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. The composite material includes at least one porous expanded fluoropolymer layer and an elastomeric material substantially filling substantially all of the pores of the porous expanded fluoropolymer.