What Is It?
A heart murmur is an abnormal sound made by turbulent blood flow within the heart. A murmur can be either a normal sound or an indication of a problem.
Most often, the turbulence is normal and is called a benign flow murmur. It happens when blood flows faster through the heart, for example in a person who is anxious, has just finished exercising, has a high fever or has severe anemia. About 10% of adults and 30% of children (most between the ages of 3 and 7) have a harmless murmur produced by a normal heart. This type of murmur is also called an innocent murmur.
A heart murmur may indicate a structural abnormality of a heart valve or heart chamber, or it may be due to an abnormal connection between two parts of the heart. Some abnormalities of the heart that create heart murmurs include:
An innocent murmur does not cause any symptoms. For other types of heart murmurs, symptoms vary depending on the cause. In general, when a heart murmur significantly interferes with the heart's ability to pump blood, you can experience one or more of the following symptoms:
Many murmurs are discovered unexpectedly when a doctor listens to someone's heart with a stethoscope during a routine physical exam. In other cases, when someone is having symptoms of heart problems, the doctor will ask questions related to a specific type of heart ailment. For example, he or she may ask about a history of rheumatic fever because rheumatic fever during childhood can cause heart valve abnormalities later in life. Because endocarditis can follow intravenous drug use or certain medical or dental procedures, your doctor may ask about these risk factors. If the patient is an infant, the doctor will ask whether there is a family history of congenital heart problems.
Because specific heart problems are associated with specific types of murmurs, your doctor often will make a tentative diagnosis based on your medical history, symptoms and the murmur's distinctive sound and timing (whether the murmur occurs when the heart is pumping or resting). As part of your medical evaluation, your doctor may order diagnostic tests, which may include:
When an innocent heart murmur is triggered by fever, anxiety or exertion, it can disappear after the condition that triggered it goes away. In healthy children with more constant innocent murmurs, the murmur often becomes softer as the child grows and can eventually disappear completely.
When a murmur is caused by a heart problem, how long it lasts depends on the type of disorder. For example, some forms of endocarditis begin suddenly and get worse rapidly over a few days, while others cause milder symptoms over weeks or months. Murmurs caused by valve problems or congenital heart problems usually last throughout life, and in some cases, they can worsen over time.
There is no way to prevent the congenital heart defects that cause some heart murmurs.
If you are at high risk of endocarditis, your doctor or dentist will prescribe special antibiotics before doing any medical or dental procedure during which bacteria could enter your blood and infect your heart. You also can help to prevent endocarditis by avoiding intravenous drug use.
You can prevent many heart-valve abnormalities by preventing rheumatic fever. To do this, take antibiotics exactly as prescribed whenever you have strep throat.
People who already have had one episode of rheumatic fever may need to take antibiotics for up to 10 years after the first attack to prevent the disease from returning.
Innocent heart murmurs do not need to be treated. Other types of murmurs that do not cause any symptoms also may not require any treatment, although your doctor should monitor them regularly. When treatment is required, it varies depending on the cause of the murmur.
When to Call a Professional
Call your doctor if you begin to experience:
In people with innocent heart murmurs, the prognosis is excellent. For people with other types of heart murmurs, the prognosis depends on the type of heart problem and its severity. In general, even when heart surgery is required, the prognosis is good.
National Heart, Lung, and Blood Institute (NHLBI)
P.O. Box 30105
Bethesda, MD 20824-0105
American Heart Association (AHA)
7272 Greenville Ave.
Dallas, TX 75231
American College of Surgeons (ACS)
633 North Saint Clair St.
Chicago, IL 60611-3211