What Is a Heart Murmur?

Here is the myth to clear away first: hearing the words "heart murmur" does not automatically mean serious heart disease. A murmur is not a diagnosis at all — it is a sound. Specifically, it is an extra or unusual sound a clinician hears through a stethoscope as blood flows through the heart, somewhere alongside the familiar lub-dub of the heartbeat itself.

The video above, "Normal and Abnormal Heart Sounds," runs about half an hour and starts from exactly that distinction. Its explanation is a good anchor: heart sounds are the noises made by the beating heart and the flow of blood through it, reflecting the turbulence created when the heart valves snap shut. A murmur is what shows up when that flow becomes noisy enough to hear — a whooshing or swishing note mixed in with the normal sounds during cardiac auscultation, which is simply the medical word for listening to the chest.

When a murmur is just passing through

Plenty of murmurs are what doctors call innocent. Blood can flow a little more forcefully or quickly than usual — during exercise, fever, or pregnancy, for example — and that faster flow alone can make a sound, even though the heart and its valves are completely normal. Innocent murmurs are especially common in children, and they often fade or come and go. If your clinician describes a murmur this way and is not concerned, that is usually the end of the story, though they may listen again at a future visit just to confirm nothing has changed.

When the sound is pointing at a valve

The other kind of murmur deserves a closer look. Because the normal heart sounds come from valves closing, an extra sound can be a clue that a valve is not opening fully or is not closing tightly, so blood leaks backward or squeezes through a narrowed opening. That is why a new murmur in an adult, a murmur that is loud or harsh, or one that arrives with symptoms — breathlessness, chest pain, dizziness, fainting, or swelling — is never simply waved away. Chest pain and fainting, in particular, need prompt assessment in their own right; our guide to what angina is explains one common cause of chest discomfort doctors work to tell apart.

What happens after a murmur is heard

Expect your clinician to listen carefully in more than one position, note when in the heartbeat the sound falls, and ask about symptoms and your history. Often that is enough to sort an innocent murmur from one that needs testing. When more detail is needed, the usual next step is an echocardiogram — an ultrasound of the heart that shows the valves opening and closing and the blood moving through them. The site's shorter companion video "Heart Sounds", at under two minutes, makes a handy recap of those normal valve sounds before you hear your results explained. Treatment, if any is needed at all, is aimed at whatever the tests find — many people simply have their murmur checked from time to time, with no procedure and no restrictions.

MedicalVideos.com has published trusted medical videos since 2007. The site was founded by Dr. Mohamed Ibrahim, MD, PhD — physician and researcher.

Frequently Asked Questions

Is a heart murmur a disease?
No. It is a sound heard through a stethoscope — an extra whooshing or swishing alongside the normal heartbeat. It can be completely innocent, or it can be a clue to a valve problem, which is why clinicians work out which kind it is.

Can a murmur be harmless?
Yes. So-called innocent murmurs happen when blood flows more quickly or forcefully, such as during exercise, fever, or pregnancy, even though the heart is normal. They are common in children and often need no treatment at all.

How long is the anchor video?
About half an hour (30 minutes 45 seconds by the video file itself). It contrasts normal and abnormal heart sounds and explains that the sounds reflect turbulence as the heart valves snap shut.

Educational only — this article is general information about heart murmurs, not medical advice and not a diagnosis. Chest pain, fainting, or new severe breathlessness needs urgent medical assessment.