Key Points

• A heart murmur is an extra or unusual sound heard during your heartbeat. Murmurs range from very faint to very loud and sometimes sound like a whooshing or swishing noise.
• Most heart murmurs are harmless (innocent).
• Sometimes a heart murmur indicates a heart problem, especially if other signs or symptoms of a heart problem are present.
• Innocent, harmless murmurs are common in healthy children. A child or adult with an innocent murmur has a normal heart.
• Doctors listen carefully to the heart with a stethoscope to help decide if a murmur is innocent or abnormal.
• Doctors listen to the loudness, location, and timing of the murmur in order to classify and describe the sound.
• Most abnormal murmurs in children are due to congenital heart defects—heart defects present at birth.
• In adults, abnormal murmurs are most often due to heart valve problems caused by infection, disease, or aging.