Heart Murmurs In Dogs

Heart Murmurs In Dogs
1) What are Heart Murmurs?
  •  It is simply a condition whereby the dog has abnormal heart sounds that is produced as a result of a disturbance in the blood flow into, through or out of the heart.

  •  Sometimes these sounds are loud enough to be heard audibly.

  •  A heart murmur is not itself an illness or disease but rather a reflection of an underlying sickness or disorder in the dog

2) What are the causes?

Heart murmur can be:

  • Congenital – the dog is born with the condition of defective heart values. Simply put, the heart valves have problems closing properly as the blood is being pumped through the heart chambers.

  •  Due to old age or underlying disease

3) What are the diseases/ conditions that can lead to heart murmurs?

Keeping in mind that heart murmur is itself not an illness but simply a condition of abnormal heart sounds, it means that they can be indicative of an underlying disease/ condition which require medical attention:

  • heart disease or failure

  • heartworm disease

  • fever or infection

  • low levels of red blood cells (Anemia) – can be caused by parasitic infection

  • low protein levels in the blood

It can also result from conditions such as pregnancy, obesity or emaciation.

4) What are the symptoms?

Many dogs with heart murmurs never show symptoms at all.

However, if the murmur is associated with structural heart disease, then your dog may display signs of congestive heart failure such as:

  • Persistent coughing

  • Weakness (lethargy)

  • Exercise intolerance

  • Decreased activity level

  • Panting (even when resting)

  • Difficulty in breathing (even when resting)

  • Agitation

  • Fainting spells or sudden collapse 

The cough happens because the effects of the defective valve put pressure on the lungs which slowly fill with fluid. 
The fainting spells happens when oxygen is not distributed properly to the body tissues through normal blood circulation. Pale gums are indications of inadequate oxygen supply. You should rush your dog to the veterinarian immediately.
It is very common for young puppies, especially large breed puppies, to develop benign heart murmur while they are growing rapidly. The murmur may first appear at 6-8 weeks of age but the puppy will usually outgrow it by about 6 months of age.
Symptoms of these short-lived heart murmurs in puppies are:

  • Poor weight gain, slow growth

  • Excessive sleepiness, lack of ‘puppy playfulness’

  • Coughing, especially at night or first thing in the morning

  • Pale gums/tongue

5) How can they be detected?

Murmurs can be easy or difficult to detect, depending upon how loud or pronounced they are, by skilled veterinarians through a stethoscope. If a veterinarian detects a heart murmur, he/ she will likely recommend advanced diagnostic testing through use of an electrocardiogram (an EKG/ECG).

6) How can it be prevented?

The murmur itself is not preventable because simply a condition of abnormal heart sounds.

For some dogs and young puppies, heavy infestation of parasites (whipworms and hookworms) can cause heart murmurs. That is why it is vital to de-worm the puppies every two weeks till 6 months of age and every 3 months for an adult dog. Check with your veterinarian for advice.

Another way of prevention is to give your pet sufficient vitamins & Omega-3 fish oils to boost its immune system and strengthen its heart.

7) What are the treatments available?

Heart murmurs cannot be treated because it is simply a condition of abnormal heart sounds.

Many heart murmurs will never require medical or surgical management, even if they are very pronounced. The veterinarian will advise you on the possible actions you can take.

One of the possible actions for minor heart murmurs is changing the diet of the dog slowly to a low sodium kibble. But if the underlying cause of the heart murmur is a heart disease, then necessary medications and treatment is required.

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