An electromagnetically controllable heart valve suitable for chronic implantation

A controllable valve suitable for chronic implantation was designed, and preliminary performance tests were conducted. A Björk-Shiley monostrut valve with an 18 mm disk was modified so that permanent magnetic material was implanted in the disk and an electromagnet was fitted around the ring of the valve. The opening of the disk is controlled by the interaction of the magnetic field created by the permanent magnets, and the field created by the electromagnet. The coil can be activated intermittently so that the valve can be held in the closed position or allowed to open and close unimpeded. The unit was designed to hold a maximum hydrostatic pressure equivalent to 50 mmHg. Power consumption by the prototype, while holding a pressure of 50 mmHg, is less than 10 watts. The overall diameter of the valve and electromagnet is 27 mm. The design and test results indicate that it is feasible to develop a unit suitable for chronic implantation in experimental animals and, possibly, in prosthetic blood pumping devices.