A. Widely split
B. Paradoxically split
Mitral stenosis affects the leaflet mobility. In mild to moderate mitral stenosis, the increased left atrial pressure causes the mobile portions of the mitral valve leaflets to be more widely separated, thus resulting in an accentuated M1 sound. In severe to critical mitral stenosis, the valve leaflets are so calcified and immobile that the M1 sound is diminished or absent.