Feline Echocardiography: colour Doppler in a cat with SAM

Colour Doppler showing a 'double jet' in a cat with systolic anterior motion (SAM) of the mitral valve. Hypertrophied papillary muscles cause displacement of the mitral valve apparatus (remember the mitral valve leaflets are supported by chordae which attach to these muscles), and this movement of the septal leaflet into the left ventricular outflow tract causes both dynamic obstruction and leakage of the mitral valve. The two jets we see on colour Doppler are turbulence in the outflow tract, and regurgitation into the left atrium.