Abnormal and "Innocent" Heart Murmurs
A heart murmur is an unusual heart sound. Many times a heart murmur isn’t dangerous and is called an “innocent” murmur. Abnormal heart murmurs may point to an underlying heart condition that should be studied further.
What causes heart murmurs?
Abnormal heart murmurs in adults are usually related to defective heart valves. Abnormal heart murmurs in adults may be related to:
- Problems of the aortic valve (aortic regurgitation, aortic stenosis)
- Problems of the mitral valve (chronic or acute mitral regurgitation, mitral stenosis)
- Hypertrophic cardiomyopathy
- Pulmonary regurgitation (backflow of blood into the right ventricle, caused by failure of the pulmonary valve to close completely)
- Pulmonary valve stenosis
- Problems of the tricuspid valve (tricuspid regurgitation, tricuspid stenosis)
Significant murmurs in children are more likely to be caused by:
- Anomalous pulmonary venous return (an abnormal formation of the pulmonary veins)
- Atrial septal defect (ASD)
- Coarctation of the aorta
- Patent ductus arteriosus (PDA)
- Ventricular septal defect (VSD)
Heart murmurs related to valve problems should receive follow-up care.
Not every murmur is associated with valve disease. Murmurs can also be caused by conditions that may temporarily increase blood flow such as:
- Exercise
- Pregnancy
- Hyperthyroidism
- Anemia
- Rapid growth spurts in children
If a murmur is detected, follow-up tests may be recommended. Although some heart murmurs indicate heart valve problems, others are considered harmless. These are “innocent” murmurs.
What are innocent heart murmurs?
Innocent heart murmurs are harmless sounds made by the blood circulating normally through the heart's chambers and valves or through blood vessels near the heart. They can be common during infancy and childhood and often disappear by adulthood. They're sometimes known as "functional" or "physiologic" murmurs.
Some harmless murmurs require additional tests such as an electrocardiogram (ECG) or echocardiogram (echo) to rule out the possibility of a problem. Read more about childhood heart murmurs.
Diagnosing the cause
Your health care professional will investigate the root cause of the heart murmur. Clues about the cause can be based on the loudness, location and quality of the murmur. Loudness is graded from 1 to 6. A grade of 1 is very faint, heard only with a special effort. A grade 6 is extremely loud and can be heard with a stethoscope even without touching the chest.
The location, duration and loudness of the murmur can help your health care provider determine which heart valve is involved as well as the severity.
Other tests may be done to decide if the murmur needs further investigation including:
As with most conditions, heart murmurs and any underlying problems can vary in severity and risk.
Any time a murmur is suspected to be associated with a valve problem that may need treatment or repair, it’s wise to look for a qualified health care professional with experience diagnosing and treating your condition. A specialist who regularly manages valve disease can assess your condition and offer treatment options.
