A thin, biocompatible, high-strength, composite material is disclosed that is suitable for use in various implanted configurations. The composite material maintains flexibility in high-cycle flexural applications, making it particularly applicable to high-flex implants such as heart pacing lead or heart valve leaflet. An implantable article for regulating blood flow direction in a human patient, comprises a leaflet comprising more than one layer of the composite material. The composite material has at least one fluoropolymer layer having a plurality of pores and an elastomeric material present in substantially all of the pores of the fluoropolymer layers, less than about 80% fluoropolymer by weight and an additional material layer between the layers of the composite material.