A heart murmur is not heart disease. It is a sound, nothing more. When a doctor listens to your chest with a stethoscope and hears a whooshing or swishing noise between heartbeats, that’s a murmur. Sometimes that sound is caused by heart disease, but very often it isn’t. The distinction matters because many people hear “murmur” and assume something is wrong with their heart, when in reality the majority of murmurs are completely harmless.
What a Heart Murmur Actually Is
A heart murmur is the sound of blood flowing through or near your heart. Think of it like water moving through a garden hose: sometimes the flow creates a noise you can hear, and sometimes it doesn’t. The noise itself isn’t a disease any more than a gurgling stomach means you have a digestive disorder. It’s a physical finding, a clue your doctor picks up during an exam.
Murmurs fall into two categories: innocent (also called “harmless” or “functional”) and abnormal (sometimes called “pathologic” or “worrisome”). Innocent murmurs are extremely common in children. In kids two years and older, a simple test can help tell the difference: if the murmur completely disappears when the child stands up, there’s a 98% chance it’s innocent. Many children outgrow these murmurs entirely, and they carry no increased risk of developing heart problems later.
When a Murmur Does Signal Heart Disease
An abnormal murmur is different. It’s still just a sound, but it’s being produced by a structural problem in the heart. In children, the most common culprits are congenital heart defects, meaning problems with the heart’s structure that were present at birth. These include holes between the heart’s chambers or abnormal connections between blood vessels that redirect blood flow in ways it shouldn’t go.
In adults, abnormal murmurs are most often caused by heart valve disease that develops over time. Your heart has four valves that open and close with every beat to keep blood moving in the right direction. As you age, calcium can build up on these valves, making them stiff and narrow so blood has to squeeze through a tighter opening. A valve can also stop closing completely, allowing blood to leak backward. Both situations create turbulent blood flow and a murmur your doctor can hear. Other conditions that can produce abnormal murmurs include a thickened heart muscle, an infection of the heart’s inner lining, and high blood pressure in the lungs.
So the relationship works in one direction: heart disease can cause a murmur, but a murmur doesn’t necessarily mean heart disease.
How Doctors Tell the Difference
When your doctor hears a murmur, they evaluate several characteristics before deciding whether it needs further investigation. They consider how loud it is (graded on a scale of 1 to 6), where exactly on the chest it’s heard, whether the sound radiates to the neck or back, its pitch, and when during the heartbeat it occurs.
Timing is one of the most telling clues. A murmur that happens while the heart is pumping blood out (during contraction) is more likely to be innocent. A murmur that occurs while the heart is filling with blood (between contractions) or that continues throughout the entire heartbeat is more concerning and typically points to a structural problem. Your doctor may also ask you to stand, squat, or bear down, because these position changes alter how blood flows through the heart and can make certain abnormal murmurs louder or softer in characteristic ways. If the doctor feels a vibration or a heaving motion on your chest wall, that also suggests a structural issue.
When there’s any doubt, the main diagnostic tool is an echocardiogram. This is an ultrasound of your heart. It creates a moving picture of the heart’s chambers, valves, and blood flow in real time, making it straightforward to see whether a valve is narrowed, leaking, or otherwise abnormal. A chest X-ray can show whether the heart is enlarged, and an electrocardiogram (a quick, painless test with sensors on your chest) checks for irregular electrical activity. In more complex cases, CT scans, MRIs, or cardiac catheterization may be used.
What Happens After Diagnosis
If your murmur is innocent, the answer is simple: nothing. No treatment, no restrictions, no follow-up testing. You live your life normally. Innocent murmurs don’t progress into heart disease and don’t need monitoring.
If the murmur turns out to be caused by valve disease or another structural problem, what happens next depends entirely on how severe the issue is. Mild valve problems often just need periodic monitoring with echocardiograms to track whether the condition is stable or progressing. You might go years without needing any intervention. For more significant valve disease, current guidelines from the American Heart Association and American College of Cardiology recommend evaluation by a heart specialist and, for severe cases, assessment by a multidisciplinary team at a specialized valve center to determine whether repair or replacement is appropriate.
The key point is that the murmur itself isn’t what gets treated. The underlying condition is. Fixing a leaky valve, for example, resolves the murmur because the turbulent blood flow that created the sound is gone.
Symptoms That Suggest Something More
Most people with innocent murmurs have zero symptoms. The murmur is discovered incidentally during a routine physical and means nothing. But certain signs alongside a murmur suggest the sound is being caused by an underlying heart problem:
- Shortness of breath during normal activities or while lying flat
- Swelling in the legs, ankles, or abdomen
- Fatigue that’s disproportionate to your activity level
- Dizziness or fainting
- A bluish tint to the skin, especially in fingertips or lips (more common in children with congenital defects)
- Poor growth or feeding difficulties in infants
If you’ve been told you have a heart murmur and you’re experiencing none of these, the odds are strongly in your favor that it’s innocent. If any of these symptoms are present, the murmur deserves a closer look with imaging to determine whether a structural heart problem is responsible.