Analysis of dynamics of mitral Starr-Edwards valve prosthesis using reflected ultrasound.

The speed of closure of the mitral valve during diastole, as recorded by ultrasonocardiography, is reduced in patients with mitral stenosis. A pattern of movement similar to that of severe mitral stenosis is seen in recordingsfrom patients with normally functioning mitral Starr-Edwards prostheses. Simultaneous ultrasound recordings of ball and cage movements show that the prosthetic valve remains fully open during diastole, and that the movement recorded during this period is due to the cage only. It is probable that in severe mitral stenosis also, the valve remainsfully open during diastole and, by analogy, the movement recorded is due to the mitral ring only. A possible explanationfor this similarity is that the vortex mechanism which is thought to occur in association with normal mitral valve function is absent in both severe mitral stenosis and in the normally functioning mitral Starr-Edwards prosthesis. The opening speed of the mitral Starr-Edwards prostheses against gravity is slower than the speed of opening in the direction of gravity. In the normally ftunctioning mitral Starr-Edwards prosthesis, a 'puff' of regurgitation occurs through the valve lumen at the onset of each systole.