A heart murmur is an unusual sound made by the blood around your cat’s heart. The sound can be similar to a swishing or swooshing sound. It is different from the typical sound heard from the opening and closing of your heart valves.
By itself, a heart murmur does not necessarily mean there is a problem with heart function. In fact, murmurs are commonly found in healthy cats. Your vet, though, may want to find out if the murmur shows the cat may have a heart condition.
What is a Heart Murmur in Cats?
During your cat’s veterinary exam, a murmur may be heard through a stethoscope. The murmur is caused by unstable blood flow in the heart or larger blood vessels leading away from the heart. When the blood is abnormally flowing, the result is the sound of a murmur.
The cause of a cat’s murmur, however, cannot usually be determined by listening alone. In many cats, benign murmurs can sound exactly like murmurs in a cat with serious heart disease.
What Are the Causes of Heart Murmur in Cats?
Many times, a heart murmur in a cat is harmless. Other times, the presence of a murmur can mean that there is an underlying heart condition.
Young kittens may have “innocent” heart murmurs that go away when they get older. A heart murmur in older cats may not show symptoms.
Structural heart problems that are present at birth can cause heart murmurs in cats. The most common of these deformities is a ventricular septal defect or atrial septal defect (deformities of the heart valves). Many times, cats with these conditions will be sluggish and underweight.
Some heart murmurs in cats are acquired or fully develop later in life. The most common of these acquired murmurs is cardiomyopathy — a general term for disease of the heart in cats and the most common cause of heart failure. Other acquired causes of heart murmurs are:
- Anemia
- Stress
- Hyperthyroidism
- Parasites
- Pregnancy
- Obesity
- Being underweight
What are the Symptoms of Heart Murmur in Cats?
Common symptoms of heart murmur in cats are:
- Weight loss
- Weakness
- Problems breathing
- Pale gums
- Laziness
- Poor appetite
A weak pulse or an abnormal heartbeat rhythm may indicate that the murmur is caused by a more serious underlying problem. Such a murmur can be a result of a condition like hyperthyroidism or high blood pressure.
If your cat has no physical problems and seems well overall, the vet may ask for another examination in a month or so to see if the murmur has changed. Usually, when there are no problems, a vet will recommend continuing exams to keep watch.
How Is a Heart Murmur in Cats Diagnosed?
A heart murmur and underlying heart disease will be diagnosed by a veterinarian. Diagnosis can be made via:
- Clinical examination
- Echocardiogram or ultrasound
- Blood tests
- X-rays
An echocardiogram with a Doppler examination is the best test to determine the location of the murmur. It will usually accurately pinpoint the location of the problem causing the murmur by measuring the speed and direction of blood flow.
What Is the Treatment for Heart Murmur in Cats?
Treatment for heart murmur in cats depends on the cause and symptoms. Physiological murmurs do not require treatment, but routine monitoring is recommended to make sure no problems develop. Murmurs caused by underlying problems will have a treatment plan that addresses the diagnosis. This may include:
- Medications
- Specialized diets
- Supportive care
- A combination of any of the above
Overall, a cat with a heart murmur's life expectancy will likely be normal. Most cats will have a symptomless murmur or a slight structural heart defect. The outlook is good for a long, healthy life.
If the murmur is caused by cardiac disease such as hypertrophic cardiomyopathy, however, the outlook can range from good to grave, depending on a number of variables. Each cat is different, and a good veterinarian will discuss all options and make the best treatment plan for your cat.
