A heart murmur is an unusual or additional sound during a heartbeat. Murmurs can be faint to very loud. Heart murmur produces a whooshing or swishing noise. It is not a disease.
There are two types of heart murmurs:
innocent (harmless), not caused by heart problems, but common in newborns and children; they may either disappear or last throughout life without causing any problem
abnormal, with symptoms of heart problems, mostly by congenital heart defects that refer to the heart structure at birth. In adults, it is often caused by acquired heart valve disease.
Symptoms depend on the problem causing the heart murmur and its severity. Innocent murmur does not show symptoms because it is not caused by heart problems. Abnormal heart murmurs may have symptoms of the heart problems causing the murmurs. These may include:
- Poor eating and failure to grow normally (in infants)
- Shortness of breath, which may occur only with physical exertion
- Excessive sweating with minimal or no exertion
- Chest pain
- Dizziness or fainting
- A bluish color on the skin, especially on the fingertips and lips
- Chronic cough
- Swelling or sudden weight gain
- Enlarged liver
- Enlarged neck veins
The causes of innocent heart murmurs are:
- Physical activity or exercise
- Changes in the structure of the heart after heart surgery
In abnormal heart murmurs, congenital heart defect in newborns is the cause. Other causes include infections and conditions that damage the heart’s structure, such as: rheumatic fever, endocarditis, valve stenosis, mitral valve prolapse.
There are no risk factors for innocent heart murmurs. There are risk factors that can cause heart murmur at birth, like: family history, taking drugs during pregnancy or diseases during pregnancy.
The risk factors for developing heart murmurs later are: endocarditis, weak heart muscle, heart attack, radiation therapy including the chest, uncontrolled hypertension, high cholesterol, or pulmonary hypertension.