Murmurs are blowing, whooshing, or rasping sounds heard during a heartbeat. The sound is caused by turbulent blood flow through the heart valves or near the heart.

Considerations

A doctor can check heart sounds by listening with a stethoscope over the surface of the chest. An echocardiogram can find the exact cause of the murmur.

The heart has four chambers: two upper chambers (atria) and two lower chambers (ventricles). The heart has valves that close with each heartbeat, causing blood to flow in only one direction. The valves are located between the atria and ventricles, and between the ventricles and the major vessels from the heart.

Murmurs occur when a valve does not close tightly and blood leaks backward (called regurgitation). They also can occur when the blood flows through a narrowed or stiff valve (called stenosis).

There are several ways in which your doctor may describe a murmur:

• Murmurs are classified ("graded") depending on how loud the murmur sounds with a stethoscope. The grading is on a scale. Grade I can barely be heard. An example of a murmur description is a "grade II/VI murmur." (This means the murmur is grade 2 on a scale of 1 - 6).
• Murmurs may be described as blowing, whooshing, or rasping.
• In addition, a murmur is described by the stage of the heartbeat when the murmur is heard. A heart murmur may be described as systolic or diastolic.

When a murmur is more prominent, the doctor may be able to feel it with the palm of the hand over the heart.

The following are important clues to the cause of the murmur:

• Does the murmur occur in the resting stage (diastole) or contracting stage (systole)?
• Does it occur early or late in the stage?
• Does it last throughout the heartbeat?
• Does it change when the doctor uses physical maneuvers?
• Can the murmur be heard in other parts of the chest, on the back, or in the neck?
• Where is the murmur heard the loudest?

For example, a presystolic murmur is heard just before systole. It is usually caused by narrowing of the mitral or tricuspid valve (the valves between the atria and the ventricles).

Causes

Many heart murmurs are harmless. These types of murmur are called innocent murmurs. They will not cause any symptoms or problems. Innocent murmurs do not need treatment.

Significant murmurs can be caused by:

• Aortic regurgitation
• Aortic stenosis
• Hypertrophic cardiomyopathy (idiopathic hypertrophic subaortic stenosis)
• Mitral regurgitation - acute
• Mitral regurgitation - chronic
• Mitral stenosis
• Pulmonary regurgitation (backflow of blood into the right ventricle, caused by failure of the pulmonary valve to close completely)
• Pulmonary stenosis
• 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)

Children often have murmurs as a normal part of development. These murmurs do not require treatment, and may include:

• Pulmonary flow murmurs
• Still's murmur
• Venous hum

What to Expect at Your Office Visit

The health care provider will usually discover a heart murmur during a physical examination. You may or may not have been aware of its presence. The physical examination will include careful attention to heart sounds.

The doctor may ask the following questions:

• Have other family members had murmurs or other abnormal heart sounds?
• Is there any family history of heart problems?
• What other symptoms do you have, such as:
  • Bluish skin color (cyanosis)
  • Chest pain
  • Distended neck veins
  • Fainting (syncope)
  • Liver enlargement
  • Lung sound changes
  • Shortness of breath
  • Swelling
  • Weight gain

The health care provider can often identify the valve involved and whether you have regurgitation or stenosis during the exam. The location, quality, and timing of the murmur are all important. The doctor may ask you to squat, stand, or hold your breath while bearing down or gripping something with your hands to listen to your heart.

Diagnostic testing to determine the cause of a "new" murmur or other abnormal heart sound may include:

• Chest x-ray
• ECG
• Echocardiography

Alternative Names

Chest sounds - murmurs; Heart sounds - abnormal; Murmur - innocent; Innocent murmur; Systolic heart murmur; Diastolic heart murmur