Abstract: The mechanical valvular prothesis for use in cardiac surgery proposed by the invention is constituted by a ring with a concave-convex swinging ring mounted in the contour thereof. The ring is provided with diametrically opposed projections at a same side thereof, the projection has inclined slots thereon. The disc is provided with a pair of appendixes that engage in both inclined slots of the ring, making it capable of translation displacement, in order to determine two approximately equal aperture passages.An inwardly projecting butt acts as a stop for the disc in the closure position and another two butts near the support points of the rotation axle of the disc, act as stop for the disc in the aperture position.The disc appendixes bend backwards in order to enhance the displacement thereof and to achieve a balanced aperture of the two halves of the surface limited by the ring itself.