A mitral valve arcade occurs when there is a direct connection of the papillary muscles to the mitral leaflets, either directly or through the interposition of unusually shorten chordae. The mitral valve cords appear thickened and shortened, thus reducing the intercordal spaces and leading to an abnormal excursion of the leaflets. This can cause varying degrees of mitral stenosis and regurgitation. When the space between the abnormal chordae is completely obliterated, a fibrous (muscular) bridge (band) joins the two papillary muscles. In the most severe form, with no chordae tendinae at all, the papillary muscles are directly fused with the free edge of the leaflet. On echo, the mitral valve demonstrates shortened chordae with restricted leaflet excursion with limited coaptation. Color Doppler often reveals multiple turbulent inflow jets through the reduced interchordal spaces with varying degrees of mitral regurgitation and stenosis which can progress over time.
Optimal echocardiographic views for this lesion: