Heart murmurs are additional sounds that a doctor might hear when listening to the beat of a heart with a stethoscope. They are sometimes called extra beats and are caused by the turbulent flow of blood. Murmurs often include a rushing or whooshing sound, although other sounds can indicate a specific cause. They can be harmless, or innocent, or they might indicate a medical problem. An innocent heart murmur is often referred to as a functional heart murmur.
A scale of 1 to 6 is used to grade heart murmurs based on their sound. The quietest murmurs receive a grade 1. The loudest murmurs are rated as grade 6. It is not unusual for even innocent murmurs to be somewhat loud and receive a grade of 3 to 6.
Frequently, heart murmurs that are heard in children are completely innocent. They might be heard a few days after birth and often are the result of the ductus — a small opening between the left and right arteries above the heart — remaining open. A murmur that is caused by an open ductus usually disappears within a few weeks. In babies who were born prematurely, the ductus might remain open and require closure at a later date. Unless the ductus is causing significant problems for the newborn, closure usually is not attempted for six months to a year.
Heart murmurs can arise within the first few days of life from the changes in circulation. When a child is born, his or her body begins to circulate blood differently so that more blood goes to certain parts of the body, such as the lungs, which were not as important before birth. These changes in circulation might cause an initial murmur that disappears shortly after birth.
Tiny differences in heart formation also might result in murmurs. These can be heard in children from birth or when children are about 2 years old. Usually, these murmurs are innocent and tend to disappear within a few years.
In adults, heart murmurs also can be innocent. People who suffer from anxiety might sometimes have additional beats called pre-atrial contractions or pre-ventricular contractions. These murmurs are quite normal and do not represent danger to the heart.
Congenital Heart Defects
Although most heart murmurs are innocent, some can indicate serious illness or problems with the heart. Children who have congenital heart defects will often have heart murmurs. Usually, these murmurs are accompanied by symptoms such as poor growth, a blue tinge to the skin, failure to thrive, an inability to eat or breathing difficulties. These types of murmurs are causes for concern, and a pediatric cardiologist can diagnose specific heart defects and determine the appropriate treatment.
Mitral Valve Prolapse
Heart murmurs that are present in teenagers and young adults and have a honking or clicking sound might indicate a defect called mitral valve prolapse. The symptoms of this defect usually are not present when a child is young. Mitral valve prolapse, a defect of the valve between the left atrium and left ventricle, usually requires treatment or replacement of the valve. The honking or clicking sound often can be heard without a stethoscope and should immediately be brought to the attention of a healthcare professional.