Canine Heart Murmur
From LoveToKnow Dogs
If your dog's heartbeat doesn't sound the way it should, it's possible that he or she has a canine heart murmur.
Health Implications of Heart Murmurs in Dogs
For some dogs, having a heart murmur doesn't have significant health consequences. Many dogs that develop murmurs never develop heart health problems that impact their quality of life or longevity. For others, the condition can be severe and can cause a wide variety of health problems.
Diagnosing Canine Heart Murmur
Only a veterinary professional can diagnose canine heart murmurs, and they can be difficult to verify simply by listening to the heartbeat. Heartbeat irregularities in puppies are sometimes detected at birth. Murmurs sometimes show up during annual checkups with older dogs. In other cases, pet owners may notice that something just doesn’t seem right about the sound of their dog's heartbeat. If you notice anything unusual about your pet's heartbeat, you should immediately make an appointment with your veterinarian for an official diagnosis.
The process of diagnosing a dog's heart murmur isn't that different from confirming the presence or absence of the same problem in a human. The initial examination will involve listening to the heart with a stethoscope. If a murmur is present, the heartbeat will make a softer, longer sound than the steady, short thump of a normal canine heartbeat. However, in many cases murmurs are very faint, and can't be confirmed without further testing.
When a murmur is suspected, veterinarians typically follow up a general exam by running an electrocardiogram (ECG) to determine if there is a problem with the dog's heart. If necessary, the ECG may be followed up with an echocardiogram and chest X-rays to determine the extent of the problem and/or damage that it may have caused.
Diagnostic Tests
- Electrocardiogram: ECG tests can reveal if there is a problem with your dog's heart. This test allows the vet to measure the heart rate and determine whether or not there are abnormal heart rhythms.
- Echocardiogram: This procedure allows the veterinary professional to determine if there are problems with the valves of your dog's heart and to determine how well the heart if functioning. This test helps the vet decide if your pet needs treatment for his or her heart condition.
- X-Ray: Viewing radiographic images of your dog's heart allows the veterinarian to see if there seem to be any abnormalities of the cardio-pulmonary system related to heart problems.
Grades of Murmurs
Once detected, all murmurs are assigned one of six different grades.
- Grades one and two: These are typically minor murmurs that don't require immediate medical intervention. Most vets will ask you to keep an eye on your dog as time goes on, and report right away if your dog develops a habitual cough or lethargy. These could be signs that the murmur is growing worse and may now require treatment.
- Grades three and four: These murmurs are a bit more serious than grades one and two, so they are cause for more concern. At grade three or four, you may notice your dog tires quickly after exercise, and there may be a persistent cough that indicates some extra fluid is collecting in the lungs. Murmurs of these grades usually require medication to help regulate them.
- Grades five and six: These are the most serious grades of murmurs. Dogs diagnosed at a five or six will require medication, and may also need surgery to try to repair the defect. Murmurs at this level may eventually develop into congenstive heart disease.
What Causes Heart Murmurs in Dogs
There are several possible causes of murmurs. If diagnostic testing reveals that your dog has a heart murmur, the next step toward determining the best course of action is to identify both the severity of the problem and its underlying cause.
Birth Defect
Some puppies are born with heart murmurs. These types of murmurs are considered to be congenital birth defects.
Anemia
Murmurs in dogs can also be caused by anemia. In such cases, the best course of action is to figure out what is causing the dog to experience anemia. Dog parasites, for example, can cause anemia. In such situations, getting rid of the parasites may cure the anemia and eliminate the heart murmur.
Heart Valve Disease
In some cases, murmurs in dogs are caused by mitral valve disease. With age, or as a result of high blood pressure or other cardiac disease conditions, the mitral valves weaken and blood leaks from them into the heart's atrium instead of being pumped out as it should. This leakage results in the audible murmur sound. This problem is more common in older dogs than younger ones, and represents the most serious form of heart murmur.
Treating Your Dog's Heart Murmur
When puppies are born with murmurs, treatment is not recommended right away unless there are signs of significant health problems associated with the murmur. As with human children, congenital heart murmurs often disappear with age. In most cases, it will take a few years to determine if a canine heart murmur is a serious problem or one that is self-correcting. In many cases, no treatment is necessary. Depending on the overall health and age of the affected dog, many heart murmur problems that do not go away on their own can be corrected via surgical procedures.
A Word of Caution
Dogs that are diagnosed with any type of hereditary heart problem should not be bred in order to avoid passing on congenital heart health problems to future generations.
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Comments
Hi Joann, and welcome to the site.
It's my understanding that it's easy to miss a grade one murmur because it's so slight. Murmurs are easier to detect the higher the grade is. The onset of cardiac disease can also cause a murmur where there wasn't one before. Hopefully your dog's murmur won't progress to a higher grade, but it is a good thing that it was diagnosed now so that your vet can monitor your dogs condition in the coming years.
Thanks for your question, and best wishes for your dog's health.
-- Contributed by: KellyI have a 4 yr old Rat Terrier, and today at his yearly exam I was told he has a 2/6 heart murmur. Why was this not detected early, or can they just appear later on?
-- Contributed by: Joann LittleHi Matthew,
Thanks for sharing your situation, and I hope that whatever the university tests reveal that your dog can still live a long and happy life. :)
-- Contributed by: Kelly
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