Heart Murmur (Still's Murmur)

Overview

A heart murmur is not a disease; but rather abnormal heart sounds that are produced as a result of turbulent blood flow which is sufficient to produce audible noise. This most commonly results from narrowing or leaking of valves or the presence of abnormal passages through which blood flows in or near the heart.

Murmurs range from very faint to very loud and sometimes sound like a whooshing or swishing noise. Most heart murmurs are innocent (harmless). However sometimes they are a sign of heart problems especially if other symptoms of a heart problem are present.

Types of Murmurs

Innocent (harmless) murmurs

A person with an innocent murmur has a normal heart and usually has no other signs or symptoms of a heart problem. Innocent murmurs are common in healthy children.

Abnormal murmurs

A person with an abnormal murmur usually has other signs or symptoms of a heart problem. Most abnormal murmurs in children are due to congenital heart defects which are present at birth. In adults abnormal murmurs are most often due to heart valve problems caused by infection disease or aging.

Causes

Innocent Heart Murmurs

Innocent murmurs are heard when blood moves noisily through a normal heart. Sometimes these murmurs occur when:

  • Blood is flowing faster than usual through the heart and blood vessels attached to the heart.
  • An increased amount of blood is flowing through the heart.

Illnesses or conditions that can cause blood to flow faster than usual through the heart include:

  • Fever
  • Anemia
  • Too much thyroid hormone in the body (hyperthyroidism)

Many if not most children will have a heart murmur heard by their doctor at some time in their lives. After childhood the most common cause of an increased amount of blood flowing through the heart is pregnancy. Most murmurs found in pregnant women are harmless. They are due to the extra blood that women's bodies make while they are pregnant.

Innocent murmurs are sometimes due to changes to the heart resulting from heart surgery or from aging.

Abnormal Heart Murmurs

The most common cause of abnormal murmurs is congenital heart defects. Congenital heart defects occur when the heart heart valves or blood vessels attached to the heart do not develop normally before a baby is born. Some babies are born with a combination of heart defects. Common defects that cause murmurs include:

  • Congenital septal defects which are holes in the wall (septum) that separates the right and left sides of the heart. They account for more than half of abnormal murmurs in children.
  • Congenital valve defects which include narrow valves that do not allow enough blood to flow through them and leaking valves that do not close properly.

Infections and other conditions that damage heart valves or other structures of the heart also may cause murmurs. These include:

  • Rheumatic fever a serious illness that can develop after a person has an untreated or incompletely treated infection caused by the bacteria that cause strep throat or scarlet fever. Rheumatic fever can lead to permanent damage to the heart. If your doctor diagnoses strep throat be sure your child takes all of the antibiotics prescribed even if he or she feels better before the antibiotics run out.
  • Endocarditis an inflammation of the inner lining of the heart and valves that is usually caused by a bacterial infection. Endocarditis is a serious disease that can lead to permanent heart damage and other complications.
  • Calcification (hardening and thickening) of valves as a result of aging. The hardened and thickened heart valves do not work as they should.

Symptoms

Most people with heart murmurs do not have any other signs and symptoms of a heart problem. The murmur is usually harmless.

Some people with heart murmurs do have signs and symptoms of a heart problem. These may include:

  • Blue coloring of the skin especially on the fingertips and inside the mouth
  • Poor eating and failure to grow normally (in infants)
  • Fast breathing
  • Excessive sweating
  • Chest pain
  • Dizziness
  • Shortness of breath
  • Fainting
  • Fatigue (feeling very tired)

The signs and symptoms depend on the cause and the severity of the problem causing the murmur.

Diagnosis

Doctors use a stethoscope to listen to heart sounds and hear murmurs. They often notice innocent heart murmurs during routine checkups or physical exams.

Doctors may also find abnormal murmurs during routine checkups. Murmurs caused by congenital heart defects are often heard at birth or during infancy. Doctors may hear murmurs caused by other heart problems at any age.

Doctors usually refer people with abnormal murmurs to a heart specialist for further evaluation and testing.

How Are Heart Murmurs Treated?

Innocent Murmurs

Healthy children with innocent murmurs do not need treatment because they have a normal heart. If your child has an innocent murmur tell your pediatrician during regular checkups. Pregnant women with innocent murmurs due to increased blood volume also do not need treatment.

If you have an innocent murmur due to an illness or condition such as anemia hyperthyroidism or fever the murmur will go away once the illness or condition is treated.

Abnormal Murmurs

The treatment for heart problems that cause abnormal murmurs varies depending on the specific heart problem.

The treatment of congenital heart defects is based on the type and severity of the heart defect or defects causing the murmur. Treatment may include medicine or surgery. The treatment of heart problems caused by infection or disease depends on the type and severity of the damage to the heart. The treatment may include medicine or surgery.