Should You Be Concerned if You Have an Innocent Heart Murmur?

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Heart murmurs are noises heard with a stethoscope when blood flows through the heart valves that separate one chamber of the heart from another. They can be caused by turbulent blood flow through a damaged valve, but the majority of murmurs are innocent. With an innocent heart murmur, a sound is heard even when blood flows through a structurally normal valve. What causes an innocent heart murmur?

Innocent Heart Murmurs are More Commonly Seen in Children

Innocent heart murmurs are more common in children. This is partially because it’s easier to hear the sounds of blood flowing through a child’s heart with a stethoscope because they have thin chest walls. Adults also have innocent heart murmurs, although they’re less common than in children. Certain medical conditions may cause transient innocent heart murmurs including pregnancy, anemia, exercise, fever and an overactive thyroid in adults.

Signs and Symptoms of a Heart Murmur That’s Innocent

Most innocent heart murmurs are soft. Murmurs are graded from one to six based on how loud they are when a doctor listens to them with a stethoscope. Murmurs that are grade three or louder are less likely to be serious than softer ones that are only grade one or two. Murmurs that become softer with changes in position are also more likely to be innocent.

Heart murmurs that are innocent cause no symptoms in either adults or children. In fact if a person has symptoms of shortness of breath, lightheadedness, dizziness, easy fatigue or chest pain along with a heart murmur, the murmur is unlikely to be innocent. Most children and adults with innocent murmurs don’t even know they have one until a doctor listens to their heart with a stethoscope.

If a murmur is grade three or louder or if there are symptoms, doctors usually do a complete heart work-up to rule out valvular heart disease or congenital heart problems that could be causing the murmur. These may include a chest x-ray to check for enlargement of the heart, an ECG tracing, and an echocardiogram to rule out a diseased heart valve.

How Are Innocent Heart Murmurs Treated?

Innocent heart murmurs require no treatment, and a child or adult will have no restrictions placed on their activities once a murmur is found to be innocent. Many innocent heart murmurs in children disappear as a child grows older, although some will persist for a lifetime. Regardless, a heart murmur shouldn’t cause problems as long as there’s no underlying heart disease. It doesn’t put a person at higher risk for heart disease or an early death later in life - as long as it’s an innocent murmur.

The Bottom Line?

Innocent heart murmurs are common, especially among children. Many of these murmurs disappear with time, and they don’t need treatment as long as there’s no underlying heart disease.

References

Pediatr Clin North Am 1984;31:1229-40.

Pediatr Clin North Am 1998;45:107-22.

American Family Physician. August 1999. “Heart Murmurs in Pediatric Patients: When Do You Refer?”