Heart Murmurs in Cats

What is a heart murmur?

A heart murmur is an abnormal noise caused by turbulent blood flow within the heart or the large vessels exiting from the heart. It is usually picked up by a vet when they listen to your cat's heart. A heart murmur is a symptom rather than a disease and it generally signifies an underlying heart condition.

The vet will then assess and grade the heart murmur, based on how loud the murmur is, however other factors are considered, for example the area in which the murmur can be heard.

The grade of the heart murmur does not always correlate with the severity of the underlying heart problem. Some loud murmurs may only represent a small heart defect, while severe heart conditions may not have anything to do with the presence of a heart murmur.

What causes a heart murmur?

A heart murmur can sometimes be caused by: disturbed blood flow through abnormal valves, outflow obstructions, diseased valves or a defect in the septum.

There are other health conditions that can also cause heart murmurs:

• Congenital heart defects
• Anemia
• Bacterial infection of the heart valve
• Hyperthyroidism
• High blood pressure
• Heartworm

What are the symptoms of a heart murmur?

The symptoms your cat will express depends on what is causing the heart murmur and in fact, in many cases there may be no symptoms at all.

• Lethargy
• Weight loss
• Loss of appetite
• Coughing
• Blue gums
• Difficulty breathing
• Swollen abdomen
• Weakness
• Poor growth

How do you treat a heart murmur?

Treatment will entirely depend on what is causing the heart murmur.

After initial diagnosis, an X-ray of the heart and/or a cardiac ultrasound will be performed. This will look to see if there is an underlying heart disease causing the murmur.

A referral to a specialist may be required as are further tests. However if your cat is generally very well and showing no clinical symptoms, then you may be asked to return in a few months to see if any changes or deterioration has occurred. If there are no real changes to your cat's condition then they may just have to be monitored periodically.

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