A heart murmur is a sound made by turbulent blood flow in the heart. It sounds like whooshing or swishing with each heartbeat. Some adults and many children have incidental heart murmurs that are harmless and are not caused by abnormalities in the heart. However, some heart murmurs can signal an underlying heart problem.
Heartbeat: Anatomy of the Heart
Benign murmurs are caused by the normal flow of blood through the heart and large vessels near the heart. The murmur may come and go over time. Some things that can increase blood flow and cause a benign heart murmur to be heard include:
Abnormal heart murmurs can be due to:
- Structural abnormalities of the heart valves (most common)—these may be congenital (present from birth) or acquired later in life. Examples include:
- Abnormal holes or connections in the structure of the heart or vessels persisting after birth:
- Structural abnormality of the heart muscle:
- Other congenital heart conditions, such as:
- Endocarditis —infection of the inner lining of heart valves and chambers (endocardium)
- Rheumatic fever—inflammation and damage of the heart valves from poorly treated strep throat
- Cardiac myxoma—a benign soft tumor within the heart (rare)
Normal heart murmurs are more common in children 3-7 years old. Pregnant women are also at increased risk.
Risk factors for abnormal heart murmurs include:
- Rheumatic fever
- High blood pressure
- Autoimmune disease
- Congenital heart defects or disease
Benign heart murmurs usually do not cause symptoms. Patients with mitral valve prolapse sometimes complain of vague chest discomfort and other symptoms. It remains unclear whether or not the valvular abnormality is causing the symptoms.
Signs and symptoms of abnormal heart murmurs can include:
- Rapid breathing or trouble breathing
- Blue lips (cyanosis)
- Lightheadedness and/or fainting
- Chest pain
- Rapid or irregular heartbeat
- Exercise intolerance
- Inability to gain weight in children
- Abdominal swelling
- Enlarged neck veins
Most benign heart murmurs are diagnosed during the course of a routine physical exam with a stethoscope. Some abnormal heart murmurs are also discovered this way. Other abnormal heart murmurs are discovered initially by their symptoms.
Your bodily fluids may be tested. This can be done with blood tests.
Images may be taken of your heart. This can be done with:
- Chest x-ray
- Cardiac catheterization
- Echocardiogram —to examine the size, shape, and motion of the heart.
Your heart's electrical activity may be tested. This can be done with electrocardiogram (ECG).
Benign heart murmurs do not require treatment. Treatment of other heart murmurs depends on the underlying cause and extent of the problem.
Medications can either treat the cause of the heart abnormality associated with the murmur or help compensate for its dysfunction:
- Diuretics, angiotensin-converting enzyme inhibitors, digitalis—to treat heart failure
- Antibiotics—to prevent or treat endocarditis
Preventing benign heart murmurs is unnecessary. To help reduce your risk of developing an abnormal heart murmur:
- Get prompt testing and treatment for strep throat to prevent rheumatic fever.
Reduce your risk of atherosclerosis to help prevent valvular heart disease in the distant future. To do this:
- Eat a healthy diet with plenty of fruits and vegetables .
- Get regular exercise .
- If you smoke, talk to your doctor about ways to quit .
- If you have high blood pressure or diabetes, follow your treatment plan.
Although not routinely recommended for every type of heart murmur, you may need to take antibiotics before and after some medical or dental procedures that could allow bacteria to enter your bloodstream. Ask your doctor if you need to take preventive antibiotics.
American Heart Association
CardioSource—American College of Cardiology
Canadian Cardiovascular Society
The College of Family Physicians of Canada
Antibiotic prophylaxis. American Dental Association website. Available at: http://www.ada.org/2157.aspx. Accessed September 22, 2015.
Heart murmurs. American Heart Association website. Available at: http://www.heart.org/HEARTORG/Conditions/More/CardiovascularConditionsofChildhood/Heart-Murmurs_UCM_314208_Article.jsp.Updated February 3, 2015. Accessed September 22, 2015.
Heart murmurs and your child. Kids Health—Nemours Foundation website. Available at: http://kidshealth.org/parent/medical/heart/murmurs.html. Updated May 2013. Accessed September 22, 2015.
Heart murmur in children. EBSCO DynaMed website. Available at: http://www.ebscohost.com/dynamed. Updated December 14, 2012. Accessed September 22, 2015.
Last reviewed September 2015 by Marcin Chwistek, MD
Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.