The in vitro assessment of left ventricular flow patterns on the closure of a new mitral valve "bioprosthesis".

: A new pulse duplication system, which we feel closely simulates not only the geometry but the pressure and flow phenomena in the left heart under phasic conditions, has been developed. A new mitral valve replacement, in a truncated cone or frustum configuration is being evaluated, utilizing this test facility. Flow patterns around the mitral valve appear to close the leaflets well prior to the onset of gradient reversal across the orifice.