Abstract: An improved heart valve prosthesis arranged for permanent implantation to replace a defective natural heart valve, wherein the improved prosthesis device includes an annular body or ring designed to retain a pair of rotatable flat plate occluders. The structure of the present invention contains modifications which improve the flow dynamics therethrough, and reduce if not eliminate the formation of eddies or areas of stasis in and along the flow pattern. The annular ring is provided with oppositely disposed pairs of spherical segments which form pivot areas for the occluders, with the occluders being provided with concavities engageable with the spherical segments. Stops are provided for controlling the degree of arcuate travel or rotational skirt of motion. The abutment surfaces are arranged at positions spaced from the axis of rotation so as to improve the distribution of stresses created during closure.

Abstract: A battery powered electronic circuit adapted for surgical implantation in the body of a patient suffering from intermittent heart block for providing electrical stimulation of the heart muscle upon detection of failure of normal heart activity. The circuit includes a pulse generator comprising an astable multivibrator which normally functions to produce a series of pulses of predetermined duration and at a predetermined repetition rate. The pulses are fed to a voltage doubler pulser which amplifies the pulses before they are applied through the output electrodes to the heart muscle. Also included in the system is an integrated circuit differential bandpass amplifier which is coupled to the output electrodes for amplifying the electrical output signal from the heart which is detected when ventricular contractions occur. The system further includes a level detector and a refractory one-shot multivibrator network.