- A heart murmur is when blood flows more rapidly than normal through the heart.
- Heart murmurs can be innocent and frequently happen during pregnancy, physical activity, or childhood growth spurts.
- Heart murmurs can also be abnormal and dangerous, like when they are associated with congenital heart defects or problems with your heart valves.
- This article was reviewed by Jason R. McKnight, MD, MS, a family medicine physician and clinical assistant professor at Texas A&M College of Medicine.
- Visit Insider's homepage for more stories.
If you put a stethoscope on a healthy beating heart, you'd typically hear "lub-dub, lub-dub," over and over again.
When the heart makes a different sound, such as a whooshing or buzzing noise, it is called a heart murmur. Sometimes, heart murmurs are harmless, but they can also be associated with dangerous heart defects. Here's what you need to know.
A heart murmur is often innocent
Many heart murmurs are not considered dangerous, and occur when blood flows more rapidly than normal through the heart. These innocent heart murmurs can happen during pregnancy, exercise, and childhood growth spurts, or with health conditions like a fever, anemia, and hyperthyroidism.
"It doesn't necessarily mean there is something wrong with your heart," says Shephal Doshi, MD, the director of cardiac electrophysiology and pacing at Providence Saint John's Health Center. "It is just a different sound from what your heart [normally] makes."
For example, as many as 90% of women experience heart murmurs during pregnancy, according to Northwestern Medicine. It is estimated that 10% of adults and 30% of kids have murmurs that are totally harmless, according to Harvard Health Publishing.
Abnormal heart murmurs can be dangerous
While a large number of heart murmurs are innocent, there are others that may indicate dangerous health conditions, like an issue with your heart valves.
"When the heart valve opens, the blood is supposed to flow through easily," says Doshi. "If the heart valve isn't opening well, then there's a resistance of flow."
This resistance could cause a buzzing sound. If the heart valve is leaking, it could make a blowing sound. Heart conditions that may cause heart murmurs include:
- Septal defects, like ventricular septal defects. These defects are congenital, which means you are born with them, and they are holes in the septum that separates the left and right side of the heart.
- A patent ductus arteriosus is also congenital. It is a connection to the aorta, which is meant to close at birth, but occasionally doesn't close. Depending on the severity, surgery may be necessary to close the hole.
- Endocarditis is an infection of the heart valves, which can affect how well they function and lead to a murmur.
- Cardiac myxoma is a rare, benign tumor that grows in the heart and is often associated with murmurs.
How to know if you have a heart murmur
When a heart murmur is a result of one of these conditions, Doshi says a person might also experience symptoms like fatigue, dizziness, lightheadedness, or chest pain.
But heart murmurs can also exist without symptoms and are usually only discovered during a visit to the doctor.
When doctors diagnose a heart murmur, Doshi says they will likely follow up with a non-invasive ultrasound called an echocardiogram. "It takes about 20 minutes," says Doshi. "It decides if a murmur is significant, if it needs treatment, or if it is benign."
If the heart murmur is caused by an underlying condition, treatment may be necessary. This could include medication, surgery, or cardiac catheterization. It is worth noting that what is being treated isn't the heart murmur, but the health condition causing the murmur.
When the heart murmur is innocent, you likely won't need any treatment. For example, children will often grow out of heart murmurs. Other murmurs may persist throughout life without causing any health problems at all, though it may be monitored by your doctor.
Related stories about heart health:
- What is congenital heart disease? The warning signs for your newborn
- What is a silent heart attack? How to recognize the warning signs
- What are the signs of a heart attack? How to know if you're at risk
- How hypertension, heart disease, and stroke are related
- What happens after a heart attack? How to get physical and mental health back on track
- How to lower blood pressure with a heart-healthy diet and exercise
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