A new device to derive the force-velocity relationship of the isolated papillary muscle using a sonomicrometer and an electromagnet.

This report deals with a simplified and improved method for measuring the force-velocity relationship of the cat papillary muscle by means of a coil-type galvanometer and a horizontally oriented lever system. The pre- and afterload generator consists of a rotor coil and a D.C. electromagnet. Because of its variable magnetic field it can easily be adapted to the tolerances of different coils and mounting systems. The ultrasound reflection method is used to measure displacements. This gives a linear and stable measurement of changes of muscle length without physical contact.