a prosthetic heart valve of the bi - leaflet type is provided that includes an annular structure comprised of biocompatible plastic and a pair of bearing blocks and a pair of leaflets equipped with ear - like projections that are all comprised of pyrolytic carbon . the leaflets associate pivotably with the bearing blocks , and , with the bearing blocks and the leaflets being initially held in a connected relationship , the annular structure is molded and formed about perimeter portions of the bearing blocks . the valve has a simple structure , yet is durable and reliable .