Lubb-dupp. Lubb-dupp. Those words are often used to describe the sound of a heartbeat. That steady, regular sound is made by heart valves, opening and closing as blood circulates through your heart. The term heart “murmur” refers to a different sound. A murmur is an abnormal extra sound that can be heard through a stethoscope.
Sometimes, the murmur sounds like a humming; it may be faint or temporary, with onset during pregnancy or fever. As quickly as it comes, the murmur may disappear. However, a murmur could be persistent and loud, easily heard like a churning mill wheel or even like a cooing seagull, indicating a serious heart problem.
A murmur can have several causes. Mayo Clinic Health System cardiologist Michel Barsoum, M.D., says it could be a heart valve problem. "The valves in your heart act as doors between the chambers, or rooms, of the heart. When heart valves are very tight or narrow, that is called stenosis."