Causes, Symptoms, and Treatment of Heart Murmurs in Cats

Heart Murmurs in Cats: Causes, Symptoms and Treatment 

Image Credit:Kirstie Shanley

When your cat’s heartbeat is being listened to using a stethoscope during a physical examination, an abnormal sound known as a cardiac murmur may be audible. When blood flow through the heart or major veins is obstructed, noise-like vibrations and turbulence known as heart murmurs result.1 Valve Disease is a Common Cause of Heart Murmurs in Cats

 Heart murmurs in cats are typically brought on by valvular heart disease, particularly mitral valve disease. The heart valves grow and become less effective at closing, which permits blood to leak in the wrong direction over time. The characteristic cardiac murmur and turbulence are caused by this transfer of blood.

Structural Defects
Congenital heart defects your cat was born with, like a hole between the left and right side of the heart, may cause a heart murmur. These defects force the heart to work harder and disrupt normal blood flow and pressure.

Low red blood cell counts due to blood loss, diseases or nutritional deficiencies can make the heart work harder to supply enough oxygen. The extra strain on the heart sometimes produces a heart murmur.

An overactive thyroid gland is common in cats and often increases heart rate and cardiac output. This added workload can result in a heart murmur in some hyperthyroid cats.

Heartworm Infection
Heartworm larvae migrate through the heart and major blood vessels, causing damage that results in blood flow disturbances and heart murmurs. Not all infected cats will have an audible murmur, however.

Heart Murmurs in Cats: Causes, Symptoms and Treatment 2

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Symptoms of Heart Murmur in Cats

Many heart murmurs, especially mild ones, do not cause noticeable symptoms. But in more severe cases with significant valvular disease or other causes, cats may show:

• Coughing or difficulty breathing
• Exercise intolerance
• Loss of appetite
• Weight loss
• Fainting or collapse
• Enlarged abdomen due to fluid buildup
• Weakness
• Blue or pale gums
• Irregular heartbeat

Diagnosis and Testing

After detecting a heart murmur during a physical exam, your veterinarian will likely recommend additional testing to determine the underlying cause. This may include:

• Chest x-rays – To evaluate the heart size and shape and check for fluid in the lungs
• Electrocardiogram (ECG or EKG)- Measures the heart’s electrical activity and detects arrhythmias
• Echocardiogram – Uses ultrasound to obtain detailed images of the heart valves and chambers in motion
• Blood tests – Screens for anemia, hyperthyroidism and other conditions
• Possible heartworm testing – Especially if the cOptionsat is not on preventatives.

Treatment and Management 

The treatment for a heart murmur in cats depends on its cause and severity. Options may include:

• Medications – Such as diuretics to manage fluid buildup, vasodilators to lower blood pressure, and heartworm preventatives.
• Heartworm treatment – If heartworms are found, antibiotics and other drugs are needed.
• Diet changes – A prescription weight loss or renal diet may be recommended.
• Surgery – Sometimes needed to repair structural heart defects in young cats.
• Lifestyle Changes – Restricting activity level based on severity.
• Monitoring – For mild cases, the cat is simply monitored for changes or worsening of the murmur.

Although the ailment is not “curable,” treatment tries to manage symptoms, postpone the underlying condition’s progression, and prolong and enhance the cat’s quality of life as much as possible. Based on the unique diagnosis and requirements of your cat, a personalized care plan is developed.

Heart Murmurs in Cats: Causes, Symptoms and Treatment  3

Image Credit:Geoff Penn

In conclusion, there are numerous potential reasons of cardiac murmurs in cats, ranging from valvular disease to anemia. While the majority of moderate murmurs don’t need to be treated, more serious ones benefit from diagnostic procedures, medications, and lifestyle changes that address the particular etiology. Your cat can have the best odds of successfully controlling a cardiac murmur over time by working together with your veterinarian and adhering to instructions.