During your dog’s regular check-up, your veterinarian says, “I’m hearing a heart murmur,” which can make any dog parent pause for a moment. The term sounds serious, and naturally, there are many questions that follow. Like, is it dangerous? Is it painful? Will my dog be okay?
The truth is, a heart murmur in dogs may point to an underlying heart condition that needs treatment. That’s why understanding the basics can help you respond calmly and confidently.
What Are Heart Murmurs in Dogs?
In a healthy heart, blood moves smoothly, producing a clear “lub-dub” sound. Simply speaking, a heart murmur is an extra “whooshing” or “swishing” sound between these normal heartbeats. The noise is due to turbulent blood flow within the heart.
How Are Heart Murmurs Graded?
Heart murmurs in dogs are graded from I to VI according to how loud the sound is.
- Grade I – Barely audible, in perfectly quiet surroundings.
- Grade II – Very soft sound, can be heard through a stethoscope.
- Grade III – Moderately loud.
- Grade IV – Loud and usually heard in multiple areas on both sides of the chest.
- Grade V—Very loud, felt as a vibration (thrill) when a hand is placed against the chest.
- Grade VI – Extremely loud, can be felt by touching the chest.
Heart murmurs are a sign that something may be affecting normal blood flow in your dog, but further testing is required to determine the cause.
What Are the Causes of Heart Murmurs in Dogs?
Anything that causes abnormal blood flow within the heart can cause a murmur. And there are multiple possible causes. It can be innocent (physiologic) or pathologic (due to heart disease).
Innocent Heart Murmurs
Innocent murmurs are very common in puppies. It is usually low-grade (Grade I or II) but typically disappears once they’re about 4-5 months of age. This type of heart murmur is not harmful.
Structural Heart Disease
The other cause is structural heart disease or an extra cardiac problem. In this situation, structural abnormalities alter blood flow patterns inside the heart.
Mitral Valve Disease
A chronic degenerative disease where the mitral valve becomes thickened, causing blood to leak. The most common occurrence is in adult and senior dogs, especially toy/small breeds.
Congenital Heart Disease (CHD)
Congenital heart disease is present in dogs from birth. Examples include:
- Patent Ductus Arteriosus (PDA)
- Subaortic Stenosis
- Pulmonic Stenosis
Dilated Cardiomyopathy (DCM)
Dilated cardiomyopathy is a serious disease that causes the muscles in the pumping chamber of the heart to become weakened and enlarged, leading to inefficient pumping. It is most common in large and giant breeds.
Non-Structural Causes (Functional Murmurs)
Sometimes functional murmurs occur without primary heart valve disease. The causes include anemia, fever, pregnancy, and physiological stress/excitement. When the underlying condition resolves, the murmur may disappear.
Well, there are multiple causes of heart murmurs in dogs, but the exact diagnosis will require further tests.
What Are the Early Signs of Heart Murmurs in Dogs?
Many dogs with mild murmurs show no symptoms at all, especially in the early stages. A heart murmur is only one sign of an underlying disease. The early signs of heart murmurs in dogs may include:
- Lethargy
- Mild coughing (especially after activity or at night)
- Increased breathing rate at rest
- Subtle weight loss
- Reduced appetite
- Poor exercise tolerance
As the disease advances, signs may include:
- Difficulty breathing
- Collapse or fainting spells
- Pale or bluish gums
These symptoms may also be indicative of a more serious health risks and not necessarily a heart murmur. So, it’s important you contact your veterinarian for a diagnosis.
This may involve chest X-rays, blood work, and an electrocardiogram, or most commonly, an echocardiogram (an ultrasound of the heart). This test shows how the valves and chambers of your dog’s heart are functioning in real time.
How to Care for Your Dog with a Heart Murmur?
Once the cause is identified, care depends on the diagnosis. There are various ways pet parents can care for their dogs with heart murmurs.
Firstly, follow veterinary guidance.
There is no over-the-counter treatment for heart murmurs in dogs. If treatment is needed, it will be prescribed based on the specific heart case. Some dogs may require treatment to help the heart pump more efficiently. Others may only need regular monitoring. Never start supplements without veterinary approval.
Monitor Your Dog
A healthy dog’s respiration rate is 15-30 RPM (breaths per minute); however, this varies between individuals. It’s important for dog parents to regularly monitor their breathing rates.
Monitoring your dog’s resting breathing rate while at rest can provide valuable information about any underlying condition. Also watch for changes in their energy levels, appetite, or coughing patterns.
Maintain Your Dog’s Overall Heart Health
To put it simply, good general health supports the cardiovascular system. Keep these things in check:
- Keep your dog at a healthy weight.
- Provide balanced, vet-recommended nutrition.
- Create a healthy, calm environment to minimize stress.
- Allow moderate exercise to maintain your dog’s health.
- Avoid excessive exertion if heart disease is confirmed.
Regular Checkups with a Veterinarian
Your vet may recommend more frequent checkups after diagnosing a heart murmur. These check-ups can monitor your dog’s current condition and help a vet adjust treatment.
Final Thoughts
The most important thing is, don’t ignore it. For some dogs, a heart murmur remains mild and never progresses. Follow up on vet-recommended tests. When heart conditions are caught early and managed properly, many dogs may continue to enjoy happy, long years.
Frequently Asked Questions
Can dogs live long with heart murmurs?
Yes, many dogs can live, especially if it’s mild or detected early. Lifespan depends on the underlying cause, how advanced the condition is, and how well it’s managed. With proper monitoring and veterinary care, some dogs live for years after diagnosis.
What to do if a vet detects a heart murmur in dogs?
First, don’t panic. Ask your veterinarian what grade the murmur is and whether further testing is recommended. Follow through with suggested diagnostics, and once a diagnosis is made, stick to the monitoring or treatment plan provided.
Can a heart murmur go away on its own?
In puppies, innocent murmurs often disappear as they grow. In adults, murmurs caused by structural heart disease usually do not go away, but they can often be managed effectively with proper care and monitoring.
