M-mode echocardiographic evaluation of rheumatic mitral valve disease using diastolic separation of mitral leaflets. Comparison between this index and direct measurement of the two-dimensional image in predicting mitral valve orifice area

Diastolic separation of mitral leaflets (DSML) on the M-mode echocardiogram as an index for the quantitative estimation of mitral stenosis, was measured in 30 patients with rheumatic mixed mitral valve disease, who subsequently underwent valve replacement. It correlated highly significantly with the mitral valve orifice area, measured on the excised valves by means of a sizer set to detect area differences up to 0.l cm² (r=0.76, P < 0.00l). In the subgroup of 15 patients who also underwent two-dimensional echocardiographic examination, the correlation between DSML and anatomical area had a higher statistical significance (P <0.00l) than the comparison between the area measured using two-dimensional echocardiography and the anatomical area (P < 0.01).These results indicate that the index we propose allows an estimate of real mitral valve orifice area which is highly reliable and has a comparable or even lower error probability than direct measurement using two-dimensional echocardiography.