What is the life expectancy of my old dog with a heart murmur

What is the life expectancy of my old dog with a heart murmur?

Last Updated: August 20, 2023
correct answerThe Short Answer is:

The variety and severity of murmurs make them difficult to predict. Therefore, life expectancy depends on several factors, including the type and breed of the murmur. Despite murmurs, some pups never develop heart disease. Congestive heart failure can, however, develop rapidly in others.

In this article you will know the answer to the query “What is the life expectancy of my old dog with a heart murmur?“.

The decline in health and vitality that comes with age is inevitable. Sadly our pets also suffer from this deterioration as do we humans. Learning that your dog is having heart problems is a frightening experience.

What is the life expectancy of my old dog with a heart murmur

One day you’ll have to face the reality that your dog isnot going to live forever. It is possible to hear a heart murmur as the result of a dire heart condition or it may only be the result of a cardiac cycle that is not working optimally.

The severity of a heart murmur can be classified in different ways and fortunately not every heart murmur is very serious. Hopefully you will gain a more comprehensive understanding of your dogs condition after reading the following information.

What is a heart murmur?

You are well aware that the heart is a muscle that carries blood throughout the body in order to provide the skeletal muscles and organs with the necessary oxygen and nutrients. By contracting it pumps the blood to where it needs to be.

It is considered healthy to have a low resting bpm (beats per minute) because it indicates that the heart is strong and can adequately pump blood through the network of arteries and veins without too much resistance.

If the heart rate is high at rest there may be weakening of the heart or other underlying conditions that reduce its effectiveness. Murmurs are created when there is an abnormality in the flow of blood. Using a stethoscope you can hear a normal heartbeat but this is quite different.

What are the possible causes of heart murmurs?

Myxomatous mitral valve degeneration (MMVD) also known as endocarditis is one of the more common causes of heart murmurs.

Mitral valves are located between the left atrium and left ventricle. Mitral valves are responsible for maintaining blood flow in the heart. A regular heartbeat is all that should be audible when listening to the heartbeat. When the mitral valve degenerates the normally thin leaflets of the valve become unusually thick and bumps develop at the edges.

In some cases this can prevent the leaflets from closing properly. In essence when the valve fails to completely close blood flow becomes unstable causing a foreign sound (murmur). It can be heard between the “lub” and the “dub” of a normal cardiac contraction in patients with myxomatous mitral valve degeneration. It is often most readily detected in the left region of the chest.

As a matter of fact MMVD is so commonly responsible for heart murmurs that many veterinarians will automatically predict that its likely to be the cause of your dogs heart murmur. Unless there are other obvious causes MMVD will undoubtedly be the top suspect. An echocardiogram and X-ray can confirm the diagnosis. Coughing is the first symptom to watch for.

When the left atrium swells due to the excess blood flow from the compromised valve the enlarged atrium adds pressure to your dogs airway making breathing more difficult. There are other factors that may also contribute to your dogs heart condition.

The abnormality might be caused by an obstruction or a diseased valve for instance.

Canines are less likely to have diastolic murmurs. A malfunctioning aorta is a primary cause of this type of murmur. Insufficient sealing of the valve of the aorta causes blood flow to be compromised.

Pulmonary valve endocarditis and mitral valve stenosis are other possible causes. Systolic murmurs on the other hand are much more common.

Pulmonary and subaortic stenosis are often the main causes in this scenario. It occurs when the blood vessels narrow uncharacteristically causing blood flow to be restricted. Systolic murmurs can also be caused by a number of other factors.

A systolic murmur can be caused by cardiomyopathy heartworm disease systolic anterior mitral motion mitral valve failure anemia hyperthyroidism or a faulty aortic valve.

Different kinds and grades of heart murmurs

Systolic and diastolic murmurs have already been described but there is a third type known as a continuous murmur. A murmur is classified according to the timing of the abnormality. When a murmur is heard when the heart contracts it is said to be systolic. When the heart is at rest (between contractions) a diastolic murmur is detected. During either or both of these stages of a cardiac cycle there is a continuous murmur.

The following categories are used to classify heart murmurs: 

  • Grade 1 – This is the least dangerous condition as the irregular sound can hardly be heard with a stethoscope.
  • Grading 2 – A stethoscope will notice the murmur even if it is light.
  • Grade 3 – At this stage the extra concern is warranted because the murmur is distinct and it is from this point upward that serious problems may manifest.
  • Grade 4 – A dogs heart can be detected on both sides of its chest if there is a murmur.
  • Grade 5 – Picking up the murmur with a stethoscope is very easy since it is very noticeable. In fact its so distinct that you can detect it just by pressing your hand against the dogs chest.
  • Grade 6 – This is basically a stronger version of grade 5. If you hold your hand on the dogs chest you can easily hear the sound and feel the irregular heartbeat.

In addition there are four discernible rhythms or configurations of murmurs that can give the veterinarian a better sense of where the cardiac inconsistency might be.

  • The crescendo-decrescendo murmurs are characterized by increasing and decreasing in volume and are thought to be caused by pulmonic stenosis and aortic stenosis.
  • Decrescendo murmurs – This occurs when a murmur is very audible at first but then gradually becomes less noticeable. Aortic valve failure or septal defects of the ventricles are usually associated with this configuration.
  • Plateau murmurs – Murmurs such as these are steady and distinct. Insufficiency of the aortic valve is often responsible for this condition.
  • Machine quality murmurs (also known as continuous murmurs) – This condition usually occurs in association with patent ductus arteriosus (PDA) a congenital cardiac condition.

It can be frightening to learn about a murmur for the first time because they come with so much information. A veterinarian will be able to identify the type of murmur your dog may be experiencing so you have a better understanding of the situation. Despite that people make mistakes including medical professionals. A second opinion from a different veterinarian could also clarify your situation if you can afford it.

Is there treatment available?

Your dogs condition may require different treatment options depending on the severity. The vet will likely recommend that your dog be kept under close watch if they suffer from myxomatous mitral valve degeneration but not congestive heart failure (CHF). Your vet may also recommend cough medicine to soothe your poochs aggravated respiratory system. There is currently little evidence to suggest that other types of therapy are necessary prior to congestive heart failure.

As soon as possible you want to know if CHF develops so regular vet visits are recommended. CHF can be treated with drugs such as furosemide (a medicine used to prevent the buildup of fluid in the dogs lungs) enalapril (used to treat heart failure high blood pressure and kidney failure) and pimobendan (a calcium sensitizer frequently used to treat heart failure in dogs). There are a few cardiac anomalies that can sometimes be corrected with surgery such as pulmonic stenosis and PDA.

You can determine the severity of your dogs condition based on the murmurs grading. Grade 5 or 6 murmurs indicate compromised cardiac function which means you should pay full attention to your dog if you want to correct the problem. The dogs who were diagnosed with heart murmurs have gone on to live long and happy lives.

Several years after being diagnosed with heart failure dogs with heart failure often live for several more years. If their situation does not look good all you can do is provide them with the best quality of life you can and make them as comfortable as possible.

Donot let them suffer from dehydration and give them a nutritious diet with moderate protein and sodium levels.


The process of aging isnot pleasant for anyone but a higher quality of life is always more important than how long you live. Depending on the severity of your dogs heart issues you can remain confident about your pets life expectancy.

Consult your veterinarian about how your dogs heart murmur is graded and what treatment options might be available to you. Please consult your veterinarian about the best diet for a frail heart condition.

The last and most important thing you can do to reduce stress in your dogs life is to try to do everything you can to reduce it. Heart failure is known to be caused significantly by stress which should be avoided or reduced as much as possible.

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Amanda Dogs Trainer

Amanda (Author)

With over a decade of experience, Amanda is a distinguished dog trainer. Her expertise in canine behavior has transformed countless lives, fostering harmonious human-canine connections. Through compassionate and personalized approaches, she empowers owners to understand and connect with their furry companions, creating a legacy of joyful tails and transformed lives.

Osvaldo Maciel Dogs Trainer

Osvaldo Maciel (Content Reviewer)

Osvaldo Maciel, a stalwart in the field with 14 years of experience, is a revered dog trainer. His journey is defined by a profound understanding of canine behavior, shaping unbreakable human-canine bonds. Osvaldo guides owners to connect with their beloved pets, leaving an indelible mark of happiness and transformation. His legacy shines through the countless lives he has touched.

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