Heart Murmur In Dogs: Symptoms, Causes, & Treatments

Vets examining greyhound with stethoscope on table in veterinary surgery

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Heart murmurs in dogs are extra vibrations or sounds in the heart that come from abnormal blood flow. A heart murmur is not a condition on its own, but rather a symptom of an underlying condition. There is no direct treatment for a heart murmur in dogs, but the causes of the heart murmur can often be treated, which may reduce the vibrations in the heart. Sometimes heart murmurs are benign, and dogs may just grow out of them, or the heart murmur can be treated with dietary changes. Other times, a heart murmur can indicate a more serious medical condition. Your veterinarian will be able to determine the cause of the heart murmur and form a treatment plan.

Vets give heart murmurs in dogs a grade of I to VI. Grade I heart murmurs are barely audible, while grade VI heart murmurs can often be heard even without a stethoscope. This doesn’t necessarily correlate to the severity of the underlying cause of the heart murmur. Vets also classify heart murmurs based on the location of strongest intensity and the pattern that the vibrations follow. These classifications, along with any other symptoms dogs have, help narrow down the cause of the heart murmur, allowing vets to form a proper diagnosis and treatment plan. Here is what you should know about the symptoms, causes, and treatments associated with heart murmurs.

Symptoms Of Heart Murmur In Dogs

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Not all heart murmurs in dogs result in apparent symptoms. Some heart murmurs are completely benign and disappear with time. However, many heart murmurs are associated with heart disease. If you see the signs of heart disease accompanied by a heart murmur, consult your veterinarian immediately. Here are a few signs of heart disease that may appear along with a heart murmur.

  • Exercise intolerance
  • Lethargy or weakness
  • Panting, coughing, or difficulty breathing
  • Pale gums or mucus
  • Distended abdomen or bloated appearance
  • Fainting or collapse

Causes of Heart Murmur In Dogs

LANDSHUT, GERMANY - MAY 13: Heard investigation of a dog on May 13, 2015 in Landshut, Germany. (Photo by Isa Foltin/Getty Images)

(Picture Credit: Isa Foltin/Getty Images)

It is common for young puppies to develop heart murmurs, though these are usually benign and known as physiologic heart murmurs. They occur when puppies, especially large breeds, grow quickly, and generally they disappear on their own after a few months. These heart murmurs cause no symptoms and aren’t a cause for concern.

Heart murmurs in dogs can be caused by a variety of conditions. They can be congenital (present at birth), result from heart defects, or appear with infections, inflammation, or other diseases. Here are a few of the conditions that can cause a heart murmur.

  • Endocardiosis
  • Endocarditis
  • Dysplasia
  • Cardiomyopathy
  • Atherosclerosis
  • Anemia
  • Heartworm
  • Hyperthyroidism
  • Valvular stenosis
  • Pulmonic stenosis
  • Tetralogy of Fallot
  • Tumors

Treatments For Heart Murmur In Dogs

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Heart murmurs in dogs are not treated directly as a heart murmur is not a condition on its own, but the underlying causes are addressed by veterinarians. Treatment can vary greatly depending on the cause and severity of the condition. Physiologic heart murmurs in puppies often don’t require treatment, but puppies should still be monitored to make sure another condition doesn’t develop. Mild heart murmurs may be treated with simple dietary changes.

Conditions that cause heart murmurs must be addressed by a veterinarian. In the case of heart defects, surgery may be required to correct the condition. Tumors may require chemotherapy. Other issues may be treated with medication. Your veterinarian will develop a proper treatment plan after forming a diagnosis if your dog suffers from a heart murmur. It is important to get regular check-ups, as heart murmurs are often caught through routine vet visits.

Has your dog ever suffered from a heart murmur? What was the cause? Let us know in the comments below!

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