Between January 1978 and September 1992, 127 patients with isolated mitral regurgitation due to prolapse underwent mitral valve reconstruction. There were 74 men and 53 women whose mean age was 49.7 years, ranging from 16 to 74 years. Follow up was 99.2% complete and totaled 483.0 patient-years (mean: 3.8 years). One hundred and forty-eight procedures were carried out to repair the prolapses using four types of techniques: (1) leaflet plication in 97 patients; (2) artificial chordal replacement with polytetrafluoroethylene sutures in 30 patients; (3) chordal shortening in 16 patients; and (4) commissural imbrication in five patients. In order to repair the annular dilation, commissural plications were done in 75 and ring prostheses were implanted in 15 patients. There were one hospital and eight late deaths. One (cerebral infarction) of all deaths was related to the reconstructed mitral valve. There were 14 reoperations (11.0%) for recurrent mitral incompetence with a freedom from reoperation of 89.0% at five, and 81.1% at 10 years. There were four cases of thromboembolism (one fatal, three non-fatal) with freedom from thromboembolism of 96.7% at five, and 93.3% at 10 years. No endocarditis or hemorrhagic complications were noted. Linearized incidence of recurrent mitral regurgitation according to repair technique for the prolapse was 1.44%/pty in the leaflet plication series, 1.45%/pty with chordal replacement, 4.37%/pty after chordal shortening and 8.67%/pty following commissural imbrication. The linearized rate of failure in annuloplasty was 2.91%/pty after commissural plication and 1.74%/pty after ring annuloplasty. Statistically significant difference was confirmed only between leaflet plication and chordal shortening.(ABSTRACT TRUNCATED AT 250 WORDS)