Atrial depressurization time measurement by Doppler ultrasound can be used to quantify stenotic mitral valve area. In this report, we present the results of a blinded trial comparing the standard Doppler method for "pressure half-time" (A) and another Doppler method we devised (B) for measurement of atrial depressurization time. Both methods were tested against valve area data from catheterization performed within 24 hours after Doppler echocardiography. Ten readers analyzed each of 10 Doppler profiles by methods A and B, in random order. After decoding, each of the 200 Doppler readings was compared to the catheterization result. Method B proved more accurate than method A by repeated measures analysis of variance (p less than 0.0001). Furthermore, method B took less than half as long to perform (p less than 0.0001). The methods presented herein provide a simple alternative means to follow the progression of mitral stenosis noninvasively and to determine optimal timing for surgery.