Heart murmurs and other sounds

Definition

A heart murmur is a blowing, whooshing, or rasping sound heard during a heartbeat. The sound is caused by rough blood flow through the heart valves or near the heart.

Considerations

The heart has four chambers:

• Two upper chambers (atria)
• 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 chambers.

Murmurs can happen for many reasons, such as:

• When a valve does not close tightly and blood leaks backward (regurgitation)
• When blood flows through a narrowed or stiff heart 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).
• 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 doctor will take the following into consideration when examining you:

• Does the murmur occur when the heart is resting or contracting?
• Does it last throughout the heartbeat?
• Does it change when you move?
• Can it be heard in other parts of the chest, on the back, or in the neck?
• Where is the murmur heard the loudest?

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

A doctor or nurse can listen to your heart sounds using a tool called a stethoscope, which is placed over your chest. You will be asked questions about your medical history and symptoms, such as:

• Have other family members had murmurs or other abnormal heart sounds?
• Do you have a 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 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.

The following tests may be done:

• Chest x-ray
• ECG
• Echocardiography