dogs in addition to the heart murmur in felines, in addition to their heart rate. They will utilize this to monitor your canine companion and spot signs of deterioration. Must this happen, then further tests might be essential.

Gladly, modern medications can support a dog with cardiovascular disease and enable them to continue with the exceptional lifestyle for months or years to come.

Remember, each dog is a person. Some defy the chances and outlast their predicted life expectancy, whilst others can unfortunately suffer a disastrous event, such as a heart attack, and deteriorate all of a sudden. However by being proactive and working with your vet, there’s every chance that you can make a difference and keep your pet pleased for longer.

Reyus Mammadli
Having engineering and medical education, in recent years actively engaged in the study of the development, reproduction of domestic animals. Special attention is paid to the treatment and prevention of diseases of Pets.
Pet Health
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  1. Dean , MD

    What triggers a heart murmur in dogs? Congenital malformations of the heart, anemia, fevers, very rapid heart rates, failure of normal ‘holes’ in the heart to close up properly after birth, valve infections or malformations, barriers to appropriate heart function such as severe lung disease or heartworms, and heart diseases that cause the valves to close poorly.

    Reply
  2. S.J.Gordon

    A heart murmur IS a symptom. It suggests that blood circulation through the heart is not as smooth as normal. This could be identified by hearing it with a stethoscope, or in very extreme cases, feeling it with your hand over the chest area. Murmurs can be from cardiovascular disease triggering heart enhancement or valve leakiness, hereditary heart conditions, anemia, fevers. They can indicate serious disease or might be innocent and momentary, as when it comes to mild murmurs in many young puppies. The only method to understand what is triggering the murmur and if it requires to be dealt with is to have your vet take a look at the dog, do chest X rays, an EKG, and a cardiac ultrasound. Numerous diseases can be treated and the impacted pets have long full lives after medical diagnosis.

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  3. Andy

    My dog was diagnosed with HM when he was approx 6 years of ages. He is now approaching 10, and is only now revealing more powerful signs of the problem.

    The only symptom we have discovered, so far, is his coughing, but he is still as active as he ever was. That is, it hasn’t slowed him down.

    He is on medication now, which stopped his coughing for over a year, however his coughing has launched once again just recently, even on the medication.

    He appears to cough when he wakes from any substantial period of rest; he will cough for a minute-or-so, then he’s alright and he just goes about his day.

    It is clearly an indication that his heart has degraded, as I said however, he is 10 years old and at this moment his only sign is the coughing, and very little of it, as the drugs seem to do their task; that is, enhance the heart so it can cope better with the malfunctioning valve.

    As this is among the most typical conditions among the K9 populations of the world, veterinarians continue to research it substantially to guarantee dogs can live longer and better lives with this disorder. Who knows, maybe one day they’ll even discover a treatment – watch this space.

    My youth dog likewise had HM, and he lived up until 10 years of age, but the medications offered back then were not at the requirement they are now, and at that time, there were no ‘science-based’ diets to ensure dogs were getting the very best nutrients for a healthy life. It was quite literally, ‘Pal’ from a can (awful processed things), or just whatever was left over from the human menu that night; and yet he STILL lived to 10 years of age with this ailment.

    I hope this has actually been useful.

    Reply
  4. Holovko, UK

    My dog likewise has a heart murmur and takes 2 medications for it. The cardiologist has suggested there is no treatment for the cough. Rather, it’s a crucial symptom that provides us a yardstick regarding the relative state of the dogs health.

    I’m sorry you’re experiencing this. I find it very upsetting in my dog.

    Reply
  5. Daddy Tom

    Heart murmurs is an entirely harmless diagnosis. Individuals and animals are born with heart murmurs every day and live long rich lives. They just indicate that the heart sounds a little different through a stethoscope due to the fact that of the way the blood is being pumped. It has something to do with a valve that is not rather as tight as it must be. My dog, who is now 13, has had them given that he she was a puppy. My sis was born with heart murmurs and she is 75. Don’t worry about it.

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