What is a heart murmur and what causes it?

What is a heart murmur and what causes it?

Normally heart produces two heart sounds, name first and second heart sounds. An audible vibration in between the heart sounds is called a heart murmur. They are generally of longer duration than heart sounds. Many murmurs are innocent murmurs due to enhanced flow across the valves producing turbulence. Normal laminar flow of blood across the valves do not produce any murmur. Murmurs are produced by turbulent flow, usually of higher velocity. Some of the murmurs are due to abnormal blood flow as in the case of leaky valve, obstructed valve or abnormal communication between the chambers of the heart in the form of birth defects in its walls.