A normal heartbeat has two sounds. A heart murmur is the extra rasping, humming or whooshing sound that can be heard in-between. It must be investigated to be sure it’s “innocent”, meaning harmless.

As opposed to an innocent heart murmur, an abnormal heart murmur may point to a serious underlying heart problem such as damaged heart valves or congenital heart defects like a hole in the heart.

“Prognosis for abnormal heart murmurs varies according to the underlying heart problem and its severity. It is excellent in patients with otherwise structurally normal hearts and poor in patients with severe underlying valvular or congenital heart defec​ts,” says doctors from the ​Department of Cardiology​, National Heart Centre Singapore​​ (NHCS), a member of the SingHealth​ group.

What causes a heart murmu​r?

The extra or unusual sound char​acteristic of a heart murmur is due to the faster blood flow through the heart valves and/or blood vessels near the heart.

Heart murmur symptoms

You may not know you have a heart murmur because you cannot hear it. Heart murmurs can only be heard through a stethoscope.

However, symptoms such as chest pain, shortness of breath, dizziness, heart palpitations or lower limb swelling may indicate an underlying heart problem that can cause a heart murmur.

Heart murmur treatment

Innocent heart murmurs do not need treatment because the heart is structurally normal. Treatment for abnormal heart murmurs varies, depending on the underlying heart problem.

For instance, the treatment may include medications to lower high blood pressure and normalise thyroid hormone levels, antibiotics to treat heart infections and surgery to repair heart valves.

See next page for the types of heart murmurs and prevention tips for abnormal heart murmurs​.​

Ref: S13