Heart Murmur



Harmless murmurs are caused by the normal flow of blood. The murmur may come and go over time. Increased blood flow can increase the murmur sound. The murmur may be louder with:

  • Exercise
  • Pregnancy
  • Extreme anxiety
  • Anemia
  • Fever
  • Hyperthyroidism

Abnormal heart murmurs can be due to:

  • Structural problems with the heart valves. These are the most common issues. They may have been present from birth or happened later in life. Examples include:
    • Mitral stenosis
    • Mitral regurgitation
    • Aortic stenosis
    • Aortic regurgitation
    • Tricuspid stenosis
    • Tricuspid regurgitation
    • Pulmonary stenosis
  • Septal defects, or a hole in the heart's inside wall
  • Patent ductus-arteriosus, an abnormal connection between major blood vessels near the heart
  • Other issues present from birth such as:
  • Changes to the heart because of heart attack, heart failure, or long-standing high blood pressure
  • Endocarditis, an infection of the inner lining of heart valves and chambers
  • Rheumatic fever,which can cause inflammation and heart valve damage. This can happen if strep throat is not treated properly.
  • Cardiac myxoma, a benign soft tumor within the heart. This is rare.

Risk Factors

Normal heart murmurs are more common in children 3 to 7 years old. Pregnant women are also at increased risk.

The risk for abnormal heart murmurs increases with any of the conditions listed above.



Harmless heart murmurs usually do not cause symptoms. A person with an abnormal heart murmur may have:

  • Rapid breathing or trouble breathing
  • Blue lips
  • Lightheadedness and/or fainting
  • Chest pain
  • Rapid or irregular heartbeat
  • Exercise intolerance
  • Problems gaining weight (in kids)
  • Belly swelling
  • Enlarged neck veins


Most heart murmurs are found during a routine exam. The murmur can be heard with a stethoscope. More tests will be done for murmurs that are causing problems. Blood tests may be done to rule out other problems. Images may be taken of the heart. This can be done with:

  • Chest x-ray
  • Cardiac catheterization
  • Echocardiogram—to look at the size, shape, and motion of the heart

The heart's electrical activity may also be tested. This can be done with an ECG.



Harmless heart murmurs do not need treatment.

Treatment for abnormal heart murmurs will be based on the cause. Treating the cause may decrease or stop the murmur. The doctor may advise:

  • Changing some habits like quitting smoking, exercising more, or drinking less alcohol.
  • Medicine to treat the murmur's cause.
  • Surgery may be needed if what is causing the murmur is a severe problem. This could include repairing or replacing a heart valve.


    A healthy heart may reduce the risk of some abnormal heart murmurs. Steps may include:

    • Eat a healthful diet with plenty of fruits and vegetables.
    • Get regular exercise.
    • If you smoke, talk to the doctor about ways to quit.
    • Follow a treatment plan if you have high blood pressure or diabetes.

    This content is reviewed regularly and is updated when new and relevant evidence is made available. This information is neither intended nor implied to be a substitute for professional medical advice. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with questions regarding a medical condition.

    Edits to original content made by Denver Health.