Presystolic murmur

Source: Wikipedia, the free encyclopedia.

A presystolic murmur, also called presystolic accentuation, is a type of

mitral valve stenosis. It is heard following the middiastolic rumble of the stenotic valve,[1] during the diastasis
phase, making it a "late diastolic" murmur.

The murmur is heard due to antegrade flow of blood through a progressively narrowing mitral opening during the end of the

atrial systole. This antegrade flow through the mitral valve before it completely closes appears to be the result of a pressure gradient at the end of diastole.[1]
As its name so indicates, the presystolic murmur is heard before the mitral valve produces the S1 heart sound.

Less often, a presystolic murmur can be heard when a right

atrial myxoma causes a tricuspid valve obstruction to blood flow.[1]

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