The science and sound of childhood heart murmurs
In children, about half of all detectable heart murmurs are known as innocent murmurs, normal whooshing sounds made by turbulence in the cardiovascular system. Physiological changes, such as exercise, fever or anemia can increase blood flow and create a temporary, innocent murmur. To a physician, an innocent murmur makes a brief, musical and localized sound, whereas structural murmurs produce extended, harsh sounds. Read related article.
Aorta (to body)
Pulmonary artery (to lungs)
Pulmonary veins (from lungs)
Unoxygenated blood from body tissues enters the right side of the heart and is pumped out to the lungs to pick up oxygen. Oxygenated blood from the lungs enters the left side of the heart and is pumped back to the body tissues.
Listen to the heartbeat:
Made when the left ventricle contracts, forcing blood into the aorta.
Listen to the murmur:
This blood vessel closes soon after birth. It normally disappears after the first day.
Atrial septal defect
A small hole between the two atria; often won't make a detectable sound until adolescence.
Ventricular septal defect
A hole in the muscle that separates the two ventricles; often closes as the child matures.
SOURCES: American Heart Association, University of Washington Department of Medicine, staff reports.