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What is a Heart Murmur?


A normal heartbeat has two sounds. The first sound is heard as two of the heart’s valves -- the mitral and tricuspid valves -- simultaneously close. The second sound is heard as the other two valves -- aortic and pulmonic – snap shut.


These two sounds create the familiar “boom boom” heartbeat sound. Doctors listen for these sounds to ensure heart health, and if something doesn’t sound right, it could indicate a problem within the heart, like a heart murmur.


So what exactly is a heart murmur?

A heart murmur is a swishing sound that is heard when there is abnormal or unstable blood flow across the heart valve. Murmurs can be considered either harmless or abnormal.


Harmless murmurs may not cause symptoms and can happen when blood flows more rapidly than normal through the heart from exercise, rapid growth in children, or pregnancy.


Abnormal murmurs may indicate a structural abnormality of a heart valve or heart chamber. You can have a murmur even if you’ve never had a prior heart or medical conditions. Or, a person can be born with valve disease (congenital) or develop a problem later in life (acquired).


What causes it?


Abnormal changes to the heart valve cause a murmur. Anemia, fever, and high blood pressure are common conditions that can lead to heart murmurs.


However, Valvular heart disease is the most common cause of a heart murmur and occurs when the heart valves don’t work properly. Causes of valvular heart disease can include:

  • Mitral valve prolapse- the valve between the heart’s upper and lower-left chambers doesn’t close properly.

  • Valvular insufficiency or “Leaky Valve”- A heart murmur can be heard if any of these heart valves have a narrowing valve opening (stenosis) that prohibits blood flow or produces a valve leak that causes blood to flow or leak backwards.

  • Congenital heart problems- This means the disorder was present at birth, often presenting as holes in the heart due to complications in utero.

  • Endocarditis- This inflammation or infection of the heart valves and heart chambers can cause a heart murmur by obstructing blood flow or forcing blood to leak backwards through the heart.

  • Cardiac myxoma- This is a rare, benign tumor that can grow inside the heart and obstruct blood flow.

  • Asymmetric septal hypertrophy- An abnormal thickening of the heart muscle inside the lower left chamber of the heart. This thickened muscle prohibits blood flow out of the aortic valve. This condition is commonly in patients with hypertrophic cardiomyopathy.

Some murmurs don’t cause any symptoms. An abnormal heart murmur may cause:

  • Shortness of breath

  • Dizziness

  • Chest pain

  • Swelling or sudden weight gain

  • Chronic cough

  • Fainting

  • Bulging veins in the neck

  • Skin that appears blue, especially on your lips and fingertips

  • Heavy sweating with little or no activity

If you’re experiencing any of these symptoms, contact your healthcare provider immediately.


Most murmurs aren’t serious, but your doctor may refer you to a cardiologist for additional tests, like an EKG or echocardiogram, to determine the severity of the heart murmur.


Regular exercise, quitting smoking, and limiting alcohol intake can help to reduce the risk of developing an abnormal heart murmur. Keep pre-existing conditions, such as high blood pressure, diabetes and high cholesterol under control.


It is also important to maintain good dental hygiene to prevent bacteria buildup from potentially getting into the bloodstream and affecting the heart valves.


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