Chordal replacement greatly extends the possibility of repair of atrioventricular valves. Both glutaraldehyde-tanned xenograft pericardial chordae (GTXP) and extruded polytetrafluorethylene chordae (ePTFE) heal to papillary muscles and cusps. Neither type elongates or shrinks. GTXP may thicken and stiffen with time. ePTFE is covered by a normal fibrosa and intima (a new chorda is grown around the ePTFE suture) experimentally and in small sizes (e.g., CV 5), retains flexibility. The results of late follow-up (5-10 years) with GTXP chordae and early follow-up (6-58 months) with ePTFE chordae are encouraging.