Assessment of mitral valve volume by quantitative three-dimensional echocardiography in patients with rheumatic mitral valve stenosis

Background: Thickening of mitral leaflets in rheumatic mitral valve stenosis is well. described in necropsy studies; however, volume computation of the thickening mitral leaflets has not been attempted. Atrial fibrillation is one of the complications of rheumatic mitral stenosis. Quantitative assessment of thickened mitral valve and its relation to clinical complications is clinically desirable. Hypothesis: The study was undertaken to compare measurement of mitral valve volume in normal subjects and in patients with rheumatic mitral valve stenosis. Methods: An HP Sonos 2500 echocardiographic system with 5 MHz multiplane transesophageal transducer was used for data acquisition, and TomTec Echoscan computer setup was used to off-line volume computation. Study subjects included 10 normal subjects (mean age 44.8 years) and 36 patients with rheumatic mitral valve stenosis (22 female, 14 male) with an age range of 25 to 69 years (mean age 47 +/- 9.6 years). Mitral valve volumes were compared between the normal subjects and patients with mitral Valve stenosis, and further comparison was made between the sinus rhythm (SR) and atrial fibrillation (AF) groups in patients with mitral valve stenosis. In all study subjects, the mitral valve area (MVA) was determined by two-dimensional echocardiography. Results: Quantitative three-dimensional (3-D) echocardiography showed that mitral valve volume was significantly larger in patients with mitral valve stenosis than in normal subjects (9.0 +/- 2.2 and 4.5 +/- 0.7 mi, respectively, p<0.001). When patients with mitral valve stenosis were divided into the SR and AF groups, mitral valve volume was found to be significantly larger in the AF group than in the SR group (9.76 +/- 2.2 ml. and 7.72 +/- 1.5 mi, respectively, p<0.01) and patients in the AF group tended to be older (p<0.05) with larger left atrial diameter CLAD) (p<0.01). However, MVA between the two groups showed no statistical significance (1.1 +/- 0.43 and 1.0 +/- 0.34 cm(2), respectively, p>0.2). When the study subjects were divided into two groups (<50 and greater than or equal to 50 years) according to age, the comparison of mitral valve volume between these two groups (9.37 +/- 2.18 and 8.56 +/- 2.14 mi, p>0.2) showed no statistical significance. Conclusions: Quantitative 3-D echocardiography can be applied for the measurement of mitral valve volume in vivo. Patients with rheumatic mitral Valve stenosis with atrial fibrillation have a propensity to have a larger mitral valve volume and are older than the patients with sinus rhythm; however, the age per se does not seem to be a cause for larger mitral valve volume.