A heart murmur is an extra or abnormal sound produced by the heart and heard with the stethoscope. In most cases the abnormal sound is the result of noisy or turbulent blood flow in the heart. The turbulence may be caused by the shape of the heart or by abnormalities of specific heart structures, such as the valves or the heart walls.
Murmurs can result from heart infections.
Rheumatic fever from streptococcal infections, such as strep throat, may cause valve damage. Some murmurs are caused by heart muscle damage resulting from coronary artery disease or hypertension. The classification of heart murmurs is based on their loudness and where in the heart pumping cycle they occur. Each pump of the heart is a two-phase process. Systole is the name for the pumping phase.