It can be alarming to see your dog panting heavily, especially if it seems excessive or out of place. When panting is paired with a known or suspected heart murmur, it’s even more concerning—your dog’s heart may not be keeping up with their needs.
We outline the connection between excessive panting in dogs and heart murmur, what you can do at home, and when to seek veterinary help.
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Dog Panting Excessively and Heart Murmur — Why It Happens
Panting excessively can be a signal that your dog’s heart isn’t pumping efficiently, especially when a heart murmur is present. Heart murmurs can be caused by valve defects, congenital abnormalities, or acquired heart disease, all of which may reduce blood flow.
This inefficiency can leave your dog short of breath and cause the body to compensate by increasing respiratory effort. Stress, activity, and even temperature can further tax a struggling cardiovascular system.
Dog Panting Excessively and Heart Murmur: Common Causes
Mitral Valve Disease
This is one of the most common heart issues in older dogs, especially small breeds like Cavaliers and Chihuahuas.
The mitral valve regulates blood flow between the heart’s chambers. When it deteriorates, blood leaks backward, reducing circulation.
Dogs with mitral valve disease may pant more often as their heart struggles to deliver oxygen.
You might also notice coughing, lethargy, or fainting spells. The murmur is often picked up during a routine vet visit before other symptoms become obvious.
Read more: Dog Panting Excessively (Here’s why)
Dilated Cardiomyopathy (DCM)
Large breeds like Dobermans and Boxers are more prone to DCM, a condition where the heart muscle becomes weak and enlarged.
Panting arises as the weakened heart cannot pump enough oxygenated blood.
Dogs may also tire quickly or seem restless, particularly at night. A murmur often accompanies DCM and becomes louder as the disease progresses.
Congestive Heart Failure
When heart disease progresses, it may lead to congestive heart failure. This means fluid is backing up in the lungs or abdomen due to poor circulation.
Excessive panting becomes a coping mechanism as your dog tries to get more oxygen.
It’s often accompanied by coughing, rapid breathing, and even abdominal swelling. A murmur will usually be present, and emergency care may be needed.
Anemia
If your dog is anemic—whether due to chronic illness, internal bleeding, or a tick-borne disease—the body may respond by breathing faster to compensate for the lack of oxygen-carrying red blood cells.
In dogs with heart murmurs, anemia places an added burden on the cardiovascular system.
You might see pale gums, weakness, and increased panting even at rest.
High Blood Pressure (Hypertension)
Systemic hypertension can exacerbate heart murmurs by placing more strain on the heart. It’s often secondary to other diseases like kidney failure or Cushing’s.
Excessive panting may be your first visible clue, especially if it’s occurring during calm periods.
A murmur may intensify as blood pressure increases, making routine monitoring crucial.
Heat or Physical Exertion
While all dogs pant to cool down, dogs with heart murmurs may pant excessively even after mild activity or in warm weather.
Their heart may be less able to respond to normal changes in activity, making them more prone to exhaustion, overheating, or fainting. These episodes should never be brushed off as “normal.”
What to Do
If your dog has a known heart murmur and is suddenly panting more than usual, start by making their environment as calm and cool as possible.
Reduce physical activity and limit their exposure to heat or stress.
Make sure your dog has access to fresh water and a quiet space to rest. Monitor their breathing rate—more than 30 breaths per minute while resting can indicate a problem.
Avoid giving human medications like aspirin or sedatives unless directed by your vet, as these can interfere with heart function.
Consider keeping a daily log of symptoms, noting panting frequency, activity levels, and appetite. This can be valuable information for your veterinarian.
If this is the first time you’re noticing heavy panting and your dog has a murmur, call your vet to schedule an exam. Early intervention can slow the progression of heart-related conditions.
When to Call or Visit Your Vet
Seek immediate veterinary care if your dog:
• Is panting heavily and seems distressed or anxious
• Has a distended belly, persistent cough, or blue-tinged gums
• Collapses, faints, or struggles to stand
• Has labored breathing even at rest
• Stops eating or shows extreme lethargy
These signs could indicate that your dog’s heart is failing to keep up with their needs. Prompt treatment can improve their comfort and possibly extend their life.
Read more: Dog Panting Excessively and Congestive Heart Failure (Why it happens)
Key Takeaway
Panting in dogs is often normal—but when it becomes excessive and your dog has a heart murmur, it’s a red flag worth investigating.
Conditions like valve disease, congestive heart failure, and anemia can all make breathing harder and heart murmurs worse.
If your dog is panting more than usual, don’t wait to act. Monitor their symptoms, reduce stress, and contact your veterinarian for guidance. With the right care, many dogs with heart murmurs can live comfortable lives for years to come.