[Measurement of the mitral area with three-dimensional cardiac echography]

Two dimensional planimetry of mitral stenosis is sometimes difficult due to the complex morphology of the mitral valve. Three dimensional cardiac echography images the projected area of the mitral valve allowing precise planimetry of the orifice. Thirty patients with mitral stenosis were included in this study in order to obtain planimetry of the mitral orifice with two dimensional and three dimensional "freehand" mode transthoracic echocardiography. In 10 patients, the measurements were taken before and after percutaneous commissurotomy. The mitral area measured with three dimensional echography was 1.36+/-0.45 cm2 and 1.39+/-0.43 cm2 in two dimensional mode. The correlation between the 2 methods was good (y=1.01x - 0.08, r=0.92, p<0.001) but three dimensional echocardiography significantly underestimated the two dimensional planimetry by 0.05+/-0.27 cm2 (4+/-20%, p<0.05). The intra- and inter-observer reproducibility of the three dimensional measurements were 0.95 and 0.91 respectively. Three dimensional free-hand mode cardiac echography allows precise measurement of the mitral orifice area in patients with mitral stenosis.