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.

It can be a mid-diastolic or presystolic murmur It is associated with severe aortic regurgitation, although the role of this sign in clinical practice has been questioned.

A presystolic murmur, also called presystolic accentuation, is a type of diastolic heart murmur typically associated with the opening snap in mitral valve stenosis.