The aim of conservative management of mitral regurgitation caused by floppy mitral valve is to restore a valvular function which closely resembles that of normal physiology. Fifty-eight patients affected by floppy mitral valve underwent surgical procedures for severe mitral regurgitation due to chordal elongation and/or rupture. Of these, 28 presented posterior mitral prolapse corrected by quadrangular excision of the prolapsed part and posterior anuloplasty achieved by apposition of a polytetrafluoroethylene conduit. The remaining 30 patients presented anterior or bilateral prolapse corrected by transposition of chordae from the posterior leaflet to the anterior cusp together together with anuloplasty. A complete echo-Doppler study was performed preoperatively, 10 days after the operation and every 6 months thereafter. Mean follow-up was 16.1 +/- 6.3 months. Preoperatively, 44 patients presented severe mitral regurgitation and 14 had moderate regurgitation (quantified by means of pulsed Doppler). All patients showed severe enlargement of the left cavities (LVDD 67.1 +/- 8.6 mm, left atrium 53.4 +/- 10.9 mm) with normal mitral area (6.08 +/- 2.14 sqcm, Doppler measurement). Following surgery we found a significant reduction in: 1) the degree of mitral regurgitation (29 patients had no regurgitation; 20 had mild protosystolic mitral regurgitation (29 patients had no regurgitation; 20 had mild protosystolic mitral regurgition, confirmed by color-M-mode; moderate or severe regurgitation was found in 6 cases); 2) the left ventricle and left atrium dimensions (LVDD 53.4 +/- 5.2 mm, p less than 0.01; left atrium 43.8 +/- 11.1 mm, p less than 0.01). Color flow imaging provided information about the recovery of a normal valvular function.(ABSTRACT TRUNCATED AT 250 WORDS)