A new formula for the measurement of diastolic mitral valve orifice area.

This study evaluated the accuracy of a new formula for the calculation of mitral valve area. Fifty-two patients with mitral stenosis who underwent cardiac catheterization were evaluated by the standard Gorlin and the new formulas. The correlation between the two formulas was excellent (r = 0.89) for valve areas of 0-1.5 cm2. When the new valve area formula yielded an area greater than 1.5 cm2, there was no correlation with the Gorlin formula. However, the likelihood of the Gorlin mitral valve area being less than 1.0 cm2 was low (10%). The results of the new formula do not appear to be affected by atrial fibrillation and are probably subject to the same limitations when used in the presence of a regurgitant lesion. Therefore, with moderate to severe mitral stenosis, this new formula shows a good correlation. However, with mild stenosis, further work is needed to determine the accuracy and limitations of the new formula.