so instead of the mv staying closed during systole because the orifice is so small it creates a negative pressure - that's called the venturi effect where basically flow has to converge through a smaller orifice and decreases the pressure when it's going through that orifice and that negative pressure/smaller pressure basically pulls the mitral valve anterior leaflet up against the septum so the leaflet itself acts as the dynamic obstruction to the lv outflow tract and instead, what you get is mitral regurg all the flow is going out of the lv outflow tract because that orifice is so small the mv pushes up towards the lv outflow tract and you get regurg instead.