A computer-driven control system for sensing and adjusting papillary muscle tension in an in-vitro model of mitral valve function

The model consists of a human mitral valve apparatus with papillary muscles and chordae tendineae intact. The structure is mounted on an elliptical sewing ring positioned in an acrylic model of the left ventricle. The papillary muscles are mounted on circular discs which are attached to rods extending out of the model. The rods are anchored to a stepper motor/load cell apparatus interfaced to a microprocessor feedback control loop. The feedback control system allows control of pulsatile papillary muscle tension curves to simulate those measured in vivo. The model has been effective in producing physiologic tension curves and can be used to investigate systolic anterior motion in hypertrophic cardiomyopathy as well as other mitral valve problems such as prolapse